隶属于beta-变形杆菌纲（proteobacteria）的根瘤菌，简称为beta-根瘤菌。申请者通过前期研究积累了丰富的beta-根瘤菌菌株资源，为深入研究beta-根瘤菌，本项目提出对beta-根瘤菌共生固氮基因分子进化及菌植互作分子基础进行初步研究。项目将通过beta-根瘤菌的全基因组测序和共生固氮基因簇的克隆测序，进行基于主要结瘤基因和主要固氮基因全长的系统发育分析，并对共生固氮基因分子的遗传和变异进行研究，对菌株全基因组中与生态适应相关的基因进行分析。同时通过对含羞草植物类黄酮物质和beta-根瘤菌结瘤因子的研究、菌植互作的差异蛋白组学研究，揭示beta-根瘤菌的分子基础及竞争结瘤机制。研究结果将丰富我国beta-根瘤菌在基因组和遗传学方面的研究资料，填补国内和国际空白，并推动beta-根瘤菌菌植互作的植物应答研究和beta-根瘤菌在工农业和环境治理方面的应用基础研究。

The term of beta-rhizobia was proposed as those rhizobium belonging to the beta-proteobacteria. At present, we had accumulated plenty of resources of beta-rhizobial strains through previous study. In order to further study these rhizobia, we intend to characterize molecular evolution of symbiotic nitrogen fixation genes of beta-rhizobia and molecular basis of plant-rhizobia interaction. The project will carry out whole genome sequencing of beta-rhizobia and symbiotic gene clusters will be cloned and sequenced to analyze phylogeny of main symbiotic nitrogen fixation gene based on full-length sequences of gene. While elucidating heredity and variation of symbiotic nitrogen fixation genes, and carry on analysis to the relate gene for ecoadaptability of beta-rhizobia through whole genome. The study will also perform to characterize flavones of Mimosa plant and nodulation factor, and study on differential proteomic of plant-rhizobial interaction for revealing the molecular basis of plant-rhizobia and the mechanisms of competitive nodulation for beta-rhizobia. The results will enrich the research data of the beta-rhizobia China in genomics and genetics, fill the blank of domestic and international, promote to study plant and beta-rhizobia interaction and basic application research in industry and agriculture or environment remediation.