詳細

坂本　勝 （サカモト　マサル）

  • 生物理工学部 生物工学科　講師
Last Updated :2024/04/25

コミュニケーション情報 byコメンテータガイド

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    植物工場に応用可能な植物の生理現象について研究しています。植物の収量や特定成分の増加を目的としています。2年半、企業での植物工場の研究開発に従事した経験があります。

研究者情報

学位

  • 博士（農学）（神戸大学）

ホームページURL

科研費研究者番号

  • 90446378

J-Global ID

現在の研究分野（キーワード）

    植物工場に応用可能な植物の生理現象について研究しています。植物の収量や特定成分の増加を目的としています。2年半、企業での植物工場の研究開発に従事した経験があります。

研究分野

  • 環境・農学 / 園芸科学

研究活動情報

論文

  • 鈴木 高広; 今本 美幸; 小見山 百絵; 大西 良浩; 笠原 正登; 梅田 智広; 田端 宣彦; 西村 照彦; 坂本 勝
    粉体工学会誌 60 6 354 - 362 一般社団法人 粉体工学会 2023年06月 
    The effectiveness of Ca supplements was evaluated to compensate for the lack of Ca intake in the Japanese people. To determine the relationship between dietary calcium intake and the rate of calcium accumulation in postmenopausal women with significant calcium loss, a crossover study was conducted using milk, calcium carbonate powder, and calcium citrate powder (UNICALTM) made from scallop shells. Calcium contents in urine, feces, and meals were measured to compare calcium accumulation rates ((intake−excretion)/intake). Results showed that UNICALTM, which is more soluble than calcium carbonate, was as effective as milk in reducing postmenopausal calcium loss. However, postmenopausal Japanese women were found to lack calcium even at 700 mg/day, above the standard recommended intake of 650 mg/day. These results suggest that further increasing the solubility of UNICALTM is very effective as a Ca supplement for Japanese people who are deficient in milk intake.
  • 今本 美幸; 小見山 百絵; 大西 良浩; 笠原 正登; 梅田 智広; 田端 宣彦; 西村 照彦; 坂本 勝; 鈴木 高広
    近畿大学生物理工学部紀要 50 21 - 32 近畿大学生物理工学部 2023年03月 
    Context: Japanese people have low intakes of milk and dairy products, and there is a high risk of fractures in postmenopausal women due to calcium deficiency; hence, effective calcium supplementation is required. Objective: To determine the relationship between dietary calcium intake and calcium accumulation rate in postmenopausal women by comparing the amount of calcium absorbed when ingesting milk, which is a calcium-containing food, and a commercially available calcium food. Subjects: A crossover study of milk and a highly absorbable calcium supplement (UNICAL™) as calcium-containing foods was conducted on 38 postmenopausal women (mean age and standard deviation: 58 ± 3.8 years) using calcium carbonate as a common comparative food. Calcium intake was set at 700 mg/day, and in addition to the basal diet (which was designed to have a calcium content of 250 mg/day), participants received 450 mg/day of calcium from milk or calcium carbonate in Study 1 (n = 19) and from UNICAL™ or calcium carbonate in Study 2 (n = 19). There was a period of no calcium supplement intake (washout period) between the two interventions. The amount of calcium in urine, feces, and meals was measured, and the calcium accumulation rate ((intake − excretion)/intake) was compared. Results: The Ca-supplemented diet accumulated −216 to −246 mg during the intervention period, and calcium loss was observed in all subjects. On the other hand, the amount of calcium accumulated during the washout period ranged from −346 to −356 mg/day, with greater losses than during the intervention, and the addition of calcium to the diet reduced calcium loss in the body. The difference between the mean accumulation rates of milk and calcium carbonate in Test 1 was −0.2% (95% CI; −52.2% to 51.8%, p = 0.99), and the difference between the accumulation rates of UNICAL™ and calcium carbonate in Test 2 was +6.1% (95% CI; −36.1% to 48.3%, p = 0.77), neither of which was significant. Conclusion: UNICAL™, a highly absorbable calcium supplement, was as effective as milk in reducing calcium loss in postmenopausal Japanese women. However, neither milk nor calcium supplements adequately controlled calcium loss in postmenopausal Japanese women at the traditional recommended intake of 650 mg/day. [和文抄録]日本人は牛乳や乳製品の摂取量が少なく慢性的にカルシウム不足のため，閉経後に骨粗鬆症を発症し骨折する女性の割合が高い。骨折は，寝たきりとなる要介護高齢者の主要因であり，骨粗鬆症を防ぐために効果的なカルシウム補給方法が求められている。そこで，牛乳と市販のカルシウム補給食品を摂取した際のカルシウム吸収量を比較することにより，閉経後女性におけるカルシウム摂取量とカルシウム蓄積率の関係を明らかにすることを試みた。閉経後女性38名（平均年齢:58歳）を対象に炭酸カルシウムを比較食品として，牛乳と高吸収性カルシウムサプリメント（UNICALTM）のクロスオーバー試験を行った。カルシウム摂取量は700mg/日に設定され，基礎食（カルシウム含有量250 mg/日）に加えて，試験1（19人）では牛乳または炭酸カルシウムから，試験2（19人）ではUNICALTMまたは炭酸カルシウムから，それぞれ450mg/日のカルシウムを摂取した。尿・便中のカルシウム排出量を測定し，摂取量に対するカルシウム蓄積率を比較した。その結果，炭酸カルシウムと比較したカルシウム蓄積率の差は，試験1における牛乳が−0.2%，試験2ではUNICALTMが6.1%といずれも大差なく，統計的に有意な差ではなかった。したがって，UNICALTMは閉経後の日本人女性のカルシウム損失を減らす効果が牛乳と同等であることが明らかとなった。しかし，牛乳，UNICALTM，炭酸カルシウムのいずれの場合も，一日あたりの摂取量（700mg/日）を上回るカルシウムが尿と便に排出されており，従来の一般的な推奨摂取量である650mg/日では，閉経後女性のカルシウム損失による骨粗鬆症の進行を防ぐことが困難であることが判明した。
  • Takahiro Suzuki; Masaru Sakamoto; Hiroshi Kubo; Yui Miyabe; Daisuke Hiroshima
    Horticulturae 9 3 309 - 309 2023年02月 
    To develop a way to mass-produce sweet potatoes (Ipomoea batatas (L.) Lam.) as an energy crop to replace fossil fuels, the effects of using a sewage supply as a fertilizer and heat source were investigated. When 25 pots planted with sweet potato vine seedlings were arranged in three layers and cultivated for 160 days from June to November by supplying treated sewage to the root zone, the yield of tuberous roots reached 19.5 kg m−2 due to the massive growth of leaves. In addition, when sweet potato seedlings were replanted in December and treated sewage was supplied to maintain the irrigation water temperature above 15 °C even in winter, overwintering cultivation was successful and 8.4 kg m−2 of tuberous roots were harvested in July. As a result, the annual production rate for 12 months increased to 25.3 kg m−2, about 10 times the national average of 2.4 kg m−2 for open-field cultivation. The results far exceed previously reported maximum production of resource crops, such as sugarcane and eucalyptus, suggesting that the mass production of sweet potatoes by supplying treated sewage could provide an alternative to fossil fuels on a large scale.
  • Takahiro Suzuki; Masaru Sakamoto; Hiroshi Kubo; Yui Miyabe; Daisuke Hiroshima
    Plants 12 2 287 - 287 2023年01月 
    The purpose of this study was to develop a novel method to dramatically improve the production efficiency of sweet potatoes (Ipomoea batatas (L.) Lam.) by elucidating the effect of solar radiation stress on the growth of sweet potato in a multilayer cultivation system. Twenty-five pots planted with sweet potato vine seedlings were arranged in three layers and cultivated for 160 days while supplying liquid fertilizer to the root zone. While solar radiation in the middle and lower layers decreased to 69% and 45% of that in the upper layer, respectively, the yield of tuberous roots was 0.89 kg/pot in the upper layer, 0.79 kg/pot in the middle layer, and 0.66 kg/pot in the lower layer. As a result, the productivity of tuberous roots reached 10.5 kg/m2, 4.4 times that of conventional farming. On the other hand, the amounts of leaves and stems increased in the lower layer than in the upper layer, and the biomass energy yield (photosynthetic efficiency) was 2.8% in the upper layer, 3.7% in the middle layer, and 5.1% in the lower layer. Leaves in the lower layer with less solar radiation had a lower polyphenol content and increased the amounts of low-brightness leaves. In contrast, the upper leaves were found to contain more polyphenols and have brighter, smaller leaves. These results suggest that the yield can be further increased by optimizing solar radiation stress by using the multilayer cultivation method.
  • Masaru Sakamoto; Yoshiki Komatsu; Takahiro Suzuki
    Horticulturae 7 12 525 - 525 2021年11月 
    In hydroponics, a continuous supply of mineral nutrients is essential for plant growth. However, constitutive nutrient-rich conditions also increase the nitrate content in the plants, which can be harmful to human health. Here, we investigated the effect of nutrient deficiency on the growth and component composition of hydroponic radish by changing the timing of nutrient removal from the hydroponic solution. Radish plants that were 14 days old were transferred to four different nutrient conditions for 14 days: nutrient deficiency for 14 days (WW), full nutrient for 14 days (NN), nutrient deficiency for the last 7 days (NW), and nutrient deficiency for the first 7 days (WN). After the treatments, the NW plants had similar taproot growth to NN plants. In contrast, the WN plants significantly reduced taproot growth. The WW plants reduced the shoot and taproot weight and their water contents. The nitrate content in the taproots was reduced in the NW and WW plants. The WW plants contained lower total phenol and higher ascorbic acid and sugar contents. These results suggest that the uptake of nutrient minerals at the young growth stage is important for the growth of radish taproot. Nutrient deficiency management can be one of the most effective tools for regulating radish growth and composition.
  • Masaru Sakamoto; Takahiro Suzuki
    Agronomy 10 11 1708 - 1708 2020年11月 [査読有り]
     
    Nutrient solution concentration (NSC) is a critical factor affecting plant growth in hydroponics. Here, we investigated the effects of hydroponic NSC on the growth and yield of sweetpotato (Ipomoea batatas (L.) Lam.) plants. First, sweetpotato cuttings were cultivated hydroponically in three different NSCs with low, medium, or high electrical conductivity (EC; 0.8, 1.4, and 2.6 dS m−1, respectively). Shoot growth and storage root yield increased at 143 days after plantation (DAP), depending on the NSC. Next, we examined the effect of NSC changes at half of the cultivation period on the growth and yield, using high and low NSC conditions. In plants transferred from high to low EC (HL plants), the number of attached leaves increased toward the end of the first half of the cultivation period (73 DAP), compared with plants transferred from low to high EC (LH plants). Additionally, the number of attached leaves decreased in HL plants from 73 DAP to the end of the cultivation period (155 DAP), whereas this value increased in LH plants. These changes occurred due to a high leaf abscission ratio in HL plants. The storage root yield showed no significant difference between HL and LH plants. Our results suggest that the regulation of hydroponic NSC during the cultivation period affects the growth characteristics of sweetpotato.
  • Masaru Sakamoto; Masanori Wada; Takahiro Suzuki
    Horticulturae 6 1 5 - 5 2020年01月 [査読有り]
     
    Hydroponics provides a stable root environment that can be easily controlled. In this paper, we investigated the effect of partial excision of early taproots of hydroponic carrots on their growth and components. Carrot taproots were excised after 30 days from sowing at 5 cm, 10 cm, and 15 cm from the stem base (C5, C10, and C15) and compared with nonexcised control plants. Time-course measurements revealed the taproot lengths of C10 and C15 plants gradually decreased. After 28 days of treatment, C5 taproot tips showed the most rounded shape among root-excised plants. Control plants possessed long taproots that were not enlarged at the site more than 15 cm from the stem base. Taproot fresh weight was lower in C5 plants and higher in C15 plants compared with controls. Although taproot sugar concentrations did not differ between treatments, total phenol concentration was higher in C5 taproots. These data suggest that partial removal of early taproots can regulate the shape and ingredients of hydroponic carrots.
  • 坂本勝; 鈴木高広
    近畿大学生物理工学部紀要 43 29 - 38 2020年
  • 鈴木高広, 坂本勝, 田端宣彦, 沖野圭修
    近畿大学生物理工学部紀要 43 29 - 38 2020年
  • 地球温暖化に起因する福島県沖巨大地震の再発メカニズムの検証と芋メタン発酵条件の検討
    鈴木高広; 坂本勝
    第31回日本太陽エネルギー学会研究発表会 2019年10月 
    地球温暖化により多発化する巨大地震の発生メカニズムを解明すると共に、M6級巨大地震の地殻ストレス予測と断層破壊トリガー要因を解析し直前予知の方法を見出した。
  • Sakamoto M; Suzuki T
    Horticulturae 5 3 62  2019年09月 [査読有り]
     
    Plant secondary metabolites with antioxidant properties, such as anthocyanins, are considered to have an important commercial value for some crops. Although anthocyanin concentration increases in response to various stimuli in plants, the mechanism of anthocyanin accumulation under multiple stimuli is not yet well understood. Here, we examined the effects of methyl jasmonate (MJ) and salinity on anthocyanin accumulation in radish (Raphanus sativus) sprouts. MJ treatments induced anthocyanin accumulation, which was enhanced by simultaneous treatment with salinity (200 mM NaCl), accompanied by growth restrictions. Sprouts treated with salinity alone did not induce anthocyanin accumulation, although sprout growth was restricted. Co-treatment with MJ and salinity increased hydrogen peroxide, total phenol content, and radical scavenging capacity more strongly than was achieved when each treatment was applied singly. Accumulation of anthocyanin was dependent on NaCl concentration and light intensity. Changing MJ and salinity treatment periods had different effects on anthocyanin accumulation and growth restriction, indicating that these phenomena might be differentially regulated. These results may provide an effective anthocyanin accumulation method without reducing plant biomass.
  • 鈴木高広; 坂本勝
    太陽/風力エネルギー講演論文集 2018 (CD-ROM) ROMBUNNO.87 - 308 東京 : 日本太陽エネルギー学会 2018年11月
  • 鈴木高広; 坂本勝
    太陽/風力エネルギー講演論文集 2018 (CD-ROM) ROMBUNNO.73 - 254 東京 : 日本太陽エネルギー学会 2018年11月
  • Sakamoto M; Suzuki T
    Sustainable Agriculture Research 7 1 137 - 145 2018年02月 [査読有り]
  • Sakamoto M; Suzuki T
    American Journal of Plant Sciences 8 7 1534 - 1549 2017年06月 [査読有り]
  • Sakamoto M; Kim DA; Imoto K; Kitai Y; Suzuki T
    Sustainable Agriculture Research 6 2 7 - 12 2017年05月 [査読有り]
  • 鈴木 高広; 坂本 勝
    日本エネルギー学会大会講演要旨集 26 126 - 127 一般社団法人 日本エネルギー学会 2017年 

    Mass production of sweetpotatoes by a cheap cultivation method was achieved with small pots by optimizing the elongation space of the roots and the hygroscopic condition of the soil. In Okinawa we planted vine of sweetpotato in October, and harvested in April. The amount of sweetpotatoes cultivated in the winter months was reached to 7.3 kg/m2, which was three times the national average to grow in the summer. The result showed that annual production of 20kg/m2 sweetpotatoes is feasible by further optimizing the growth condition. For the purpose to use sweetpotatoes as fuel, technological issues of the methane fermentation and the gas power generation system were investigated.

  • Sakamoto M; Uenishi M; Miyamoto K; Suzuki T
    Journal of Agricultural Science 8 5 122 - 131 2016年05月 [査読有り]
  • 鈴木 高広; 坂本 勝
    日本エネルギー学会大会講演要旨集 25 78 - 79 一般社団法人 日本エネルギー学会 2016年 

    The innovation is required to production of a large amount of biomass by cultivation of domestic photosynthetic plant and to replace fossil fuels. The author has found that the best crop is sweetpotato cultivated in multilayer system. So far, the 4-layers cultivation method using a triangular shelf showed that it is possible to sweetpotato production of about 20kg/m2. This is eight times the amount of domestic average yield (2.5kg/m2). However, the soil hygroscopic level decreased quickly and the production of the sweetpotatoes suppressed significantly, were found by the multi-layer cultivation system. Therefore we investigated the influence of the basic irrigation state to produce sweetpotatoes. As the result the yield of sweetpotatoes cultivated with root zone irrigation system increased to 179% of the amount of the past. In addition, the root zone irrigation system was effective to increase the weight of the mass production of sweetpotatoes by increasing the density of the vine seeding per area.

  • 鈴木高広; 堀端章; 坂本勝; 古川道郎; 神田紀
    太陽/風力エネルギー講演論文集 2015 455‐458 - 458 日本太陽エネルギー学会 2015年11月
  • Sakamoto M; Suzuki T
    American Journal of Plant Sciences 6 14 2350 - 2360 2015年09月 [査読有り]
  • Sakamoto M; Suzuki T
    Agricultural Sciences 6 8 749 - 757 2015年08月 [査読有り]
  • SAKAMOTO Masaru; SUZUKI Takahiro
    Mem Fac Biol Oriented Sci Technol Kinki Univ 35 35 1 - 6 近畿大学生物理工学部 2015年03月 
    [Abstract] It is well known that plants produce antimicrobial and antioxidative secondary metabolites such as polyphenols in response to pathogen attacks; however, the practical use of this phenomenon for cultivating high-value crops has scarcely been examined till date. We attempted to produce high anthocyanin-containing lettuce using plant defense elicitors. Among the elicitors tested, methyl jasmonate (MJ) clearly induced the production of anthocyanin and total phenols in red baby leaf lettuce. MJ-induced anthocyanin accumulation was concentration and light dependent. Co-treatment of MJ with other elicitors had no effect on the production of anthocyanin and total phenols. These results indicate that MJ treatment can be a useful method for producing high anthocyanin-containing lettuce under a low light intensity condition such as that in a closed-type plant factory. [要旨]植物は病原菌の感染に応答してポリフェノールなどの抗菌性, 抗酸化性二次代謝産物を生成することがよく知られている. しかしながら, この現象を高付加価値作物栽培に実用化するための試験例は現在までほとんどない. 我々は, 植物抵抗性エリシターを用いて高アントシアニン含有レタスを作出することを試みた. 試験に用いたエリシターの中で, ジャスモン酸メチルが赤系ベビーリーフレタスのアントシアニンと総フェノール生成量を顕著に増加させた. ジャスモン酸メチルにより誘導されるアントシアニン蓄積は, 処理濃度と光量に依存した. ジャスモン酸メチルと他のエリシターと共処理は, アントシアニンと総フェノール生成量に影響を与えなかった. これらの結果から, ジャスモン酸メチル処理が閉鎖型植物工場のような低光量下での高アントシアニン含有レタスの作出に利用可能な方法であると示唆された.
  • 鈴木 高広; 坂本 勝
    日本エネルギー学会大会講演要旨集 24 124 - 125 一般社団法人日本エネルギー学会 2015年 
    Innovation is required to alternative production of fossil fuels by domestic photosynthetic organisms. The author has found that the best crop is sweetpotato cultivated in multilayer system. So far, the 4-layers cultivation method using a triangular shelf showed that it is possible to sweetpotato production of about 20kg/m^2. This is eight times the amount of domestic average yield (2.5kg/m^2). To commercialize this cultivation method, the sunshine conditions with the development of low-cost production system was studied. As a result, a three-layers cultivation method which produced sweetpotatoes of 20kg/m^2 (about 150MJ/m^2 in the cultivation period 8 months, the conversion rate of about 3.5% of the sunlight) that can be realized has been found. These results showed that production of 15 million TJ renewable energy every year is possible, if cultivated sweetpotatoes at 10 million ha, 26% of the national land. Thus, the alternative production of total fossil fuels by domestic crop is feasible.
  • 鈴木 高広; 坂本 勝; 阿野 貴司; 新谷 昇
    日本生物工学会大会講演要旨集 65 公益社団法人日本生物工学会 2013年08月
  • Reiko Tomita; Ken-Taro Sekine; Hiroyuki Mizumoto; Masaru Sakamoto; Jun Murai; Akinori Kiba; Yasufumi Hikichi; Kazumi Suzuki; Kappei Kobayashi
    MOLECULAR PLANT-MICROBE INTERACTIONS 24 1 108 - 117 2011年01月 [査読有り]
     
    The pepper L gene conditions the plant's resistance to Tobamovirus spp. Alleles L(1), L(2), L(3), and L(4) confer a broadening spectra of resistance to different virus pathotypes. In this study, we report the genetic basis for the hierarchical interaction between L genes and Tobamovirus pathotypes. We cloned L(3) using map-based methods, and L(1), L(1a), L(1c), L(2), L(2b), and L(4) using a homology-based method. L gene alleles encode coiled-coil, nucleotide-binding, leucine-rich repeat (LRR)-type resistance proteins with the ability to induce resistance response to the viral coat protein (CP) avirulence effectors by themselves. Their different recognition spectra in original pepper species were reproduced in an Agrobacterium tuntefaciens-mediated transient expression system in Nicotiana benthamiana. Chimera analysis with L(1), which showed the narrowest recognition spectrum, indicates that the broader recognition spectra conferred by L(2), Lab, L(3), and L(4) require different subregions of the LRR domain. We identified a critical amino acid residue for the determination of recognition spectra but other regions also influenced the L genes' resistance spectra. The results suggest that the hierarchical interactions between L genes and Tobamovirus spp. are determined by the interaction of multiple subregions of the LRR domain of L proteins with different viral CP themselves or some protein complexes including them.
  • Masaru Sakamoto; Reiko Tomita; Kappei Kobayashi
    FEBS LETTERS 583 15 2552 - 2556 2009年08月 [査読有り]
     
    In this study, we characterized a Capsicum hypersensitive response (HR)-associated gene, SS52, which encodes a protein that contains an N-terminal C2 domain and a C-terminal XYPPX repeat. Expression analyses revealed that SS52 and its homologue in Arabidopsis were induced by infection with incompatible viruses, indicating the conserved function of this gene. SS52 was not induced by treatment with defense-related hormones, but was induced by abiotic stresses, including wounding. Overexpression of SS52 in tobacco plants suppressed the spread of HR cell death and restricted the spread of an incompatible virus from local lesions. Collectively, the results suggest that SS52 negatively regulates plant HR cell death. (c) 2009 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.
  • Kappei Kobayashi; Reiko Tomita; Masaru Sakamoto
    JOURNAL OF GENERAL PLANT PATHOLOGY 75 2 87 - 91 2009年04月 [査読有り]
     
    The isolation of viral replicative form (RF) double-stranded RNA (dsRNA) is a classic technique for plant virus detection when the virus species cannot be predicted from disease symptoms. However, the method has not been very widely used, most likely because dsRNA isolation using CF-11 cellulose is laborious and time-consuming. Here we report an alternative tool, a recombinant plant dsRNA-binding protein, to isolate dsRNA. This tool enables us to isolate viral RF dsRNA in an hour from either extracted nucleic acids or crude detergent extracts. Combining this technique with sequence-non-specific reverse transcription, PCR amplification, cloning, and sequencing, a variety of viruses were efficiently detected using a single set of reagents and procedures.
  • R. Tomita; J. Murai; Y. Miura; H. Ishihara; S. Liu; Y. Kubotera; A. Honda; R. Hatta; T. Kuroda; H. Hamada; M. Sakamoto; I. Munemura; O. Nunomura; K. Ishikawa; Y. Genda; S. Kawasaki; K. Suzuki; K. Meksem; K. Kobayashi
    THEORETICAL AND APPLIED GENETICS 117 7 1107 - 1118 2008年11月 [査読有り]
     
    The tobamovirus resistance gene L(3) of Capsicum chinense was mapped using an intra-specific F2 population (2,016 individuals) of Capsicum annuum cultivars, into one of which had been introduced the C. chinense L(3) gene, and an inter-specific F2 population (3,391 individuals) between C. chinense and Capsicum frutescence. Analysis of a BAC library with an AFLP marker closely linked to L(3)-resistance revealed the presence of homologs of the tomato disease resistance gene I2. Partial or full-length coding sequences were cloned by degenerate PCR from 35 different pepper I2 homologs and 17 genetic markers were generated in the inter-specific combination. The L(3) gene was mapped between I2 homolog marker IH1-04 and BAC-end marker 189D23M, and located within a region encompassing two different BAC contigs consisting of four and one clones, respectively. DNA fiber FISH analysis revealed that these two contigs are separated from each other by about 30 kb. DNA fiber FISH results and Southern blotting of the BAC clones suggested that the L(3) locus-containing region is rich in highly repetitive sequences. Southern blot analysis indicated that the two BAC contigs contain more than ten copies of the I2 homologs. In contrast to the inter-specific F2 population, no recombinant progeny were identified to have a crossover point within two BAC contigs consisting of seven and two clones in the intra-specific F2 population. Moreover, distribution of the crossover points differed between the two populations, suggesting linkage disequilibrium in the region containing the L locus.
  • M. Sakamoto; R. Tomita; H. Hamada; Y. Iwadate; I. Munemura; K. Kobayashi
    PLANT PATHOLOGY 57 5 825 - 833 2008年10月 [査読有り]
     
    One or a few nucleotide changes in the coat protein gene reportedly confer Pepper mild mottle virus (PMMoV) with the ability to overcome L(3) gene-mediated resistance in Capsicum plants. Primer-introduced restriction analysis-PCR (PIRA-PCR) was set up to detect four known resistance-breaking mutations. Each mutation from the L(3)-breaking PMMoV strains was successfully detected by reverse transcription-PCR amplification of the viral coat protein gene, PCR amplification of the regions containing the mutations with restriction site-introducing primers, followed by restriction analysis. Since PIRA-PCR primers were designed such that only PCR products from L(3)-breaking PMMoV strains can be digested by appropriate restriction enzymes, L(3)-breaking strains could be detected when they comprised no more than 20% of the mixture with non-L(3)-breaking strain. Using this PIRA-PCR-based method, L(3)-breaking PMMoV was detected in field soil samples taken from the base of both diseased and non-diseased plants harbouring L(3). The results show that PIRA-PCR is useful to quickly detect L(3)-breaking PMMoV strains not only in Capsicum plants harbouring the L(3) resistance gene but also in field soil, which serves as a reservoir of infectious viruses.
  • Masaru Sakamoto; Ikuko Munemura; Reiko Tomita; Kappei Kobayashi
    PLANT JOURNAL 56 1 13 - 27 2008年10月 [査読有り]
     
    Although auxin and ethylene play pivotal roles in leaf abscission, the subsequent signaling molecules are poorly understood. This is mainly because it is difficult to effectively treat the intact abscission zone (AZ) with pharmacological reagents. We developed an in vitro experimental system that reproduces stress-induced leaf abscission in planta. In this system, 1-mm-thick petiole strips, encompassing the AZ, were separated within 4 days of abscission at the AZ through cell wall degradation in an auxin depletion- and ethylene-dependent manner. The system allowed us to show that hydrogen peroxide (H(2)O(2)) is involved in abscission signaling. Microscopic analyses revealed continuous H(2)O(2) production by AZ cells. H(2)O(2) scavengers and diphenylene iodonium, an inhibitor of NADPH oxidase, suppressed in vitro abscission and cellulase expression. Conversely, the application of H(2)O(2) promoted in vitro abscission and expression of cellulase. Ethephon-induced abscission was suppressed by inhibitors of H(2)O(2) production, whereas the expression of ethylene-responsive genes was unaffected by both H(2)O(2) and an H(2)O(2) inhibitor. These results indicated that H(2)O(2) acts downstream from ethylene in in vitro abscission signaling. In planta, salinity stress induced the expression of genes that respond to ethylene and reactive oxygen species, and also induced H(2)O(2) production at the AZ, which preceded leaf abscission. These results indicate that H(2)O(2) has roles in leaf abscission associated with ethylene both in vitro and in planta.
  • Masaru Sakamoto; Ikuko Munemura; Reiko Tomita; Kappei Kobayashi
    Plant Signaling and Behavior 3 11 1014 - 1015 2008年 [査読有り]
     
    Reactive oxygen species (ROS) are produced in response to many environmental stresses, such as UV, chilling, salt and pathogen attack. These stresses also accompany leaf abscission in some plants, however, the relationship between these stresses and abscission is poorly understood. In our recent report, we developed an in vitro abscission system that reproduces stress-induced pepper leaf abscission in planta. Using this system, we demonstrated that continuous production of hydrogen peroxide (H 2O2) is involved in leaf abscission signaling. Continuous H2O2 production is required to induce expression of the cell wall-degrading enzyme, cellulase and functions downstream of ethylene in abscission signaling. Furthermore, enhanced production of H2O 2 occurs at the execution phase of abscission, suggesting that H 2O2 also plays a role in the cell-wall degradation process. These data suggest that H2O2 has several roles in leaf abscission signaling. Here, we propose a model for these roles. ©2008 Landes Bioscience.
  • Masaru Sakamoto; Yasuomi Tada; Hitoshi Nakayashiki; Yukio Tosa; Shigeyuki Mayama
    Journal of General Plant Pathology 71 6 387 - 394 2005年12月 [査読有り]
     
    Reactive oxygen species (ROS) are thought to be involved in various forms of programmed cell death (PCD) in animal and plant cells. PCD, along with the production of ROS, occurs during plant-pathogen interactions. Here we show that victorin, a host-specific toxin produced by Cochliobolus victoriae, which causes victoria blight of oats, induces two phases of intracellular ROS production in victorin-sensitive oat mesophyll cells. The initial production of ROS is restricted at mitochondria and not accompanied with cellular oxidative damage. Later production of ROS is dispersed into cells concomitant with lipid peroxidation, chloroplast dysfunction, and cell death. Superoxide dismutase can clearly suppress the initial ROS production and delay the progression of cell death. These data indicate that the initial ROS production may be involved in the cell death induction process, and the later ROS production may play important roles in events leading to cellular disruption. © The Phytopathological Society of Japan and Springer-Verlag 2005.
  • Y Tada; Y Ohura; S Betsuyaku; T Shinogi; M Sakamoto; Y Ohura; S Hata; T Mori; Y Tosa; S Mayama
    PLANT AND CELL PHYSIOLOGY 46 11 1787 - 1798 2005年11月 [査読有り]
     
    The host-selective toxin victorin is produced by Cochliobolus victoriae, the causal agent of victoria blight of oats. Victorin has been shown to bind to the P protein of the glycine decarboxylase complex (GDC) in mitochondria, and induce defense-related responses such as phytoalexin synthesis, extracellular alkalization and programmed cell death. However, evidence demonstrating that the GDC plays a critical role in the onset of cell death is still lacking, and the role of defense-like responses in the pathogenicity has yet to be elucidated. Here, cytofluorimetric analyses, using the fluorescein (VicFluor) or bovine serum albumin-fluorescein derivative of victorin (VicBSA), demonstrated that victorin-induced cell death occurs before these conjugates traverse the plasma membrane. As with native victorin, VicBSA clearly elicits apoptosis-like cell death, production of phytoalexin, extracellular alkalization, and generation of nitric oxide and reactive oxygen intermediates. These results suggest that the initial recognition of victorin takes place on the cell surface, not in mitochondria, and leads to the activation of a battery of victorin-induced responses. Pharmacological studies showed that extracellular alkalization is the essential regulator for both victorin- and VicBSA-induced cellular responses. We propose a model where victorin may kill the host cell by activating an HR-like response, independent of the binding to the GDC, through ion fluxes across the plasma membrane.
  • K Kusaka; Y Tada; T Shigemi; M Sakamoto; H Nakayashiki; Y Tosa; S Mayama
    FEBS LETTERS 578 3 363 - 367 2004年12月 [査読有り]
     
    We have developed an oat cell-free apoptosis system to investigate the execution mechanisms of plant apoptosis. Cell extracts derived from oat tissues undergoing toxin (victorin)-induced apoptosis caused nuclear collapse and internucleosomal DNA fragmentation in isolated nuclei. Pharmacological studies revealed that cysteine protease, which is E-64-sensitive but insensitive to caspase-specific inhibitors, is a crucial component in the morphological change of isolated nuclei, and that nuclease and the cysteine protease act cooperatively to induce the apoptotic DNA laddering. Interestingly, this finding is contrasted with those in well-studied animal cell-free systems in which an apoptotic endonuclease is solely responsible for the DNA fragmentation. (C) 2004 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.
  • Y Tada; T Mori; T Shinogi; N Yao; S Takahashi; S Betsuyaku; M Sakamoto; P Park; H Nakayashiki; Y Tosa; S Mayama
    MOLECULAR PLANT-MICROBE INTERACTIONS 17 3 245 - 253 2004年03月 [査読有り]
     
    Nitric oxide (NO) acts as a signaling molecule in many cellular responses in plants and animals. Oat plants (Avena sativa L.) evoke the hypersensitive response (HR), which shares morphological and biochemical features with mammalian apoptosis, such as DNA laddering and heterochromatin condensation, in response to the avirulent crown rust fungus (Puccinia coronata f. sp. avenae). We examined the role of NO and reactive oxygen species (ROS) in the initiation of hypersensitive cell death, which is induced by direct contact with the pathogen, and apoptotic cell death in the adjacent cells. Cytofluorimetric analysis using the fluorescent NO probe DAF and the H2O2 probe DCF demonstrated that NO and H2O2 were generated simultaneously in primary leaves at an early stage of the defense response. The NO scavenger 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (cPTIO) markedly enhanced H2O2 accumulation detected by 3,3-diaminobenzidine staining and DCF, whereas treatment with the NO donor S-nitroso-N-acetylpenicillantine (SNAP) strongly suppressed it. Superoxide dismutase (SOD) increased NO accumulation, suggesting that endogenous NO may modulate the level of H2O2 by interacting with O-2(-) in the HR lesion. Cytological observation showed that administration of cPTIO, SNAP, or SOD had no effect on elicitation of hypersensitive cell death, but clearly reduced heterochromatin condensation in the nearby cells and DNA laddering. These findings indicate that NO and ROS are not essential mediators for the initiation of hypersensitive cell death. However, NO and O-2(-) but not H2O2 are required for the onset of apoptotic cell death in the adjacent cells, where excess NO may exert its anti-apoptotic function by regulating cellular redox state.
  • Nitric oxide and reactive oxygen species are not required for hypersensitive cell death but induce apoptosis in the adjacent cells during the defense response of oats.
    TADA Y; MORI T; SHINOGI T; YAO N; TAKAHASHI S; BETSUYAKU S; SAKAMOTO M; PARK P; NAKAYASHIKI Hitoshi; TOSA Yukio; MAYAMA Shigeyuki
    Mol. Plant-Microbe Interact. 17,245-253 2004年
  • N Yao; Y Tada; M Sakamoto; H Nakayashiki; P Park; Y Tosa; S Mayama
    PLANT JOURNAL 30 5 567 - 579 2002年06月 [査読有り]
     
    Apoptotic cell response in oats is induced by victorin, a host-selective toxin secreted by Cochliobolus victoriae and thought to exert toxicity by inhibiting mitochondrial glycine decarboxylase (GDC) in Pc-2/Vb oats. We examined the role of mitochondria, especially the organelle-derived production of reactive oxygen species (ROS), in the induction of apoptotic cell death. Cytofluorimetric analysis showed that victorin caused mitochondrial AT,, breakdown and mitochondrial oxidative burst. Ultrastructural analysis using a cytochemical assay based on the reaction of H2O2 with CeCl3 detected H2O2 eruption at permeability transition pore-like sites on the mitochondrial membrane in oat cells treated with victorin. ROS generation preceded the apoptotic cell responses seen in chromatin condensation and DNA laddering. Both aminoacetonitrile (a specific GDC inhibitor) and antimycin A (a mitochondrial complex III inhibitor) also induced mitochondrial H2O2 eruption, and led to the apoptotic response in oat cells. ROS scavengers such as N-acetyl-L-cysteine and catalase suppressed the mitochondrial oxidative burst and delayed chromatin condensation and DNA laddering in the victorin- or antimycin A-treated leaves. These findings indicate possible involvement of mitochondria, especially mitochondrial-derived ROS generation, as an important regulator in controlling apoptotic cell death in oats.

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  • 日本学術振興会：科学研究費助成事業
    研究期間 : 2023年04月 -2026年03月 
    代表者 : 坂本 勝
  • 日本学術振興会：科学研究費助成事業
    研究期間 : 2020年04月 -2023年03月 
    代表者 : 坂本 勝
     
    本研究の目的は、植物において未解明である硫化水素シグナルの全体像を明らかにすることであり、その中でも硫化水素処理によりレタスに誘導されるアントシアニン蓄積現象に関して、その現象の詳細の解明とシグナル因子の探索を行うことである。昨年度は、実験の基盤として、硫化水素の処理方法について検討を行い、硫化水素ドナーとして硫化水素ナトリウムを用い、スプレー処理や浸漬処理、間接暴露処理、水耕液処理などの方法を、処理時間・処理濃度を変えて検討し結果、水耕液処理で硫化水素ナトリウム処理によりレタスのアントシアニン蓄積が促進されることを確認した。 本年度、処理条件を検討したところ、本実験の硫化水素誘導性アントシアニン蓄積現象は、培養液処理下では顕著な蓄積は生じず、栄養欠乏条件（水処理）下で顕著な蓄積現象が認められた。そこで、この栄養欠乏時のレタスの生理的な変化を観察したところ、栄養欠乏単独でもアントシアニン蓄積が誘導されることが明らかとなった。また、栄養欠乏時の硫化水素を定量したところ、アントシアニン蓄積時に根部で含量が増加することが明らかとなった。植物の生理的な現象の中で、アントシアニン蓄積と硫化水素増加がリンクする現象が見出されたことから、この現象の解明についてさらに研究を行っていく予定である。特に、栄養欠乏時に誘導されるアントシアニン蓄積現象に関して、硫化水素や活性酸素、エチレンがどのように関わっているのかを明確にしていく予定である。

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