2018 Fiscal Year Final Research Report
Regulation of photosynthesis under variable light
| Project/Area Number |
26251033
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| Research Category |
Grant-in-Aid for Scientific Research (A)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Plant molecular biology/Plant physiology
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| Research Institution | National Institute for Basic Biology |
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Principal Investigator |
Minagawa Jun 基礎生物学研究所, 環境光生物学研究部門, 教授 (80280725)
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| Co-Investigator(Kenkyū-buntansha) |
得津 隆太郎 基礎生物学研究所, 環境光生物学研究部門, 助教 (60613940)
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| Research Collaborator |
Kamada Konomi
Yonezawa Harumi
Kojima Youko
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| Project Period (FY) |
2014-04-01 – 2018-03-31
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| Keywords | 光合成 |
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| Outline of Final Research Achievements |
Light is essential for photosynthesis, but the amounts of light that exceed an organism's assimilation capacity cause photooxidative stress. Photosynthetic organisms minimize such potential harm through protection mechanisms referred to as non-photochemical quenching. One such mechanism called qE quenching is readily activated under high-light conditions. In this study, we investigated the details of the induction mechanism of qE quenching in a green alga Chlamydomonas reinhardtii. LHCSRs have been proposed to mediate qE quenching in C. reinhardtii when grown under high-light conditions. We showed that qE requires blue-light perception by phototropin, LHCSRs gene expression, and light dissipation by LHCSRs transported in the chloroplast. We further showed that the phot mutation can be suppressed by mutations in an E3 ubiquitin ligase CUL4-DDB1(DET1), suggesting this DET1-dependent E3 ubiquitin ligase plays a vital role in the blue light signal transduction in green algae.
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| Free Research Field |
光合成
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| Academic Significance and Societal Importance of the Research Achievements |
ほぼすべての光合成生物は直射日光を苦手としていることが明らかになり、光合成生物が過剰光をいかに凌いで光合成を行うかの重要性の認識が高まっている。地球上の二酸化炭素固定量の約半分は水中の光合成生物（藻類）が担うが、多くの藻類では過剰光をしのぐ仕組み（qEクエンチング）を、必要に応じて「誘導」していることが知られている。本研究はこの誘導の根幹を分子レベルで初めて明らかにした。フォトトロピンという陸上植物では光屈性等で知られる青色光受容体が藻類では光防御の起点となることがわかった。さらにその下流のシグナル伝達因子も明らかになり、本研究により光合成の環境適応研究は細胞生物学の領域に入った。
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