Mechanisms of symbiotic evolution and N2O mitigation of soybean bradyrhizobia

2016 Fiscal Year Final Research Report

• Project/Area Number: 26252065
• Research Category: Grant-in-Aid for Scientific Research (A)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Applied molecular and cellular biology
• Research Institution: Tohoku University
• Principal Investigator: Minamisawa Kiwamu 東北大学, 生命科学研究科, 教授 (70167667)
• Co-Investigator(Kenkyū-buntansha): 佐藤 修正 東北大学, 生命科学研究科, 准教授 (70370921) ; 内田 隆史 東北大学, (連合)農学研究科(研究院), 教授 (80312239)
• Project Period (FY): 2014-04-01 – 2017-03-31
• Keywords: 生物間相互作用 / 共生 / 脱窒 / タンパク質分泌系 / エフェクター / 根粒菌 / ダイズ

Outline of Final Research Achievements

Rj2 restricts nodulation by specific rhizobial strains including Bradyrhizobium diazoefficiens USDA122. We identified a T3SS effector gene that induces the incompatibility to Rj2-soybeans. These results suggested that hosts monitor the rhizobial T3SS effector during infection and reject nodulation via host R protein. B. diazoefficiens is able to scavenge the greenhouse gas N2O through the N2O reductase. Comparative analysis of Nos(++) mutant genomes showed that nasS mutation of resulted in Nos(++) phenotype. nasS mutation induced nosZ via NasT. NO3(-) addition dissociated the NasS-NasT complex in vitro, suggesting the release of the activator NasT. Disruption of nasT led to a marked decrease in nosZ transcription. Thus NasST regulates the NO3(-) -mediated response of nosZ gene. EMSA analysis suggested that nos expression is subjected to antitermination on both H1 and H2 hairpins upstream of nosR.

Free Research Field

植物微生物学、土壌微生物学