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AKIYAMA Ryota
Graduate School of Agricultural Science / Department of Agrobioscience
Assistant Professor

Researcher basic information

■ Research Keyword
  • 孵化促進物質
  • シストセンチュウ
  • グリコアルカロイド
  • ジオキシゲナーゼ
  • 二次代謝産物
■ Research Areas
  • Life sciences / Bioorganic chemistry
  • Life sciences / Applied biochemistry
■ Committee History
  • 2025 - 2026, 第42回 日本植物バイオテクノロジー学会（神戸）大会, 大会実行委員

Research activity information

■ Award
  • Sep. 2020 日本植物バイオテクノロジー学会, The JSPB Excellent Paper Award, Characterization of steroid 5α-reductase involved in α-tomatine biosynthesis in tomatoes.
    Ryota Akiyama, Hyoung Jae Lee, Masaru Nakayasu, Keishi Osakabe, Yuriko Osakabe, Naoyuki Umemoto, Kazuki Saito, Toshiya Muranaka, Yukihiro Sugimoto, Masaharu Mizutani

  • Sep. 2020 Japanese Society for Plant Biotechnology, The JSPB Award for Young Scientists, Elucidation of steroidal glycoalkaloid biosynthesis in Solanum species
    Ryota Akiyama

■ Paper
  • Ryota Akiyama, Yuki Ikeyama, Hyoung Jae Lee, Naoyuki Umemoto, Kenji Asano, Tetsuya Mori, Toshiya Muranaka, Kazuki Saito, Yukihiro Sugimoto, Masaharu Mizutani
    Apr. 2026, Proceedings of the National Academy of Sciences
    [Refereed]
    Scientific journal

  • Ryota Akiyama, Yuki Ikeyama, Hyoung Jae Lee, Bunta Watanabe, Naoyuki Umemoto, Kenji Asano, Toshiya Muranaka, Kazuki Saito, Yukihiro Sugimoto, Masaharu Mizutani
    Feb. 2026, Plant and Cell Physiology
    [Refereed]
    Scientific journal

  • Ryota Akiyama, Yui Kawano, Kosuke Shimizu, Soichiro Makino, Karen Akanuma, Haru Nagatomo, Masami Yokota Hirai, Yukihiro Sugimoto, Atsuhiko Kushida, Keiji Tanino, Masaharu Mizutani
    Aug. 2025, New Phytologist
    [Refereed]
    Scientific journal
    Link to Kobe Univ. Repository (Kernel)

  • Ryota Akiyama, Daiki Terami, Aozora Noda, Bunta Watanabe, Naoyuki Umemoto, Toshiya Muranaka, Kazuki Saito, Yukihiro Sugimoto, Masaharu Mizutani
    Summary Steroidal glycoalkaloids (SGAs) are specialized metabolites primarily produced by Solanaceae plants such as potatoes and tomatoes. Notably, α‐solanine and α‐chaconine are recognized as toxic substances in potatoes. While the biosynthetic pathways of SGAs are largely understood, the final steps of α‐solanine and α‐chaconine biosynthesis remained elusive. In this study, we discovered that two reductase‐encoding genes, reductase for potato glycoalkaloid biosynthesis 1 (RPG1) and RPG2, complete SGA biosynthesis in potato. Knockout of both RPG1 and RPG2 in potato hairy roots halted α‐solanine production, leading to the accumulation of zwittersolanine. We analyzed the catalytic function of recombinant enzymes and conducted structural determination of the reaction products by nuclear magnetic resonance. As a result, RPG1 converted zwittersolanine to 16‐iminiumsolanine, and RPG2 further converted it to α‐solanine. RPG2 also transformed zwittersolanine to 22‐iminiumsolanine, which RPG1 then converted to α‐solanine. Similar processes were observed for α‐chaconine synthesis from zwitterchaconine. Due to differences in enzymatic reaction efficiency, the biosynthetic pathway via 16‐iminiumsolanine/16‐iminiumchaconine was suggested to be predominant in potato. Our results could pave the way for tailoring SGA structures within Solanum plants, enabling the development of Solanum crop varieties with reduced toxicity or enhanced resistance to diseases and pests.
    Wiley, Jan. 2025, New Phytologist
    [Refereed]
    Scientific journal
    Link to Kobe Univ. Repository (Kernel)

  • Adam Jozwiak, Sayantan Panda, Ryota Akiyama, Ayano Yoneda, Naoyuki Umemoto, Kazuki Saito, Shuhei Yasumoto, Toshiya Muranaka, Sachin A. Gharat, Yana Kazachkova, Yonghui Dong, Shlomy Arava, Inna Goliand, Reinat Nevo, Ilana Rogachev, Sagit Meir, Masaharu Mizutani, Asaph Aharoni
    Decades of research on the infamous antinutritional steroidal glycoalkaloids (SGAs) in Solanaceae plants have provided deep insights into their metabolism and roles. However, engineering SGAs in heterologous hosts has remained a challenge. We discovered that a protein evolved from the machinery involved in building plant cell walls is the crucial link in the biosynthesis of SGAs. We show that cellulose synthase–like M [GLYCOALKALOID METABOLISM15 (GAME15)] functions both as a cholesterol glucuronosyltransferase and a scaffold protein. Silencing GAME15 depletes SGAs, which makes plants more vulnerable to pests. Our findings illuminate plant evolutionary adaptations that balance chemical defense and self-toxicity and open possibilities for producing steroidal compounds in heterologous systems for food, cosmetics, and pharmaceuticals.
    American Association for the Advancement of Science (AAAS), Dec. 2024, Science, 386(6728) (6728)
    [Refereed]
    Scientific journal

  • Shuhei Yasumoto, Hyoung Jae Lee, Ryota Akiyama, Satoru Sawai, Masaharu Mizutani, Naoyuki Umemoto, Kazuki Saito, Toshiya Muranaka
    Japanese Society for Plant Cell and Molecular Biology, Sep. 2024, Plant Biotechnology, 41(3) (3), 289 - 293
    [Refereed]
    Scientific journal

  • Naoyuki Umemoto, Shuhei Yasumoto, Muneo Yamazaki, Kenji Asano, Kotaro Akai, Hyoung Jae Lee, Ryota Akiyama, Masaharu Mizutani, Yozo Nagira, Kazuki Saito, Toshiya Muranaka
    Japanese Society for Plant Cell and Molecular Biology, Sep. 2023, Plant Biotechnology, 40(3) (3), 211 - 218
    [Refereed]
    Scientific journal

  • Ryota Akiyama, Naoyuki Umemoto, Masaharu Mizutani
    Lead, Japanese Society for Plant Cell and Molecular Biology, Sep. 2023, Plant Biotechnology, 40(3) (3), 185 - 191
    [Refereed]
    Scientific journal

  • Miki Hatada, Ryota Akiyama, Moeko Yamagishi, Kimitsune Ishizaki, Masaharu Mizutani
    Abstract Sterols are the essential components of the eukaryotic cell membranes. However, studies on sterol biosynthesis in bryophytes are limited. This study analyzed the sterol profiles in the bryophyte model plant Marchantia polymorpha L. The thalli contained typical phytosterols such as campesterol, sitosterol, and stigmasterol. BLASTX analysis of the M. polymorpha genome against the Arabidopsis thaliana sterol biosynthetic genes confirmed the presence of all of the enzymes responsible for sterol biosynthesis in M. polymorpha. In this study, we focused on characterizing two genes, MpDWF5A and MpDWF5B, which showed high homology with A. thaliana DWF5, encoding Δ5,Δ7-sterol Δ7-reductase. Functional analysis using a yeast expression system revealed that MpDWF5A converted 7-dehydrocholesterol to cholesterol, indicating that MpDWF5A is a Δ5,Δ7-sterol Δ7-reductase. Mpdwf5a-knockout lines (Mpdwf5a-ko) were constructed using CRISPR/Cas9 mediated genome editing. GC-MS analysis of Mpdwf5a-ko revealed that phytosterols such as campesterol, sitosterol, and stigmasterol disappeared, and instead, the corresponding Δ7-type sterols accumulated. The thalli of Mpdwf5a-ko grew smaller than those of the wild type, and excessive formation of apical meristem in the thalli was observed. In addition, the gemma cups of the Mpdwf5a-ko were incomplete, and only a limited number of gemma formations were observed. Treatment with 1 µM of castesterone or 6-deoxocastasterone, a bioactive brassinosteroid, partly restored some of these abnormal phenotypes, but far from complete recovery. These results indicate that MpDWF5A is essential for the normal growth and development of M. polymorpha and suggest that the dwarfism caused by the MpDWF5A defect is due to the deficiency of typical phytosterols and, in part, a brassinosteroid-like compound derived from phytosterols.
    Oxford University Press (OUP), May 2023, Plant And Cell Physiology, 64(7) (7), 826 - 838
    [Refereed]
    Scientific journal
    Link to Kobe Univ. Repository (Kernel)

  • Kosuke Shimizu, Ryota Akiyama, Yuya Okamura, Chihiro Ogawa, Yuki Masuda, Itaru Sakata, Bunta Watanabe, Yukihiro Sugimoto, Atsuhiko Kushida, Keiji Tanino, Masaharu Mizutani
    The potato cyst nematode (PCN) causes extensive crop losses worldwide. Because the hatching of PCN requires host-derived molecules known as hatching factors (HFs), regulating HF production in host plants may help to control this harmful pest. Solanoeclepin A (SEA), isolated from potato, is the most active HF for PCN; however, its biosynthesis is completely unknown. We discovered a HF called solanoeclepin B (SEB) from potato and tomato root exudates and showed that SEB was biosynthesized in the plant and converted to SEA outside the plant by biotic agents. Moreover, we identified five SEB biosynthetic genes encoding three 2-oxoglutarate-dependent dioxygenases and two cytochrome P450 monooxygenases in tomato. Exudates from tomato hairy roots in which each of the genes was disrupted contained no SEB and had low hatch-stimulating activity for PCN. These findings will help to breed crops with a lower risk of PCN infection.
    Lead, American Association for the Advancement of Science (AAAS), Mar. 2023, Science Advances, 9(11) (11)
    [Refereed]
    Scientific journal

  • Ryota Akiyama, Bunta Watanabe, Junpei Kato, Masaru Nakayasu, Hyoung Jae Lee, Naoyuki Umemoto, Toshiya Muranaka, Kazuki Saito, Yukihiro Sugimoto, Masaharu Mizutani
    Abstract Cultivated tomato (Solanum lycopersicum) contains α-tomatine, a steroidal glycoalkaloid (SGA), which functions as a defense compound to protect against pathogens and herbivores; interestingly, wild species in the tomato clade biosynthesize a variety of SGAs. In cultivated tomato, the metabolic detoxification of α-tomatine during tomato fruit ripening is an important trait that aided in its domestication, and two distinct 2-oxoglutarate-dependent dioxygenases (DOXs), a C-23 hydroxylase of α-tomatine (Sl23DOX) and a C-27 hydroxylase of lycoperoside C (Sl27DOX), are key to this process. There are tandemly duplicated DOX genes on tomato chromosome 1, with high levels of similarity to Sl23DOX. While these DOX genes are rarely expressed in cultivated tomato tissues, the recombinant enzymes of Solyc01g006580 and Solyc01g006610 metabolized α-tomatine to habrochaitoside A and (20R)-20-hydroxytomatine and were therefore named as habrochaitoside A synthase (HAS) and α-tomatine 20-hydroxylase (20DOX), respectively. Furthermore, 20DOX and HAS exist in the genome of wild tomato S. habrochaites accession LA1777, which accumulates habrochaitoside A in its fruits, and their expression patterns were in agreement with the SGA profiles in LA1777. These results indicate that the functional divergence of α-tomatine-metabolizing DOX enzymes results from gene duplication and the neofunctionalization of catalytic activity and gene expression, and this contributes to the structural diversity of SGAs in the tomato clade.
    Lead, Oxford University Press (OUP), May 2022, Plant and Cell Physiology, English, Domestic magazine
    [Refereed]
    Scientific journal

  • Ryota AKIYAMA, Masaharu MIZUTANI
    Japan Society for Bioscience, Biotechnology, and Agrochemistry, Mar. 2022, KAGAKU TO SEIBUTSU, 60(3) (3), 107 - 109
    Scientific journal

  • Masaru Nakayasu, Naoyuki Umemoto, Ryota Akiyama, Kiyoshi Ohyama, Hyoung J. Lee, Haruka Miyachi, Bunta Watanabe, Toshiya Muranaka, Kazuki Saito, Yukihiro Sugimoto, Masaharu Mizutani
    Wiley, Oct. 2021, The Plant Journal, 108(1) (1), 81 - 92
    [Refereed]
    Scientific journal

  • Ryota Akiyama, Masaru Nakayasu, Naoyuki Umemoto, Junpei Kato, Midori Kobayashi, Hyoung Jae Lee, Yukihiro Sugimoto, Yoko Iijima, Kazuki Saito, Toshiya Muranaka, Masaharu Mizutani
    Abstract Tomato (Solanum lycopersicum) contains α-tomatine, a steroidal glycoalkaloid that contributes to the plant defense against pathogens and herbivores through its bitter taste and toxicity. It accumulates at high levels in all the plant tissues, especially in leaves and immature green fruits, whereas it decreases during fruit ripening through metabolic conversion to the nontoxic esculeoside A, which accumulates in the mature red fruit. This study aimed to identify the gene encoding a C-27 hydroxylase that is a key enzyme in the metabolic conversion of α-tomatine to esculeoside A. The E8 gene, encoding a 2-oxoglutalate-dependent dioxygenase, is well known as an inducible gene in response to ethylene during fruit ripening. The recombinant E8 was found to catalyze the C-27 hydroxylation of lycoperoside C to produce prosapogenin A and is designated as Sl27DOX. The ripe fruit of E8/Sl27DOX-silenced transgenic tomato plants accumulated lycoperoside C and exhibited decreased esculeoside A levels compared with the wild-type (WT) plants. Furthermore, E8/Sl27DOX deletion in tomato accessions resulted in higher lycoperoside C levels in ripe fruits than in WT plants. Thus, E8/Sl27DOX functions as a C-27 hydroxylase of lycoperoside C in the metabolic detoxification of α-tomatine during tomato fruit ripening, and the efficient detoxification by E8/27DOX may provide an advantage in the domestication of cultivated tomatoes.
    Lead, Oxford University Press (OUP), Oct. 2021, Plant and Cell Physiology, 62(5) (5), 775 - 783, English, Domestic magazine
    [Refereed]
    Scientific journal

  • ジャガイモとトマトはおいしい野菜だが，毒がある？
    秋山 遼太, 中安 大, 水谷 正治
    Lead, Aug. 2021, ファルマシア, 57(8) (8), 726 - 730, Japanese

  • Ryota Akiyama, Bunta Watanabe, Masaru Nakayasu, Hyoung Jae Lee, Junpei Kato, Naoyuki Umemoto, Toshiya Muranaka, Kazuki Saito, Yukihiro Sugimoto, Masaharu Mizutani
    AbstractPotato (Solanum tuberosum), a worldwide major food crop, produces the toxic, bitter tasting solanidane glycoalkaloids α-solanine and α-chaconine. Controlling levels of glycoalkaloids is an important focus on potato breeding. Tomato (Solanum lycopersicum) contains a bitter spirosolane glycoalkaloid, α-tomatine. These glycoalkaloids are biosynthesized from cholesterol via a partly common pathway, although the mechanisms giving rise to the structural differences between solanidane and spirosolane remained elusive. Here we identify a 2-oxoglutarate dependent dioxygenase, designated as DPS (Dioxygenase for Potato Solanidane synthesis), that is a key enzyme for solanidane glycoalkaloid biosynthesis in potato. DPS catalyzes the ring-rearrangement from spirosolane to solanidane via C-16 hydroxylation. Evolutionary divergence of spirosolane-metabolizing dioxygenases contributes to the emergence of toxic solanidane glycoalkaloids in potato and the chemical diversity in Solanaceae.
    Lead, Springer Science and Business Media {LLC}, Feb. 2021, Nature Communications, 12(1) (1)
    [Refereed]
    Scientific journal

  • Kosuke Shimizu, Atsuhiko Kushida, Ryota Akiyama, Hyoung Jae Lee, Yuya Okamura, Yuki Masuda, Itaru Sakata, Keiji Tanino, Seiji Matsukida, Tsutomu Inoue, Yukihiro Sugimoto, Masaharu Mizutani
    Japanese Society for Plant Cell and Molecular Biology, Sep. 2020, Plant Biotechnology, 37(3) (3), 319 - 325, English
    [Refereed]
    Scientific journal

  • Nakayasu M, Akiyama R, Kobayashi M, Lee HJ, Kawasaki T, Watanabe B, Urakawa S, Kato J, Sugimoto Y, Iijima Y, Saito K, Muranaka T, Umemoto N, Mizutani M
    Tomato plants (Solanum lycopersicum) contain steroidal glycoalkaloid α-tomatine, which functions as a chemical barrier to pathogens and predators. α-Tomatine accumulates in all tissues and at particularly high levels in leaves and immature green fruits. The compound is toxic and causes a bitter taste, but its presence decreases through metabolic conversion to nontoxic esculeoside A during fruit ripening. This study identifies the gene encoding a 23-hydroxylase of α-tomatine, which is a key to this process. Some 2-oxoglutarate-dependent dioxygenases were selected as candidates for the metabolic enzyme, and Solyc02g062460, designated Sl23DOX, was found to encode α-tomatine 23-hydroxylase. Biochemical analysis of the recombinant Sl23DOX protein demonstrated that it catalyzes the 23-hydroxylation of α-tomatine and the product spontaneously isomerizes to neorickiioside B, which is an intermediate in α-tomatine metabolism that appears during ripening. Leaves of transgenic tomato plants overexpressing Sl23DOX accumulated not only neorickiioside B but also another intermediate, lycoperoside C (23-O-acetylated neorickiioside B). Furthermore, the ripe fruits of Sl23DOX-silenced transgenic tomato plants contained lower levels of esculeoside A but substantially accumulated α-tomatine. Thus, Sl23DOX functions as α-tomatine 23-hydroxylase during the metabolic processing of toxic α-tomatine in tomato fruit ripening and is a key enzyme in the domestication of cultivated tomatoes.
    Jan. 2020, Plant & cell physiology, 61(1) (1), 21 - 28, English, Domestic magazine
    [Refereed]
    Scientific journal

  • Akiyama R, Lee HJ, Nakayasu M, Osakabe K, Osakabe Y, Umemoto N, Saito K, Muranaka T, Sugimoto Y, Mizutani M
    α-tomatine and dehydrotomatine are steroidal glycoalkaloids (SGAs) that accumulate in the mature green fruits, leaves, and flowers of tomatoes (Solanum lycopersicum) and function as defensive compounds against pathogens and predators. The aglycones of α-tomatine and dehydrotomatine are tomatidine and dehydrotomatidine (5,6-dehydrogenated tomatidine), and tomatidine is derived from dehydrotomatidine via four reaction steps: C3 oxidation, isomerization, C5α reduction, and C3 reduction. Our previous studies (Lee et al. 2019) revealed that Sl3βHSD is involved in the three reactions except for C5α reduction, and in the present study, we aimed to elucidate the gene responsible for the C5α reduction step in the conversion of dehydrotomatidine to tomatidine. We characterized the two genes, SlS5αR1 and SlS5αR2, which show high homology with DET2, a brassinosteroid 5α reductase of Arabidopsis thaliana. The expression pattern of SlS5αR2 is similar to those of SGA biosynthetic genes, while SlS5αR1 is ubiquitously expressed, suggesting the involvement of SlS5αR2 in SGA biosynthesis. Biochemical analysis of the recombinant proteins revealed that both of SlS5αR1 and SlS5αR2 catalyze the reduction of tomatid-4-en-3-one at C5α to yield tomatid-3-one. Then, SlS5αR1- or SlS5αR2-knockout hairy roots were constructed using CRISPR/Cas9 mediated genome editing. In the SlS5αR2-knockout hairy roots, the α-tomatine level was significantly decreased and dehydrotomatine was accumulated. On the other hand, no change in the amount of α-tomatine was observed in the SlS5αR1-knockout hairy root. These results indicate that SlS5αR2 is responsible for the C5α reduction in α-tomatine biosynthesis and that SlS5αR1 does not significantly contribute to α-tomatine biosynthesis.
    Lead, Dec. 2019, Plant biotechnology (Tokyo, Japan), 36(4) (4), 253 - 263, English, Domestic magazine
    [Refereed]
    Scientific journal

  • Wakabayashi T, Hamana M, Mori A, Akiyama R, Ueno K, Osakabe K, Osakabe Y, Suzuki H, Takikawa H, Mizutani M, Sugimoto Y
    Strigolactones (SLs) are carotenoid-derived phytohormones and rhizosphere signaling molecules for arbuscular mycorrhizal fungi and root parasitic weeds. Why and how plants produce diverse SLs are unknown. Here, cytochrome P450 CYP722C is identified as a key enzyme that catalyzes the reaction of BC-ring closure leading to orobanchol, the most prevalent canonical SL. The direct conversion of carlactonoic acid to orobanchol without passing through 4-deoxyorobanchol is catalyzed by the recombinant enzyme. By knocking out the gene in tomato plants, orobanchol was undetectable in the root exudates, whereas the architecture of the knockout and wild-type plants was comparable. These findings add to our understanding of the function of the diverse SLs in plants and suggest the potential of these compounds to generate crops with greater resistance to infection by noxious root parasitic weeds.
    American Association for the Advancement of Science (AAAS), Dec. 2019, Science advances, 5(12) (12), eaax9067 - eaax9067
    [Refereed]
    Scientific journal

  • Lee HJ, Nakayasu M, Akiyama R, Kobayashi M, Miyachi H, Sugimoto Y, Umemoto N, Saito K, Muranaka T, Mizutani M
    α-Tomatine and dehydrotomatine are major steroidal glycoalkaloids (SGAs) that accumulate in the mature green fruits, leaves and flowers of tomato (Solanum lycopersicum), and function as defensive compounds against bacteria, fungi, insects and animals. The aglycone of dehydrotomatine is dehydrotomatidine (5,6-dehydrogenated tomatidine, having the Δ5,6 double bond; the dehydro-type). The aglycone of α-tomatine is tomatidine (having a single bond between C5 and C6; the dihydro-type), which is believed to be derived from dehydrotomatidine via four reaction steps: C3 oxidation, isomerization, C5 reduction and C3 reduction; however, these conversion processes remain uncharacterized. In the present study, we demonstrate that a short-chain alcohol dehydrogenase/reductase designated Sl3βHSD is involved in the conversion of dehydrotomatidine to tomatidine in tomato. Sl3βHSD1 expression was observed to be high in the flowers, leaves and mature green fruits of tomato, in which high amounts of α-tomatine are accumulated. Biochemical analysis of the recombinant Sl3βHSD1 protein revealed that Sl3βHSD1 catalyzes the C3 oxidation of dehydrotomatidine to form tomatid-4-en-3-one and also catalyzes the NADH-dependent C3 reduction of a 3-ketosteroid (tomatid-3-one) to form tomatidine. Furthermore, during co-incubation of Sl3βHSD1 with SlS5αR1 (steroid 5α-reductase) the four reaction steps converting dehydrotomatidine to tomatidine were completed. Sl3βHSD1-silenced transgenic tomato plants accumulated dehydrotomatine, with corresponding decreases in α-tomatine content. Furthermore, the constitutive expression of Sl3βHSD1 in potato hairy roots resulted in the conversion of potato SGAs to the dihydro-type SGAs. These results demonstrate that Sl3βHSD1 is a key enzyme involved in the conversion processes from dehydrotomatidine to tomatidine in α-tomatine biosynthesis.
    Jun. 2019, Plant & cell physiology, 60(6) (6), 1304 - 1315, English, Domestic magazine
    [Refereed]
    Scientific journal

  • Nakayasu M, Akiyama R, Lee HJ, Osakabe K, Osakabe Y, Watanabe B, Sugimoto Y, Umemoto N, Saito K, Muranaka T, Mizutani M
    Lead, Elsevier BV, Apr. 2018, Plant physiology and biochemistry : PPB, 131, 70 - 77
    [Refereed]
    Scientific journal

  • Akiyama Ryota, Nakayasu Masaru, Umemoto Naoyuki, Muranaka Toshiya, Mizutani Masaharu

    Steroidal glycoalkaloids （SGAs） are toxic specialized metabolites that are found in Solanaceae. Potato （Solanum tuberosum） contains the SGAs α-solanine and α-chaconine, which are biosynthesized from cholesterol. Several biosynthetic genes including SSR2 and two cytochrome P450 genes （CYP72A188 and CYP72A208） have been identified, and the transgenic potato plants silencing these biosynthetic genes showed SGA-reduced phenotypes. Here we summarize our recent results and strategy towards metabolic engineering of potato accumulating pharmaceutically useful compounds by genome editing. CYP88B1, which is involved in a later step of the SGA biosynthetic pathway with unknown catalytic function, is co-ordinately expressed with the SGA biosynthetic genes. We applied CRISPR/Cas9 system to knockout potato CYP88B1. The CYP88B1-knockout potatoes showed no accumulation of SGAs, and furthermore the corresponding amounts of steroidal saponins were accumulated in the knockout potatoes.

    The Japanese Society for Chemical Regulation of Plants, 2017, Regulation of Plant Growth & Development, 52(2) (2), 92 - 98, Japanese

■ MISC
  • シスト線虫孵化促進物質 : 単離構造決定と今後の展望—Hatching factors : Plant cues for cyst nematodes
    秋山 遼太, 串田 篤彦, 水谷 正治
    東京 : 植物化学調節学会, 2024, 植物の生長調節 = Regulation of plant growth & development, 59(2) (2), 109 - 114, Japanese

  • ジャガイモシストセンチュウ孵化促進物質ソラノエクレピンBおよび,その生合成遺伝子の発見
    秋山遼太, 水谷正治
    2024, 作物生産と土づくり, 56(2) (2)

  • ジャガイモシストセンチュウ類の孵化を促進する新規化合物「ソラノエクレピンB」の発見 ソラノエクレピンBの発見
    秋山遼太, 水谷正治
    2024, 化学と生物, 62(5) (5)

  • Analysis of biosynthesis mechanism of hatching factors for potato cyst nematodes
    秋山遼太, 清水宏祐, 串田篤彦, 谷野圭持, 杉本幸裕, 水谷正治
    2024, 日本植物生理学会年会(Web), 65th

  • Bioproduction of active vitamin D3 in transgenic tomato hairy roots
    水田珠希, 山岸萌子, 中川真太郎, 秋山遼太, 村中俊哉, 杉本幸裕, 水谷正治
    2024, 日本農芸化学会大会講演要旨集(Web), 2024

  • Identification of a novel hatching factor for potato cyst nematode, solanoeclepin B, and investigation of its biosynthesis
    秋山遼太, 清水宏祐, 坂田至, 串田篤彦, 渡辺文太, 谷野圭持, 杉本幸裕, 水谷正治
    2023, 日本植物生理学会年会(Web), 64th

  • ジャガイモシストセンチュウ孵化促進物質「ソラノエクレピンB」の発見
    秋山遼太, 水谷正治
    2023, バイオサイエンスとインダストリー, 81(5) (5)

  • トマトにおけるノルトロパンアルカロイド生合成の解析
    中江亜理紗, 秋山遼太, 加藤敦, 杉本幸裕, 水谷正治
    2023, 日本農芸化学会関西支部講演会講演要旨集, 528th

  • Analysis of acyl sugars secreted by tomato hairy roots
    石坂日和, 小川千景, 岡村勇哉, 秋山遼太, 杉本幸裕, 水谷正治
    2023, 植物の生長調節, 58(Supplement) (Supplement)

  • Biosynthesis and physiological roles of hatching factor for potato cyst nematodes
    秋山遼太, 清水宏祐, 坂田至, 串田篤彦, 谷野圭持, 杉本幸裕, 水谷正治
    2023, 植物の生長調節, 58(Supplement) (Supplement)

  • Structural analysis of substances related to potato cyst nematode hatching acceleration
    河野結, 秋山遼太, 清水宏祐, 坂田至, 串田篤彦, 谷野圭持, 杉本幸裕, 水谷正治
    2023, 植物の生長調節, 58(Supplement) (Supplement)

  • ジャガイモの毒はトマトの苦味から進化した!-ステロイドグリコアルカロイドの生合成研究で発見した新経路
    秋山遼太, 水谷正治
    2022, 化学, 77(2) (2)

  • ジャガイモの毒ソラニン生合成の鍵となる酵素の発見 酸素添加酵素の機能分化が生み出す構造多様性
    秋山遼太, 水谷正治
    2022, 化学と生物, 60(3) (3)

  • Marchantia DWF5A which is responsible for sterol 7-position reduction reaction, is involved in the development of thallus
    畑田珠希, 秋山遼太, 石崎公庸, 水谷正治
    2022, 日本植物生理学会年会(Web), 63rd

  • Metabolic engineering of active vitamin D3 by transgenic plants
    山岸萌子, 中川真太郎, 畑田珠希, 秋山遼太, 三浦謙治, 刑部敬史, 刑部祐里子, 鈴木宗典, 杉本幸裕, 水谷正治
    2022, 日本農芸化学会大会講演要旨集(Web), 2022

  • Functional analysis of a novel candidate gene involved in steroidal glycoalkaloid biosynthesis
    米田彩乃, 秋山遼太, 中安大, 中安大, 刑部敬史, 刑部祐里子, 梅基直行, 斎藤和季, 村中俊哉, 安本周平, 三浦謙治, 杉本幸裕, 水谷正治
    2022, 日本農芸化学会大会講演要旨集(Web), 2022

  • Identification of novel hatching factor for potato cyst nematode from potato hydroponic culture solution
    清水宏祐, 増田裕貴, 岡村勇哉, 小川千景, 秋山遼太, 渡辺文太, 坂田至, 串田篤彦, 谷野圭持, 杉本幸裕, 水谷正治
    2022, 日本農芸化学会大会講演要旨集(Web), 2022

  • Tomato mutations in the E8 gene on chromosome 9 that affect taste and flavor
    梅基直行, 秋山遼太, 山本英司, 斉藤和季, 水谷正治
    2022, 園芸学研究 別冊, 21(2) (2)

  • Evolution of steroid biosynthetic enzymes in plants and their use in metabolic engineering
    水谷正治, 秋山遼太
    2022, 植物の生長調節, 57(2) (2)

  • Exploration of a novel hatching factor for potato cyst nematode
    清水宏祐, 秋山遼太, 増田裕貴, 坂田至, 串田篤彦, 谷野圭持, 刑部敬史, 渡辺文太, 杉本幸裕, 水谷正治
    2022, 植物の生長調節, 57(Supplement) (Supplement)

  • Lack of delta 5,7-sterol-delta7-reductase (DWF5) in Marchantia polymorpha causes brassinosteroid deficiency
    畑田珠希, 秋山遼太, 石崎公庸, 水谷正治
    2022, 植物の生長調節, 57(Supplement) (Supplement)

  • 2-oxoglutarate dependent dioxygenases involved in biosynthesis of steroidal glycoalkaloids
    秋山遼太, 中安大, 中安大, 渡辺文太, 加藤純平, LEE Hyoung Jae, 飯島陽子, 梅基直行, 村中俊哉, 齊藤和季, 齊藤和季, 杉本幸裕, 水谷正治
    2022, 日本植物生理学会年会(Web), 63rd

  • ジャガイモとトマトのアルカロイドの毒性を決定するジオキシゲナーゼの発見
    秋山遼太, 水谷正治
    2021, バイオサイエンスとインダストリー, 79(5) (5)

  • Elucidation of biosynthetic pathway of canonical strigolactone
    若林孝俊, 若林孝俊, 濱名実咲, 森采美, 北野友里恵, 支田香澄, 秋山遼太, 刑部敬史, 刑部祐里子, 水谷正治, 杉本幸裕, 杉本幸裕
    2020, 日本農芸化学会大会講演要旨集(Web), 2020

  • カーラクトン酸をオロバンコールへ変換する新規オロバンコール合成酵素の同定
    若林孝俊, 若林孝俊, 濱名実咲, 森采美, 刑部敬史, 刑部祐里子, 秋山遼太, 水谷正治, 杉本幸裕, 杉本幸裕
    2019, 植物の生長調節, 54(Supplement) (Supplement)

  • ジャガイモのソラニン生合成系のソラニダン形成に関わる還元酵素の解析
    野田蒼空, 秋山遼太, 李榮宰, 中安大, 刑部敬史, 刑部祐里子, 梅基直行, 斉藤和季, 村中俊哉, 杉本幸裕, 水谷正治
    2019, 日本農芸化学会関西支部講演会講演要旨集, 510th

  • ジャガイモのソラニン生合成におけるソラニダン骨格形成機構の解析
    秋山遼太, 中安大, 李けい宰, 加藤純平, 梅基直行, 渡辺文太, 村中俊哉, 斉藤和季, 斉藤和季, 杉本幸裕, 水谷正治
    2019, 日本植物細胞分子生物学会大会・シンポジウム講演要旨集, 37th

  • ジャガイモシストセンチュウ孵化促進物質の生合成に関与する酸化酵素の探索
    清水宏祐, 増田裕貴, 秋山遼太, 坂田至, 串田篤彦, 谷野圭持, 刑部敬史, 刑部祐里子, 杉本幸裕, 水谷正治
    2019, 日本植物細胞分子生物学会大会・シンポジウム講演要旨集, 37th

  • トマトにおけるα-トマチン生合成に関わる5位還元酵素の解析
    秋山遼太, 李ヒョン宰, 中安大, 刑部敬史, 刑部祐里子, 梅基直行, 村中俊哉, 杉本幸裕, 水谷正治
    2018, 日本植物細胞分子生物学会大会・シンポジウム講演要旨集, 36th

  • ナス属植物におけるステロイドグリコアルカロイドの構造多様性の進化
    水谷正治, 秋山遼太, 加藤純平, 中安大, 李栄宰, 渡辺文太, 浅野賢治, 梅基直行, 斉藤和季, 村中俊哉
    2018, 日本植物細胞分子生物学会大会・シンポジウム講演要旨集, 36th

  • 栽培種および野生種トマトにおけるα-トマチン代謝酵素遺伝子の機能解析
    秋山遼太, 加藤純平, LEE Hyong Jae, 渡辺文太, 中安大, 小林緑, 飯島陽子, 梅基直行, 村中俊哉, 杉本幸裕, 水谷正治
    2018, 日本農芸化学会大会講演要旨集(Web), 2018

  • ゲノム編集技術を用いた16DOX遺伝子の破壊による有用形質ジャガイモの作出
    藤本大輝, 秋山遼太, 中安大, 安本周平, 澤井学, 李榮宰, 李榮宰, 刑部祐里子, 刑部敬史, 梅基直行, 斉藤和季, 水谷正治, 村中俊哉
    2018, 日本農芸化学会関西支部講演会講演要旨集, 506th

  • ジャガイモのα-ソラニン生合成遺伝子と共発現する還元酵素の解析
    野田蒼空, 秋山遼太, 李榮宰, 中安大, 刑部敬史, 刑部祐里子, 梅基直行, 村中俊哉, 杉本幸裕, 水谷正治
    2018, 日本植物細胞分子生物学会大会・シンポジウム講演要旨集, 36th

  • ゲノム編集によるジャガイモCYP88B1遺伝子の破壊
    安本周平, LEE Hyoung Jae, 秋山遼太, 澤井学, 島津知華, 關光, 梅基直行, 水谷正治, 斉藤和季, 村中俊哉
    2018, 日本農芸化学会大会講演要旨集(Web), 2018

  • CRISPR/Cas9によるジャガイモα-ソラニン生合成遺伝子のゲノム編集
    秋山遼太, 中安大, LEE Hyong Jae, 刑部敬史, 刑部祐里子, 梅基直行, 村中俊哉, 斉藤和季, 杉本幸裕, 水谷正治
    2017, 日本農芸化学会大会講演要旨集(Web), 2017

  • ジャガイモα-ソラニン生合成遺伝子St16DOXのゲノム編集
    秋山遼太, 中安大, 李栄宰, 刑部敬史, 刑部祐里子, 渡辺文太, 梅基直行, 村中俊哉, 斉藤和季, 杉本幸裕, 水谷正治
    2017, 日本植物細胞分子生物学会大会・シンポジウム講演要旨集, 35th

  • ステロイドグリコアルカロイド生合成遺伝子CYP88B1をターゲットとしたゲノム編集ジャガイモの解析
    秋山遼太, 中安大, 李えい宰, 刑部敬史, 刑部祐里子, 梅基直行, 斉藤和季, 村中俊哉, 杉本幸裕, 水谷正治
    2016, 日本植物細胞分子生物学会大会・シンポジウム講演要旨集, 34th

  • ナス科作物のステロイドグリコアルカロイド生合成遺伝子を標的としたゲノム編集植物の解析
    水谷正治, 秋山遼太, 中安大, 李栄宰, 刑部敬史, 刑部祐里子, 梅基直行, 斉藤和希, 杉本幸裕, 村中俊哉
    2016, 日本植物学会大会研究発表記録, 80th

  • ステロイドグリコアルカロイド生合成遺伝子SGA3をターゲットとしたゲノム編集トマトの解析
    秋山遼太, 中安大, LEE Hyoung-Jae, 刑部敬史, 刑部祐里子, 梅基直行, 村中俊哉, 斉藤和希, 斉藤和希, 杉本幸裕, 水谷正治
    2016, 日本農芸化学会大会講演要旨集(Web), 2016

  • ジャガイモCYP88B1のゲノム編集による有毒α-ソラニンから有用サポニンへの代謝変換
    秋山遼太, 中安大, 李榮宰, 刑部敬史, 刑部祐里子, 梅基直行, 村中俊哉, 斉藤和季, 杉本幸裕, 水谷正治
    2016, 日本農芸化学会関西支部講演会講演要旨集, 497th

■ Lectures, oral presentations, etc.
  • ソラノエクレピン生合成経路の解析
    秋山 遼太, 赤沼 花恋, 須澤 尚太, 串田 篤彦, 谷野 圭持, 水谷 正治
    日本農芸化学会2026年度京都大会, Mar. 2026
    Oral presentation

  • Solanoeclepin Bにアセチル基を転移させてsolanoeclepin Cを生成するナス科由来アセチル基転移酵素の同定
    須澤尚太, 永友陽, 秋山遼太, 串田篤彦, 谷野圭持, 水谷正治
    日本農芸化学会2026年度京都大会, Mar. 2026, Japanese
    Oral presentation

  • Identification of an acetyltransferase involved in solanoeclepin C. biosynthesis in tomato
    Shota Suzawa, Ryota Akiyama, Haru Nafatomo, Atsuhiko Kushida, Keiji Tanino, Yukihiro Sugimoto, Masaharu Mizutani
    第42回 日本植物バイオテクノロジー学会（神戸）大会, Sep. 2025, Japanese
    Poster presentation

  • Analysis of genes encoding oxidase involved in Solanoeclepin biosynthesis in tomato
    赤沼花恋, 須澤尚太, 秋山遼太, 串田 篤彦, 谷野 圭持, 水谷 正治
    第42回 日本植物バイオテクノロジー学会（神戸）大会, Sep. 2025, Japanese
    Poster presentation

  • Functional Analysis of Glycoside Hydrolase involved in Steroid Glycoalkaloid Biosynthesis in Solanaceae Plants
    Yuki Ikeyama, Ryota Akiyaa, Naoyuki Umemoto, Masaharu Mizutani
    第42回 日本植物バイオテクノロジー学会（神戸）大会, Sep. 2025, Japanese
    Poster presentation

  • シストセンチュウ孵化促進物質 ：単離構造決定と今後の展望
    秋山遼太, 水谷正治
    2025年度（第32回）日本線虫学会大会, Sep. 2025, Japanese
    [Invited]
    Public discourse

  • Neofunctionalization of dioxygenases drives the structural diversity of steroidal glycoalkaloids in wild potato
    Yuki Ikeyama, Ryota Akiyama, Hyoung Jae Lee, Bunta Watanabe, Naoyuki Umemoto, Kazuki Saito, Yukihiro Sugimoto, Masaharu Mizutani
    TERPNET 2025, Aug. 2025, English
    Poster presentation

  • Identification of an acetyltransferase involved in the conversion of solanoeclepin B to solanoeclepin C
    Shota Suzawa, Ryota Akiyama, Haru Nagatomo, Atsuhiko Kushida, Keiji Tanino, Yukihiro Sugimoto, Masaharu Mizutani
    TERPNET 2025, Aug. 2025, English
    Poster presentation

  • Solanoeclepin C: A potential rhizosphere signaling molecule converted by soil microbes and hijacked by potato cyst nematodes
    Ryota Akiyama, Soichiro Makino, Karen Akanuma, Yukihiro Sugimoto, Atsuhiko Kushida, Keiji Tanino, Masaharu Mizutani
    TERPNET 2025, Aug. 2025, English
    Poster presentation

  • 新規ソラノエクレピン：ソラノエクレピンCの単離構造決定
    秋山 遼太, 河野 結, 串田篤彦, 谷野圭持, 杉本 幸裕, 水谷 正治
    植物化学調節学会第59回大会 (静岡), Nov. 2024, Japanese
    Poster presentation

  • ソラノエクレピンBからソラノエクレピンCへの変換を担う酵素の探索
    永友 陽, 秋山 遼太, 河野 結, 串田 篤彦, 谷野 圭持, 杉本 幸裕, 水谷 正治
    第41回日本植物バイオテクノロジー学会（仙台）大会, Aug. 2024, Japanese
    Oral presentation

  • トマト水耕液におけるソラノエクレピン類の生産条件の検討
    牧野壮一郎, 秋山 遼太, 串田 篤彦, 谷野 圭持, 杉本 幸裕, 水谷 正治
    第41回日本植物バイオテクノロジー学会（仙台）大会, Sep. 2024, Japanese
    Oral presentation

  • Isolation and structural determination of a novel solanoeclepin
    Ryota Akiyama, Yui Kawano, Atsuhiko Kushida, Keiji Tanino, Yukihiro Sugimoto, Masaharu Mizutani
    第41回日本植物バイオテクノロジー学会（仙台）大会, Sep. 2024, Japanese
    Oral presentation

  • Glycoalkaloid Diversity Caused by Dioxygenases from Duplication in the Potato Genome
    池山 倖, 秋山 遼太, 李 栄宰, 渡辺 文太, 浅野 賢治, 杉本 幸裕, 水谷 正治
    第41回日本植物バイオテクノロジー学会（仙台）大会, Aug. 2024, Japanese
    Oral presentation

  • Analysis of methyltransferases involved in solanoeclepin biosynthesis in tomato
    赤沼花恋, 須澤尚太, 秋山遼太, 串田 篤彦, 谷野 圭持, 水谷 正治
    第41回日本植物バイオテクノロジー学会（仙台）大会, Aug. 2024, Japanese
    Oral presentation

  • メタボローム解析によるソラノエクレピンの生合成経路の解析
    須澤 尚太, 秋山 遼太, 串田 篤彦, 谷野 圭持, 杉本 幸裕, 水谷 正治
    第41回日本植物バイオテクノロジー学会（仙台）大会, Aug. 2024, Japanese
    Oral presentation

  • Analysis of biosynthesis mechanism of hatching factors for potato cyst nematodes
    Ryota Akiyama, Kosuke Shimizu, Atsuhiko Kushid, Keiji Tanino, Yukihiro Sugimoto, Masaharu Mizutani
    第65回日本植物生理学会年会, Mar. 2024, Japanese
    Poster presentation

  • Solanoeclepin B, a novel hatching factor for potato cyst nematode
    Ryota Akiyama
    理化学研究所セミナー, Jan. 2024, Japanese
    [Invited]
    Public discourse

  • トマト根由来のアシル糖の解析
    石坂日和, 小川千景, 岡村勇哉, 秋山遼太, 杉本幸裕, 水谷正治
    植物化学調節学会第58回大会 (川崎), Nov. 2023, Japanese
    Poster presentation

  • ジャガイモシストセンチュウ孵化促進関連物質の構造解析
    河野 結, 秋山遼太, 清水 宏祐, 坂田至, 串田篤彦, 谷野圭持, 杉本 幸裕, 水谷 正治
    植物化学調節学会第58回大会 (川崎), Nov. 2023, Japanese
    Poster presentation

  • シストセンチュウ孵化促進物質の植物生理機能解明を志向した生合成研究
    秋山 遼太, 清水 宏祐, 坂田至, 串田篤彦, 谷野圭持, 杉本 幸裕, 水谷 正治
    植物化学調節学会第58回大会 (川崎), Nov. 2023, Japanese
    Poster presentation

  • Analysis of biosynthetic genes for solanoeclepin B, a hatching factor for potato cyst nematodes
    Ryota Akiyama, Kosuke Shimizu, Atsuhiko Kushid, Keiji Tanino, Yukihiro Sugimoto, Masaharu Mizutani
    第40回 日本植物バイオテクノロジー学会（千葉）大会, Sep. 2023, Japanese
    Oral presentation

  • 植物はなぜシストセンチュウ孵化促進物質を生産するのか?
    秋山 遼太, 清水 宏祐, 串田 篤彦, 谷野 圭持, 杉本 幸裕, 水谷 正治
    第8回 植物の栄養研究会, Sep. 2023, Japanese
    Poster presentation

  • Solanoeclepin B, a novel hatching factor for potato cyst nematode
    Ryota Akiyama, Kosuke Shimizu, Itaru Sakata, Bunta Watanabe, Yukihiro Sugimoto, Atsuhiko Kushid, Keiji Tanino, Masaharu Mizutan
    The 24th International Conference on Plant Growth Substances, Jul. 2023
    Oral presentation

  • Identification of a novel hatching factor for potato cyst nematode, solanoeclepin B, and investigation of its biosynthesi
    Ryota Akiyama, Kosuke Shimizu, Itaru Sakata, Atsuhiko Kushid, Bunta Watanabe, Keiji Tanino, Yukihiro Sugimoto, Masaharu Mizutani
    第64回 日本植物生理学会年会, Mar. 2023, Japanese
    Oral presentation

  • Tandem Gene Duplication of Dioxygenases Drives the Structural Diversity of Steroidal Glycoalkaloids in Solanaceae
    Ryota Akiyama, Masaru Nakayasu, Bunta Watanabe, Hyoung Jae Lee, Naoyuki Umemoto, Toshiya Muranaka, Kazuki Saito, Yukihiro Sugimoto, Masaharu Mizutani
    The XVII International Conference on the Plant Family of Solanaceae (SOL2022), Nov. 2022, English
    Oral presentation

  • Exploration of novel hatching factor for potato cyst nematode
    Ryota Akiyama, Kosuke Shimizu, Atsuhiko Kushida, Keiji Tanino, Bunta Watanabe, Yukihiro Sugimoto, Masaharu Mizutani
    The XVII International Conference on the Plant Family of Solanaceae (SOL2022), Nov. 2022, English
    Poster presentation

  • Analysis of biosynthesis of potato cyst nematode hatching factor using tomato hairy roots
    秋山遼太, 清水宏祐, 河野結, 坂田至, 串田 篤彦, 谷野 圭持, 刑部 敬史, 刑部 祐里子, 渡辺 文太, 杉本 幸裕, 水谷 正治
    第39回 日本植物バイオテクノロジー学会(堺)大会, Sep. 2022, Japanese
    Oral presentation

  • ジャガイモシストセンチュウ孵化促進物質生合成の解析
    秋山遼太, 清水宏祐, 岡村勇哉, 小川千景, 渡辺 文太, 串田篤彦, 谷野圭持, 杉本幸裕, 水谷正治
    「予知生合成科学」第一回若手シンポジウム, Aug. 2022, Japanese
    Oral presentation

  • ステロイドグリコアルカロイド生合成に関わる 2-オキソグルタル酸依存性ジオキシゲナーゼ
    秋山遼太, 中安大, 渡辺文太, 加藤純平, 李滎宰, 飯島陽子, 梅基直行, 村中俊哉, 齊藤和季, 杉本幸裕, 水谷正治
    第63回日本植物生理学会年会, Mar. 2022, Japanese
    Oral presentation

  • Elucidation of steroidal glycoalkaloid biosynthesis in Solanum species
    秋山遼太
    第38回 日本植物バイオテクノロジー学会(つくば)大会, Sep. 2021, Japanese
    [Invited]
    Invited oral presentation

■ Research Themes
  • マメ科植物におけるエクレピン類生合成機構の解明
    秋山 遼太
    日本学術振興会, 科学研究費助成事業, 学術変革領域研究(A), 国立研究開発法人理化学研究所, Apr. 2025 - Mar. 2027

  • 植物はなぜシストセンチュウ孵化促進物質を生産するのか?
    秋山 遼太
    日本学術振興会, 科学研究費助成事業 若手研究, 若手研究, 神戸大学, Apr. 2023 - Mar. 2026

  • シストセンチュウ孵化促進物質の植物―土壌微生物間相互作用における機能の解析
    サントリー生命科学財団, SUNBORグラント, 2023 - 2025

  • シストセンチュウ孵化促進物質生合成の解明と新奇防除法への応用
    科学技術振興機構（JST）, 戦略的創造研究推進事業 ACT-X「環境とバイオテクノロジー」領域, Oct. 2021 - Mar. 2024, Principal investigator

  • ナス科植物ステロイドグリコアルカロイドの化学進化
    秋山 遼太
    Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research Grant-in-Aid for JSPS Fellows, Grant-in-Aid for JSPS Fellows, Kobe University, Apr. 2019 - Mar. 2021
    1. トマトにおいてα-トマチン生合成に関わるステロイド5α位還元酵素遺伝子を同定した。トマトのRNA-seqデータより、候補遺伝子SlS5αR1とSlS5αR2を選抜した。組換え酵素を用いた機能解析では、SlS5αR1とSlS5αR2ともに推定生合成中間体に対してステロイド5α位還元活性を示した。さらに、CRISPR/Cas9によってそれぞれの遺伝子破壊系統を作成した結果、SlS5αR1ノックアウトではα-トマチン量は変化せず、SlS5αR2ノックアウトではα-トマチン量が大幅に低下した。以上より、SlS5αR1とSlS5αR2は同様の酵素機能を持つが、SlS5αR2のみがα-トマチン生合成に関わるステロイド5α位還元酵素遺伝子であることを明らかとなった。 2. ジャガイモにおけるα-ソラニン生合成の鍵酵素遺伝子であるStDOXSDが染色体上で7つのDOX遺伝子とクラスターを形成していることを見出した。このクラスターに含まれるDOX遺伝子のうちStDOXSDL1、StDOXSDL2の全長ORFを単離した。そのうち、StDOXSDL1はStDOXSDと同様の活性を有することが明らかとした。RNA干渉法による発現抑制実験の結果、StDOXSDL1はほとんどソラニン生合成には関与していないこと明らかとなった。StDOXSDは既知のSGAと同様な発現パターンを示すのに対してStDOXSDL1は異なった発現パターンを示した。ソラニン型SGAを生産しないトマトにもStDOX130同様の活性を有する酵素をコードする遺伝子が存在するが、単一遺伝子であり多重化していない。さらにこの遺伝子は全草で遺伝子の発現が見られなかった。以上の結果より、StDOXSDの祖先遺伝子がジャガイモにおいて多重化し、新たな発現制御を獲得することでソラニンを生産するようになったと示唆される。

■ Industrial Property Rights
  • Plant having enhanced resistance against colorado potato beetle and method for producing same, and method for evaluating resistance against colorado potato beetle in plant
    Naoyuki Umemoto, Masaharu Mizutani, Ryota Akiyama, Kenji Asano, Haruyasu HAMADA, Yozo NAGIRA, Akira Endo, Kazuki Saito
    特願17905518, 特開12391955
    Patent right

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