細川　宗孝（ホソカワ　ムネタカ）

農学部 農業生産科学科教授/研究科長

Last Updated :2024/07/20

■教員コメント

コメント

園芸作物の育種・生産および病気の予防や治療に関する研究を行っています。また、花の色や模様の機能解明を遺伝子レベルで行っています。

■研究者基本情報

学位

  • 農学博士

ホームページURL

J-Global ID

研究キーワード

  • 園芸・造園学   Horticultural Science   

現在の研究分野（キーワード）

園芸作物の育種・生産および病気の予防や治療に関する研究を行っています。また、花の色や模様の機能解明を遺伝子レベルで行っています。

研究分野

  • 環境・農学 / 園芸科学

■経歴

経歴

  • 2018年04月 - 現在  近畿大学農業生産科学科教授
  • 1997年10月  - 京都大学農学部助手
  • 1997年04月 - 1997年09月  日本学術振興会特別研究員

学歴

  •         - 1995年   京都大学   農学研究科   農学専攻
  •         - 1995年   京都大学   Graduate School, Division of Agriculture
  •         - 1993年   京都大学   農学部   農学科
  •         - 1993年   京都大学   Faculty of Agriculture
  • 1986年04月 - 1988年03月   芝浦工業大学付属高等学校

委員歴

  • 2021年04月 - 現在   園芸学会   副会長
  • 2018年03月 - 現在   園芸学会   理事
  • 2020年04月 - 2022年03月   園芸学会   園芸学研究 編集委員長

■研究活動情報

論文

  • Mayu Ikemoto; Akira Yamazaki; Toru Ohnishi; Taichi Ishigami; Jin Fukumitsu; Kazuma Oike; Kiyoshi Inoue; Koichi Uegaki; Munetaka Hosokawa
    The Journal of Horticultural Science and Biotechnology 1 - 10 2024年01月
  • Akira Yamazaki; Ao Takezawa; Kazusa Nishimura; Ko Motoki; Kyoka Nagasaka; Ryohei Nakano; Tetsuya Nakazaki; Munetaka Hosokawa
    The Horticulture Journal 2024年
  • Kenta Shirasawa; Tomoya Esumi; Akihiro Itai; Katsunori Hatakeyama; Tadashi Takashina; Takuji Yakuwa; Katsuhiko Sumitomo; Takeshi Kurokura; Eigo Fukai; Keiichi Sato; Takehiko Shimada; Katsuhiro Shiratake; Munetaka Hosokawa; Yuki Monden; Makoto Kusaba; Hidetoshi Ikegami; Sachiko Isobe
    2023年07月 
    Abstract Flowering cherry cultivar ‘Somei-Yoshino’ (Cerasus×yedoensis) has been clonally propagated and spread all around the world including Japan. ‘Somei-Yoshino’ is thought to be an interspecific hybrid derived fromC. spachianaandC. speciosa; however, its origin is unclear. Since somatic mutations are randomly induced in genomes and stably transmitted through generations, we aimed to identify somatic mutations in the genome of ‘Somei-Yoshino’ to trace its propagation path. A total of 46 ‘Somei-Yoshino’ clones were collected from all over Japan and subjected to whole-genome sequencing. The results revealed 684 single nucleotide variants, of which 71 were found in more than two clones. Clustering analysis of the 46 clones using these 71 variants revealed six groups, four of which contained 40 of the 46 clones. In addition, because each of the four clones closely planted in Ueno Park, Tokyo, Japan, clustered into the four different groups, we considered that these four clones could be the ancestors of the ‘Somei-Yoshino’ clones found in Japan. Furthermore, based on the comparison of mutant alleles with the genomes ofCerasusspecies, one of the four trees was concluded as the closest to the origin. Here, we propose that the origin of ‘Somei-Yoshino’ is a chimera derived from at least four somatic mutants.
  • Yu Kinoshita; Ko Motoki; Munetaka Hosokawa
    Theoretical and Applied Genetics 136 3 2023年03月
  • Akira Yamazaki; Ao Takezawa; Ryohei Nakano; Kazusa Nishimura; Ko Motoki; Munetaka Hosokawa; Tetsuya Nakazaki
    Journal of Horticultural Research 30 2 105 - 116 2023年01月 
    Abstract “Autonomous fruit set” refers to self-pollination and fruit set without pollen vectors such as vibration or insects. Autonomous fruit set under high-temperature stress is an important breeding goal as climate change can reduce fruit yields in Capsicum. We screened Capsicum cultivars for autonomous fruit set ability in a greenhouse environment and investigated pollen germination, viability, pollen grains number, chlorophyll fluorescence (Fv/Fm), style length, anther cone length, and anthesis stage under high temperatures in order to identify indicator traits for screening more genotypes with autonomous fruit set ability. The fruit set of the ‘Takanotsume’ (57.7 ± 20.6%) and ‘Goshiki Kyokko’ (52.2 ± 14.2%) cultivars (both C. annuum) were higher than those of other cultivars. Correlation analysis showed that pollen germination had the highest correlation with fruit set in C. annuum cultivars (r = 0.63). These results indicate that ‘Takanotsume’ and ‘Goshiki Kyokko’ are useful cultivars for novel breeding programs focusing on autonomous fruit sets under high temperatures, and pollen germination in C. annuum was a convincing candidate for an indicator trait of autonomous fruit set ability under high temperatures.
  • Ayumu Kono; Ayumu Kawabata; Akira Yamazaki; Yuma Ohkubo; Adriano Sofo; Munetaka Hosokawa
    The Horticulture Journal 2023年
  • Ko Motoki; Yu Kinoshita; Ryohei Nakano; Munetaka Hosokawa; Tetsuya Nakazaki
    The Horticulture Journal 92 1 66 - 76 2023年
  • Kenta Shirasawa; Munetaka Hosokawa; Yasuo Yasui; Atsushi Toyoda; Sachiko Isobe
    2022年09月 
    Abstract Here, we report the genome sequence of a popular Japanese chili pepper landrace, Capsicum annuum ‘Takanotsume’. We used long-read sequencing and optical mapping, together with the genetic mapping technique, to obtain the chromosome-scale genome assembly of ‘Takanotsume’. The assembly consists of 12 pseudomolecules, which corresponds to the basic chromosome number of C. annuum, and is 3,058.5 Mb in size, spanning 97.0% of the estimated genome size. A total of 34,324 high-confidence genes were predicted in the genome, and 83.4% of the genome assembly was occupied by repetitive sequences. Comparative genomics of linked-read sequencing-derived de novo genome assemblies of two Capsicum chinense lines and whole-genome resequencing-derived genome assemblies of Capsicum species revealed not only nucleotide sequence variations but also genome structure variations (i.e., chromosomal rearrangements) between ‘Takanotsume’ and its relatives. Overall, the genome sequence data generated in this study will accelerate the pan-genomics and breeding of Capsicum, and facilitate the dissection of genetic mechanisms underlying the agronomically important traits of ‘Takanotsume’.
  • Sho Ohno; Haruka Yamada; Kei Maruyama; Ayumi Deguchi; Yasunari Kato; Mizuki Yokota; Fumi Tatsuzawa; Munetaka Hosokawa; Motoaki Doi
    Planta 256 3 2022年09月
  • Ko Motoki; Yu Kinoshita; Ryohei Nakano; Munetaka Hosokawa; Tetsuya Nakazaki
    Plant and Cell Physiology 63 9 1230 - 1241 2022年07月 
    Abstract Grafting-induced flowering is a key phenomenon to understand systemic floral induction caused by florigen. It can also be used as breeding technique enabling rapid seed production of crops with long generation times. However, the degree of floral induction in grafted plants is often variable. Moreover, it is difficult in some crop species. Here, we explored the factors promoting variability in the grafting-induced flowering of cabbage (Brassica oleracea L. var. capitata), an important vegetable crop with a long generation time, via the quantitative analysis of florigen accumulation. Significant variability in the flowering response of grafted cabbage was observed when rootstocks of different genotypes were used. As reported previously, B. oleracea rootstocks didn’t induce flowering of grafted cabbage plants, but radish (Raphanus sativus L.) rootstocks unstably did, depending on the accessions used. Immunoblotting analysis of the FLOWERING LOCUS T (FT) protein, a main component of florigen, revealed that floral induction was quantitatively correlated with the level of accumulated FT protein in the grafted scion. To identify rootstock factors that cause variability in the floral induction of the grafted scion, we investigated FT protein accumulation and flowering response in grafted scions when the transcription levels of FT and the leaf area of rootstocks were altered by vernalization, daylength, and leaf trimming treatments. We concluded that increasing the total amount of FT protein produced in the rootstock is important for stable floral induction of the grafted cabbage, and this can be accomplished by increasing FT transcription and the leaf area of the rootstock.
  • Emi Ota; Fumihiro Nishimura; Mitsutaka Mori; Masaya Tanaka; Takeshi Kanto; Munetaka Hosokawa; Masahiro Osakabe; Mamoru Satou; Minoru Takeshita
    Plant Pathology 70 6 1378 - 1387 2021年04月 [査読有り]
  • Tamanna Abedin; Atsushi Yamamoto; Takahiro Hayashi; Munetaka Hosokawa
    Scientia Horticulturae 276 109604 - 109604 2021年01月
  • Yu Kinoshita; Ko Motoki; Munetaka Hosokawa
    The Horticulture Journal 90 4 374 - 381 2021年
  • Akira Yamazaki; Kenta Shirasawa; Munetaka Hosokawa
    EUPHYTICA 216 11 2020年10月 
    Breeding for thermotolerance in processes determining fruit set and pollen germination is increasingly needed as global warming progresses. We previously reported good yields at high temperatures from the F-1 hybrid of the Capsicum chinense cultivars 'Sy-2' and 'No. 3686', both of which yield poorly at high temperatures. Moreover, the percentages of fruit set at high temperature in the F-2 population segregated quantitively. In addition, percentages of fruit set in some F-2 individuals exceeded those of the F-1 hybrid. Analysis of the F-2 population using double-digest restriction site-associated DNA sequencing (ddRAD-Seq) shows that the percentage of fruit set under high temperature is strongly associated to single nucleotide polymorphisms (SNPs) in a certain gene region of chromosome 6 and weakly associated to a gene region on the chromosome 3. Furthermore, the pollen germination rate is strongly associated to SNPs of the same regions on chromosomes 3 and 6. Analysis of the genotypes and traits in another F-2 population shows that the genotype determined by the cleaved amplified polymorphic sequence marker designed on the candidate gene region is associated to the percentage of fruit set and the pollen germination rate at high temperatures, supporting the results of ddRAD-Seq. The presence of alleles from both the gene regions of chromosome 3 from 'No. 3686' and chromosome 6 from 'Sy-2' increased the percentage of fruit set additively. We suggest that genes controlling fruit set and pollen germination at high temperature are located in these two gene regions.
  • Daichi Tomimori; Munetaka Hosokawa; Shinichi Aoki; Masahiro Osakabe
    Environmental entomology 49 4 886 - 894 2020年08月 [査読有り]
     
    Perilla, Perilla frutescens (L.) Britton var. crispa (Thunb.) H. Deane, is traditionally cultivated as an edible/medicinal crop in East Asia. Its essential oil contains many bioactive compounds that are expected to have high pharmacological functionality, as well as antimicrobial and insecticidal activity. Spider mites are a major pest group for perilla cultivation. The two-spotted spider mite, Tetranychus urticae Koch, possesses divergent detoxification enzymes and has developed resistance against most acaricides. The essential oil content of perilla halves from the pre-flowering phase to the flowering phase, and ultraviolet (UV)-B radiation generally increases defense compounds. To clarify the effects of this change in essential oil content and the effects of UV-B pretreatment, we investigated the developmental success and egg production of T. urticae on leaves from the preflowering and flowering phases cultivated with and without nighttime UV-B irradiation. Both the parameters significantly increased on leaves from the flowering phase in comparison with that from the preflowering phase, suggesting that constitutively produced essential oil provided protection against mite pests in a growth phase-specific manner. The defense system also extended the developmental period of mites on red perilla leaves, but not on green perilla leaves, in preflowering phase. Although egg production was lower on red perilla leaves pretreated with UV-B, no negative effects were caused on the developmental success and duration on red and green perilla and the egg production on green perilla by UV-B pretreatment. Our findings reveal a significant impact of investment allocation of perilla plants and a small contribution of UV-B irradiation to the plant defense system.
  • Hiroshi Okada; Tamanna Abedin; Atsushi Yamamoto; Takahiro Hayashi; Munetaka Hosokawa
    Scientia Horticulturae 267 109252 - 109252 2020年06月
  • Increased percentage of fruit set of F1 hybrid of Capsicum chinense during high-temperature period.
    細川 宗孝
    Sci. Hortic. 243 421 - 427 2019年 [査読有り]
  • 細川 宗孝
    Sci. Hortic 244 1 - 9 2019年 [査読有り]
  • Tomoyuki Nabeshima; Yosuke Matsushita; Munetaka Hosokawa
    Viruses 10 12 729 - 729 2018年12月 [査読有り]
     
    Chrysanthemum stunt viroid (CSVd) is one of the most severe threats in Chrysanthemum morifolium production. Over the last decade, several studies have reported the natural occurrence of CSVd resistance in chrysanthemum germplasms. Such CSVd-resistant germplasms are desirable for the stable production of chrysanthemum plants. Current surveys include finding new resistant chrysanthemum cultivars, breeding, and revealing resistant mechanisms. We review the progress, from discovery to current status, of CSVd-resistance studies, while introducing information on the improvement of associated inoculation and diagnostic techniques.
  • Sho Ohno; Wakako Hori; Munetaka Hosokawa; Fumi Tatsuzawa; Motoaki Doi
    Planta 247 2 413 - 428 2018年02月 [査読有り]
     
    MAIN CONCLUSION: Post-transcriptional gene silencing (PTGS) of a chalcone synthase ( DvCHS2 ) occurred in the white part of bicolor petals and flavonoid-poor leaves; however, it did not in red petals and flavonoid-rich leaves. Petal color lability is a prominent feature of bicolor dahlia cultivars, and causes plants to produce not only original bicolor petals with colored bases and pure white tips, but also frequently single-colored petals without white tips. In this study, we analysed the molecular mechanisms that are associated with petal color lability using the red-white bicolor cultivar 'Yuino'. Red single-colored petals lose their white tips as a result of recover of flavonoid biosynthesis. Among flavonoid biosynthetic genes including four chalcone synthase (CHS)-like genes (DvCHS1, DvCHS2, DvCHS3, and DvCHS4), DvCHS1 and DvCHS2 had significantly lower expression levels in the white part of bicolor petals than in red petals, while DvCHS3, DvCHS4, and other flavonoid biosynthetic genes had almost the same expression levels. Small RNAs from the white part of a bicolor petal were mapped onto DvCHS1 and DvCHS2, while small RNAs from a red single-colored petal were not mapped onto any of the four CHS genes. A relationship between petal color and leaf flavonoid accumulation has previously been demonstrated, whereby red petal-producing plants accumulate flavonoids in their leaves, while bicolor petal-producing plants tend not to. The expression level of DvCHS2 was down-regulated in flavonoid-poor leaves and small RNAs from flavonoid-poor leaves were mapped onto DvCHS2, suggesting that the down-regulation of DvCHS2 in flavonoid-poor leaves occurs post-transcriptionally. Genomic analysis also suggested that DvCHS2 is the key gene involved in bicolor formation. Together, these results suggest that post-transcriptional gene silencing of DvCHS2 plays a key role in phenotypic lability in this bicolor dahlia.
  • Sho Ohno; Wakako Hori; Munetaka Hosokawa; Fumi Tatsuzawa; Motoaki Doi
    Horticulture Journal 87 1 140 - 148 2018年 [査読有り]
     
    Bicolor flowering dahlias are a group of cultivars that produce inflorescences with bicolored petals characterized by a colored basal part and a white tip. However, they frequently produce single-colored petals, even if they are vegetatively propagated. In a previous study, strong relationships between inflorescence color and leaf phenotype were observed in a red–white bicolor flowering dahlia ‘Yuino’ red petal-producing individuals accumulate flavonoids in leaves, whereas only bicolor petal-producing individuals tend not to accumulate them in leaves. Flavonoids in leaves are assumed to be chalcones. In this study, we investigated flavonoids in the leaves of ‘Yuino’ by nuclear magnetic resonance analysis and identified six caffeoyl esters, four flavonol derivatives, and three novel butein derivatives in the flavonoid-rich leaves of ‘Yuino’. The three novel compounds were butein 4',4-O-di-[2-O-(β-glucopyranosyl)-β-glucopyranoside], butein 4'-O-[2-O-(β-glucopyranosyl)-β-glucopyranoside]-4-O-β-glucopyranoside, and butein 4'-[6-O-(3-hydroxy-3-methylglutaryl)-β-glucopyranoside]-4-O-β-glucopyranoside. On the other hand, only caffeoyl esters were detected in flavonoid-poor leaves. These data demonstrated that flavonoid-rich leaves accumulated the flavonoids of butein and flavonol derivatives. The common enzyme for the biosynthesis of butein and flavonol derivatives is chalcone synthase thus, the importance of chalcone synthase for phenotypic lability in ‘Yuino’ was confirmed.
  • Ko Motoki; Yu Kinoshita; Munetaka Hosokawa
    Frontiers in plant science 9 1967 - 1967 2018年 [査読有り]
     
    Cabbage (Brassica oleracea var. capitata) requires a long-term low-temperature exposure for floral induction, causing a delay in the breeding cycle. The objective of this study is to develop a method to induce flowering in cabbage without low-temperature treatment, using a grafting method. We conducted grafting experiments using two flower-induced Chinese kale cultivars (B. oleracea var. alboglabra) and seven radish cultivars/accessions as rootstocks and investigated the flowering response of grafted cabbage scions without low-temperature treatment. "Watanabe-seiko No.1" cabbage, when grafted onto the two Chinese kale cultivars, did not formed flower buds. Flowering was successfully induced in "Watanabe-seiko No.1" by grafting onto three out of the seven tested radish cultivars, and in "Kinkei No.201" and "Red cabbage" by grafting onto one tested radish cultivar. In "Watanabe-seiko No.1," the earliest flower bud appearance was observed at 29 days after grafting. Seeds were also obtained from the three cabbage cultivars that flowered by grafting. Gene expression analysis of "Watanabe-seiko No.1" cabbage scions which formed flower buds by grafting, revealed high expression of the homolog of the floral integrator, SUPPRESSOR OF OVEREXPRESSION OF CONSTANS 1 (BoSOC1), at the time of flower bud appearance. However, in the same leaf samples, we observed low expression of two homologs of florigen, FLOWERING LOCUS T (BoFT.C2 and BoFT.C6). In addition, two homologs of the floral repressor FLOWERING LOCUS C (BoFLC3 and BoFLC4), which are known to be down-regulated before flower bud differentiation in the vernalization pathway, were highly expressed, indicating that grafting onto radish induces cabbage flowering independently of the vernalization pathway. The expression level of the radish FT homolog (RsFT) in "Rat's tail-G2," which had highly induced flowering in the grafted cabbage scion, was higher than in the other radish cultivars. However, although "Rat's tail-CH" effectively induced flowering in the cabbage scion, the expression of RsFT was low in this cultivar. In this study, floral induction of non-vernalized cabbage cannot be explained by the expression levels of RsFT in rootstock plants, alone. The flowering of non-vernalized cabbage would be induced by transmissible agents from rootstocks and not by the expression of cabbage FT, BoFT, from the scion itself.
  • Jaime A. Teixeira Da Silva; Yaser Hassan Dewir; Adhityo Wicaksono; Leela Sahijram; Haenghoon Kim; Songjun Zeng; Stephen F. Chandler; Munetaka Hosokawa
    Folia Horticulturae 29 2 99 - 111 2017年12月 [査読有り]
     
    As a result of its domestication, breeding and subsequent commercialization, African violet (Saintpaulia ionantha H. Wendl.) has become the most famous and popular Saintpaulia species. There is interest in producing cultivars that have increased resistance to pests and low temperature, in the introduction of novel horticultural characteristics such as leaf shape, flower colour, size and form, and in improved productivity and enhanced flower duration in planta. In African violet, techniques such as the application of chemical mutagens (ethylmethanesulfonate, N-nitroso-N-methylurea), radiation (gamma (γ)-rays, X-rays, carbon ion beams) and colchicine have been successfully applied to induce mutants. Among these techniques, γ radiation and colchicine have been the most commonly applied mutagens. This review offers a short synthesis of the advances made in African violet breeding, including studies on mutation and somaclonal variation caused by physical and chemical factors, as well as transgenic strategies using Agrobacterium-mediated transformation and particle bombardment. In African violet, Agrobacterium-mediated transformation is affected by the Agrobacterium strain, selection marker, and cutting-induced wounding stress. Somaclonal variation, which arises in tissue cultures, can be problematic in maintaining true-To-Type clonal material, but may be a useful tool for obtaining variation in flower colour. The only transgenic African violet plants generated to date with horticulturally useful traits are tolerant to boron (heavy metal) stress, or bear a glucanase-chitinase gene.
  • Soo-Jung Yang; Sho Ohno; Ayumi Deguchi; Mitsuru Sato; Mariko Goto; Motoaki Doi; Miki Ohnishi; Fumi Tatsuzawa; Munetaka Hosokawa
    SCIENTIA HORTICULTURAE 223 10 - 18 2017年09月 [査読有り]
     
    In this study, we revealed how the petals of Saintpaulia fuse into a corolla by using pinwheel phenotype cultivars. Striped patterns in petal, called pinwheel in Saintpaulia, are attractive phenotypes and thought to be the result of periclinal chimerism. For the selection of a genuine periclinal chimeric cultivar from three pinwheel cultivars, adventitious shoots were induced from leaf lamina. Shoot regeneration was observed from the epidermis in all cultivars by microscopic observation. All regenerated shoots from 'Kaname' flowered as monochromatic pink flowers, corresponding to an Ll phenotype of the cultivar. From the other two cultivars, many shoots flowered not only as an epidermal phenotype but also as a phenotype of the inner layer. In addition, shoot regeneration was induced from epidermis-peeled petioles from these three cultivars. All shoots from 'kaname' flowered as monochromatic blue flowers, corresponding to an L2 phenotype. On the other hand, many shoots from 'Kilauea' flowered not only as monochromatic flowers, corresponding to an L2 phenotype, but also as bi-colored flowers. 'Innocent Pink' did not produce shoots from epidermal-peeled petioles. These results suggested that 'Kaname' is a genuine periclinal chimera, while the other two cultivars have other mechanisms for pinwheel expression. Genomic PCR using primers that amplifies almost the full length of flavonoid 3',5'-hydroxylase (F3'5'H) revealed the gene to be non-functional in pink flowers from Ll of 'Kaname'. From monochromatic pink plants and pink portions of the corolla of 'Raname', full-length F3'5'H was not amplified. Similar results were obtained by quantitative PCR. Finally, we observed the fused portion of the petals and revealed that the petal fusion did not occur by postgenital fusion but by "connection". The process, in Saintpaulia, comprises periclinal cell division in Ll during petal development, active cell division at the edge of the petal, adhesion to the next petals, and fusion. These steps create a striped flower color in Saintpaulia.
  • Jaime A. Teixeira da Silva; Songjun Zeng; Adhityo Wicaksono; Mafatlal M. Kher; Haenghoon Kim; Munetaka Hosokawa; Yaser Hassan Dewir
    SOUTH AFRICAN JOURNAL OF BOTANY 112 501 - 507 2017年09月 [査読有り]
     
    African violet (Saintpaulia ionantha H. Wendl.) (Gesneriaceae) is a popular ornamental pot plant that is easy to culture ex vitro and in vitro relative to other herbaceous ornamentals. This quality makes it an ideal system for in vitro regeneration experiments. This review summarizes the studies that have been conducted on the in vitro culture and micropropagation of this plant. Although shoot regeneration from internodes, floral buds, anthers and protoplasts has been achieved, leaf blades and petioles have been a popular source tissue for regeneration. An effective and reproducible protocol for the direct induction of shoots, without the formation of any intermediary callus, involves the use of a cytokinin like BA or kinetin, usually in combination with an auxin likeNAA, bothwithin a concentration range of 0.1 to 1 mg/L, and on a Murashige and Skoog basalmedium. Shoots can form in both light and darkness, but most effectively in the light, and rooting can be induced from shoots, even in the absence of an auxin, although a low concentration (0.1-0.5 mg/L) of NAA or IAA is recommended. African violets acclimatize easily, even in a simple soil-based substrate, and can flowerwithin 4 months of transfer to ex vitro conditions. These protocols, including somatic embryogenesis and cryopreservation, may also benefit the in vitro culture and conservation of wild species of Saintpaulia. (C) 2017 SAAB. Published by Elsevier B.V. All rights reserved.
  • Nao Ota; Tomoyuki Nabeshima; Masahiro Osakabe; Shinichi Aoki; Tatsuya Awano; Munetaka Hosokawa
    HORTICULTURE JOURNAL 86 3 349 - 356 2017年07月 [査読有り]
     
    Although ultraviolet-B (UV-B) light (280-315 nm) irradiation effectively controls spider mites in horticultural crop production, it also causes plant damage, leading to growth suppression, changes in morphology, and leaf scorching. However, sensitivity to UV-B varies among plant species. Here, we assessed the effect of UV-B on growing perilla (Perilla frutescens var. crispa) plants. Three experiments were conducted. In the first experiment, plants of the variety 'Akachirimenshiso' were grown in a plastic house with natural light conditions and subjected to three treatments: natural UV (control), -UV, and natural UV plus artificial UV-B treatment (50 mW.m(-2)) from 0:00 to 3:00. The length of leaf blades that received additional UV-B treatment was reduced by 16.5% and 32.3% in two trials compared with that of the respective controls. In this experiment, additional UV-B irradiation turned the leaf color greener. During UV-B treatment, the values of leaf a*, an indicator of leaf redness, were significantly lower than their respective controls in both trials: 21.5 vs. 31.6 in trial I and 20.2 vs. 30.7 in trial H. For most of the parameters measured in this experiment, no differences were observed between the control and -UV treatment groups. In the second experiment, plants were irradiated with UV-B for 3 weeks at nighttime (0:00-3:00) or daytime (12:00-15:00). In the cultivar 'Houkouakashiso', the length of leaf blades significantly decreased by 15.9% and 20.6% under nighttime UV-B irradiation at 80 and 120 mW.m(2), respectively, compared with that of the non-irradiated controls. Irradiation at 80 mW.m(-2) also decreased the width of the leaf blades by 13.1% and that at 120 mW.m(-2) further decreased it by 25.0%. These results showed that UV-B irradiation at night decreased the size of perilla leaves. In addition, the value of a* became lower under UV-B irradiation in the nighttime. Thus, UV-B irradiation appeared to turn purple perilla leaves green. When plants were irradiated with UV-B in the daytime, there was no significant difference between irradiated and non-irradiated plants in the length or width of leaf blades, a*, or fresh weight of aerial parts and number of nodes on the main stem. In the third experiment, visible rays (VIS) emitted by fluorescent lamps were applied at 0:00-3:00 and 6:00-22:00. Plants were irradiated with 120 mW.m(2) of UV-B at 0:00-3:00. UV-B + VIS treatment of 'Akachirimenshiso' with VIS from fluorescent lamps did not significantly affect the parameters measured in this experiment compared to -UV treatment. The results of this study suggest that UV-B damage to perilla leaves can be avoided by combined irradiation with visible light.
  • Tomoyuki Nabeshima; Soo-Jung Yang; Sho Ohno; Keita Honda; Ayumi Deguchi; Motoaki Doi; Fumi Tatsuzawa; Munetaka Hosokawa
    Frontiers in plant science 8 1749 - 1749 2017年 [査読有り]
     
    Saintpaulia ionantha is propagated by adventitious buds in horticulture, and periclinal chimeral cultivars are usually difficult to propagate. However, some periclinal chimeral cultivars can be propagated with adventitious buds, and the mechanism of which has been unknown. Striped flower cultivars "Kaname," "Concord," and "Monique" were used to investigate what causes flower color separation in adventitious shoot-derived plants by tissue culture. These cultivars were revealed to have mutated flavonoid 3', 5' hydroxylase (SiF3'5'H), WDR1 (SiWDR1), or flavonoid 3 hydroxylase (SiF3H), respectively, in their L1 layer. From our previous study using "Kaname," all flowers from adventitious shoots were colored pink, which was the epidermal color of mother plants' flowers. We used "Concrd" and "Monique" from which we obtained not only monochromatic-colored plants the same as the epidermal color of mother plants, but also plants with a monochromatic colored plants, same as the subepidermal color, and a striped flower color the same as mother plants. Histological observations revealed that epidermal cells divided actively at 14 d after culture and they were involved in the formation of adventitious shoots in the cultured leaf segments of "Kaname." On the other hand, in "Concord" and "Monique," the number of divided cells in the subepidermis was rather higher than that of epidermal cells, and subepidermal cells were sometimes involved in shoot formation. In addition, the plant and leaf size of L1-derived plants from "Concord" and "Monique" were non-vigorous and smaller than those derived from the subepidermal layer. In conclusion, periclinal chimeral cultivars of Saintpaulia can be divided into two types. One type has a high cell division activity in the L1 layer, from which only single flower-colored plants derived from L1 can be obtained as adventitious shoots. Another type has a low cell division activity in the L1 layer, from which striped flower-colored plants the same as mother plants derived from several layers including L1 can be obtained as adventitious shoots. In the periclinal chimeral cultivar capable of propagation with adventitious shoots, the possibility was shown that cells in the L2 layer could form shoots by involving cells of the L1 layer with a low division activity.
  • Tomoyuki Nabeshima; Motoaki Doi; Munetaka Hosokawa
    Frontiers in plant science 8 1940 - 1940 2017年 [査読有り]
     
    Chrysanthemum stunt viroid (CSVd) was inoculated into two chrysanthemum (Chrysanthemum morifolium) cultivars, the CSVd-susceptible cultivar Piato and the CSVd-resistant cultivar Mari Kazaguruma. For CSVd inoculation, grafting and Agrobacterium-mediated inoculation were used. In grafting experiments, CSVd was detectable in Mari Kazaguruma after grafting onto infected Piato, but after removal of infected rootstocks, CSVd could not be detected in the uppermost leaves. In agroinfection experiments, CSVd systemic infection was observed in Piato but not in Mari Kazaguruma. However, agro-inoculated leaves of Mari Kazaguruma accumulated circular CSVd RNA to levels equivalent to those in Piato at 7 days post-inoculation. In situ detection of CSVd in inoculated leaves revealed that CSVd was absent in phloem of Mari Kazaguruma, while CSVd strongly localized to this site in Piato. We hypothesize that CSVd resistance in Mari Kazaguruma relates not to CSVd replication but to CSVd movement in leaves.
  • Boubourakas Iraklis; Hiroko Kanda; Tomoyuki Nabeshima; Mayu Onda; Nao Ota; Sota Koeda; Munetaka Hosokawa
    Plant cell reports 35 8 1617 - 28 2016年08月 [査読有り]
     
    KEY MESSAGE: CSVd could not infect Nicotiana benthamiana when the plants were pretreated with crude leaf extract of Capsicum chinense 'Sy-2'. C. chinense leaves were revealed to contain strong RNA-digesting activity. Several studies have identified active antiviral and antiviroid agents in plants. Capsicum plants are known to contain antiviral agents, but the mechanism of their activity has not been determined. We aimed to elucidate the mechanism of Capsicum extract's antiviroid activity. Chrysanthemum stunt viroid (CSVd) was inoculated into Nicotiana benthamiana plants before or after treating the plants with a leaf extract of Capsicum chinense 'Sy-2'. CSVd infection was determined using quantitative reverse transcription-polymerase chain reaction (qRT-PCR) 3 weeks after inoculation. When Capsicum extract was sprayed or painted onto N. benthamiana before inoculation, it was effective in preventing infection by CSVd. To evaluate CSVd digestion activity in leaf extracts, CSVd was mixed with leaf extracts of Mirabilis, Phytolacca, Pelargonium and Capsicum. CSVd-digesting activities were examined by quantifying undigested CSVd using qRT-PCR, and RNA gel blotting permitted visualization of the digested CSVd. Only Capsicum leaf extract digested CSVd, and in the Capsicum treatment, small digested CSVd products were detected by RNA gel blot analysis. When the digesting experiment was performed for various cultivars and species of Capsicum, only cultivars of C. chinense showed strong CSVd-digesting activity. Our observations indicated that Capsicum extract contains strong RNA-digesting activity, leading to the conclusion that this activity is the main mechanism for protection from infection by CSVd through spraying or painting before inoculation. To our knowledge, this is the first report of a strong RNA-digesting activity by a plant extract.
  • Li Liu; Jelli Venkatesh; Yeong Deuk Jo; Sota Koeda; Munetaka Hosokawa; Jin-Ho Kang; Sandra Goritschnig; Byoung-Cheorl Kang
    TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik 129 8 1541 - 56 2016年08月 [査読有り]
     
    KEY MESSAGE: The sy - 2 temperature-sensitive gene from Capsicum chinense was fine mapped to a 138.8-kb region at the distal portion of pepper chromosome 1. Based on expression analyses, two putative F-box genes were identified as sy - 2 candidate genes. Seychelles-2 ('sy-2') is a temperature-sensitive natural mutant of Capsicum chinense, which exhibits an abnormal leaf phenotype when grown at temperatures below 24 °C. We previously showed that the sy-2 phenotype is controlled by a single recessive gene, sy-2, located on pepper chromosome 1. In this study, a high-resolution genetic and physical map for the sy-2 locus was constructed using two individual F2 mapping populations derived from a cross between C. chinense mutant 'sy-2' and wild-type 'No. 3341'. The sy-2 gene was fine mapped to a 138.8-kb region between markers SNP 5-5 and SNP 3-8 at the distal portion of chromosome 1, based on comparative genomic analysis and genomic information from pepper. The sy-2 target region was predicted to contain 27 genes. Expression analysis of these predicted genes showed a differential expression pattern for ORF10 and ORF20 between mutant and wild-type plants; with both having significantly lower expression in 'sy-2' than in wild-type plants. In addition, the coding sequences of both ORF10 and ORF20 contained single nucleotide polymorphisms (SNPs) causing amino acid changes, which may have important functional consequences. ORF10 and ORF20 are predicted to encode F-box proteins, which are components of the SCF complex. Based on the differential expression pattern and the presence of nonsynonymous SNPs, we suggest that these two putative F-box genes are most likely responsible for the temperature-sensitive phenotypes in pepper. Further investigation of these genes may enable a better understanding of the molecular mechanisms of low temperature sensitivity in plants.
  • Tomoyuki Nabeshima; Motoaki Doi; Munetaka Hosokawa
    Journal of virological methods 234 169 - 73 2016年08月 [査読有り]
     
    Agroinfiltration was tested as a method of inoculation of chrysanthemum plants with chrysanthemum stunt viroid (CSVd). Binary vectors harboring dimeric CSVd sequences in sense and antisense orientations were constructed, and Agrobacterium transfected with these binary vectors was infiltrated into chrysanthemum leaves. Northern blotting and reverse transcription polymerase chain reaction analysis showed that local infection was established within 7 days and systemic infection within 20 days. CSVd polarities showed no difference in infectivity. This study showed that agroinfiltration of chrysanthemum plants is an easy, rapid, and cost-effective method for CSVd inoculation.
  • Sho Ohno; Wakako Hori; Munetaka Hosokawa; Fumi Tatsuzawa; Motoaki Doi
    HORTICULTURE JOURNAL 85 2 177 - 186 2016年04月 [査読有り]
     
    Bicolor flowering dahlias generally produce inflorescences with bicolor petals characterized by a colored basal part and a white tip; however, they frequently produce single-colored petals. This petal color lability prevents uniform production of cut or pot flowers of bicolor dahlias and reduces the economic value of bicolor cultivars. In this study, to reveal the underlying mechanism and control color lability, the pattern of occurrence of single colored petals was characterized in a red white bicolor flowering cultivar 'Yuino'. 'Yuino' produced inflorescences with bicolor petals, red petals, and both red and bicolor petals. Red petals occurred almost always at the outer whorls or sectorally in a mixed inflorescence, similar to a chimera or a lateral mutant. The occurrence of red petals was higher in field experiments during May to December than in greenhouse experiments during October to next July. We identified the "R-line" plant, which produced red petals with high frequency during the winter to spring cultivation; this characteristic to produce red petals with high frequency was retained through vegetative propagation. There were strong relationships between inflorescence color and leaf phenotype; red petal-producing plants accumulated flavonoids in leaves, whereas only bicolor petal-producing plants tended not to accumulate flavonoid in leaves. This suggests that petal color of 'Yuino' is associated with flavonoid synthetic potential in shoot. Therefore, a phenotypic difference is observed not only in petal colors but also at the whole plant level.
  • Fumi Tatsuzawa; Munetaka Hosokawa
    HORTICULTURE JOURNAL 85 1 63 - 69 2016年01月 [査読有り]
     
    The flower colors and anthocyanin constitution of sixteen cultivars of Saintpaulia were surveyed to determine the relationship between their flower colors and anthocyanin components. Six anthocyanins were isolated from the flowers of these cultivars as major anthocyanins along with three minor ones, and their structures were identified by co-HPLC or chemical and spectroscopic techniques. Among them, a novel anthocyanin, pelargonidin 3-O-[6-O-(4-O-(acetyl)-alpha-rhamnopyranosyl)-beta-glucopyranoside] (pelargonidin 3-acetyl-rutinoside; 8) was found in cultivars of 'Georgia' and 'Jessica' as a major anthocyanin. Regarding the flower color variation in these cultivars, the hue values (b*/a*) of these flower colors were responsible for the glycosidic positions in the anthocyanidin molecule and also the combination of anthocyanins. These flower colors were classified into six groups, A-F, based on the flower colors and anthocyanin components were arranged as follows. In violet-blue flowers of group A (hue values b*/a* = -2.61--1.72, VB N89B-VB 94B) and purple-violet flowers of group B (-1.06 and -0.81, PV N82A and PV N80B), malvidin 3-acetyl-rutinoside-5-glucoside was the most effective major anthocyanin for flower colors. In purple-violet flowers (-0.69 and -0.53, PV N80B and PV N81A) of group C, peonidin 3-acetyl-rutinoside-5-glucoside was the most effective major anthocyanin for flower colors. In red-purple flowers (-0.44--0.27, RP 73A-RP N74B) of groups D, pelargonidin 3-acetyl-rutinoside-5-glucoside, in red-purple flowers (-0.03 and -0.02, RP 60D and RP 71D) of group E, pelargonidin 3-acetyl-rutinoside, and in red-purple flowers (0.04 and 0.13, RP 61A and RP 71A) of group F, peonidin 3-acetyl-rutinoside were the most effective major anthocyanins for flower colors. From these results, the glucosylation of 5-OH in anthocyanidin 3-acetyl-rutinoside and an increase in the methylation of the B-ring in anthocyanidin were considered to have the most important effects on flower color variations in these Saintpaulia cultivars.
  • 出口 亜由美; 立澤 文見; 細川 宗孝; 土井 元章; 大野 翔
    The Horticulture Journal 85 4 340 - 350 一般社団法人 園芸学会 2016年 

    ダリア（Dahlia variabilis）の黒色花はシアニジン（Cy）系アントシアニンの高蓄積に起因するものであることが先行研究により示唆されていた．そのため，ダリア花弁に蓄積する Cy 系アントシアニンはペラルゴニジン（Pg）系アントシアニンよりも花弁の明度 L* および彩度 C* を下げるはたらきが強く，花弁黒色化への寄与度が高いことが予想されたが，これまでにそれを示した報告はない．本研究では，ダリア花弁に蓄積する 4 種類の主要なアントシアニン，Pg 3,5-ジグルコシド（Pg 3,5diG），Cy 3,5-ジグルコシド（Cy 3,5diG）Pg 3-（6''-マロニルグルコシド）-5-グルコシド（Pg 3MG5G）および Cy 3-（6''-マロニルグルコシド）-5-グルコシド（Cy 3MG5G）を抽出精製し，異なる pH（3.0，4.0，4.5，5.0，5.5，6.0 あるいは 7.0）あるいは異なる濃度（0.25，0.5，1.0，2.0 あるいは 3.0 mg·mL−1）における溶液の色（CIE L*a*b*C*）を in vitro で評価した．各アントシアニンの色は溶液の pH により変化した．ダリア花弁の pH に近い pH 5.0 およびアントシアニンが比較的安定な構造を保つ pH である pH 3.0 のいずれにおいても，Cy 3,5diG の L* および C* は Pg 3,5diG と同様あるいは高かったことから，Cy 3,5diG は Pg 3,5diG よりも花弁黒色化への寄与度が高いわけではないと考えられた．一方で，Cy 3MG5G の L* および C* は Pg 3MG5G よりも，特に 2.0 mg·mL−1 以上の高濃度において有意に低く，花弁黒色化への寄与度が高いことが示唆された．同様の傾向が Pg 系アントシアニンと Cy 系アントシアニンを様々な割合で混合した色素の測色でもみられた．Pg 3MG5G の L* および C* は他の 3 種のアントシアニンよりも極めて高かったことから，Pg 3MG5G は 4 種のアントシアニンのなかで最も黒色から遠い色を示すことが考えられた．ダリア花弁に蓄積する Pg 系アントシアニンと Cy 系アントシアニンの量比は品種によって様々であったのに対し，いずれの品種においても 3MG5G 型アントシアニンの蓄積量は 3,5diG 型アントシアニンよりも多かった．これらの結果から，ダリア花弁においては 3MG5G 型アントシアニンが主要に蓄積しており，かつ，Cy 3MG5G が Pg 3MG5G よりも花弁 L* および C* を下げるはたらきが強く花弁黒色化への寄与度が高いために，Cy 系アントシアニンの高蓄積が花弁の黒色化に重要であると示唆された．個々のアントシアニンの花弁黒色化への寄与度は各アントシアニンの構造により決まると考えられたため，L* および C* が最も低いアントシアニンを特定し，それを高濃度で花弁に蓄積させることで，様々な花卉品目において黒花品種を作成することが可能になると考えられた．

  • Sota Koeda; Elly Kesumawati; Yuri Tanaka; Munetaka Hosokawa; Motoaki Doi; Akira Kitajima
    Tropical Agriculture and Development 60 2 64 - 64 日本熱帯農業学会 2016年 [査読有り]
     

    Hot peppers (Capsicum spp.) are essential spice in Indonesian meal. Recently, diseases caused by viruses are emerging as serious problems in pepper production at northern Sumatra. Viruses are destabilizing farmers' incomes and the prices of spice used daily by the consumers. In the present study, to obtain the fundamental knowledge of severe damage in pepper production, field research and molecular study were conducted to assess the genetic identity and diversity of pepper-infecting viruses. Five local farmers' fields located at the suburbs of Banda Aceh were chosen for the study. At each field approximately 500 to 3,000 plants of C. annuum were cultivated. The yellow leaf curl symptoms were observed in more than 81 % of plants in all the fields, and symptoms reached 100 % at four fields out of five. As yellow leaf curl symptoms are often caused by begomoviruses, DNA-A full-length sequences were determined and clarified that Pepper yellow leaf curl Indonesia virus (PepYLCIV), Tomato yellow leaf curl Kanchanaburi virus (TYLCKaV), and Ageratum yellow vein virus (AYVV) were infecting pepper plants. By detecting three different begomoviruses independently using specific primers, it was suggested that most of pepper plants were infected with two to three viruses. The present study inferred that mixed infection of begomoviruses is associated with the serious virus problems in pepper production at northern Sumatra, Indonesia.

  • Ayumi Deguchi; Fumi Tatsuzawa; Munetaka Hosokawa; Motoaki Doi; Sho Ohno
    Planta 242 3 663 - 75 2015年09月 [査読有り]
     
    MAIN CONCLUSION: Tobacco streak virus suppressed post-transcriptional gene silencing and caused a flower color change in black dahlias, which supported the role of cyanidin-based anthocyanins for black flower appearance. Black flower color of dahlia (Dahlia variabilis) has been attributed, in part, to the high accumulation of cyanidin-based anthocyanins that occurs when flavone synthesis is reduced because of post-transcriptional gene silencing (PTGS) of flavone synthase II (DvFNS). There are also purple-flowering plants that have emerged from a black cultivar 'Kokucho'. We report that the purple color is not caused by a mutation, as previously thought, but by infection with tobacco streak virus (TSVdahlia), which suppresses the PTGS of DvFNS. When TSVdahlia was eliminated from the purple-flowering 'Kokucho' by leaf primordia-free shoot apical meristem culture, the resulting flowers were black. TSVdahlia-infected purple flowers had lower numbers of siRNAs to DvFNS than black flowers, suggesting that TSVdahlia has a silencing suppressor. The graft inoculation of other black cultivars with TSVdahlia altered their flower color drastically except for 'Fidalgo Blacky', a very deep black cultivar with the highest amount of cyanidin-based anthocyanins. The flowers of all six TSVdahlia-infected cultivars accumulated increased amounts of flavones and reduced amounts of cyanidin-based anthocyanins. 'Fidalgo Blacky' remained black despite the change in pigment accumulation, and the amounts of cyanidin-based anthocyanins in its TSVdahlia-infected plants were still higher than those of other cultivars. We propose that black flower color in dahlia is controlled by two different mechanisms that increase the amount of cyanidin-based anthocyanins: DvFNS PTGS-dependent and -independent mechanisms. If both mechanisms occur simultaneously, the flower color will be blacker than if only a single mechanism is active.
  • Mahmoud Sharaf-Eldin; Shereen Elkholy; Munetaka Hosokawa; Kai Yanagawa; Eiji Nawata; Keiichi Takagi; Jose-Antonio Fernandez
    ZEITSCHRIFT FUR ARZNEI- & GEWURZPFLANZEN 20 2 84 - 87 2015年06月 [査読有り]
     
    The detection of new mutations in saffron flowers with increased number of stigmata has been reported, and the other mutants in floral whorls were discussed. Referable to the sexual sterility of saffron, it is concluded that if the observed mutations verified to be external stimuli determined; the cause which may be detected could increase saffron spice production and; reduce the cost of saffron production in the future. Mutagenic effects of carbon-ion beam on corms of saffron have been reported in this study.
  • Fumi Tatsuzawa; Sayumi Matsuda; Kazuhisa Kato; Munetaka Hosokawa
    HORTICULTURE JOURNAL 84 1 77 - 82 2015年01月 [査読有り]
     
    A new acetylated anthocyanin was extracted from the red-purple flowers of Saintpaulia 'Tomoko' with 5% HOAc-H2O or 5% formic acid-H2O, and determined to be peonidin 3-O-[6-O-(4-O-(acetyl)-alpha-rhamnopyranosyl)-beta-glucospyranoside] (1), by chemical and spectroscopic methods. In addition, two known acetylated cyanidin glycosides, cyanidin 3-O-[6-O-(4-O-(acetyl)-alpha-rhamnopyranosyl)-beta-glucospyranoside] (2) and cyanidin 3-O-[2-O-(beta-xylopyranosyl)-6-O-(acetyl)-beta-glucopyranoside] (3), were also identified in the redpurple flowers and grayed-purple leaves of S. 'Tomoko', respectively. These three anthocyanins have not been reported hitherto in plant tissues in the genus Saintpaulia.
  • Sayumi Matsuda; Mitsuru Sato; Sho Ohno; Soo-Jung Yang; Motoaki Doi; Munetaka Hosokawa
    JOURNAL OF THE JAPANESE SOCIETY FOR HORTICULTURAL SCIENCE 83 4 308 - 316 2014年10月 [査読有り]
     
    For determination of the endogenous and exogenous causes of somaclonal variation in in vitro culture, a bioassay system was developed using the variegated Sairupaulia (African violet) 'Thamires' (Saintpaulia sp.), having pink petals with blue splotches caused by transposon VGs1 (Variation Generator of Saintpaulia 1) deletion in the promoter region of flavonoid 3',5'-hydroxylase. Not only true-to-type but also many solid blue and chimeric plants regenerate in vitro-cultured explants of this cultivar. Using multiplex PCR that enables the determination of these variations, we attempted to evaluate the effects of four candidate triggers of mutation: pre-existing mutated cells, shooting conditions in vitro or ex vitro, cutting treatment of explants, and addition of plant growth regulators (PGRs) to the medium. The percentages of somaclonal variations among total shoots regenerated from leaf segments and stamens were 46.6 and 56.5, which were higher than the percentages expected from pre-existing mutated cells (3.6 and 1.4, respectively). These results indicate that pre-existing mutated cells are not a main cause of somaclonal variations. The percentage of somaclonal variation was independent of culture conditions for mother plants; the mutation percentages of adventitious shoots regenerated from ex vitro- and in vitro-grown leaves were 9.2% and 8.5%, respectively. In addition, the percentage of somaclonal variations of adventitious shoots regenerated under in vitro conditions from the in vitro grown mother plants was also low, at 4.9%. This indicates that the in vitro condition itself is not a main cause of somaclonal variation. However, when adventitious shoots were regenerated from 10 x 5-mm cut-leaf laminas on a PGR-free medium, the percentage of somaclonal variation was 26.4%. In addition, the percentage of somaclonal variations dramatically increased when PGRs were added to the medium for both leaves and leaf segments (39.9 and 46.6, respectively). The bioassay system using Saintpaulia 'Thamires' will enable the screening of many environmental factors because of its rapidity and ease of use and will facilitate the development of a new tissue culture technology for avoiding mutation.
  • Sota Koeda; Kosuke Sato; Kenichi Tomi; Yoshiyuki Tanaka; Rihito Takisawa; Munetaka Hosokawa; Motoaki Doi; Tetsuya Nakazaki; Akira Kitajima
    JOURNAL OF THE JAPANESE SOCIETY FOR HORTICULTURAL SCIENCE 83 3 244 - 251 2014年07月 [査読有り]
     
    'No.80' (Capsicum chinense) from the Caribbean is a valuable genetic source from the aspect of its non-pungent and highly aromatic traits. In the present study, the non-pungency, volatile components, and phylogenetic origin of 'No.80' were analyzed with another C. chinense cultivar, 'No.2' from Brazil, which is also non-pungent but less aromatic. Expressions and deduced amino acid sequences of acyltransferase (Punl) of 'No.80' and 'No.2' were normal compared with a pungent cultivar, 'Habanero'. Insertions of 7-bp and 8-bp resulting in frameshift mutations were found in the coding regions of putative aminotransferase (p-AMT) of 'No.80' and 'No.2', respectively. Co-segregation of these insertions with the non-pungent phenotypes in F-1 and F-2 populations obtained from crossing 'No.80' or 'No.2' with 'Habanero' suggested that non-pungency in these cultivars arose from genetic mutations of p-AMT that occurred independently. Moreover, molecular phylogenetic analysis suggested that 'No.80', a close relative of 'No.2', originates from capsicums migrated from the South American mainland. In addition to pungency, we assessed the volatile components of the highly aromatic 'No.80', the less aromatic 'No.2', and their F-1 hybrid using gas chromatography. 'No.80' contained higher levels of aroma-contributing volatiles than 'No.2', which correlated with the stronger and weaker aromas of two cultivars. Further, the fruit of F-1 progenies emitted a number of volatile compounds between or higher than their corresponding parents. Based on these results, the approaches for breeding highly aromatic non-pungent cultivars are discussed.
  • T. Nabeshima; M. Hosokawa; S. Yano; K. Ohishi; M. Doi
    JOURNAL OF HORTICULTURAL SCIENCE & BIOTECHNOLOGY 89 1 29 - 34 2014年01月 [査読有り]
     
    A total of 199 chrysanthemum (Chrysanthemum x morifolium Ramat.) cultivars were used in screening for resistance to chrysanthemum stunt viroid (CSVd). Plants were inoculated with CSVd by attaching leaf primordia-free, shoot apical meristems to CSVd-infected root tips of a CSVd-sensitive cultivar. CSVd titres in the first and third youngest expanded leaves were analysed after 2 months in culture, and a systematic classification into four groups was conducted. Long-term cultivation records provided by a breeding nursery confirmed our findings of those screened cultivars classified in vitro as "non-detected-type" (i.e., those expected to have a high level of resistance). In addition, of the 15 candidate cultivars selected as "non-detected-type", four cultivars were shown to have a high level of CSVd-resistance by ex vitro grafting experiments. From the results of our in vitro and ex vitro experiments, the advantages of our newly-developed in vitro-screening system are discussed.
  • Yoshiyuki Tanaka; Hirotsugu Yoneda; Munetaka Hosokawa; Tetsuya Miwa; Susumu Yazawa
    SCIENTIA HORTICULTURAE 165 242 - 245 2014年01月 [査読有り]
     
    Capsinoids are a group of low-pungent capsaicinoid analogs produced in Capsicum fruits. Their bioactivities are similar to those of capsaicinoids, such as the suppression of fat accumulation and antioxidant activity. Capsinoids have low pungency and thus are more easily used as food ingredients than capsaicinoids. Capsinoids are, however, unstable in water and upon heating, and their content decreases during fruit maturation. Therefore, capsinoid-containing fruits should be consumed raw and before maturation. Previous genetic study showed that capsinoid biosynthesis is controlled by two genes, p-AMT and Pun1, designated as A and B, respectively. It is expected that aaBB and aaBb represent low-pungent plants containing capsinoids. In this study, DNA markers of p-AMT and Pun1 were used in an attempt to develop a new fresh cultivar containing capsinoids in a cross-breeding program. The genotypes of each progeny derived from the cross of 'Murasaki' (AAbb) x 'CH-19 Sweet' (aaBB) were determined using the DNA markers. Specifically, p-AMT genotypes were determined using a dCAPS marker and Pun1 genotypes using a SCAR marker. From the results of genotyping, aaBB or aaBb plants were selected and developed as a new cultivar, 'Maru Salad'. The capsinoid content of fruits of 'Maru Salad' at harvest was approximately 700 mu g/gDW. Fruits of 'Maru Salad' are larger than those of 'CH-19 Sweet' and are suitable to be consumed raw. (C) 2013 Elsevier B.V. All rights reserved.
  • Sota Koeda; Munetaka Hosokawa; Hiroki Saito; Motoaki Doi
    Journal of plant research 126 5 675 - 84 2013年09月 [査読有り]
     
    Plants in tropical regions experience temperature fluctuation only in non-extreme ambient temperatures. Thus, moderate changes in temperatures, which they never experience in their local environments, might be sufficient to manifest the locally hidden phenotype caused by natural mutation. To validate this hypothesis, temperature-treating experiments were performed on Capsicum accessions collected from tropical regions. Thirty-six Capsicum accessions, collected from Caribbean countries, were screened for temperature sensitivity. Similarities in their temperature sensitivities were compared with Sy-2 (C. chinense) from Seychelles, which was previously found to be a temperature-sensitive accession. Tr-13 from Trinidad & Tobago exhibited developmental abnormalities at temperatures below 24 °C. Expression of defense-related genes was induced, and salicylic acid, which is a key molecule in the plant's defense response, accumulated in Tr-13 at temperatures below 24 °C. Tr-13 and Sy-2 appeared normal when they were grown at temperatures simulating those in Trinidad and Seychelles, respectively. Crossing Tr-13 with No. 3341 or Sy-2 revealed that the temperature-sensitive phenotype of Tr-13 was caused by a genetic mutation in the same locus as Sy-2. Plants having a temperature-sensitive phenotype that is caused by natural mutations evade artificial selection and exist as crops in specific environments, such as tropical regions.
  • Sho Ohno; Ayumi Deguchi; Munetaka Hosokawa; Fumi Tatsuzawa; Motoaki Doi
    Planta 238 2 331 - 43 2013年08月 [査読有り]
     
    The study was aimed to identify the factors that regulate the intensity of flower color in cyanic dahlia (Dahlia variabilis), using fifteen cultivars with different color intensities in their petals. The cultivars were classified into three groups based on their flavonoid composition: ivory white cultivars with flavones; purple and pink cultivars with flavones and anthocyanins; and red cultivars with flavones, anthocyanins, and chalcones. Among the purple, pink, and ivory white cultivars, an inverse relationship was detected between lightness, which was used as an indicator for color intensity and anthocyanin content. A positive correlation was detected between anthocyanin contents and the expression of some structural genes in the anthocyanin synthesis pathway that are regulated by DvIVS, a basic helix-loop-helix transcription factor. A positive correlation between anthocyanin content and expression of DvIVS was also found. The promoter region of DvIVS was classified into three types, with cultivars carrying Type 1 promoter exhibited deep coloring, those carrying Type 2 and/or Type 3 exhibited pale coloring, and those carrying Type 1 and Type 2 and/or Type 3 exhibited medium coloring. The transcripts of the genes from these promoters encoded full-length predicted proteins. These results suggested that the genotype of the promoter region in DvIVS is one of the key factors determining the flower color intensity.
  • Ayumi Deguchi; Sho Ohno; Munetaka Hosokawa; Fumi Tatsuzawa; Motoaki Doi
    Planta 237 5 1325 - 35 2013年05月 [査読有り]
     
    Black color in flowers is a highly attractive trait in the floricultural industry, but its underlying mechanisms are largely unknown. This study was performed to identify the bases of the high accumulation of anthocyanidins in black cultivars and to determine whether the high accumulation of total anthocyanidins alone leads to the black appearance. Our approach was to compare black dahlia (Dahlia variabilis) cultivars with purple cultivars and a purple flowering mutant of a black cultivar, using pigment and molecular analyses. Black cultivars characteristically exhibited low lightness, high petal accumulation of cyanidin and total anthocyanidins without flavones, and marked suppression of flavone synthase (DvFNS) expression. A comparative study using black and purple cultivars revealed that neither the absence of flavones nor high accumulation of total anthocyanidins is solely sufficient for black appearance, but that cyanidin content in petals is also an important factor in the phenotype. A study comparing the black cultivar 'Kokucho' and its purple mutant showed that suppression of DvFNS abolishes the competition between anthocyanidin and flavone synthesis and leads to accumulation of cyanidin and total anthocyanidins that produce a black appearance. Surprisingly, in black cultivars the suppression of DvFNS occurred in a post-transcriptional manner, as determined by small RNA mapping.
  • Munetaka Hosokawa; Takayoshi Yamauchi; Masayoshi Takahama; Mariko Goto; Sachiko Mikano; Yuki Yamaguchi; Yoshiyuki Tanaka; Sho Ohno; Sota Koeda; Motoaki Doi; Susumu Yazawa
    Plant cell reports 32 5 601 - 9 2013年05月 [査読有り]
     
    KEY MESSAGE: The corolla of Petunia 'Magic Samba' exhibits unstable anthocyanin expression depending on its phosphorus content. Phosphorus deficiency enhanced post-transcriptional gene silencing of chalcone synthase - A in the corolla. Petunia (Petunia hybrida) 'Magic Samba' has unstable red-white bicolored corollas that respond to nutrient deficiency. We grew this cultivar hydroponically using solutions that lacked one or several nutrients to identify the specific nutrient related to anthocyanin expression in corolla. The white area of the corolla widened under phosphorus (P)-deficient conditions. When the P content of the corolla grown under P-deficient conditions dropped to <2,000 ppm, completely white corollas continued to develop in >40 corollas until the plants died. Other elemental deficiencies had no clear effects on anthocyanin suppression in the corolla. After phosphate was resupplied to the P-deficient plants, anthocyanin was restored in the corollas. The expression of chalcone synthase-A (CHS-A) was suppressed in the white area that widened under P-suppressed conditions, whereas the expression of several other genes related to anthocyanin biosynthesis was enhanced more in the white area than in the red area. Reddish leaves and sepals developed under the P-deficient condition, which is a typical P-deficiency symptom. Two genes related to anthocyanin biosynthesis were enhanced in the reddish organs. Small interfering RNA analysis of CHS-A showed that the suppression resulted from post-transcriptional gene silencing (PTGS). Thus, it was hypothesized that the enhancement of anthocyanin biosynthetic gene expression due to P-deficiency triggered PTGS of CHS-A, which resulted in white corolla development.
  • M. Doi; N. Nakamura; Y. Takizawa; M. Wakita; F. Shimizu; Y. Kitamura; M. Hosokawa
    Scientia Horticulturae 150 441 - 447 2013年02月 [査読有り]
     
    The harvest characteristics of canna (Canna x generalis L.H. Bailey) 'Butter Cup' leaves were investigated. Leaves harvested during the daytime under fair conditions inrolled rapidly and then browned. The severities of these physiological disorders were closely related to the leaf age and harvest time. Aged leaves harvested from shoots with senescing inflorescences exhibited severe disorders, whereas young leaves harvested from shoots with tight inflorescences exhibited less physiological disorders. In addition, aged leaves harvested just before sunrise did not show any physiological disorders, but the severity of leaf inrolling and browning increased with the increase in integrated solar radiation at harvest. The transpiration rate of young leaves decreased after harvest, whereas that of aged leaves sharply increased 10 min after harvest and then gradually decreased. The leaf resistance of both young and aged leaves was inversely correlated to transpiration rates. The behavior of stomata after harvest was also consistent with these two parameters, suggesting that loss of water is responsible for inrolling of aged leaves. Three min after harvest, a rapid change in the leaf electric potential was detected in aged leaves. Several postharvest treatments indicated that suppressing transpiration rates inhibit both leaf inrolling and leaf browning, and that oxygen is needed for leaf browning. However, none of the treatments were effective in preventing the leaf inrolling and browning after the treatments were conducted and leaves were exposed to ambient air. (C) 2012 Elsevier B.V. All rights reserved.
  • F. Tatsuzawa; M. Hosokawa; N. Saito; T. Honda
    SOUTH AFRICAN JOURNAL OF BOTANY 79 71 - 76 2012年03月 [査読有り]
     
    Three new acylated anthocyanidin 3-rutinoside-5-glucosides were isolated from the violet-blue flowers of Saintpaulia 'Thamires' (Saintpaulia sp.) along with a known flavone glycoside. Three new acetylated anthocyanins were determined to be 3-O-[6-O-(4-O-(acetyl)-alpha-rhamnopyranosyl)-beta-glucopyranoside]-5-O-(beta-glucopyranoside)s of malvidin (pigment 1), peonidin (pigment 2), and pelargonidin (pigment 3) by chemical and spectroscopic methods. HPLC analysis revealed that malvidin 3-O-acetylrutinoside-5-O-glucoside existed as a dominant pigment in the violet-blue flowers. Moreover, the isolated flavone was identified to be apigenin 4'-O-beta-glucuronopyranoside (pigment 4). On the visible absorption spectral curves of fresh violet-blue petals and in their crude extracts in pH 5.0 buffer solution, two characteristic absorption maxima at 547 and 577 nm, with a shoulder near 620 nm, were observed. In contrast, the absorption curves of malvidin 3-O-acetylrutinoside-5-O-glucoside and its deacyl anthocyanin exhibited only one maximum at 535 nm in pH 5.0 buffer solution, and its color was violet and soon fell into decay. However, by addition of apigenin 4'-O-glucuronide, the color of malvidin 3-O-acetylrutinoside-5-O-glucoside changed from violet to violet-blue, similar to that of the fresh flower in pH 5.0 buffer solution. The absorption curve of its violet-blue solution exhibited two similar absorption maxima at 547 and 577 nm, with a shoulder near 620 nm. These results suggest that intermolecular copigmentation between malvidin 3-O-acetylrutinoside-5-O-glucoside and apigenin 4'-O-glucuronide may be responsible for the violet-blue flower color of S. 'Thamires'. (C) 2011 SAAB. Published by Elsevier B.V. All rights reserved.
  • 鍋島 朋之; 細川 宗孝; 矢野 志野布; 大石 一史; 土井 元章
    園芸学会雑誌 81 3 285 - 294 一般社団法人 園芸学会 2012年 
    キクわい化ウイロイド（CSVd）抵抗性のキク品種（Chrysanthemum × morifolium Ramat.）の利用は安定的なキク生産を可能にする．我々は，CSVd を接種した CSVd 抵抗性のキク系統において CSVd が茎頂分裂組織のみならず葉原基にも存在しないことを明らかにしている．本研究では，この性質を表現型マーカーとして使うことで，いくつかの抵抗性品種を得ることに成功した．85 品種の茎頂分裂組織を CSVd に感染したキク根端に移植培養することによって，CSVd を茎頂分裂組織に接種して，新たな展開葉における CSVd 感染の有無を調査した．その結果，85 品種のうち 20 品種の抵抗性候補品種を得られた．これらの品種は CSVd 感染の特徴から 2 つのタイプに分けることができた．すなわち，感染してもその濃度上昇が遅いタイプ，および感染したあとに CSVd が消失するタイプである．20 の候補品種のうち，4 品種を CSVd に感染した'ピアト'に接ぎ木し，新たに展開する葉の CSVd 濃度を調査した．2 つの候補品種においては CSVd 濃度が接ぎ木 2 か月後に上昇し，高保毒台木から切り離しても濃度は減少しなかった．一方，'精の一世'においては，接ぎ木後に CSVd が検出された個体もあったが，台木から切り離した後に新しく展開する葉においては CSVd 濃度が減少した．また，この品種の茎頂部ではほとんど CSVd のシグナルが認められなかった．また，'鞠風車'は接ぎ木後の濃度上昇が極めて遅い抵抗性品種であると考えられた．異なるタイプの CSVd 抵抗性はキクの抵抗性育種に貢献するであろう．さらなる改良は必要であるが，ここで開発した選抜法は CSVd 抵抗性品種の遺伝資源の拡充に利用できると考えられた．
  • S. Koeda; M. Hosokawa; B.-C. Kang; C. Tanaka; D. Choi; S. Sano; T. Shiina; M. Doi; S. Yazawa
    Journal of Plant Research 125 1 137 - 45 2012年01月 [査読有り]
     
    Temperature is one of the most important environmental factors that influence plant growth and development. Recent studies imply that plants show various responses to non-extreme ambient temperatures. Previously, we have found that a pepper cultivar cv. Sy-2 (Capsicum chinense) shows developmental defects at temperatures below 24°C. In this study, to gain new insights into the temperature sensitivity of cv. Sy-2, temperature-sensitive genes were screened using microarray techniques. At restrictive temperature of 20°C, almost one-fourth of the 411 up-regulated genes were defense related or predicted to be defense related. Further expression analyses of several defense-related genes showed that defense-related genes in cv. Sy-2 were constitutively expressed at temperatures below 24°C. Moreover, accumulation of high level of salicylic acid (SA) in cv. Sy-2 grown at 20°C suggests that the defense response is activated in the absence of pathogens. To confirm that the defense response is induced in cv. Sy-2 below 24°C, we evaluated the resistance to biotrophic bacterial pathogen Xanthomonas campestris pv. vesicatoria and necrotrophic fungal pathogen Cercospora capsici. Cv. Sy-2 showed enhanced resistance to X. campestris pv. vesicatoria, but not to C. capsici.
  • Sho Ohno; Munetaka Hosokawa; Misa Kojima; Yoshikuni Kitamura; Atsushi Hoshino; Fumi Tatsuzawa; Motoaki Doi; Susumu Yazawa
    Planta 234 5 945 - 58 2011年11月 [査読有り]
     
    Garden dahlias (Dahlia variabilis) are autoallooctoploids with redundant genes producing wide color variations in flowers. There are no pure white dahlia cultivars, despite its long breeding history. However, the white areas of bicolor flower petals appear to be pure white. The objective of this experiment was to elucidate the mechanism by which the pure white color is expressed in the petals of some bicolor cultivars. A pigment analysis showed that no flavonoid derivatives were detected in the white areas of petals in a star-type cultivar 'Yuino' and the two seedling cultivars 'OriW1' and 'OriW2' borne from a red-white bicolor cultivar, 'Orihime', indicating that their white areas are pure white. Semi-quantitative RT-PCR showed that in the pure white areas, transcripts of two chalcone synthases (CHS), DvCHS1 and DvCHS2 which share 69% nucleotide similarity with each other, were barely detected. Premature mRNA of DvCHS1 and DvCHS2 were detected, indicating that these two CHS genes are silenced post-transcriptionally. RNA gel blot analysis revealed that small interfering RNAs (siRNAs) derived from CHSs were produced in these pure white areas. By high-throughput sequence analysis of small RNAs in the pure white areas with no mismatch acceptance, small RNAs were mapped to two alleles of DvCHS1 and two alleles of DvCHS2 expressed in 'Yuino' petals. Therefore, we concluded that simultaneous siRNA-mediated post-transcriptional gene silencing of redundant CHS genes results in the appearance of pure white color in dahlias.
  • Sho Ohno; Munetaka Hosokawa; Atsushi Hoshino; Yoshikuni Kitamura; Yasumasa Morita; Kyeung-Ii Park; Akiko Nakashima; Ayumi Deguchi; Fumi Tatsuzawa; Motoaki Doi; Shigeru Iida; Susumu Yazawa
    Journal of experimental botany 62 14 5105 - 16 2011年10月 [査読有り]
     
    Dahlias (Dahlia variabilis) exhibit a wide range of flower colours because of accumulation of anthocyanin and other flavonoids in their ray florets. Two lateral mutants were used that spontaneously occurred in 'Michael J' (MJW) which has yellow ray florets with orange variegation. MJOr, a bud mutant producing completely orange ray florets, accumulates anthocyanins, flavones, and butein, and MJY, another mutant producing completely yellow ray florets, accumulates flavones and butein. Reverse transcription-PCR analysis showed that expression of chalcone synthase 1 (DvCHS1), flavanone 3-hydroxylase (DvF3H), dihydroflavonol 4-reductase (DvDFR), anthocyanidin synthase (DvANS), and DvIVS encoding a basic helix-loop-helix transcription factor were suppressed, whereas that of chalcone isomerase (DvCHI) and DvCHS2, another CHS with 69% nucleotide identity with DvCHS1, was not suppressed in the yellow ray florets of MJY. A 5.4 kb CACTA superfamily transposable element, transposable element of Dahlia variabilis 1 (Tdv1), was found in the fourth intron of the DvIVS gene of MJW and MJY, and footprints of Tdv1 were detected in the variegated flowers of MJW. It is shown that only one type of DvIVS gene was expressed in MJOr, whereas these plants are likely to have three types of the DvIVS gene. On the basis of these results, the mechanism regulating the formation of orange and yellow ray florets in dahlia is discussed.
  • Munetaka Hosokawa; Hisanao Suzue; Takashi Fudano; Motoaki Doi
    JOURNAL OF THE JAPANESE SOCIETY FOR HORTICULTURAL SCIENCE 80 4 461 - 468 2011年10月 [査読有り]
     
    Vigorous shoots in chrysanthemums (Chrysanthemum morifolium) often develop from shoot tips (apical meristems with two leaf primordia) cultured in vitro following particle bombardment. The average fresh weight of regenerated shoots from a bombarded shoot tip of chrysanthemum 'Jinba' was 10 times more than that regenerated from unbombarded shoot tips. The average number of leaves per bombarded shoot tip was also more than that from an unbombarded shoot tip. The average number of leaves developing from a shoot tip increased with an increase in the amount of gold particles shot into the shoot tips. In addition, when the area destroyed in a shoot apical meristem (SAM) was varied by bombardment through nylon mesh with different pore sizes, the total number of leaves produced from each shoot tip increased with the size of the destroyed SAM area. Knowing the origin of these vigorous shoots, which may be from the bombarded meristem or from the lateral meristems, is important for the screening of transgenic plants. When the entire surface of a SAM was destroyed by bombardment, it was unable to rebuild itself; instead, lateral meristems were initiated at the base of the leaf primordia. Furthermore, the initiation of lateral meristems at the base of the leaf primordia was also observed in instances of restoration of the area of a partially destroyed SAM. This result indicates that vigorous lateral shoots initiate and develop from the bases of leaf primordia when SAMs are damaged to varying degrees. When leaf primordia-free shoot apical meristems (LP-free SAMs) were cultured after bombardment, vigorous shoots failed to develop from the wounded SAM; instead, the wounded LP-free SAMs regenerated a SAM by repairing the wounded areas and developed a non-vigorous single shoot. It was concluded the vigorous shoots do not participate in transgenic plant production because vigorous shoots arise from unbombarded lateral meristems. Finally, an effective and versatile method for transgenic plant production was established by combining micro-wound treatment on a SAM by bombardment and LP-free SAM culture to suppress the growth of vigorous lateral shoots after wounding.
  • M. Sato; T. Kawabe; M. Hosokawa; F. Tatsuzawa; M. Doi
    Plant Cell Reports 30 5 929 - 39 2011年05月 [査読有り]
     
    The variegated Saintpaulia cultivar Thamires (Saintpaulia sp.), which has pink petals with blue splotches, is generally maintained by leaf cuttings. In contrast, tissue culture-derived progeny of the cultivar showed not only a high percentage of mutants with solid-blue petals but also other solid-color variants, which have not been observed from leaf cuttings. Solid-color phenotypes were inherited stably by their progeny from tissue culture. Petals from each solid-color variant were analyzed by high-performance liquid chromatography and shown to contain different proportions of three main anthocyanin derivatives: malvidin, peonidin, and pelargonidin. Analysis of flavonoid 3', 5'-hydroxylase (F3'5'H) sequences showed no differences in the coding region among the variants and variegated individuals. However, a transposon belonging to the hAT superfamily was found in the promoter region of variegated individuals, and the presence of transposon-related insertions or deletions correlated with the observed flower-color phenotypes. Solid-blue flower mutants contained 8-base pair (bp) insertions (transposon excision footprints), while solid-pink mutants had 58- to 70-bp insertions, and purple- and deep-purple mutants had 21- and 24-bp deletions, respectively. Real-time reverse transcription polymerase chain reaction (RT-PCR) analysis showed that F3'5'H expression levels correlated with insertions and deletions (indels) caused by hAT excision, resulting in flower-color differences. Our results showed that tissue culture of Saintpaulia 'Thamires' elicits transposon excision, which in turn alters F3'5'H expression levels and flower colors.
  • Song-Ji An; Devendra Pandeya; Soung-Woo Park; Jinjie Li; Jin-Kyung Kwon; Sota Koeda; Munetaka Hosokawa; Nam-Chon Paek; Doil Choi; Byoung-Cheorl Kang
    TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik 122 3 459 - 70 2011年02月 [査読有り]
     
    A temperature-sensitive mutant of Capsicum chinense, sy-2, shows a normal developmental phenotype when grown above 24°C. However, when grown at 20°C, sy-2 exhibits developmental defects, such as chlorophyll deficiency and shrunken leaves. To understand the underlying mechanism of this temperature-dependent response, phenotypic characterization and genetic analysis were performed. The results revealed abnormal chloroplast structures and cell collapse in leaves of the sy-2 plants grown at 20°C. Moreover, an excessive accumulation of reactive oxygen species (ROS) resulting in cell death was detected in the chlorophyll-deficient sectors of the leaves. However, the expression profile of the ROS scavenging genes did not alter in sy-2 plants grown at 20°C. A further analysis of fatty acid content in the leaves showed the impaired pathway of linoleic acid (18:2) to linolenic acid (18:3). Additionally, the Cafad7 gene was downregulated in sy-2 plants. This change may lead to dramatic physiological disorder and alteration of leaf morphology in sy-2 plants by losing low-temperature tolerance. Genetic analysis of an F(2) population from a cross between C. chinense 'sy-2' and wild-type C. chinense 'No. 3341' showed that the sy-2 phenotype is controlled by a single recessive gene. Molecular mapping revealed that the sy-2 gene is located at a genomic region of the pepper linkage group 1, corresponding to the 300 kb region of the Ch1_scaffold 00106 in tomato chromosome 1. Candidate genes in this region will reveal the identity of sy-2 and the underlying mechanism of the temperature-dependent plant response.
  • Mitsuru Sato; Munetaka Hosokawa; Motoaki Doi
    PloS one 6 8 e23541  2011年 [査読有り]
     
    BACKGROUND: The origin of somaclonal variation has not been questioned previously, i.e., "pre-existing mutations" in explants and "newly induced mutations" arising from the tissue culture process have not been distinguished. This is primarily because there has been no reliable molecular method for estimating or quantifying variation. METHODOLOGY/PRINCIPAL FINDINGS: We adopted a petal-variegated cultivar of Saintpaulia 'Thamires' (Saintpaulia sp.) as the model plant. Based on the difference between the pre- and post-transposon excision sequence of the promoter region of flavonoid 3', 5'-hydoroxylase (F3'5'H), we estimated mutated (transposon-excised) cell percentages using a quantitative real-time PCR. Mutated cell percentages in leaf laminae used as explants was 4.6 and 2.4% in highly or low variegation flower plants, respectively, although the occurrences of blue color mutants in their regenerants were more than 40%. Preexisting mutated cell percentages in cultured explants were considerably lower than the mutated plant percentage among total regenerants via tissue culture. CONCLUSIONS/SIGNIFICANCE: The estimation of mutated cell percentages became possible using the quantitative real-time PCR. The origins of mutations were successfully distinguished; it was confirmed that somaclonal variations are mainly caused by newly generated mutations arising from tissue culture process.
  • Yoshiyuki Tanaka; Munetaka Hosokawa; Tetsuya Miwa; Tatsuo Watanabe; Susumu Yazawa
    Journal of agricultural and food chemistry 58 22 11762 - 7 2010年11月 [査読有り]
     
    Capsinoids are a group of nonpungent capsaicinoid analogues produced in Capsicum fruits. They have similar bioactivities to capsaicinoids such as suppression of fat accumulation and antioxidant activity. They are more palatable ingredients in dietary supplements than capsaicinoids because of their low pungency. Previous studies on nonpungent Capsicum annuum cultivars showed that capsinoid biosynthesis is caused by loss-of-function putative aminotransferase (p-amt) alleles. This study showed that three mildly pungent cultivars of Capsicum chinense (Zavory Hot, Aji Dulce strain 2, and Belize Sweet) contain high levels of capsinoid. It was shown that these cultivars have novel p-amt alleles, which contain mutations that differ from those of C. annuum. Sequence analysis of p-amt in Belize Sweet revealed that a 5 bp insertion (TGGGC) results in a frameshift mutation. A transposable element (Tcc) was found in the p-amt of Zavory Hot and Aji Dulce strain 2. Tcc has features similar to those of the hAT transposon family. This was inserted in the fifth intron of Zavory Hot and in third intron of Aji Dulce strain 2. The p-amt alleles harboring Tcc cannot produce an active p-AMT. These mildly pungent cultivars will provide a new natural source of capsinoids.
  • 土井元章; 脇田牧子; 細川宗孝
    園芸学研究 別冊 9 2 571  2010年09月 [査読有り]
  • Yoshiyuki Tanaka; Munetaka Hosokawa; Tetsuya Miwa; Tatsuo Watanabe; Susumu Yazawa
    Journal of agricultural and food chemistry 58 3 1761 - 7 2010年02月 [査読有り]
     
    Capsinoids make up a group of nonpungent capsaicinoid analogues produced in Capsicum fruits. They have bioactivities similar to those of capsaicinoids such as suppression of fat accumulation and antioxidant activity. Because of their low pungency, they are more palatable ingredients in dietary supplements than capsaicinoids. We recently reported that capsinoid biosynthesis is caused by nonsense mutation in a putative aminotransferase gene (p-AMT) in a nonpungent cultivar CH-19 Sweet. Here we report on the screening of nonpungent germplasm that revealed a nonpungent cultivar Himo, which contains high levels of capsinoids. We have shown that Himo has a recessive allele of p-amt, which contains a mutation different from that of CH-19 Sweet. Sequence analysis of p-amt in Himo revealed that a single-nucleotide substitution results in one amino acid substitution from cysteine to arginine in the pyridoxal 5-phosphate binding domain. Genetic analysis using a cleaved amplified polymorphic sequence marker confirmed that the p-AMT genotype was precisely cosegregated with capsinoid biosynthesis and nonpungency. Himo will provide a new natural source of capsinoids.
  • Yoshikuni Kitamura; Munetaka Hosokawa; Tatsuya Uemachi; Susumu Yazawa
    SCIENTIA HORTICULTURAE 124 1 134 - 138 2010年02月 [査読有り]
     
    Hydrangea (Hydrangea spp.) has two types of florets in an inflorescence. One has decoratively developed sepals and is termed as the decorative floret. The other has plain sepals and is termed as the non-decorative floret. Hydrangea is classified into two types according to its inflorescence: globular (hortensia) and lacecap. In hortensia, the surface of inflorescence is covered with decorative florets. In lacecap, decorative florets are situated around the periphery of the inflorescence. Japanese hydrangea phyllody (JHP) phytoplasma infection often leads to an increase in the number of decorative florets. JHP phytoplasma was inoculated into ten hortensia and five lacecap cultivars by grafting. The ratios of decorative florets to total florets were compared between the JHP phytoplasma-infected and noninfected plants. The infected plants showed lower decorative floret ratios in six hortensia cultivars and higher decorative floret rations in four lacecap cultivars. The composition of inflorescence was investigated using infected and non-infected plants of 'Midoribanaajisai' (hortensia cultivar) and 'Libelle' (lacecap cultivar). In 'Libelle', the lacecap type, an alteration in the lateral non-decorative floret to the decorative floret was observed and considered to be the main cause of increase in the decorative floret ratio. (C) 2009 Elsevier B.V. All rights reserved.
  • 伊藤弘顕; 西川久仁子; 粟野達也; 細川宗孝; 矢澤進
    園芸学研究 9 1 19-23 (J-STAGE)  2010年 [査読有り]
  • Yoshikuni Kitamura; Munetaka Hosokawa; Tatsuya Uemachi; Susumu Yazawa
    SCIENTIA HORTICULTURAE 122 4 603 - 609 2009年11月 [査読有り]
     
    The mechanism underlying the green colouration of floral organs in phytoplasma-infected hydrangeas was studied. Elucidation of morphological changes of floral organs induced by phytoplasma infection and a comparison of the expression level of genes related to floral organ morphogenesis between phytoplasma-infected and non-infected hydrangea plants was conducted. Sixteen hydrangea (Hydrangea spp.) cultivars were used to study structural changes in floral organs induced by Japanese Hydrangea Phyllody (JHP) phytoplasma infection. The homeotic conversion of sepals to leaves was observed in different number of florets between cultivars, and was observed in 75.8-100% of the decorative florets and 2.7-67.3% of the non-decorative florets of JHP phytoplasma-infected inflorescences. The homeotic conversion of carpels to leaves was observed in 1.2-17.9% of the decorative florets and 0.1-18.9% of the non-decorative florets of infected inflorescences. The expression levels of hydrangea orthologues of class A, B and C genes were suppressed in the infected inflorescences during the developmental stage in which no morphological differences in the internal structure of floral organs have been observed. The contribution of this suppression to homeotic conversion of sepals and carpels to leaves was suggested. (C) 2009 Elsevier B.V. All rights reserved.
  • S. Koeda; M. Hosokawa; B.-C. Kang; S. Yazawa
    Journal of Plant Research 122 6 623 - 31 2009年11月 [査読有り]
     
    When a pepper cultivar (Capsicum chinense cv. Seychelles-2, Sy-2) native to the Seychelles was grown in Japan, all seedlings showed seasonal developmental abnormalities such as development of abnormally shaped leaves. Other pepper cultivars grew well in all seasons while the growth of cv. Sy-2 was stunted. In this study, we first examined the effects of various changes in temperature and photoperiod on the cv. Sy-2 phenotype. The results showed that temperatures lower than 24 degrees C led to the formation of abnormal leaves. Second, morphological and anatomical analyses of cotyledons and true leaves developed at 28 and 20 degrees C were conducted. The narrower and thicker cotyledons developed at 20 degrees C had fewer palisade cells in the leaf-length direction, and more cells in the leaf-thickness direction. True leaves developed at 20 degrees C were irregularly shaped, thicker and had smaller leaf area. In addition, true leaves developed at 20 degrees C had fewer palisade cells in the leaf-length and leaf-width directions and had more cells in the leaf-thickness direction. Furthermore, abnormal periclinal cell divisions in the mesophyll and/or epidermal cell layers were observed during leaf blade development at 20 degrees C. These results suggest that the observed changes in cell proliferation and abnormal periclinal cell divisions were related, at least in part, to abnormal leaf development of cv. Sy-2 at temperatures below 24 degrees C.
  • 細川宗孝; 大野翔; 北村嘉邦; 児島未沙; 中島明子; 星野敦; 立澤文見; 土井元章
    園芸学研究 別冊 8 2 528  2009年09月 [査読有り]
  • Hisanao Suzue; Munetaka Hosokawa; Susumu Yazawa
    HORTSCIENCE 44 5 1501 - 1503 2009年08月 [査読有り]
     
    Exposing the shoot apical meristem (SAM) is necessary in horticultural practices such as shoot tip culture, colchicine treatment, gene transfer, and so on. However, ordinary methods of exposing SAMs require extensive training and are labor-intensive. We developed equipment to expose SAMs quickly and easily by blowing compressed air on the shoot tips. Using this equipment allowed SAMs to be exposed more rapidly than the ordinary methods. Exposure time was shortened from 27.8 s to 7.4 s, 15.7 s to 7.9 s, and 59.7 s to 6.8 s in chrysanthemum (Chrysanthemum morifolium), dahlia (Dahlia spp.), and Lilium leichtlinii, respectively. To determine whether blowing compressed air caused injury to SAMs, we used shoots in which the SAMs had been already exposed and observed resin sections of SAMs that had been subjected to the additional compressed air treatment for several seconds. Results showed that blowing additional compressed air for as long as 9 s did not injure SAMs. Using this equipment, we can expose SAMs without using a stereomicroscope by blowing compressed air to the top of shoots for several seconds. Over 70% of SAMs could he exposed in a 7- to 13-s blowing treatment without injury. We could successfully use this equipment in shoot tip culture and leaf primordia-free SAM culture.
  • Hitomi Omori; Munetaka Hosokawa; Hayato Shiba; Naoki Shitsukawa; Koji Murai; Susumu Yazawa
    JOURNAL OF THE JAPANESE SOCIETY FOR HORTICULTURAL SCIENCE 78 3 350 - 355 2009年07月 [査読有り]
     
    Chrysanthemum stunt viroid (CSVd) is one of the problematic pathogens known to infect chrysanthemum (Dendranthema grandiflorum) plants and causes various symptoms, such as a reduction in plant height, which is a serious problem in cut flower production. No natural sources with resistance to CSVd have been reported. By quantifying the CSVd titer within the plant, we identified the cultivar 'Utage' as a plant in which the increase of the CSVd titer was slowest among 6 cultivars tested. 'Utage' self-pollinated, and 67 resulting seedlings were screened for CSVd resistance using reverse transcription polymerase chain reaction (RT-PCR), nested-PCR, micro-tissue (MT) direct RT-PCR, and real-time RT-PCR. Of these 67 seedlings, 9 plants lacked the obvious CSVd band detected by RT-PCR. Five months after grafting to CSVd-infected plants, the CSVd titers of 3 plants (C7, A30, and A27) were about 1/240, 1/41000, and 1/125000 compared to that of 'Utage', respectively. These 3 plants were comfirmed to have strong resistance to CSVd. In C7, local distribution of CSVd was observed in the youngest expanded leaf by micro-tissue direct RT-PCR and in situ hybridization. For A30 and A27, CSVd was hardly detected in the whole plant. These 3 plants will contribute to the elucidation of CSVd resistance mechanisms.
  • Yoshiyuki Tanaka; Munetaka Hosokawa; Keigo Otsu; Tatsuo Watanabe; Susumu Yazawa
    Journal of agricultural and food chemistry 57 12 5407 - 12 2009年06月 [査読有り]
     
    Capsiconinoid is a group of nonpungent capsaicinoid analogues produced in Capsicum fruits, which we recently identified. Capsiconinoids have agonist activity for transient receptor potential vanilloid type 1 (TRPV1), which is reported to be a receptor for capsaicin. It is, therefore, important to screen cultivars containing high levels of capsiconinoid for their use as a vegetable or dietary supplement. This study describes the quantitative analysis of capsiconinoid content in fruits of 35 Capsicum cultivars: 18 cultivars of C. annuum, 7 of C. baccatum, 5 of C. chinense, 4 of C. frutescens, and 1 of C. pubescens. Using high-performance liquid chromatography (HPLC), we found that 10 cultivars contained capsiconinoids. Capsiconinoid Baccatum (CCB) (C. baccatum var. praetermissum) showed the highest capsiconinoid content (3314 microg/g DW) and Charapita (C. chinense) had the second highest content. The other 8 cultivars had much lower capsiconinoid content than these two cultivars (<300 microg/g DW). Time-course analysis during fruit development clarified that capsiconinoid content in CCB fruits increased until 30 days after flowering (DAF) and then decreased rapidly until 40 DAF.
  • Yang Zhang; Takahiro Hayashi; Munetaka Hosokawa; Susumu Yazawa; Yuhua Li
    SCIENTIA HORTICULTURAE 121 2 213 - 217 2009年06月 [査読有り]
     
    The mechanism of sparkling metallic lustre formation in leaves of Begonia rex Putz. was investigated. On the metallic lustre and normal green areas of one leaf, we, observed two light reflection patterns, one a spotted pattern (SP) composed of white spots formed on the centre of epidermal cells and the other a polygonal pattern (PP) composed of white polygons formed around the epidermal cell edges. The SP was observed both in metallic lustre and normal green areas, and the intensity did not differ significantly, but the PP was much stronger in the metallic lustre area. Different reflection of the PP in metallic lustre and normal green areas indicated that metallic lustre formation was attributable to the PP. Light reflection of the PP was mainly derived from interior light reflection because the PP became very weak after air removal from leaf. The formation of the PP is associated with the interior structure of the leaf, such as chlorophyll density, cell arrangement and air space. The experimental results indicated that interior air space is an important factor in forming the polygonal pattern. (c) 2009 Elsevier B.V. All rights reserved.
  • Elly Kesumawati; Munetaka Hosokawa; Takushi Kimata; Tatsuya Uemachi; Susumu Yazawa
    SCIENTIA HORTICULTURAE 121 2 199 - 205 2009年06月 [査読有り]
     
    To determine the effect of light intensity on flower greening, the Japanese hydrangea phyllody (JHP) phytoplasma-infected hydrangea cultivars 'Midori', 'Libelle', 'Rosea' and 'Madame E. Mouillere' plants were grown under different shade conditions. In the first-year experiment, the results indicate that the flowers of the JHP-phytoplasma-infected hydrangea become green under shaded conditions (70% and 49% sunlight intensities). On the other hand, under full sunlight intensity (100% sunlight intensity), the flowers of 'Midori','Rosea', and 'Libelle' plants were blue, pink or white. To calculate the percentage of flower greening, inflorescences of these plants were separated and divided into individual flowers, and classified into four types by green-area ratio, calculated using Adobe Photoshop. Under shading with one sheet of cheesecloth (70% sunlight intensity), the inflorescences of 'Midori', 'Libelle' and 'Madame E. Mouillere' plants were composed of more than 40% completely green flowers (0.8 <= green-area ratio), whereas those of 'Rosea' plant had 0% completely green flowers. Under shading with two sheets of cheesecloth (49% sunlight intensity), the inflorescences of 'Midori', 'Libelle' and 'Madame E. Mouillere' plants had more than 75% completely green flowers; 'Rosea' plants had 28%. In the second-year experiment, under full sunlight intensity, 'Midori' plants had four types of flower depending on their green-area ratio, namely, completely blue or pink, pink-green, greenish and completely green flowers. Under shading with two sheets of cheesecloth, 'Midori' plants had more than 90% completely green flowers. The JHP-phytoplasma could not be identified by PCR analysis in flowers with a green-area ratio = 0 (completely blue/pink/white flowers). On the other hand, in flowers with a green-area ratio > 0, the JHP-phytoplasma was detected by PCR analysis. Thus, we conclude that shading enhances flower greening in hydrangea by increasing the JHP-phytoplasma concentration in the flowers. (c) 2009 Elsevier B.V. All rights reserved.
  • Yoshikuni Kitamura; Munetaka Hosokawa; Chihiro Tanaka; Susumu Yazawa
    JOURNAL OF THE JAPANESE SOCIETY FOR HORTICULTURAL SCIENCE 77 4 418 - 425 2008年10月 [査読有り]
     
    In some plant species, bacterial contamination frequently occurs in hi vitro culture. Also, in hydrangea (Hydrangea spp.), microbial contamination frequently occurs when their explants are cultured in vitro. We identified bacterial flora near hydrangea shoot apical meristems (SAMs) by analyzing their 16S ribosomal DNA (16S rDNA) sequences. Sequences of 16S rDNA fragments amplified from bacteria isolated from SAMs of 8 hydrangea cultivars were identical to those of 12 bacterial species. Because I to 9 bacterial species were detected only once in each cultivar, and we focused on bacteria that can colonize on Nutrient Broth medium, in this reserch we could not cover all bacterial species existing near SAMs. The appropriate chlorine concentration for sterilizing SAMs was decided using 'Miss Hepburn'. When shoot tips with stripped SAMs were dipped in chlorine solution with 0.0005%-0.5% available chlorine concentration for 30 min, no bacterial colony was observed in the treatment with 0.05% chlorine. From this result, direct exposure of the stripped meristem to chlorine solution is a suitable method for sterilizing hydrangea shoot tip culture explants, and the bacteria causing in vitro contamination in hydrangea shoot-tip culture are not endophytic butepiphytic. A successful method for in vitro culture of hydrangea was established using 8 hydrangea cultivars in Exp. 3 and in 7 cultivars, we could gain 5 to 19 viable plants from 20 cultured explants without bacterial contamination by sterilizing shoot tips for 30 min with a sterilization solution of 0.05% available chlorine concentration after removal of all but two pairs of leaf primordia. No viable explant was gained from 'Flambeau', so the chlorine concentration must be reconsidered to sterilize such cultivars that have chlorine-sensitive meristems. One hundred and thirty days after culture initiation, no contamination was observed and cultured explants grew sufficiently to be transplanted out of the bottle. Surface sterilization of the SAM can be applied for many plants in which bacterial contamination poses a big problem in shoot-tip culture.
  • Munetaka Hosokawa
    JOURNAL OF THE JAPANESE SOCIETY FOR HORTICULTURAL SCIENCE 77 4 341 - 349 2008年10月 [査読有り]
     
    Viroids are the smallest and one of the most problematic pathogens known in horticulture. Despite not coding for proteins they replicate in nuclei or chloroplasts using host enzymes. From many pathological studies, it is obvious that viroids are completely different agents from viruses. For the past 40 years, elimination of viroids from infected plants has been the main theme in horticulture and several approaches have been established; however, these procedures remain complicated. Leaf primordia-free shoot apical meristem culture is a newly established method that can effectively eliminate viroids. Therefore, in this review, the method is summarized and the mechanism of viroid elimination is discussed.
  • Kuniko Nishikawa; Hiroaki Ito; Tatsuya Awano; Munetaka Hosokawa; Susumu Yazawa
    Annals of botany 102 1 31 - 7 2008年07月 [査読有り]
     
    BACKGROUND AND AIMS: Helichrysum bracteatum is called an 'eternal flower' and has large, coloured, scarious bracts. These maintain their aesthetic value without wilting or discoloration for many years. There have been no research studies of cell death or cell morphology of the scarious bract, and hence the aim of this work was to elucidate these characteristics for the bract of H. bracteatum. METHODS: DAPI (4'6-diamidino-2-phenylindol dihydrochloride) staining and fluorescence microscopy were used for observation of cell nuclei. Light microscopy (LM), transmission electron microscopy (TEM) and polarized light microscopy were used for observation of cells, including cell wall morphology. KEY RESULTS: Cell death occurred at the bract tip during the early stage of flower development. The cell wall was the most prominent characteristic of H. bracteatum bract cells. Characteristic thickened secondary cell walls on the inside of the primary cell walls were observed in both epidermal and inner cells. In addition, the walls of all cells exhibited birefringence. Characteristic thickened secondary cell walls have orientated cellulose microfibrils as well as general secondary cell walls of the tracheary elements. For comparison, these characters were not observed in the petal and bract tissues of Chrysanthemum morifolium. CONCLUSIONS: Bracts at anthesis are composed of dead cells. Helichrysum bracteatum bracts have characteristic thickened secondary cell walls that have not been observed in the parenchyma of any other flowers or leaves. The cells of the H. bracteatum bract differ from other tissues with secondary cell walls, suggesting that they may be a new cell type.
  • Y. Zhang; T. Hayashi; M. Inoue; Y. Oyama; M. Hosokawa; S. Yazawa
    PROCEEDINGS OF THE INTERNATIONAL SYMPOSIUM ON ORNAMENTALS, NOW! 766 766 469 - 475 2008年 [査読有り]
     
    The textures of flowers are important ornamental characteristics. Reflected light from the surface of petals, including colorful bracts and leaves, is a key factor determining the texture of flowers. The results of experiments in which we examined various species of flower petals indicated that there are two types of reflected light: one is superficial reflected light, which is determined by the shape of the epidermal cells. More light is reflected by flat epidermal cells than by papillate ones. In particular, when the angle of incident light was changed, the belt-shaped reflected light was only observed through the microscope from the side of the papillate epidermal cells. The other type of reflected light is scattered reflected light, which is determined by the petal structure, and the higher the pigment content in a petal, the more light is absorbed. The intensity and origin of scattered reflected light depends on the volume and location of air spaces in the petal that are distributed among the epidermal, palisade, and spongy cells. There are three typical flower textures: velvet luster (e.g., Viola tricolor), which occurs due to superficial reflected light, and metallic luster (e.g., Begonia rex) and diamond dust (e.g., Saintpaulia ionantha), which are caused by scattered reflected light.
  • Akiko Nakashima; Munetaka Hosokawa; Shigeichi Maeda; Susumu Yazawa
    Journal of General Plant Pathology 73 3 225 - 227 2007年06月 [査読有り]
     
    For the first time, Chrysanthemum stunt viroid (CSVd) was detected in commercial dahlia bulbs in Japan. CSVd was found in 77.2% of the tested plants (Dahlia spp.). In nucleotide sequence analysis, a CSVd variant was detected consisting of 354 nucleotides, which differed slightly from previously reported CSVd variants. © 2007 The Phytopathological Society of Japan and Springer.
  • Munetaka Hosokawa; Hayato Shiba; Takashi Kawabe; Akiko Nakashima; Susumu Yazawa
    JOURNAL OF THE JAPANESE SOCIETY FOR HORTICULTURAL SCIENCE 76 1 60 - 65 2007年01月 [査読有り]
     
    The economically important Chrysanthemum stunt viroid (CSVd) and Chrysanthemum chlorotic mottle viroid (CChMVd) were detected from infected chrysanthemum (Dendranthema grandiflorum) plants by a multiplex reverse transcription-polymerase chain reaction (RT-PCR) assay developed in this investigation. The antisense hexamer AAAGGA (5'-3') was designed. The antisense hexamer 5'AAAGGA 3' annealing at 5'TCCTTT3' is located at nucleotide positions 186-191 and 245-250 of CSVd (gb: AB006737), and 231-236 of CChMVd in their sequences. Using CSVd- and CChMVd-cDNA templates which were transcribed simultaneously by the hexamer, the following multiplex PCR could detect both viroids from doubly-infected plants without nonspecific amplification. When the hexamer was used for the RT reaction, the sensitivity of detection of CSVd or CChMVd by multiplex RT-PCR was similar to that of standard RT-PCR when each viroid was detected separately. Furthermore, multiplex RT-PCR successfully detected both CSVd and CChMVd in direct templates obtained by inserting a syringe needle into the stem, leaf, and shoot tips of infected chrysanthemum plants. The direct multiplex RT-PCR method developed in this study may reduce the cost, time, and labor required for the production of viroid-free chrysanthemum plants.
  • Soo Jung Yang; Yoshikuni Kitamura; Munetaka Hosokawa; Susumu Yazawa
    JOURNAL OF THE JAPANESE SOCIETY FOR HORTICULTURAL SCIENCE 75 6 476 - 480 2006年11月 [査読有り]
     
    Hypersensitivity is induced in many species of Acanthaceae and Gesneriaceae by local mechanical wounding. Once a plant of these species sustains a wounded leaf, it exhibits a temporary hypersensitive state and severe injury easily occurrs even in unwounded leaves. Locally wounded African violet (Saintpaulia sp.) plants sometimes show severe injury even at a noninjurious temperature for this species. This study was aimed to clarify changes in the temperature sensitivity of hypersensitivity-induced African violet plants by local wounding. The basal leaves of African violet 'Ritali' plants were cut as a local wounding treatment. The locally wounded plants were transferred to growth chambers at various temperatures and we evaluated the degree of leaf injury using an analysis software. In locally wounded plants, temperature sensitivity increased and leaf injury was observed even at 11 degrees C, which is a noninjurious temperature for unwounded African violet. Such a wound-induced sensitivity to low temperature treatment (7 degrees C for 1h) quantitatively increased with local wounding severity. For the investigation of time-course changes in the hypersensitive state (wounding memory) of locally wounded plants, the plants were transferred to low temperature conditions at various intervals after the wounding treatment. The wounding memory was short-lived, that is, it was generally observed immediately after local wounding and then almost disappeared 30 min after. In conclusion, the low temperature sensitivity of African violet plants was enhanced by prewounding treatment.
  • E Kesumawati; T Kimata; T Uemachi; M Hosokawa; S Yazawa
    SCIENTIA HORTICULTURAE 108 1 74 - 78 2006年03月 [査読有り]
     
    The interaction between phytoplasma concentration and green-flowering stability was studied in hydrangea cultivars. Three green and 18 nongreen cultivars were subjected to polymerase chain reaction (PCR) analysis to determine Japanese hydrangea phyllody (JHP) phytoplasma infection. The results showed that JHP-phytoplasma was detected only in 'Midori' plants, which have green sepal, 'Midori' plants were propagated, and from 29 rooted cutting plants, they were grouped into three types on the basis of sepal color. that is. green (75,9%). blue-green (13.8%) and blue (10.3%) sepals. To clarify the variability in the sepal color of 'Midori' plants. JHP-phyloplasma concentration in the sepals and leaves of green-, blue-green- and blue-flowering plants was determined by PCR analysis, The semiquantitative PCR comparisons of 370 bp DNA fragments showed that the JHP-phytoplasma concentrations in green sepals were 16 times higher than that in blue-green sepals, JHP-phytoplasma could not be identified by PCR analysis in blue sepals and leaves. These results showed that JHP-phytoplasma concentration correlated with green sepal stability in 'Midori' plants. A histological observation of sepals showed that epidermal cells of blue and blue-green sepals had a dome shape. Otherwise, green sepals were leaflike with flat epidermal cells, and palisade parenchyma cells with numerous, chloroplasts. (c) 2006 Elsevier B.V. All rights reserved.
  • M Hosokawa; Y Matsushita; H Uchida; S Yazawa
    JOURNAL OF VIROLOGICAL METHODS 131 1 28 - 33 2006年01月 [査読有り]
     
    A direct reverse transcription-polymerase chain reaction (RT-PCR) method for detecting the chrysanthemum stunt viroid (CSVd) and chrysanthemum chlorotic mottle viroid (CChMVd) to screen for a viroid-free chrysanthemum plant at a small plant size was established and named microtissue direct RT-PCR. A razor or syringe needle was used for RNA template preparations. Under a stereoscopic microscope, a razor or syringe needle was used to pierce, a tissue sample to a depth of 0.1-0.2 mm, and the sample was directly transferred to the RT mixtures. Methods using razors or needles for the preparation of templates could detect CSVd and CChMVd with a high sensitivity. The most sensitive method used a razor or syringe needle to acquire template from the shoot tips. Using the microtissue direct RT-PCR method, both viroids could be detected from the high- and low-viroid-concentration plants. The microtissue direct RT-PCR method was more sensitive than a conventional template preparation method. Using the microtissue direct RT-PCR method established in this study, the laborious subculture step could be omitted because detecting viroids and screening for viroid-free plants even at a small plant size before the subculture could be possible. In addition, the microtissue direct RT-PCR method could also be a powerful tool for clarifing the viroid distribution among microtissues, such as shoot apical meristems. (c) 2005 Elsevier B.V. All rights reserved.
  • M Hosokawa; Y Matsushita; K Ohishi; S Yazawa
    JOURNAL OF THE JAPANESE SOCIETY FOR HORTICULTURAL SCIENCE 74 5 386 - 391 2005年09月 [査読有り]
     
    The disease symptoms of chrysanthemum chlorotic mottle viroid (CChMVd) that had not been observed in chrysanthemum (Dendranthema grandiflorum) plants grown in Japan were found recently. In our first experimental test to examine whether the disease symptoms, such as chlorosis of newly expanded leaves in Japanese chrysanthemum, confirmed that the disease was induced by CChMVd. The viroid was detected in cultivars with the disease symptoms by polymerase chain reaction (PCR). The nucleotide sequence of CChMVd extracted from an infected 'Piato' plant, almost completely agreed with that of the non-symptomatic CChMVd strain that was reported previously. In the second experiment from cultivars randomly collected from various areas in Japan, namely, Fukuoka, Hiroshima, Osaka, Shiga, Kyoto and Aichi prefectures, CChMVd was detected in many of the collected cultivars. Moreover, CChMVd was detected in several samples at low concentrations from cut chrysanthemum flowers sold in Kyoto prefecture shipped from various areas in Japan and the Netherlands. Hence, we concluded that CChMVd had already spread in Japan. In the third experiment to develop a CChMVd- free plant through a newly established method, that is, leaf primordia-free shoot apical meristem (LP-free SAM) culture was utilized to eliminate CChMVd from infected cultivars. These excised LP- free SAMs derived from CChMVd -infected 'Piato' and 'Sttetsuman' plants were attached to the root tip of in vitro-sown cabbage (Brassica oleracea) 'Harunami' and regenerated. One out of 29 regenerated 'Piato' plants and two out of 6 regenerated 'Sttetsuman' plants were ascertained to be CChMVd -free by nested PCR.
  • Munetaka Hosokawa; Emi Ueda; Kazushi Ohishi; Ayaka Otake; Susumu Yazawa
    Planta 220 1 64 - 70 2004年11月 [査読有り]
     
    Chrysanthemum ( Dendranthema grandiflorum Kitam.) is one of the qualitative short-day flowering plants. Therefore, the flowering of chrysanthemum can usually be controlled by photoperiod. However, it was noted that 'Piato' plants infected by the chrysanthemum stunt viroid (CSVd) flowered autonomously even under long-day conditions. In this study, CSVd-free and CSVd-infected plants were prepared by culturing different-sized dissected shoot apical meristems (SAMs) of 'Piato'. Using these CSVd-free and CSVd-infected plants, we clarified the relationship between CSVd infection and the autonomous flowering of 'Piato'. Under natural short-day conditions, the flowering of plants regenerated from SAMs containing leaf primordia (LPs) was 1 month earlier than plants regenerated from LP-free SAMs. CSVd was detected from these early flowering plants by reverse transcription-polymerase chain reaction. On the other hand, CSVd was not detected in plants regenerated from LP-free SAMs. CSVd-infected and CSVd-free plants were grown under long-day conditions simulated by night-break lighting at 22:00 p.m. to 2:00 a.m. All CSVd-infected plants flowered autonomously even under long-day conditions; on the other hand, CSVd-free chrysanthemum plants maintained their vegetative growth. When the CSVd-free plants were inoculated with CSVd by grafting them to CSVd-infected rootstocks, they flowered autonomously even under night-break lighting. In this study, the results suggest that CSVd may control the qualitative development process, flowering, i.e. CSVd can induce the autonomous flowering of chrysanthemum.
  • M Hosokawa; A Otake; K Ohishi; E Ueda; T Hayashi; S Yazawa
    PLANT CELL REPORTS 22 11 859 - 863 2004年06月 [査読有り]
     
    In this research we eliminated chrysanthemum stunt viroid (CSVd) from a highly infected chrysanthemum cultivar using a newly established method. 'Piato' is one of the most difficult cultivars in which to obtain CSVd-free plants by conventional methods. Leaf primordium-free shoot apical meristems (LP-free SAMs) of 'Piato' plants were dissected and attached to CSVd-free chrysanthemum or cabbage root tips. As shown by nested-PCR, CSVd was not detected in some shoots regenerated on both types of root tip. The production rates of CSVd-free plants using chrysanthemum and cabbage root tips were 14% and 3%, respectively. Regeneration of plants from LP-free SAMs of chrysanthemum plants by attaching these SAMs to root tips is an efficient method of generating CSVd-free chrysanthemum plants.
  • M Hosokawa; A Otake; Y Sugawara; T Hayashi; S Yazawa
    PLANT CELL REPORTS 22 7 443 - 448 2004年02月 [査読有り]
     
    A new method to regenerate plants from leaf primordia-free shoot apical meristem domes (LP-free SAMs) was developed by establishing the meristem dome on the cut surface of root tips. Ten days after culture, the viable rate of LP-free SAMs of chrysanthemum 'Piato' attached to chrysanthemum root tips was >40%. Shoot regeneration was not observed from LP-free SAMs without the root tips. When LP-free SAMs of chrysanthemum were transferred to root tips of either petunia, cabbage, or carnation, the highest shoot regeneration rate was observed with cabbage root tips. Microscopic observation documented that the LP-free SAM temporarily adhered to the cut surface of the root tip of cabbage.
  • SJ Yang; M Hosokawa; T Hayashi; S Yazawa
    JOURNAL OF THE JAPANESE SOCIETY FOR HORTICULTURAL SCIENCE 72 4 286 - 291 2003年07月 [査読有り]
     
    To evaluate the effect of wounding on the incidence of leaf browning to a sudden temperature drop, Ruellia macrantha, cuttings of a highly wound-sensitive Acanthaceae species, were briefly immersed in water (3- 9 degreesC lower than the leaf temperature for 3 sec). Leaf browning occurred in wounded plants but not in intact ones. The incidence and the severity of leaf browning increased with decreased temperatures, but even the immersion in 25 degreesC water induced leaf browning in injured plants (25 degreesC). These responses indicate that the water stimulates leaf browning in a wounded plant, whereas the reduced temperature intensifies the responsiveness. This wound-induced increase in sensitivity to water stimulus is referred to as hypersensitivity. Injuring the leaf, petiole, stem or root by cutting or crushing induced hypersensitivity only in young expanded leaves above the wound site. The hypersensitivity reached maximum 2 or 3 min after wounding and disappeared after 30 min. In addition, cutting the shoot a short distance from the apex resulted in severe leaf browning, indicating that the distance from young expanded leaves to the site of wounding affects the level of hypersensitivity. Our data indicate that a wound signal is rapidly translocated to the unwounded leaves to play a role in inducing hypersensitive responses to mechanical stimuli, such as water stimulus and sudden temperature drop.
  • EU Ahmed; T Hayashi; Y Zhu; M Hosokawa; S Yazawa
    SCIENTIA HORTICULTURAE 96 1-4 187 - 194 2002年12月 [査読有り]
     
    Explants from various parts of Caladium bicolor Ait. plants were cultured on MS medium containing 1 ppm naphthalene acetic acid (NAA) and 1 ppm 6-benzyladenine (BA). Variations in the shape and color pattern were observed in the regenerated plants. In plants regenerated from shoot tip explants including the two youngest leaves, young leaves (third and fourth leaves from the top), unexpanded leaves (fifth or sixth leaves), expanded leaves and petiole, the frequency of the occurrence of variants was 14, 24, 41, 53 and 70%, respectively. Plants regenerated from young leaves of lateral buds or root tips also produced only a few variants (12-14%). Thus, explants from younger tissue having meristematic tissue produced fewer variations than explants from older tissue. The mode of variation (color pattern and shape of leaves) also varied with the age of the explant. We conclude that young tissue should be used to propagate Caladium plants by tissue culture. (C) 2002 Elsevier Science B.V. All rights reserved.
  • S Ahmed; E Nawata; M Hosokawa; Y Domae; T Sakuratani
    PLANT SCIENCE 163 1 117 - 123 2002年07月 [査読有り]
     
    Photosynthetic rate (P), leaf water potential (psi(L)) and chlorophyll fluorescence were studied in mungbean plants subjected to waterlogging in a plastic greenhouse, and leaf samples were collected for the analysis of enzymes involved in anti-oxidant photoprotection. Waterlogging caused a fast decline in the photosynthetic rate and water use efficiency without changes of transpiration rate and stomatal conductance during the early waterlogging period, which indicates that reduction of photosynthetic rate might be due to a mechanism independent from stomatal closure. Early reduction of Fv/Fm value of chlorophyll fluorescence by waterlogging indicates that the early reduction of photosynthetic rate is correlated with photo inhibition of photosystem II (PSII). Stomatal conductance and water use efficiency was decreased progressively during prolonged waterlogging while psi(L) was unchanged, indicating stomatal closure without water stress. The activities of active oxygen processing enzymes, such as superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX) and glutathione reductase (GR) decreased during prolonged waterlogging indicating no evidence of oxidative stress and/or damage in leaves of mungbean by waterlogging. Our results suggest that oxidative damage is not directly involved in damage to the photosynthetic machinery during waterlogging in mungbean plants. (C) 2002 Elsevier Science Ireland Ltd. All rights reserved.
  • SJ Yang; M Hosokawa; T Hayashi; S Yazawa
    JOURNAL OF THE JAPANESE SOCIETY FOR HORTICULTURAL SCIENCE 71 4 535 - 537 2002年07月 [査読有り]
     
    Leaf browning was induced at sites distant from the wounds in detached leaves in 6 species of Acanthaceae and 13 species of Gesneriaceae plants. This injury was observed in unwounded young leaves after their detachment from the mother plant, and sometimes in unwounded leaves on the wounded plant, e.g., when stem cuttings were made. The injury is restricted to one layer of palisade cells; the response is rapid. Chlorophyll fluorescence intensity decreased irreversibly in an injured tissue within seconds at sites distant from the wound.
  • SJ Yang; M Hosokawa; Y Mizuta; JG Yun; J Mano; S Yazawa
    SCIENTIA HORTICULTURAE 88 1 59 - 69 2001年03月 [査読有り]
     
    The relationship between the susceptibility to rapid temperature drop induced leaf injury, i.e. "leaf spot", and the antioxidant capacities of several Saintpaulia (African violet) cultivars was examined. Cultivars 'Ritali' and 'Tamiko', that are more susceptible to leaf spot caused by a rapid drop in leaf temperature from 30 to 15 degreesC than are cultivars 'Maui' and 'New Jersey'. The susceptible cultivars were also more susceptible to oxidative stress caused by H2O2 and active chlorine than the tolerant cultivars. Reduction of available chlorine, considered to be accelerated by antioxidants of leaf tissue, was rapid in 'Maui' and 'New Jersey'. Activity of the antioxidant enzymes superoxide dismutase and catalase were higher in the leaves of 'Maui' and 'New Jersey' than in the susceptible cultivars. These findings show a correlation between leaf spot injury and antioxidant capacity in Saintpaulia leaves. (C) 2001 Elsevier Science B.V. All rights reserved.
  • 細川 宗孝
    Plant Tissue Culture and Biotechnology,4/1,35 4 35 - 41 1998年 [査読有り]

MISC

講演・口頭発表等

  • 当年開花性が異なるアジサイの品種間での花成関連遺伝子の経時的発現量の違い  [通常講演]
    川西陽子; 礼埜高志; 細川宗孝; 北村嘉邦
    平成30年度園芸学会春季大会 2018年
  • アジサイにおける葉のサイズおよびその成長速度にみられる季節変化  [通常講演]
    礼埜高志; 北村嘉邦; 片山千絵; 細川宗孝
    平成30年度園芸学会春季大会 2018年
  • 春化処理したカブ（Brassica rapa）のFLC遺伝子をプロトプラスト培養およびカルス誘導によって初期化することは可能か  [通常講演]
    木下有羽; 元木 航; 土井元章; 細川宗孝
    平成30年度園芸学会春季大会 2018年
  • ダリアにおける黄色色素ブテイン生合成を司るカルコンレダクターゼ遺伝子の探索  [通常講演]
    山田晴香; 出口亜由美; 細川宗孝; 立澤文見; 土井元章; 大野 翔
    平成30年度園芸学会春季大会 2018年
  • トウガラシにおけるアントシアニン着色不安定化遺伝子の解析  [通常講演]
    上野舞子; 細川宗孝; 土井元章; 大野翔
    平成30年度園芸学会春季大会 2018年
  • トウガラシ(Capsicum chinense)雑種第一代で見られる花粉媒介昆虫の非存在下での自家受粉  [通常講演]
    山崎 彬; 細川宗孝
    平成30年度園芸学会春季大会 2018年
  • UV-B照射による数種アブラナ科スプラウトの抗酸化活性への効果  [通常講演]
    伊藤隆太郎; 立澤文見; 細川宗孝
    平成30年度園芸学会春季大会 2018年
  • トウガラシにおける種間交雑障壁に関与する遺伝子の探索  [通常講演]
    梅林綾香; 白澤健太; 安井康夫; 小枝壮太; 山崎 彬; 細川宗孝
    平成30年度園芸学会春季大会 2018年
  • ダイコンへの接ぎ木により低温非遭遇で開花したキャベツにおいてFLC遺伝子ホモログの発現量は低下しない  [通常講演]
    元木 航; 土井元章; 細川宗孝
    平成30年度園芸学会春季大会 2018年
  • トウガラシ(Capsicum chinense)の高温期における着果率に関わる遺伝子の探索  [通常講演]
    山崎 彬; 白澤健太; 細川宗孝
    平成30年度園芸学近畿支部大阪大会 2018年
  • Capsicum属の種間交雑不親和性を引き起こすエピスタシス遺伝子の座乗染色体の特定  [通常講演]
    梅林綾香; 白澤健太; 安井康夫; 山崎 彬; 細川宗孝
    平成30年度園芸学近畿支部大阪大会 2018年
  • UV-B照射によるスプラウトの抗酸化活性の向上  [通常講演]
    伊藤隆太郎; 立澤文見; 細川宗孝
    平成29年度園芸学近畿支部滋賀大会 2017年
  • トウガラシ（Capsicum chinense）F1における花粉の寿命延長および開葯速度の向上  [通常講演]
    山崎彬; 細川宗孝
    平成29年度園芸学近畿支部滋賀大会 2017年
  • ダイコンへの接ぎ木により低温非遭遇で開花したキャベツの花成関連遺伝子の発現解析  [通常講演]
    元木航; 土井元章; 細川宗孝
    平成29年度園芸学近畿支部滋賀大会 2017年
  • トウガラシにおけるアントシアニン着色不安定化遺伝子の探索  [通常講演]
    上野舞子; 細川宗孝; 土井元章; 大野翔
    平成29年度園芸学近畿支部滋賀大会 2017年
  • ダリアにおける黄色色素ブテインの合成に関わるカルコンレダクターゼ遺伝子の探索  [通常講演]
    山田晴香; 出口亜由美; 細川宗孝; 立澤文見; 土井元章; 大野翔
    平成29年度園芸学近畿支部滋賀大会 2017年
  • 核SSRマーカーおよびITS領域によるインドネシア産アジサイの系統解析  [通常講演]
    片山千絵; 礼埜高志; 北村嘉邦; 上町達也; Elly Kesumawati; 細川宗孝
    平成29年度園芸学会秋季大会 2017年
  • 近縁アブラナ科植物への接ぎ木によるキャベツの無低温処理・早期開花系  [通常講演]
    元木航; 土井元章; 細川宗孝
    平成29年度園芸学会秋季大会 2017年
  • ダリア‘祝盃’から発生した枝変わり品種群の花色変異  [通常講演]
    山田晴香; 加藤泰成; 出口亜由美; 細川宗孝; 立澤文見; 土井元章; 大野 翔
    平成29年度園芸学会春季大会 2017年
  • UV-B照射によるシソおよび赤キャベツスプラウトの生育および機能性への効果  [通常講演]
    伊藤隆太郎; 立澤文見; 細川宗孝
    平成29年度園芸学会春季大会 2017年
  • トウガラシ（Capsicum chinense）の雑種第一代で現れる自動着果機構の解明  [通常講演]
    山崎 彬; 細川宗孝
    平成29年度園芸学会春季大会 2017年
  • 複色花ダリアの複色模様形成を引き起こす候補遺伝子  [通常講演]
    大野 翔; 保里和香子; 細川宗孝; 立澤文見; 土井元章
    平成28年度園芸学会秋季大会 2016年
  • Capsicum属の葉が持つRNase活性の特徴と遺伝的特性  [通常講演]
    細川宗孝; 宮下英理子; 恩田麻由; 安井康夫
    平成28年度園芸学会秋季大会 2016年
  • キク矮化ウイロイド（CSVd）抵抗性のキク品種‘ 鞠風車’におけるCSVdの接種葉での増殖  [通常講演]
    鍋島朋之; 土井元章; 細川宗孝
    平成28年度園芸学会春季大会 2016年
  • ダリア花弁のシアニジン系アントシアニンの蓄積割合を制御する候補因子  [通常講演]
    出口亜由美; 細川宗孝; 立澤文見; 土井元章; 大野 翔
    平成28年度園芸学会春季大会 2016年
  • 複色花ダリア‘ 結納’のフラボノイドを蓄積しない葉におけるCHSの転写後ジーンサイレンシング  [通常講演]
    大野 翔; 保里和香子; 細川宗孝; 立澤文見; 土井元章
    平成28年度園芸学会春季大会 2016年
  • UV-B照射によるシソ葉のダメージは昼夜で異なる  [通常講演]
    大田奈央; 刑部正博; 青木慎一; 細川宗孝
    平成28年度園芸学会春季大会 2016年
  • アカジソへのUV-B照射による葉中ペルオキシダーゼ活性の上昇  [通常講演]
    細川宗孝; 大田奈央; 出口亜由美; 大野 翔; 青木慎一; 刑部正博
    平成28年度園芸学会春季大会 2016年
  • ダリア花弁の黒色化に対する各種アントシアニンの寄与度の定量的評価  [通常講演]
    出口亜由美; 細川宗孝; 立澤文見; 土井元章; 大野 翔
    平成27年度園芸学会秋季大会 2015年
  • BougainvilleaとCapsicumの葉抽出液によるPMMoVの感染抑制メカニズム  [通常講演]
    I.N.ブブラカス; 恩田麻由; 鍋島朋之; 細川宗孝
    平成27年度園芸学会秋季大会 2015年
  • セントポーリア花弁に蓄積する黄色色素の同定  [通常講演]
    出口亜由美; 大野 翔; 立澤文見; 土井元章; 細川宗孝
    平成27年度園芸学会秋季大会 2015年
  • 複色花ダリアにおける不安定な花色は葉のフラボノイド蓄積と関連する  [通常講演]
    保里和香子; 細川宗孝; 立澤文見; 土井元章; 大野 翔
    平成27年度園芸学会秋季大会 2015年
  • アグロインフィルトレーション法によるキクわい化ウイロイドの接種  [通常講演]
    鍋島朋之; 土井元章; 細川宗孝
    平成27年度園芸学会秋季大会 2015年
  • セントポーリア周縁キメラ品種において不定芽由来植物でみられる花色分離の品種間差は不定芽形成時の各細胞層の細胞分裂活性に起因する  [通常講演]
    本田慶太; 鍋島朋之; 大野 翔; 土井元章; 細川宗孝
    平成27年度園芸学会春季大会 2015年
  • キクわい化ウイロイドの感染抑制剤としてのブーゲンビレアとカプシカムの混合抽出  [通常講演]
    I.N.ブブラカス; 細川宗孝
    平成27年度園芸学会春季大会 2015年
  • ブーゲンビレアの抽出液によるベンサミアナタバコへのPMMoV, PVX, TSWVおよびCSVdの感染回避  [通常講演]
    I.N.ブブラカス; 細川宗孝
    平成27年度園芸学会春季大会 2015年
  • 黒色系ダリアではタバコ条斑ウイルスの感染により花弁にフラボンが蓄積される  [通常講演]
    出口亜由美; 細川宗孝; 立澤文見; 土井元章; 大野 翔
    平成27年度園芸学会春季大会 2015年
  • 複色花ダリア‘ 結納’で発生した単色花弁を生じやすい系統  [通常講演]
    大野翔; 細川宗孝; 土井元章
    平成26年度園芸学会秋季大会 2014年
  • シアニジン系アントシアニンはぺラルゴニジン系アントシアニンよりもダリア花弁の黒色化への寄与が大きい  [通常講演]
    出口亜由美; 細川宗孝; 立澤文見; 土井元章; 大野 翔
    平成26年度園芸学会秋季大会 2014年
  • キクにおけるキクわい化ウイロイド(CSVd)の細胞内分布  [通常講演]
    鍋島朋之; 粟野達也; 土井元章; 細川宗孝
    平成26年度園芸学会秋季大会 2014年
  • トウガラシ果実における発散香気成分とカプサイシノイドおよびカプシノイド含量との関係解析  [通常講演]
    土井元章; 久保田瑞季; 小枝壮太; 大野翔; 細川宗孝
    平成26年度園芸学会秋季大会 2014年
  • ダイコンの構成的花成促進経路の存在について  [通常講演]
    土井元章; 田内康裕; 大野翔; 細川宗孝
    平成26年度園芸学会近畿支部大会 2014年
  • ダリア‘ 祝盃’ から生じた枝変わり品種群の花色変異機構の解析  [通常講演]
    加藤泰成; 出口亜由美; 細川宗孝; 立澤文見; 土井元章; 大野 翔
    平成26年度園芸学会近畿支部大会 2014年
  • セントポーリア不定芽由来の組織培養変異の発生には外植体に既存の変異細胞はほとんど関与しない  [通常講演]
    細川宗孝; 松田沙弓; 大野 翔; 土井元章
    平成26年度園芸学会春季大会 2014年
  • サフランのin vitroでの不定芽誘導における問題点の抽出  [通常講演]
    柳川開・M. Sharaf-Eldin; 土井元章; 縄田栄治; 細川宗孝
    平成26年度園芸学会春季大会 2014年
  • トウガラシ2種間における葉抽出液のRNase活性の違い  [通常講演]
    細川宗孝; 神田紘子; 恩田麻由; 小枝壮太; 鍋島朋之; 土井元章
    平成26年度園芸学会春季大会 2014年
  • 黒色系ダリア‘ 黒蝶’における赤紫色花の出現にはタバコ条斑ウイルス様ウイルスの感染が関与する  [通常講演]
    出口亜由美; 大野 翔; 細川宗孝; 立澤文見; 土井元章
    平成25年度園芸学会秋季大会 2013年
  • トランスポゾンの切り出しによるセントポーリアの組織培養変異を引き起こす環境要因の探索  [通常講演]
    細川宗孝; 松田沙弓; 大野 翔; 土井元章
    平成25年度園芸学会秋季大会 2013年
  • 超微小茎頂分裂組織培養法を用いた短期間のキクわい化ウイロイド抵抗性の評価  [通常講演]
    鍋島朋之; 細川宗孝; 矢野志野布; 大石一史; 土井元章
    平成25年度園芸学会秋季大会 2013年
  • ダリア花弁のアントシアニン高蓄積に関わるDvIVSハプロタイプ  [通常講演]
    大野 翔; 出口亜由美; 細川宗孝; 立澤文見; 土井元章
    平成25年度園芸学会春季大会 2013年
  • 異なる種類の植物における葉の抽出液が持つRNase活性の比較  [通常講演]
    細川宗孝; 神田紘子; 土井元章
    平成25年度園芸学会春季大会 2013年
  • 黒色系ダリアでは花弁のシアニジン量が多い  [通常講演]
    出口亜由美; 大野 翔; 細川宗孝; 立澤文見; 土井元章
    平成25年度園芸学会春季大会 2013年
  • 組織培養苗を用いた赤白複色花ダリア‘結納’における花色不安定性の緩和  [通常講演]
    大野 翔; 細川宗孝; 土井元章
    平成24年度園芸学会秋季大会 2012年
  • ダリア花弁のアントシアニン合成に関与する転写因子DvIVSのプロモーターの遺伝子型と花色の濃淡との関係  [通常講演]
    大野 翔; 出口亜由美; 細川宗孝; 立澤文見; 土井元章
    平成24年度園芸学会秋季大会 2012年
  • ダリア花色の多様性機構の解明（公開シンポジウム ?花色発現を制御する諸要因）  [通常講演]
    細川宗孝
    平成24年度園芸学会秋季大会 2012年
  • キクわい化ウイロイドはモデル植物であるNicotiana benthamianaに感染する  [通常講演]
    細川宗孝; 鈴木直裕; 神田紘子; 土井元章
    平成24年度園芸学会春季大会 2012年
  • キクわい化ウイロイド（CSVd）抵抗性キク品種におけるCSVd生体内分布  [通常講演]
    細川宗孝; 鍋島朋之; 矢野志野布; 大石一史; 土井元章
    平成24年度園芸学会春季大会 2012年
  • ダリア黒色系品種の花弁におけるFlavone synthaseの発現抑制  [通常講演]
    大野 翔; 出口亜由美; 細川宗孝; 立澤文見; 土井元章
    平成24年度園芸学会春季大会 2012年
  • FLOWRING LOCUS Cの発現から見たダイコンの低温および高温遭遇に対する花成反応  [通常講演]
    土井元章; 村石悠介; 細川宗孝
    平成24年度園芸学会春季大会 2012年
  • 自然変異によるトウガラシの生育温度域での温度反応性形質は恒温性地域において潜在化する  [通常講演]
    小枝壮太; 細川宗孝; 土井元章
    平成24年度園芸学会春季大会 2012年
  • トウガラシ葉の粗抽出液がもつ強いRNA分解活性  [通常講演]
    Iraklis Boubourakas; 神田紘子; 細川宗孝; 土井元章
    平成24年度園芸学会春季大会 2012年
  • トウガラシ‘Sy-2’の防御応答は生育温度が24℃を下回ると誘導される  [通常講演]
    小枝壮太; 細川宗孝; B.C. Kang; 田中千尋; D. Choi; 佐野 智; 椎名 隆; 土井元章; 矢澤 進
    日本植物学会第75回大会 2011年
  • ダリア黒色花弁にみられるフラボノイド系色素の特徴的な蓄積  [通常講演]
    大野 翔; 出口亜由美; 細川宗孝; 立澤文見; 土井元章
    平成23年度園芸学会秋季大会 2011年
  • セントポーリア花弁の縞模様の形成に関わる表皮細胞の並層分裂  [通常講演]
    細川宗孝; 大西美輝; 後藤真理子; 佐藤 充; 土井元章
    平成23年度園芸学会秋季大会 2011年
  • 大量スクリーニング法を利用したキクわい化ウイロイド抵抗性品種の探索  [通常講演]
    細川宗孝; 鍋島朋之; 矢野志野布; 大石一史; 土井元章
    平成23年度園芸学会秋季大会 2011年
  • 赤白複色花ダリアから発生する単色花シュートでは葉のCHS発現量が異なる  [通常講演]
    大野 翔; 細川宗孝; 星野 敦; 立澤文見; 土井元章
    平成23年度園芸学会秋季大会 2011年
  • ダリアにおける花弁のアントシアニン含量とDvIVS発現量との関わり  [通常講演]
    細川宗孝; 出口亜由美; 大野 翔; 立澤文見; 土井元章
    平成23年度園芸学会春季大会 2011年
  • ダリア花弁の純白化に関わる2種類のCHSの同時的転写後分解  [通常講演]
    細川宗孝; 大野 翔; 星野 敦; 立澤文見; 土井元章
    平成23年度園芸学会春季大会 2011年
  • キクわい化ウイロイドに抵抗性を持つキク品種の探索  [通常講演]
    細川宗孝; 鍋島朋之; 矢野志野布; 大石一史; 土井元章
    平成23年度園芸学会春季大会 2011年
  • 光酸素ストレスによるカンナ葉の収穫後の褐変障害  [通常講演]
    土井元章; 脇田牧子; 細川宗孝
    平成22年度園芸学会秋季大会 2010年
  • ダリア純白花弁における2種類のCHSの転写後抑制  [通常講演]
    細川宗孝; 大野 翔; 星野 敦; 立澤文見; 土井元章
    平成22年度園芸学会秋季大会 2010年
  • 花弁に斑をもつセントポーリア‘タミレス’の葉身上に存在する変異細胞率の定量  [通常講演]
    細川宗孝; 佐藤 充; 土井元章
    平成22年度園芸学会秋季大会 2010年
  • セントポーリア‘タミレス’の培養変異を検出する遺伝子マーカーの作出  [通常講演]
    細川宗孝; 佐藤 充; 土井元章
    平成22年度園芸学会春季大会 2010年
  • 遺伝子マーカーを用いたカプシノイドを含む生食用トウガラシ品種の育成  [通常講演]
    田中義行; 細川宗孝; 渡辺達夫; 土井元章; 矢澤 進
    平成22年度園芸学会春季大会 2010年
  • ダリアの白色花弁化に関与する2つの異なるメカニズム  [通常講演]
    細川宗孝; 児島未沙; 大野 翔; 立澤文見; 土井元章
    平成22年度園芸学会春季大会 2010年
  • ダリア花弁のアントシアニン合成制御にはbHLH 様転写因子DvIVSが関与する  [通常講演]
    細川宗孝; 大野 翔; 北村嘉邦; 児島未沙; 星野 敦; 立澤文見; 土井元章
    平成22年度園芸学会春季大会 2010年
  • ヘリクリサム(Helichrysum bracteatum)をはじめとしたいくつかの乾膜質な花葉組織における中性糖の組成  [通常講演]
    伊藤弘顕; 粟野達也; 東 順一; 細川宗孝; 土井元章
    2009年
  • 花弁に斑を有するセントポーリアの組織培養後代における花色変異体の発生に関わるトランスポゾン  [通常講演]
    細川宗孝; 佐藤 充; 土井元章
    2009年
  • ダリア花弁のアントシアニンおよびカルコン/オーロン発現に関わる花色遺伝子の探索  [通常講演]
    細川宗孝; 大野 翔; 北村嘉邦; 児島未沙; 中島明子; 星野 敦; 立澤文見; 土井元章
    2009年
  • トウガラシ果実における新規機能性物質カプシノイドの生合成にはp-AMT遺伝子の変異が関与する.  [通常講演]
    田中義行; 細川宗孝; 三輪哲也; 土井元章; 矢澤 進
    2009年
  • アジサイ花房におけるファイトプラズマ感染による装飾花形成数の増加  [通常講演]
    北村嘉邦; 細川宗孝; 上町達也; 矢澤 進
    2009年
  • リンが花弁のアントシアニン合成を制御するペチュニアの組織培養後代で多発する白花個体  [通常講演]
    細川宗孝; 後藤真理子; 山口有希; 矢澤 進
    2009年
  • 生育適温下でセーシェル産トウガラシの葉に生じる異常な細胞分裂  [通常講演]
    小枝壮太; 細川宗孝; 矢澤 進
    2009年
  • ファイトプラズマ感染によるアジサイ花器官の形態変化に関わる遺伝子群の発現解析  [通常講演]
    北村嘉邦; 細川宗孝; 上町達也; 矢澤 進
    2008年
  • ヘリクリサム（Helichrysum bracteatum）の花葉組織における二次的な細胞壁の形成過程  [通常講演]
    伊藤弘顕; 西川久仁子; 粟野達也; 吉永 新; 細川宗孝; 矢澤 進
    2008年
  • キクわい化ウイロイド（CSVd）抵抗性を異にするキクの茎頂部でのCSVdの分布  [通常講演]
    細川宗孝; 尾森仁美; 矢澤 進
    2008年
  • ヘリクリサムをはじめとした様々な植物の乾膜質な花葉組織における二次的な細胞壁の形成  [通常講演]
    伊藤弘顕; 西川久仁子; 粟野達也; 細川宗孝; 矢澤 進
    2008年
  • 生育適温下で生じるセーシェル産トウガラシの生育障害に関与する遺伝子の探索  [通常講演]
    小枝壮太; 細川宗孝; 矢澤 進
    2008年
  • キクわい化ウイロイドに強い抵抗性を持つキク植物体の選抜  [通常講演]
    細川宗孝; 尾森仁美; 矢澤 進
    2008年
  • 圧縮空気を利用した茎頂分裂組織の露出装置の開発  [通常講演]
    細川宗孝; 鈴江久尚; 矢澤 進
    2008年
  • 難除去性病原体であるタバコ条斑ウイルスのダリア茎頂近傍における分布  [通常講演]
    中島明子; 細川宗孝; 仲 照史; 矢澤 進
    2007年
  • JHPファイトプラズマによって引き起こされるアジサイの各花器官における形態変化  [通常講演]
    北村嘉邦; 細川宗孝; 矢澤 進
    2007年
  • 花弁の質感発現について−その光学的実体と目による認知−  [通常講演]
    張 暘; 林 孝洋; 細川宗孝; 矢澤 進
    2007年
  • 25℃付近で生じるセーシェル産トウガラシの縮葉発現-温度に反応し、縮葉になる葉の生育ステージの特定-  [通常講演]
    小枝壮太; 細川宗孝; 矢澤 進
    2007年
  • ヘリクリサムの乾膜質苞葉における二次的な細胞壁の形成  [通常講演]
    西川久仁子; 伊藤弘顕; 粟野達也; 細川宗孝; 矢澤 進
    2007年
  • キクわい化ウイロイドの濃度上昇が遅いキク品種の探索  [通常講演]
    細川宗孝; 芝 勇人; 矢澤 進
    2006年
  • ヘリクリサムの乾膜質総苞片の発達初期に見られる細胞核の消失  [通常講演]
    伊藤弘顕; 西川久仁子; 細川宗孝; 矢澤 進
    2006年
  • 花弁におけるベルベット様光沢の光学的発現機構について  [通常講演]
    張 暘; 林 孝洋; 細川宗孝; 矢澤 進
    2006年
  • アジサイの茎頂近傍に存在する表在性細菌の除去  [通常講演]
    北村嘉邦; 細川宗孝; 矢澤 進
    2006年
  • ダリアにおけるキクわい化ウイロイドの感染  [通常講演]
    細川宗孝; 中島明子; 前田茂一; 矢澤 進
    2006年
  • キクの茎頂分裂組織における2種のウイロイドの検出  [通常講演]
    細川宗孝; 川部 崇; 矢澤 進
    2006年
  • Multiplex micro tissue-direct RT-PCRによるキクに感染する2種のウイロイドの同時検出  [通常講演]
    細川宗孝; 矢澤 進
    2005年
  • ベゴニア・レックス(Begonia rex)の葉に生じる金属様光沢とその発現機構  [通常講演]
    張 暘; 林 孝洋; 細川宗孝; 矢澤 進
    2005年
  • ファイトプラズマ感染によって緑色花化の安定する品種ではファイトプラズマ濃度が高い  [通常講演]
    エリー ケスマワティ; 北村嘉邦; 上町達也; 細川宗孝; 矢澤 進
    2005年
  • キクの微小組織からのmicro tissue-direct PCRを用いたキククロロティックモトルウイロイドの高感度検出  [通常講演]
    細川宗孝; 松下陽介; 内田寛子; 矢澤 進
    2005年
  • ファイトプラズマに感染したアジサイの装飾花の萼片の緑色化は葉への器官変化によるものである  [通常講演]
    エリー ケスマワティ; 細川宗孝; 上町達也; 矢澤 進
    2005年
  • ペチュニア'マジックサンバ'の花色発現機構はリンが制御する  [通常講演]
    細川宗孝; 三甲野祥子; 山内孝悦; 高濱雅幹; 矢澤 進
    2005年
  • わが国のキクにおけるキククロロティックモトルウイロイドと見られる病原体の感染  [通常講演]
    細川宗孝; 松下陽介; 大石一史; 矢澤 進
    2004年
  • キャベツ根へのキク茎頂分裂組織の移植培養法によるキクわい化ウイロイド除去個体の作出  [通常講演]
    細川宗孝; 安田奈菜子; 大石一史; 矢澤 進
    2004年
  • ファイトプラズマに感染したアジサイ装飾花の緑花発生の光強度の調節による安定化  [通常講演]
    エリー ケスマワティ; 細川宗孝; 上町達也; 矢澤 進
    2004年
  • 根への移植培養を利用した強い単為結果性を有するトマト品種の茎頂分裂組織培養法の確立  [通常講演]
    細川宗孝; 勝村聡子; 矢澤 進
    2004年
  • セントポーリアにおける摘葉による低温障害の感受性増大  [通常講演]
    梁 修静; 北村嘉邦; 細川宗孝; 矢澤 進
    2004年

所属学協会

  • 園芸学会   

共同研究・競争的資金等の研究課題

  • 日本学術振興会：科学研究費助成事業 基盤研究(B)
    研究期間 : 2020年04月 -2024年03月 
    代表者 : 細川 宗孝; 白澤 健太; 安井 康夫
     
    Capsicum chinenseとC．annuumの間で交雑不和合性を引き起こす組み合わせで、交雑集団を作成した。また、現在までに流通しているリフェレンスにはターゲット領域で大きな組み換えや転座が認められ、このままリファレンスを使用することはできないと考え、新たなリファレンス作りに取り組んだ。リファレンスは’タカノツメ’を材料に10XシークエンスをSupernovaにて作成した。また、HiFiロングリードによるシークエンスも行った。これらをもとにしてリファレンスづくりを完了させた。リファレンスのコンティグ間の連鎖解析なども同時に行っており、年度内には完了する予定となっている。 次に、交雑集団を準備し、RAD-seqおよび推定された領域でのｄCAPｓマーカーによる組み換え個体のスクリーニングを行った。これによって、候補領域の2.7Mbまで領域を狭めることができた。候補領域内におけるリファレンスの遺伝子予測などを行いSNPeffを行う予定である。 今後の予定としては、候補領域におけるRNAseqデータの発現解析を行い、候補となった遺伝子はVIGSで解析する予定にしており、実験の準備を整えているところである。実験が順調に進めば、細胞質の遺伝子の発現解析を進める予定であり、現在、正逆交雑のシリーズを整えているところである。また、現在は片側の種の原因遺伝子の特定をお行っているが、もう一方の種の遺伝子については候補領域が大きく、集団作成を更に進める必要がある。次年度の課題としたい。
  • 日本学術振興会：科学研究費助成事業 基盤研究(C)
    研究期間 : 2018年04月 -2021年03月 
    代表者 : 村上 賢治; 細川 宗孝
     
    2018年度は、研究代表者らが育成した辛味果がほとんど発生しないシシトウの系統（低辛味系統）とその野生型、それらの交雑F1、F2を用いて、辛味果発生形質の遺伝様式を調査した。高温期の種子の少ない果実で辛味果発生の多いことがこれまでに明らかにされていることから、7月下旬～8月上旬の高温期に開花した花に2,4-Dを処理して単為結果を誘導し、成熟し着色開始した果実を株当たり2果サンプリングした。果実の胎座と隔壁部分を採取し、生体重gの4倍の数値（ml）の99%アセトニトリルに浸漬してカプサイシノイドを抽出し、HPLCで抽出液の濃度を測定した。実験の結果、野生型では約40%の個体で20mg/L以上の高濃度を示したが、4mg/L以下の濃度の個体が27%みられた。この結果から、野生型集団について、環境要因等によって辛味果とならないか、または遺伝子型にバラツキのある可能性が示唆された。低辛味系統では4mg/L以上の濃度の個体はなく、60%以上の個体でカプサイシノイドが全く検出されなかった。F1では、約2/3の個体が10mg/L以下、約1/3の個体が15mg以上のカプサイシノイド濃度であり、分離がみられた。F2では、大部分の個体でカプサイシノイド濃度が10mg/L以下で、低辛味側にシフトしていた。 2018年度の実験でのF2集団の中から、カプサイシノイドが全く検出されなかった50株と、カプサイシノイド濃度が4mg/L以上であった50株について、抽出したDNAのバルクを作成しQTL-seqを行った。その結果、低辛味形質のマーカーを作出できる可能性が示され、さらに、シシトウの不時辛味発現に関わる遺伝子を探究する手がかりが得られる可能性が示された。 また、シシトウでのPun1の量的変異を調べるための、鷹の爪（辛味性品種）×シシトウ（野生型、低辛味系統）の交雑F2集団を育成した。
  • 日本学術振興会：科学研究費助成事業 基盤研究(B)
    研究期間 : 2017年04月 -2020年03月 
    代表者 : 平川 英樹; 細川 宗孝; 白澤 健太
     
    前年度にPacific Biosciences社製Sequelにより得られた12セル分のセントポーリアの半数体のロングリードに対して、FALCON/FALCON-Unzipによるde novoアセンブルを行い、その後、Arrowにより補正することで、3,221本のprimaryコンティグ（総延長：704.2 Mb、N50長：1.3 Mb）と1,508本のassociateコンティグ（総延長：121.0 Mb、N50長：131.1 kb）を構築した。primaryコンティグとassociateコンティグを合わせ、500 bp以上の配列を採用することで、4,692本から構成されるゲノム配列SIO_r1.0（総延長：825.3 Mb、N50長：958.3 kb）を得た。これまでに取得したRNA-Seqデータについて、SIO_r1.0に対するマップ率を調べた結果、品種キラウェアでは86.9～91.9％、チコでは82.8～83.4％となった。一方、small RNAのマップ率は、キラウェアで78.6～79.2％、チコで72.7～76.4%となった。イルミナ社製HiSeqにより半数体のゲノムシークエンスを行った結果、ゲノムサイズは768.3 Mbと推定された。この結果からprimaryコンティグのみを採用し、最終的に3,184本のドラフト配列SIO_r1.0_p（総延長：704.4 Mb、N50長：1.25 Mb）を得た。BUSCO解析によるComplete％は96.1％となり、ドラフトゲノム配列の遺伝子の網羅性は高いと考えられた。Canuも用いてde novoアセンブルを行った結果、6,548本のコンティグが形成され、その総延長は911.5 Mb、N50長は487.6 kbとなり、FALCON/FALCON-Unzipよりも長く繋がらなかった。このため、SIO_r1.0_pをドラフトゲノム配列として決定した。
  • 日本学術振興会：科学研究費助成事業 基盤研究(A)
    研究期間 : 2016年04月 -2020年03月 
    代表者 : 細川 宗孝; 大野 翔; 白澤 健太; 安井 康夫
     
    ・B遺伝子の特定：前年までに200Mbに特定したが、20組以上のdCAPsマーカーを作成し、PCRを行うことで、候補領域を数Mbまで狭めることができた。現在は本研究を継続するとともに、SNP impactによってCapsicum chinenseとの間で、交雑和合と交雑不和合の品種間で異なる遺伝子を探索し、いくつかの候補遺伝子を得ている。 ・A遺伝子の特定：A遺伝子はC. chinenseとC. annuumとの間で異なるものを探索する必要があるが、遺伝子が大きく異なるので、まずはdCAPsでより候補領域を狭めることとして交雑集団を増やしているところである。また、最終年度の解析に向け、マッピング集団を準備している。 ・ミトコンドリア：カリフォルニアワンダーの細胞質（ミトコンドリア）は交雑不和合性を打破する可能性がある。そこで、カリフォルニアワンダーのミトコンドリアの全ゲノムシークエンスを作成し、交雑不和合性品種と比較する必要がある。本年度はリファレンスとして用いるため、カリフォルニアワンダーの全ゲノムシークエンスを行い、解析を終了させた。 ・RNase：C. chinenseとC. annuumの雑種を育成する一つの目的として、RNase活性の強さがあり、この形質は果実収穫後の植物残渣の二次利用を可能とするものである。そこで、RNase座を特定することを目的として実験を行った。前年度の科研費によって候補遺伝子の特定を行った。本年度の科研費では、RNaseの配列を特定し、品種間で比較した。 ・その他：かずさDNA研究所では種間交雑による葉の形態異常がどちらの親ゲノム由来であるのかを調査するパイプラインを開発・発展させている。
  • 日本学術振興会：科学研究費助成事業 基盤研究(B)
    研究期間 : 2014年04月 -2019年03月 
    代表者 : 細川 宗孝; 札埜 高志; 北村 嘉邦
     
    ベーサルシュートの開花率が最も高かった‘ロゼア’と，同調査でベーサルシュートが開花しなかった‘舞姫’について，ベーサルシュートの葉におけるHmFT，HmTFL1-1およびHmTFL1-2の発現を解析した．その結果，‘ロゼア’と‘舞姫’のベーサルシュートの葉で認められたHmFTとHmTFL1-2の発現様相の違いは，‘ロゼア’と‘舞姫’のベーサルシュートの開花性の違いに関係している可能性が高い.インドネシアでのアジサイの四季咲き性において指標にできる遺伝子を今回見つけることができた．
  • 花の模様形成を決める細胞の位置別エピジェネティックスの解明
    学術振興会：科学研究費
    研究期間 : 2017年 -2019年
  • Capsicum属の交雑不親和性を打破する核および細胞質遺伝子の特定
    学術振興会：科学研究費
    研究期間 : 2016年 -2019年 
    代表者 : 細川宗孝
  • 研究ユニット2：紫外光による病害虫防除技術の確立と誘導抵抗性の関与機構の解析
    研究期間 : 2015年 -2019年
  • 日本学術振興会：科学研究費助成事業 挑戦的萌芽研究
    研究期間 : 2015年04月 -2018年03月 
    代表者 : 細川 宗孝; 大野 翔
     
    起源層別の不定芽誘導個体の花色形質から‘キラウエア’は非キメラ性品種‘かなめ’, ‘モニーク’、‘コンコルド’はキメラ性品種であることが明らかになった。キメラ性品種に関してはPCRによって各起源層の遺伝子型を特定した。また、L1層由来のRNAを用いたRT-PCRによって、起源層間を移動する物質はmRNAではないものと思われた。非キメラ性品種においてはsiRNAなどが起源層間を移動しているのではないかと考えられたが網羅解析の結果からこの仮説は否定された。現在はsequelの配列をもとにして、全ゲノムメチル化解析を行い、模様に関与する遺伝子とその遺伝子の不安定性のメカニズムを解析している。
  • 赤道恒温性気候帯において温帯性木本植物が四季咲き化する環境因子の同定
    学術振興会：科学研究費
    研究期間 : 2014年 -2018年 
    代表者 : 細川宗孝
  • 花の模様形成に関わる細胞間移行物質の特定
    学術振興会：科学研究費
    研究期間 : 2015年 -2017年 
    代表者 : 細川宗孝
  • 日本学術振興会：科学研究費助成事業 基盤研究(B)
    研究期間 : 2013年04月 -2016年03月 
    代表者 : 細川 宗孝; 粟野 達也
     
    トウガラシ(Capsicum annuum)品種群の中から、RNase活性が極めて弱い品種を選抜した。RNase活性の高いC. chinense ‘CP’との間で種間雑種を作成し、さらにBC1系統を得た。これらの組み合わせの活性調査の結果、RNase活性を制御する遺伝子は1遺伝子である可能性が高かった。また、タンパク質の抽出・精製によって活性成分を特定しようと試みたが、特定には至らなかった。分離集団を用いたポジショナルクローニングが有力な方法であろうと考えられた。
  • Capsicum属の交雑不親和性を打破する核および細胞質遺伝子の特定
    先進ゲノム支援：科学研究費
    研究期間 : 2016年 
    代表者 : 細川宗孝
  • 日本学術振興会：科学研究費助成事業 特別研究員奨励費
    研究期間 : 2014年04月 -2015年03月 
    代表者 : 細川 宗孝; BOUBOURAKAS Iraklis
     
    100種以上の植物種から抗ウイルス活性を持つ植物種をいくつかスクリーニングすることが出来た。特に、ブーゲンビレアはこれまでに抗ウイルス活性が報告されているオシロイバナ科植物であるが、非常に強い活性を確認した。20種・品種以上のブーゲンビレアについて活性物質であるRIPの転写活性を確認したところ、品種間で違いが見られた。この転写活性の違いはタンパク質量レベルでも確認できた。特にRIPの転写活性の強い品種を実験に用いた。本品種の抽出液をNicotiana benthamianaに接種前あるいは接種後に散布することによって、CSVd, TSWV, PVXなど複数のウイルス・ウイロイドの感染抑制を確認することが出来た。また、RIPの全長を同定し、リコンビナントタンパク質の精製に成功した。このリコンビナントタンパク質の効果については今後調査する予定である。ブーゲンビレアの抽出液の接種前散布において、接種部位と異なる葉に散布しても一定の効果があった。RNAseq解析によって散布植物で発現が大聞く上昇した遺伝子がいくつか見つかったが、いずれも抵抗性の獲得に関係する遺遺伝子であった。次に、これまでに感染抑制を確認していたトウガラシの抽出液との混合効果を確認した。トウガラシ単独、あるいはブーゲンビレア単独では効果が小さかったが、二つをあわせると効果が強くなった。これはトウガラシの効果がRNaseによる遺伝子の分解であり、ブーゲンビレアがRNAの脱プリン反応および植物体への抵抗性の付与である、すなわち作用部位がそれぞれ異なることによる総加的効果であろうと考えられた。これらの知見を元にして抗ウイルス・ウイロイド剤の開発を続けて行く予定である。
  • 日本学術振興会：科学研究費助成事業 挑戦的萌芽研究
    研究期間 : 2012年04月 -2015年03月 
    代表者 : 土井 元章; 細川 宗孝
     
    ダイコンは，花成に低温を要求する種子春化型植物である．また，低温後の高温により脱春化することが知られている．本研究では，春化・脱春化の分子機構を花成関連遺伝子の発現挙動を調査することで明らかにした．‘早太り聖護院’では低温遭遇によってRsFLCの発現が低下し，その後RsFT, RsSOC1の発現が増大することで開花するようになった．また，９日の低温後に高温に遭遇すると脱春化され，その場合RsFLCの発現はやや回復した．‘早太り聖護院’や‘和歌山’では，RsFLCの発現挙動と春化・脱春化の様相には関連が認められたが，‘時なし’では18日の低温でRsFLCの発現が低下するだけでは春化されなかった．
  • 日本学術振興会：科学研究費助成事業 挑戦的萌芽研究
    研究期間 : 2012年04月 -2015年03月 
    代表者 : 細川 宗孝
     
    本研究では、キクわい化ウイロイド(CSVd)の細胞内局在性を明らかにし、モデルRNAとして本実験に適切であることを明らかにした。そこで、CSVdをいくつかの大きさの分子に切断し、それぞれの分子を発現するベンサミアナタバコを育成した。F2まで育成し、現在、継続して組み換え体の作成を行っている。RNAseq法を用いてCSVdで発現誘導される遺伝子が8つ、発現抑制される遺伝子が6つ見つかった。これらのCSVd結合性候補遺伝子についてはウェットな解析を行っている。 また、キクにおけるウイロイド結合性タンパク質のスクリーニング方法を確立し、遺伝子組み換え体を作成した。
  • トウガラシに見出された強力な二本鎖RNA分解酵素の同定と生体内での役割解明
    学術振興会：科学研究費
    研究期間 : 2013年 -2015年 
    代表者 : 細川宗孝
  • ＦＬＣの発現レベルからみたダイコンにおける脱春化の分子機構
    学術振興会：科学研究費
    研究期間 : 2012年 -2015年
  • 日本学術振興会：科学研究費助成事業 基盤研究(B)
    研究期間 : 2010年04月 -2014年03月 
    代表者 : 土井 元章; 林 孝洋; 細川 宗孝; 水田 洋一
     
    花卉の香り育種に有用な知見を得るため，バラを用いて以下の実験を行った．芳香性品種の花弁からは，モノテルペノイド，セスキテルペノイド，芳香族アルコール，酢酸エステル，ジメトキシトルエンが検出された．また，これらのバラ切り花の香りには鎮静効果と精神的疲労低減効果が認められた．モノテルペノイド合成酵素遺伝子として２遺伝子がクローニングされた．このうちRhMTS2は被子植物の非環式モノテルペノイド合成酵素遺伝子群に分類され，芳香性品種のかたい蕾で高発現していた．ゲラニル二リン酸合成酵素としては，RhGPPS-LSU1，RhGPPS1が単離でき，前者は芳香性品種すべてと非芳香性の１品種で高発現していた．
  • 生体内移動性mRNAの開発に向けたウイロイド結合タンパク質の同定と機能解析
    学術振興会：科学研究費
    研究期間 : 2012年 -2014年 
    代表者 : 細川宗孝
  • 芳香性花卉の非メバロン酸経路を介する香り発散特性の分子機構
    学術振興会：科学研究費
    研究期間 : 2010年 -2014年
  • 日本学術振興会：科学研究費助成事業 基盤研究(B)
    研究期間 : 2010年 -2012年 
    代表者 : 細川 宗孝; 土井 元章; 小枝 壮太
     
    トウガラシ(Capsicum chinense) 'Sy-2'の縮葉発生の引き金は 24℃以下の温度であり、24℃以下遭遇によってサリチル酸が生産され、抵抗性遺伝子が過剰に誘発されることが縮葉の原因であるものと考えられた。 'Sy-2'は恒温性地域在来の品種であり、現地では微小な温度をセンシングして病害抵抗性を誘導している可能性が考えられた。しかし、 'Sy-2'をインドネシアのウイルス多発地域で栽培したところ、正常に生育したが、ウイルスには罹病した。次に、恒温性地域で種々のトウガラシ品種を収集した。カリブ海地域には'Sy-2'と同じ微小の温度差で成育不全となる品種が存在することが明らかになった。最後に、インドネシアの在来品種の現地でのウイルスからの回復現象について調査した。インドネシアの恒温性地域で栽培されているトウガラシにはウイルスの罹病後にウイルス病から回復する品種が存在し、恒温性地域で何らかの環境をセンシングしている可能性が考えられた。恒温性地域では植物は微小な温度差をセンシングしている可能性が考えられたが、今回は証明には至らず継続的な研究の必要性があるものと考えられた。
  • 目指せ発病ゼロ！ウイロイドによって引き起こされるキクわい化病の防除体系の確立
    研究期間 : 2010年 -2012年
  • 25℃遺伝子スイッチ:微小温度差を環境応答に利用する熱帯地域在来ナス科植物の探索
    学術振興会：科学研究費
    研究期間 : 2010年 -2012年 
    代表者 : 細川宗孝
  • 日本学術振興会：科学研究費助成事業 挑戦的萌芽研究
    研究期間 : 2009年 -2011年 
    代表者 : 細川 宗孝
     
    ピンク色の花弁に青い斑が入るセントポーリア'タミレス'(Saintpaulia sp.)の組織培養を行うと,青単色花をはじめとする花色変異が葉挿しの場合よりも高い確率で生じるのに加えて,葉挿しでは得られなかった青以外の多様な花色変異が生じることが分かった. また,リアルタイムPCRを応用することにより,サンプル中の青変異細胞の割合を定量する系を構築した.これを利用し,外植片における変異細胞率は十分に低く,組織培養の過程で変異が新たに発生することが初めて確認された.変異の発生率がin vitro環境によって高められていることも示された.
  • 抗変異原性物質を用いた組織培養突然変異の発生抑制
    学術振興会：科学研究費
    研究期間 : 2009年 -2011年 
    代表者 : 細川宗孝
  • 日本学術振興会：科学研究費助成事業 基盤研究(B)
    研究期間 : 2008年 -2010年 
    代表者 : 細川 宗孝; 海道 真典; 松下 陽介
     
    CSVdの全長あるいは部分配列を付加配列につなぎ、付加配列の長距離移行性を調べた。CSVdの一部の配列を付けた付加配列が長距離移行性を持ったことから、CSVdの配列にはRNAを長距離移行させる能力があるものと推定された。本事実を確認するため、同様の配列を過剰発現するタバコの組み換え体をCSVdの部分配列シリーズについて作成した。全長配列のCSVdを持つタバコ組み換え体(Nicotiana tabacum)にNicotiana benthamianaの穂木を接ぎ木し付加配列の長距離移行性を調べたが、長距離移行は認められなかった。他の配列については現在も実験を継続中である。 また、CSVd配列には35Sプロモーターの活性を増強させる機能があることが示唆された。さらにはCSVdが持つと予想されるRNAを鋳型にしたRNAの転写する能力がタバコの組み換え体で確認されたことから、mRNAの植物体内での増殖が可能である可能性が考えられた。
  • ウイロイドに隠された園芸学的に重要な高度機能性RNA配列の探索
    学術振興会：科学研究費
    研究期間 : 2008年 -2010年 
    代表者 : 細川宗孝
  • 25℃付近におけるトウガラシの生育激変機構の分子生物学的解明
    研究期間 : 2007年 -2008年 
    代表者 : 細川宗孝
  • 日本学術振興会：科学研究費助成事業 基盤研究(B)
    研究期間 : 2006年 -2007年 
    代表者 : 矢澤 進; 渡辺 達夫; 細川 宗孝
     
    得られた研究成果は以下のようになる. 1.Capsicum baccatum var.praetermissumの果実に多量に含まれる新規非辛味性カプサイシノイド類似物質を発見し,それらの化学構造を明らかにした.また,これらの物質群をカプシコニノイドと命名した.カプシコニノイドは,カプシコニエイトとジハイドロカプシコニエイトに分けられた. 2.カプシコニノイドのリパーゼを用いた酵素合成法による人工合成に成功し,カプシコニノイドはTRPV1に対してカプサイシノイドと同様の反応があることを明らかにした. 3.トウガラシ属果実に含まれるカプシコニノイド含量を調査し,C.annuum,C.chinenseの多くの品種の果実の中にカプシコニエイト,ジヒドロカプシコニエイトを含むことを明らかにした. 4.果実中のカプシコニノイドは受粉3週間後から生成されはじめ,果実が赤熟化(完熟化)すると急激に分解し,高温期にはその含量が1/10に激減する.また,カプシコニノイドは果実の胎座表皮で生合成されることを明らかにした. 5.カプサイシノイドに関与するアシルトランスフェラーゼ遺伝子のDNAマーカーを構築し,このマーカーを用いて非辛味性果実を持つ多汁性トウガラシの品種育成に成功した. 6.非辛味性カプサイシノイド類似物質カプシノイドを約1000ppm(乾物当たり)含むサラダ用非辛味トウガラシの育成に成功した.これらの新品種は1株当たり4〜5kgの果実収量があった.
  • 日本学術振興会：科学研究費助成事業 萌芽研究
    研究期間 : 2006年 -2007年 
    代表者 : 細川 宗孝; 札埜 高志
     
    昨年度に実験で茎頂分裂組織にパーティクルガンで傷つけ処理を施すことで、キクの茎頂から多数のシュートが発生することを確認した。また、キクやキャベツは品種によって傷を付けた茎頂分裂組織は傷口を修復することを組織学的な観察によって確認した。ただし、本実験は実験を行う時期や植物体の状態によって結果が大きく左右されるため、多数の試行が必要であると考えられた。そこで、本年度はまず実験効率を上げることを目的として、茎頂分裂組織を機械的に露出する装置を開発することとした。0.7KPaの圧縮空気を茎頂部に噴射することによって葉原基を吹き飛ばす装置を開発することができた。本装置を用いるとキク'神馬'の茎頂分裂組織を約7秒で、また、ダリアの茎頂分裂組織を約8秒で露出することができる。さらには、顕微鏡を用いなくとも80%以上の割合で茎頂分裂組織を露出することが可能であることを認めた。本装置で露出させた茎頂分裂組織は圧縮空気による付傷は認められなかった。本装置を用いて、キク'神馬'の茎頂分裂組織を顕微鏡下で露出させ超微小茎頂分裂組織培養を行ったところ、問題なく外植体が生存し植物体に生長することを確認した。そこで、本装置を用いて茎頂分裂組織を露出させたシュートにex vitroで金粒子を撃ち込み、処理した茎頂分裂組織を低融点ゲル化寒天で包埋し、挿し木した。これまでの観察で茎頂分裂組織の修復が見られる個体が多かったが、中には茎頂分裂組織が分割され複数のシュートが発生する可能性がある個体があった。多数の個体を短時間で処理する実験系が開発されたことから、茎頂分割による周縁キメラ植物の増殖などを目的とした詳細な実験ができる様になった。
  • 茎頂分裂組織の微細手術による難増殖性園芸作物の新しいクローン増殖技術の開発
    学術振興会：科学研究費
    研究期間 : 2006年 -2007年 
    代表者 : 細川宗孝
  • 日本学術振興会：科学研究費助成事業 基盤研究(B)
    研究期間 : 2005年 -2007年 
    代表者 : 細川 宗孝; 海道 真典
     
    キク'ピアト'は開花のためには短日条件を必要とするが、CSVdが感染すると長日条件下でも開花することをこれまでに認めた。また、CSVdが感染したキクにおいてsiRNAが存在していることを認めた。このことはCSVd分子が生体内で分解されていることを示すものであり、この分解産物がキクの生態反応に影響を及ぼしている可能性も考えられた。'I-69-8'および'セイヴィスタ'を用いて形質転換を行った。形質転換にはキクわい化ウイロイド(CSVd)の1-120ntまでの120bpをイントロン配列を挟んでセンスとアンチセンス方向に組み込んだsiRNAベクター(1)、および1-120ntの120bpをセンス方向に組み込んだベクター(2)を用いた。両ベクター共に'I-69-8'では形質転換が作出できた。作出した'I-69-8'に関しては、CSVdに対する形質転換系統の反応性を確認することを目的として以下の実験を行った。'I-69-8'の形質転換系統を穂木としてCSVdに高保毒の'ピアト'を台木として接ぎ木を行った。接ぎ木5か月後に穂木のCSVd濃度を調査したところ、ベクター(1)を形質転換した1系統とベクター(2)を多質転換した2系統で明らかなCSVd濃度の変動が見られた。つまり、これらの系統ではCSVd濃度が一端上昇した後に、CSVd濃度の低下が見られた。また、siRNA誘発遺伝子を組み込んだ1系統において葉でのCSVdの局在性がみられた。CSVdの局在性はCSVd抵抗性を示す指標であることをこれまでに認めている。これらのことはCSVdが組み込んだRNAによって分解されている可能性をも示唆するものであるが、分解産物であるsiRNAの確認を行う必要がある。また、これらの系統は開花反応に特に違いは見られなかったため、今後は形質転換系統を台木とした'ピアト'の開花反応を調査する必要がある。
  • 新規に開発した病原体フリー植物作出系のマニュアル化とその展開
    研究期間 : 2005年 -2007年 
    代表者 : 細川宗孝
  • 植物における機能性RNAとして作用するウイロイド-開花機構の分子生物学的解明-
    学術振興会：科学研究費
    研究期間 : 2005年 -2007年 
    代表者 : 細川宗孝
  • 日本学術振興会：科学研究費助成事業 基盤研究(B)
    研究期間 : 2004年 -2006年 
    代表者 : 林 孝洋; 細川 宗孝
     
    1.質感を広義の花色ととらえることにより,色素による色彩に加えて花の観賞性を多様に表現できる. 2.花弁の質感は,表皮細胞の形状と花弁内部の構造によって決まる. 3.光源から花弁への入射光は,表皮細胞の表面反射光,内部散乱光,および透過光に分けられる.質感は目に入る花弁からの表面反射光と内部散乱光の比率によって決まる. 4.ベルベット光沢の実体は表皮細胞表面のハイライトであった,このハイライトが光沢として認知されるためには,表皮細胞が高濃度に色素を持つこと,ならびに人間の目の分解能(視力1.0で約300dpi)に応じて認知できる下限程度の大きさを持つ必要があった.光源に対する花弁の傾斜角度のよって光沢が変化するのはこのためである. 5.金属光沢は,表面反射光と内部散乱光の組み合わせによって生じる.色素によって光が吸収され暗くなった背景に表面反射光および内部散乱光によって生じるハイライトが,目の分解能下限程度の大きさで生じるとき,人間の目には金属光沢の質感として認知されることが分かった. 6.ダイアモンドダストの実体は,内部散乱光による強く大きなハイライトであった. 7.質感を認知するメカニズムについては脳科学の分野においても研究例が少なく,今後の研究課題と考えられた. 8.表皮細胞表面に存在するstriation(筋状微細構造)は花弁内部への光の透過量を増やし(すなわち,表面反射光を減らし),質感として深み感を高めることが明らかになった.
  • 花色発現機構の光学的解明と花色関連遺伝子導入による多彩化
    学術振興会：科学研究費
    研究期間 : 2004年 -2006年
  • 日本学術振興会：科学研究費助成事業 萌芽研究
    研究期間 : 2003年 -2004年 
    代表者 : 矢澤 進; 細川 宗孝
     
    セーシェル諸島で見いだしたトウガラシ(Capsicum chinense)‘Sy-2'は、トウガラシの生育適温である25℃付近に劇的な生育反応の変曲点があることを認めた。すなわち、24℃以下では縮葉を展開し、著しい生育遅延が認められるが、26℃以上では縮葉は全く認められなかった。また、縮葉のみならず花粉稔性、種子発達にも温度反応が認められることを明らかにした。本年度は縮葉反応に焦点を絞り、温度反応の形態学的・分子生物学的な研究を行った。 縮葉は葉の表皮細胞や柵状細胞の形態異常が主な原因であることを明らかにし、また、縮葉ではクロロプラストが小さくトルイジンブルーによる染色性が低いことを認めた。また、24℃以下で育成した‘Sy-2'植物体の茎頂分裂組織には形態的な異常は認められなかったことから、分化した葉原基が温度反応をするものと推定された。そこで、‘Sy-2'植物体の茎頂部より抽出した全タンパク質を二次元電気泳動で分離したところ、28℃で育成した植物体にのみ強く発現するスポットを見いだした。このスポットを解析したところ、クロロフィルの形成と強く関係があるタバコのPsaHタンパク質と一致した。さらに、植物体の茎頂部より抽出・精製したRNAを鋳型としたディファレンシャルディスプレイ法を行ったところ、それぞれの温度で栽培した植物体に特異的な数本のバンドを認め、現在解析を進めている。本研究から、PsaHタンパクの発現量の低下が縮葉反応に関与していることが示唆された。今回の研究から、‘Sy-2'の生育適温でのわずかな温度差による劇的な生育変化のメカニズムが分子レベルで明らかになりつつあり、今後、園芸作物の温度管理に向けた新しい知見が得られるものと考える。
  • 日本学術振興会：科学研究費助成事業 若手研究(B)
    研究期間 : 2003年 -2004年 
    代表者 : 細川 宗孝
     
    キクの難除去性病原体であるキクわいかウイロイド(CSVd)に関しては現在までほとんどフリー化の報告がない。そこで、研究代表者が考案した超微小茎頂分裂組織培養法を適用し、CSVdフリーのキク植物体を作出した。作出率は3%程度であったが、超微小茎頂分裂組織培養法を繰り返し適用することで、作出率が10%以上に向上した。また、新しくキククロロティックモトルウイロイド(CChMVd)がわが国のキクにも感染していることを発見し、CChMVdに関しても本法を適用し、フリー化に成功した。両ウイロイドの除去に成功したことから、本法が難除去性病原体のフリー化に有効な手段であることが示された。 また、作出したCSVdフリーのキクでは一部の品種で、開花のための日長感応性に大きな変化が認められた。すなわち、日長感応性を示さず四季咲き性であった品種をフリー化したところ、明らかな日長反応性が認められ短日開花性を示した。また、CSVdをフリー化したキク植物体に接ぎ木によってCSVdを再感染させたところ、再び日長反応性を示さなくなった。本研究から、CSVdがキクの日長反応性を攪乱させている可能性があることを認めた。その際、生体内のCSVd濃度とキクの開花特性の変化は量的関係ではなく、CSVdが一定の濃度以上になって初めて日長反応性の攪乱が起こることを認めた。さらに、様々な品種に人為的にCSVdを感染させ、その開花に対する日長反応性を調査したところ、開花が早まるもの、遅くなるもの、変わらないものに分けることができた。 mRNAをコードしないCSVdはsiRNAとしてキクの開花反応を攪乱させている可能性も考えられ、メカニズムの解明が急がれる。
  • 新規に関発した超微小茎頂分裂組識培養による難除法病原体フリー個体の作出とその評価
    学術振興会：科学研究費
    研究期間 : 2003年 -2004年 
    代表者 : 細川宗孝
  • 日本学術振興会：科学研究費助成事業 基盤研究(B)
    研究期間 : 2000年 -2002年 
    代表者 : 林 孝洋; 細川 宗孝
     
    1.当該研究期間の間に,急激な葉温降下ストレスに敏感な植物として,イワタバコ科15種,キツネノマゴ科3種が見つかった. 2.急激な温度変化が刺激として認知されるには,温度の降下速度が重要であると考えられる.速度を変えて実験したところ,3℃/秒以上の速さで温度が降下したときに障害が発生した.温度の絶対的な降下程度ではなく,降下の速さが重要で,急激な表皮収縮が外部刺激として認知されるのではないかと考えられた. 3.植物体への物理的な傷つけ処理(葉やシュートの切除を含む)は,その処理部位と離れた健全部に葉温降下ショックと類似の障害(細胞の褐変壊死)を引き起こした.傷つけ処理と葉温降下ショックは,障害の引き金として同じ反応を引き起こすものと推察された. 4.傷刺激に対する急激な細胞死には温度,光強度,湿度などの環境要因が関与していること,および植物には物理刺激に対して非常に敏感な状態(過敏感状態)が存在することが示唆された.過敏感状態はそれ以前に受けた傷や温度変化などで誘導された興奮(警戒)状態で,その後の外部刺激に対して全身の感度を高める状態ではないかと考えられた. 5.乾燥条件で水ストレスがかかるほど,傷つけによる興奮状態誘導が起こりやすいことが明らかになった. 6.高温は興奮状態を誘導しやすい条件であることが示された. 7.興奮状態の誘導には日変化があることが示された.午前中は誘導の程度が低く,午後に高まり,夜には誘導されなくなった.この結果から,頭上かん水を行う場合は,午前の方が好適であることが示唆された.
  • 園芸作物の栽培でこれまで見過ごされてきた急激な葉温降下のストレス―その生理障害の重要性と発生機構の解明
    学術振興会：科学研究費
    研究期間 : 2000年 -2002年
  • 日本学術振興会：科学研究費助成事業 萌芽的研究
    研究期間 : 1999年 -2000年 
    代表者 : 細川 宗孝
     
    人工キメラ植物の作出は、接ぎ木処理後の組織癒合部より不定芽を誘導することによりおこなわれてきた。しかし、現行の方法で作出可能なキメラ植物は、接ぎ木ができる組み合わせであること、不定芽が誘導できる植物種であることなど種々の制約を受ける。我々は、植物の茎頂分裂組織(生長点)を微細手術し、異種植物の組織や器官を移植することでキメラ植物を作出する方法の開発を目指し研究をおこなった。 未分化組織への微細手術を目的として、茎頂分裂組織のみを培養する方法を開発した。茎頂分裂組織は非常に微小な組織であり、単独での培養が困難である。本実験ではキクを用いたが、茎頂分裂組織のみを単独培養した際の生存率は著しく低かった。そこで、茎頂分裂組織を根端を含む根の切り口に移植し培養したところ、高い確率で生存し植物体となることを見いだした。また、茎頂分裂組織を摘出する機器を堂阪イーエムと共同開発し、熟練を要する茎頂分裂組織の摘出操作を確実に行えるようにした。さらに茎頂分裂組織を移植する組織として、他種植物を利用することも可能であることがわかった。例えば、ニンニクの茎頂分裂組織の移植先としてニンニクの根のみならずネギの実生由来の根を使うことができた。次に茎頂分裂組織に葉原基などの組織を移植して組織接着が可能かどうかを確かめた。キャベツの茎頂分裂組織に、他品種の葉原基を移植する方法で実験をおこなった。手術は全て根の上に移植した茎頂分裂組織に対しておこなった。キャベツでは、一部葉原基が接着した個体が見られた。これに関しては組織学的に細胞接着を確認する必要があるが、移植した葉原基が茎頂分裂組織の上で生長しているのが観察された。現在まで、茎頂分裂組織への組織移植は非常に困難であった。今回実験に進展が見られた理由の一要因として、茎頂から分化した組織(葉原基)を全て除去し、未分化な組織のみを取り扱ったことが考えられた。
  • 人工キメラ植物の作出法の開発と新たな園芸品種の育成
    学術振興会：科学研究費
    研究期間 : 1999年 -2000年 
    代表者 : 細川宗孝
  • 植物におけるウイロイドの感染と抵抗性の分子生物学
    研究期間 : 1998年
  • Molecular Biology of Viroid infection and resistance of plants
    研究期間 : 1998年
  • 複数の病原体（ウイルス、ウイロイドなど）が除去された植物無病苗の作出・評価・利用
  • 人工キメラ植物の作出に関する実験
  • Study on breeding of synthetic chimera
  • エピゲノム解析によるトマトの最適超低温保存技術の開発
    代表者 : 細川宗孝

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