Regulation of leguminous nodule development by communication between host symbiosis pathway and existing pathways

2022 Fiscal Year Final Research Report

• Project/Area Number: 19K05959
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 38060:Applied molecular and cellular biology-related
• Research Institution: National Institute for Basic Biology
• Principal Investigator: Soyano Takashi 基礎生物学研究所, 共生システム研究部門, 准教授 (60532819)
• Project Period (FY): 2019-04-01 – 2022-03-31
• Keywords: 根粒共生 / 根粒進化 / 器官形成 / 遺伝子発現制御 / ミヤコグサ

Outline of Final Research Achievements

To elucidate the spatial regulation of nodule formation in legumes, we focused on Lotus japonicus PUCHI gene as being involved in the lateral inhibition of nodule primordium formation and found that it acts in a positive feedback pathway to regulate NIN transcription factor gene that is essential for nodule formation based on phenotypes and gene expression profiles in roots overexpressing PUCHI. This regulation was mediated by the NIN promoter region required for its cytokinin response. We also analyzed the relationship between ethylene, a diffusible factor that suppresses nodule primordium formation, and PUCHI and found that PUCHI positively regulates the expression of an ethylene synthesis gene, which is induced by rhizobia.

Free Research Field

植物微生物相互作用

Academic Significance and Societal Importance of the Research Achievements

根粒共生は既存の様々な経路を流用しながら進化したと考えられている。側根の発達にも作用するPUCHI遺伝子が根粒の発達に影響することを明らかにし、先行研究で提唱した側根発達経路の根粒形成への流用といった考え方を補完する結果が得られた。さらにPUCHIが根粒形成を直接的に制御する遺伝子の発現を誘導したことから、共生経路が単に側根発達経路に働きかけているだけでなく、双方向に相互作用していることが分かり、これまでの考え方をさらに発展させた。