Unraveling mechanism underlying phototropin signaling based on cell-aunomous function of RPT2

• Project/Area Number: 19K06721
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 44030:Plant molecular biology and physiology-related
• Research Institution: The University of Tokyo (2021); Kyoto University (2019-2020)
• Principal Investigator: Noriyuki Suetsugu 東京大学, 大学院総合文化研究科, 准教授 (60514156)
• Project Period (FY): 2019-04-01 – 2022-03-31
• Project Status: Completed (Fiscal Year 2021)
• Budget Amount: ¥4,290,000 (Direct Cost: ¥3,300,000、Indirect Cost: ¥990,000); Fiscal Year 2021: ¥1,300,000 (Direct Cost: ¥1,000,000、Indirect Cost: ¥300,000); Fiscal Year 2020: ¥1,300,000 (Direct Cost: ¥1,000,000、Indirect Cost: ¥300,000); Fiscal Year 2019: ¥1,690,000 (Direct Cost: ¥1,300,000、Indirect Cost: ¥390,000)
• Keywords: フォトトロピン / 青色光 / シロイヌナズナ / ゼニゴケ / 光受容体 / 葉緑体運動

Outline of Research at the Start

光屈性、葉の展開、葉緑体運動など様々な光応答の青色光受容体であるフォトトロピンの相互作用因子RPT2は、組織・器官レベルの応答である光屈性と葉の展開だけでなく、細胞自律的な光応答である葉緑体運動の制御にも関わる。そのため、フォトトロピンによる信号伝達の初発過程は、RPT2を介した未知の細胞自律的機構によって統一的に説明できると考えられる。
そこで本研究では、RPT2を介したフォトトロピンシグナル発信の本質を解明するため、RPT2およびそのホモログNCH1の機能解析を徹底的に行う。さらに、遺伝子機能解析の容易なゼニゴケを利用し、陸上植物に共通するフォトトロピンシグナル発信の本質解明の迅速化を図る。

Outline of Final Research Achievements

To know how a phototropin (phot), a green-plant-specific blue-light photoreceptor, regulates blue-light responses at the cellular, tissue, and organ levels (i.e., chloroplast movement, phototropism, and leaf flattening), I analyzed two phototropin-interacting proteins, ROOT PHOTOTROPISM 2 (RPT2) and NRL PROTEIN FOR CHLOROPLAST MOVEMENT 1 (NCH1). Although RPT2 and NCH1 are highly similar, RPT2 mediates chloroplast movement, phototropism, and leaf flattening whereas NCH1 is specific to chloroplast movement. So, I examined the difference in the domains and the phosphorylation status between RPT2 and NCH1. Furthermore, I analyzed RPT2 and NCH1 complexes to reveal the mechanism underlying a phototropin signaling pathway.

Academic Significance and Societal Importance of the Research Achievements

本研究は光合成に必要な光の利用効率を最適化する現象である光屈性、葉の平滑化、葉緑体運動を制御する青色光受容体フォトトロピンの信号伝達系を明らかにすることにより、弱光環境下でも効率よく光を利用し最大限光合成を行いバイオマスを増進できる植物の作出に関する応用研究に役立つことが期待される。

Research Products

• [Int'l Joint Research] University of Glasgow(英国)
• [Journal Article] Regulation of plant phototropic growth by NPH3/RPT2-like substrate phosphorylation and 14-3-3 binding. (2021)
  • Author(s): Sullivan S, Waksman T, Paliogianni D, Henderson L, Lutkemeyer M, Suetsugu N, Christie JM.
  • Journal Title: Nat Commun. Volume: 12 Issue: 1 Pages: 6129-6129
  • DOI: 10.1038/s41467-021-26333-5
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Light-induced chloroplast movements in Oryza species (2020)
  • Author(s): Kihara M, Ushizima T, Yamagata Y, Tsuruda Y, Higa T, Abiko T, Kubo T, Wada M, Suetsugu N, Gotoh E
  • Journal Title: Journal of Plant Research Volume: in press
  • NAID: 40022267384
  • Peer Reviewed
• [Journal Article] Phototropin 2 contributes to the chloroplast avoidance response at the chloroplast-plasma membrane interface (2020)
  • Author(s): Ishishita K, Higa T, Tanaka H, Inoue S, Chung A, Ushizima T, Matsushita T, Kinoshita T, Nakai M, Wada M, Suetsugu N, Gotoh E
  • Journal Title: Plant Physiology Volume: in press Issue: 1 Pages: 59-59
  • DOI: 10.1104/pp.20.00059
  • Peer Reviewed / Open Access
• [Journal Article] Kinase in the liverwort Marchantia polymorpha; A photosynthesis-dependent kinase for carbon metabolism (2020)
  • Author(s): Koide E, Suetsugu N, Iwano M, Gotoh E, Nomura Y, Stolze SC, Nakagami H, Kohchi T, Nishihama R
  • Journal Title: Plant Cell & Physiology Volume: 61 Issue: 3 Pages: 631-643
  • DOI: 10.1093/pcp/pcz232
  • Peer Reviewed / Int'l Joint Research
• [Presentation] Elucidating the mechanism underlying phototropin signaling. How do phototropins regulate chloroplast movement? (2019)
  • Author(s): Suetsugu N
  • Organizer: 9th Asia and Oceania Conference for Photobiology “AOCP2019”
  • Int'l Joint Research / Invited
• [Book] 光合成 (2021)
  • Author(s): 日本光合成学会
  • Total Pages: 224
  • Publisher: 朝倉書店
  • ISBN: 9784254171761