Elucidation of the host-mediated selection mechanism for rhizobia after intracellular symbiosis establishment and evaluation of its impact on the soil rhizobial community

2022 Fiscal Year Final Research Report

• Project/Area Number: 20H02884
• 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: Tohoku University
• Principal Investigator: Sato Shusei 東北大学, 生命科学研究科, 教授 (70370921)
• Project Period (FY): 2020-04-01 – 2023-03-31
• Keywords: 宿主-根粒菌相互作用 / Cheating根粒菌 / 宿主制裁機構 / 溶菌制御 / G x G 相互作用

Outline of Final Research Achievements

The host sanction system against cheating rhizobia (infectious but non-nitrogen fixing rhizobia) is the crucial mechanisms for maintaining symbiotic relationships. In this study, we investigated the molecular mechanisms of host sanction system by using its mutant isolated in L. japonicus and filed isolated cheating rhizobia with different levels of nitrogen fixation. As a result, we revealed that the sanctions against cheating rhizobia are mediated through the control of membrane mediated rhizobial lysis levels corresponding to their nitrogen-fixing abilities. Additionally, we found that the causal gene of the mutant is widely conserved in angiosperms, and their expression levels decrease during symbiosis with functional rhizobia.

Free Research Field

植物-微生物相互作用

Academic Significance and Societal Importance of the Research Achievements

本研究により、これまで不明であった根粒特異的な抗菌ペプチドを持たないミヤコグサにおけるcheating根粒菌に対する制裁機構が、マメ科植物に特異的なものではなく、被子植物に広く保存されている防御反応を応用している可能性が示された。今後この遺伝子の機能解析や共生過程で制御機構の解析を進めることにより、細胞内共生の成立起源につながるような知見が得られることが期待される。