| Project/Area Number |
14560088
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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 |
Bioproduction chemistry/Bioorganic chemistry
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| Research Institution | RIKEN (The Institute of Physical and Chemical Research) |
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Principal Investigator |
ASAMI Tadao RIKEN (The Institute of Physical and Chemical Research), Plant Functions Laboratory, Senior Scientist, 植物機能研究室, 副主任研究員 (90231901)
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| Co-Investigator(Kenkyū-buntansha) |
NAKANO Takeshi RIKEN (The Institute of Physical and Chemical Research), Plant Functions Laboratory, Senior Research Scientist, 植物機能研究室, 先任研究員 (30281653)
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| Project Period (FY) |
2002 – 2003
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| Project Status |
Completed (Fiscal Year 2003)
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| Budget Amount *help |
¥3,500,000 (Direct Cost: ¥3,500,000)
Fiscal Year 2003: ¥900,000 (Direct Cost: ¥900,000)
Fiscal Year 2002: ¥2,600,000 (Direct Cost: ¥2,600,000)
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| Keywords | abscisic acid / dioxygenase / carotenoid cleaving enzyme / phaseic acid / catabolism enzyme / cytochrome P450 / triazole / plant hormones / アブシシン酸 / カトテノイド開裂酵素 / 生合成阻害剤 / リグノステイルベン / NCED / NDGA / エポキシカロテノイド / キサントキシン / 気孔 |
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| Research Abstract |
In higher plants, the ABA biosynthesis pathway involves the oxidative cleavage of 9-cis-epoxycarotenoids, which may be the key regulatory step in the pathway catalyzed by 9-cis-epoxycarotenoid dioxygenase (NCED). We developed a new inhibitor of ABA biosynthesis targeting NCED and named it abamine (abscisic acid biosynthesis inhibitor with an amine moiety). Abamine is a competitive inhibitor of NCED, with a K_i of 38.8 μM. In 0.4 M mannitol solution, which mimics the effects of osmotic stress, abamine both inhibited stomatal closure in spinach leaves, which was restored by co-application of ABA, and increased luminescence intensity in RD29B::LUC transgenic Arabidopsis. The ABA content of plants in 0.4 M mannitol was increased approximately 16-fold as compared with that of controls, whereas 50 to 100 μM abamine inhibited about 50% of this ABA accumulation in both spinach leaves and Arabidopsis. Abamine-treated Arabidopsis was more sensitive to drought stress and showed a significant decrease in drought tolerance than untreated Arabidopsis. These results suggest that abamine is a novel ABA biosynthesis inhibitor that targets the enzyme catalyzing oxidative cleavage of 9-cis-epoxycarotenoids. To test the effect of abamine on plants other than Arabidopsis, it was applied to cress plants. Abamine enhanced radicle elongation in cress seeds, which could be due to a decrease in the ABA content of abamine-treated plants. Thus, it is possible to think that abamine should enable us to elucidate the functions of ABA in cells or plants and to find new mutants involved in ABA signaling.
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