Studies on the induction mechanism and physiological role of chloroplast aggregative movements commonly observed in mesophyll cells of C4 plants

2022 Fiscal Year Final Research Report

• Project/Area Number: 20H02966
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Review Section: Basic Section 39020:Crop production science-related
• Research Institution: Nagoya University
• Principal Investigator: Taniguchi Mitsutaka 名古屋大学, 生命農学研究科, 教授 (40231419)
• Co-Investigator(Kenkyū-buntansha): 大井 崇生 名古屋大学, 生命農学研究科, 助教 (60752219)
• Project Period (FY): 2020-04-01 – 2023-03-31
• Keywords: C4植物 / 葉緑体 / 光合成 / 環境ストレス / 葉緑体運動 / CO2 / 葉肉細胞 / シコクビエ

Outline of Final Research Achievements

When C4 plants are exposed to environmental stresses, mesophyll chloroplasts scattered at the cell periphery undergo "aggregative movement" toward bundle sheath cells. In this study, we aimed to elucidate the induction mechanism and physiological role of the aggregative movement, and obtained the following results.
(1) The universality of aggregative movement in C4 plants was confirmed in a total of 36 C4 plant species across 11 different evolutionary lineages, including three C4 subtypes. (2) Decrease in CO2 concentration in leaves promotes aggregative movement under blue light. (3) The aggregative movement is also induced by low temperature stress under light. (4) Photorespiration may be involved in the induction of aggregative movement. (5) A different maldistribution of chloroplasts from the aggregative arrangement occurs in mesophyll cells of C3 plants.

Free Research Field

作物生理生化学

Academic Significance and Societal Importance of the Research Achievements

凝集運動は、高温，強光，乾燥などの過酷な環境下でも旺盛に生育するC4植物が獲得した生存戦略の一つである可能性が高い。凝集運動がC4植物全般で起こるとともに、低温ストレスでも誘導され、葉内CO2濃度低下や光呼吸との関連性が示されたことから、この葉緑体運動がストレス下での光合成能維持やストレス耐性能発揮のために重要であることがより鮮明となった。今後、運動の分子機構を明らかにし，作物の光合成能やストレス耐性能向上のための新たな分子基盤を提供できると考えられる。