2018 Fiscal Year Final Research Report
Elucidation of mechanism for GS2-dependent ammonium sensitivity in Arabidopsis thaiana
| Project/Area Number |
17K15237
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| Research Category |
Grant-in-Aid for Young Scientists (B)
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| Allocation Type | Multi-year Fund |
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| Research Field |
Plant nutrition/Soil science
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| Research Institution | Shimane University (2018)
Nagoya University (2017) |
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Principal Investigator |
HACHIYA TAKUSHI 島根大学, 学術研究院農生命科学系, 助教 (80709311)
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| Project Period (FY) |
2017-04-01 – 2019-03-31
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| Keywords | アンモニア毒性 / アンモニウム毒性 / グルタミン合成酵素 / 酸ストレス |
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| Outline of Final Research Achievements |
The aim of the present study is to elucidate mechanism for ammonium toxicity with focus on an ammonium sensitivity gene GS2 that was captured by my positive screen. I have found that (1) proton-producing GS2 reaction overflowed proton-consuming GOGAT capacity in wild-type grown under ammonium than under nitrate, which was attenuated in gs2 mutant, (2) expression of acidic stress-responsive genes was stimulated and tissue acidity was increased in ammonium-grown wild-type, which was suppressed in ammonium-grown gs2 mutant, (3) an elevation of medium pH by applying alkaline ammonia alleviated ammonium toxicity in ammonium-grown wild-type. These suggest that acidic stress is a primary cause of ammonium toxicity.
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| Free Research Field |
植物栄養分子生理学
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| Academic Significance and Societal Importance of the Research Achievements |
近年のラボ及びフィールドでの解析から、21世紀後半に予測される高CO2環境において、C3型光合成を行う作物の硝酸態窒素の利用効率が大きく低下することが明らかになった。僅か1%の窒素利用効率の低下によって、世界で年間11億ドルものコストが増加するという試算もある。作物種の多くが好硝酸性のC3型であることから、主要作物の好アンモニア化は分子育種上重要な課題である。本研究は、アンモニア毒性の主要メカニズムを明らかにしただけでなく、作物の好アンモニア化に向けた分子ターゲットも提示することができた。
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