2022 Fiscal Year Final Research Report
Experimental evaluation of the different evolution in photosynthetic regulation
| Project/Area Number |
21K19258
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| Research Category |
Grant-in-Aid for Challenging Research (Exploratory)
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| Allocation Type | Multi-year Fund |
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| Review Section |
Medium-sized Section 44:Biology at cellular to organismal levels, and related fields
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| Research Institution | Kyoto University |
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Principal Investigator |
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| Project Period (FY) |
2021-07-09 – 2023-03-31
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| Keywords | 光合成 / 葉緑体 / KEA3 / Flavidiironタンパク質 / シトクロムb6f複合体 / 変動光 / 気孔 / 光化学系Ⅰ |
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| Outline of Final Research Achievements |
Under fluctuating light conditions, photosynthetic electron transport toward photosystem I is downregulated by controlling the activity of the cytochrome b6f complex. This photosynthetic control is induced by monitoring the acidification of the thylakoid lumen. The process is essential especially for angiosperms because they lacked the safety valve (Flv) of electrons functioning at the acceptor side of photosystem I. To test whether the introduction of Flv into angiosperms permits the weaker operation of photosynthetic control, resulting in the higher efficiency of photosynthesis, we combined two transgenes, Flv and KEA3ox in Arabidopsis. Flv alleviated the photodamage of photosystem I under the KEA3ox background in the fluctuating light. We also observed the Flv-dependent upregulation of CO2 fixation and plant growth. The enhanced photosynthesis mainly depended on the larger stomatal opining in the Flv background.
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| Free Research Field |
植物生理学
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| Academic Significance and Societal Importance of the Research Achievements |
光化学系Ⅰを光傷害から守るには、上流での電子伝達抑制（photosynthetic control）とFlvによる下流からの電子の吸い出しが有効である。被子植物はFlvを失い、上流での制御に依存する戦略を選んだ。本研究は、シロイヌナズナにFlvを導入し、上流のブレーキを軽減することで、光化学系Ⅰの光傷害を防ぎながら光合成の効率を上げられるかを調べた挑戦的なものである。当初の予想を超え、Flvが変動光下で、気孔の開度を上げることで、CO2固定速度と植物の生育を上昇させることを明らかにした。電子伝達と気孔の開閉のリンクの未知の部分に光を当てる、学術、応用の両面で意義ある研究である
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