Improvement of N use efficiency in photosynthesis and plant productivity via enhancement of the photosynthetic carbon metabolism from carbon fixation to triose phosphate production

2023 Fiscal Year Final Research Report

• Project/Area Number: 21H02084
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Review Section: Basic Section 38010:Plant nutrition and soil science-related
• Research Institution: Iwate University
• Principal Investigator: Suzuki Yuji 岩手大学, 農学部, 教授 (80374974)
• Project Period (FY): 2021-04-01 – 2024-03-31
• Keywords: 光合成 / カルビンサイクル / 遺伝子組換え / イネ

Outline of Final Research Achievements

In this study, N use efficiency in photosynthesis and plant productivity was tried to be improved in rice. For this purpose, the photosynthetic carbon metabolism from carbon fixation to triose phosphate production was enhanced. Firstly, the reactions downstream carbon fixation were investigated and the enzyme for metabolic enhancement was identified. Then, three enzymes, including one previously found to be effective, were simultaneously overexpressed. However, photosynthesis or its N use efficiency was scarcely affected. Possibly, simultaneous overexpression of two enzymes downstream carbon fixation was not enough for substantial enhancement in the photosynthetic carbon metabolism. It seems necessary to simultaneously enhance the ATP and NADPH supply, which are required in this pathway.

Free Research Field

植物栄養学

Academic Significance and Societal Importance of the Research Achievements

本研究の最終的な目的は果たせなかったが、今後の光合成炭酸同化系の強化ポイント特定に有用な情報を提示することができた。方法的には、光合成炭酸同化に関与する酵素の三重増強という世界的に類を見ない試みがなされ、本研究の独自性となっている。また、これまでの光合成に関する常識を覆す結果等も得られている。例えば、これまでは光合成にとって大過剰に存在するとされてきた酵素が、実際には大過剰ではなく光合成をある程度律速しうるものであった。以上から、本研究の成果は、光合成炭酸同化の研究において、世界的にみても貴重なものとなっている。