Elucidation of the mechanism of phototropism and gravitropism of higher plants

2021 Fiscal Year Final Research Report

• Project/Area Number: 19K22268
• Research Category: Grant-in-Aid for Challenging Research (Exploratory)
• Allocation Type: Multi-year Fund
• Review Section: Medium-sized Section 38:Agricultural chemistry and related fields
• Research Institution: University of Tsukuba
• Principal Investigator: Shigemori Hideyuki 筑波大学, 生命環境系, 教授 (70202108)
• Co-Investigator(Kenkyū-buntansha): 平 修 福島大学, 食農学類, 教授 (30416672)
• Project Period (FY): 2019-06-28 – 2022-03-31
• Keywords: 光屈性 / 重力屈性 / 屈性制御物質 / raphanusanin / MTBI / Bruinsma-Hasegawa説 / MSイメージング

Outline of Final Research Achievements

The purpose of this study was to elucidate the mechanism of phototropism and gravitropism in plants using MTBI and raphanusanin, which are phototropism and gravitropism-regulated substances. Total syntheses of these tropism-regulated substances was carried out, various derivatives thereof were synthesized, and the structure-activity relationship of these compounds was investigated to identify the structural site important for the expression of activity. In addition, biological activity tests related to various tropism phenomena were conducted using these tropism-regulated substances, and the regulated mechanism was elucidated. Furthermore, using MS imaging, it was elucidated that these tropism-regulated substances were deviated and distributed at the tropic site. From the above, the results support the Bruinsma-Hasegawa theory that the tropism-regulated substances are involved in phototropism and gravitropism.

Free Research Field

天然物化学

Academic Significance and Societal Importance of the Research Achievements

Oxford大学やCambridge大学など海外の著名な大学の教科書にBruinsma-Hasegawa説が記載されているものの、日本の高校の生物の教科書では相変わらず Darwin, Boysen-Jensen, Wentらの古典的な実験が図解入りで記載されており、Cholodny-Went説によって光屈性のメカニズムが説明され、大学入試でも出題されている。本研究を通して光屈性および重力屈性の全容が分子レベルから解明されることによって、生物の教科書が改訂・補完されることになれば、学術の面だけでなく教育の面においても極めて重要な意義がある。