2000 Fiscal Year Final Research Report Summary
Study on biosynthesis and signal transduction of brassinosteroids
| Project/Area Number |
11460057
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| Research Category |
Grant-in-Aid for Scientific Research (B).
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Bioproduction chemistry/Bioorganic chemistry
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| Research Institution | Teikyo University |
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Principal Investigator |
YOKOTA Takao Teikyo University School of Science and Engineering, Professor, 理工学部, 教授 (40011986)
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| Co-Investigator(Kenkyū-buntansha) |
KUNO Norihito Teikyo University Hitachi, Ltd., Researcher, 基礎研究所, 研究員
FURUYA Masaki Teikyo University Advanced Research Laboratory, 基礎研究所, 研究員
KAJITANI Masayuko Teikyo University School of Science and Engineering, Lecturer, 理工学部, 講師 (40233720)
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| Project Period (FY) |
1999 – 2000
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| Keywords | brassinosteroid / biosynthesis / signal transduction / gene / Pisum satiuum / tomato / gene expression |
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| Research Abstract |
1. Cloning of brassinosteroid biosynthesis and perception/signal transduction genes of Pisum sativum-The brassinosteroid biosynthesis gene LKB and signal transduction gene LKA were successfully cloned and their structures were elucidated. Furthermore, mutations in the lkb and lka mutants were specified, thereby revealing that these mutants are biosynthesis and perception/signal transduction mutants, respectively.
2. Regulation of brassinosteroid biosynthesis rates-The levels of endogenous brassinosteroids in shoots of pea, Arabidopsis and tomato were quantified. Based on these data, the presence of three common rate-limiting steps in these plants was demonstrated, including conversion of campestanol to 6-deoxocathasterone (C-22 hydroxylation), of 6-deoxocathasterone to 6-deoxoteasterone (C-23 hydroxylation) and of 6-deoxocastasterone to castasterone (C-6 oxidation). Using the tomato mutant cu-3 that is insensitive to brassinosteroids, the C-6 oxidation is feedback regulated by perception/signaling gene (s).
3. Gene expression-Genes upregulated by brassinolide that were termed BLU1 and BLU2 were isolated using the dwarf pea mutant lkb. BLU1 coded a new protein with 26 amino acid repeats and had a high homology to the pea gene S2 that was known to be expressed in stems, as well as to the chickpea gene CanST-2 that may be involved in cell elongation. BLU2 encoded a new cytochrome P450 with a high homology to the CYP766B15 gene that is involved in the synthesis of coumarin, a defense compound.
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