2004 Fiscal Year Final Research Report Summary
Post-genomic approaches to reaction mechanism and ecophysiological functions of P450 and terpene synthases of leguminous plants
| Project/Area Number |
14540603
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
植物生理
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| Research Institution | Nihon University |
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Principal Investigator |
AYABE Shin-ichi Nihon University, College of Bioresource Sciences, Professor, 生物資源科学部, 教授 (40050679)
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| Co-Investigator(Kenkyū-buntansha) |
AOKI Toshio Nihon University, College of Bioresource Sciences, Associate Professor, 生物資源科学部, 助教授 (80287606)
AKASHI Tomoyoshi Nihon University, College of Bioresource Sciences, Assistant Professor, 生物資源科学部, 助手 (80328707)
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| Project Period (FY) |
2002 – 2004
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| Keywords | The Leguminosae / Model plant / Lotus japonicus / Cytochrome P450 / Triterpene synthase / Molecular evolution / Isoflavonoid / Transformation |
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| Research Abstract |
Cytochrome P450s and triterpene synthases (oxidosqualene cyclases, OSCs) are responsible for the remarkable diversity of plant constituents. In this project, their protein/gene structures, catalysis modes, specific expression and ecophysiological functions, and the mechanism of their molecular evolution were investigated. The main experimental material was the model legume Lotus japonicus.
Following cataloging of P450s of L.japonicus, the gene structure of P450 IFS, the critical enzyme for the construction of legume-characteristic isoflavonoid skeleton was analyzed, and a specific tandem localization of an IFS gene with an OMT of the isoflavonoid pathway in L.japonicus genome was clarified. The gene structure and expression of a P450 which was estimated to be important in the development and functions of nitrogen fixing root nodules were also examined. Further, key amino acid residues for the unique aryl migration during the P450 IFS reaction were identified through protein engineering
… More
approaches.
OSC genes of L.japonicus were analyzed as comprehensively as possible, and eight genes including β-amyrin, lupeol and cycloartenol synthases and a pseudogene were identified. Molecular phylogenetic analysis with L.japonicus and other plant OSC genes indicated the remarkable diversity of triterpene skeletons is mainly brought about through mutations in β-amyrin synthase genes. Transgenic L.japonicus plants in which OSCs are overexpressed or suppressed are being produced to examine the physiological functions of these genes, and protein engineering of OSCs to clarify the catalytic mechanism producing skeletal diversity is envisaged. For the overall analysis of transcription of the metabolic enzymes and accumulation of the products, profiling of the constituents of the organs and cultured cells of L.japonicus is also performed.
This project yielded interesting findings especially in the protein/gene structures to produce specific natural products and also in the mechanism of molecular evolution of plant secondary metabolism. Less
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[Journal Article] cDNA cloning and biochemical characterization of S-adenosyl-L-methionine : 2,7,4'-trihydroxyisoflavanone 4'-O-methyltransferase, a critical enzyme of the legume isoflavonoid phytoalexin pathway2003
Author(s)
Akashi, T., Sawada, Y., Shimada, N., Sakurai, N., Aoki, T., Ayabe, S.
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Journal Title
Plant and Cell Physiology 44(2)
Pages: 103-112
Description
「研究成果報告書概要(欧文)」より
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[Journal Article] A cluster of genes encodes the two types of chalcone isomerase involved in the biosynthesis of general flavonoids and legume-specific 5-deoxy(iso) flavonoids in Lotus japonicus2003
Author(s)
Shimada, N., Aoki, T., Sato, S., Nakamura, Y., Tabata, S., Ayabe, S.
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Journal Title
Plant Physiology 131(3)
Pages: 941-951
Description
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[Journal Article] Cloning of cDNAs Encoding P450s in the Flavonoid/Isoflavonoid Pathway from Elicited Leguminous Cell Cultures2002
Author(s)
Ayabe, S., Akashi, T., Aoki, T.
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Journal Title
Methods in Enzymology, Cytochrome P450, Part C (Eds, Johnson, E.F., Waterman, M.R.)(Academic Press, San Diego)
Pages: 360-369
Description
「研究成果報告書概要(欧文)」より
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