根瘤菌的固氮效应是影响豆科作物生长的关键因素之一，而根瘤菌的群体感应(QS)则在该过程中发挥着极其重要的作用。目前，关于酸性土壤中铝胁迫条件下大豆根际可培养优势根瘤菌的QS及其介导的固氮效应还知之甚少。本研究拟以耐铝及铝敏感大豆为材料，采用宏基因组深度测序、C18反相薄层层析分析、GC-MS分析、结瘤及固氮效应分析、real-time PCR分析等策略，通过分离和鉴定耐铝及铝敏感大豆根际可培养优势根瘤菌、可培养优势根瘤菌的QS现象及其信号分子组成分析、QS所介导的大豆结瘤及固氮效应分析、大豆生长发育的多元指数特征分析等，阐明酸性土壤中铝胁迫条件下耐铝及铝敏感大豆的优势可培养根瘤菌及其QS差异以及介导的大豆固氮效应分子机制。本项目的完成将为深入理解酸性土壤中铝胁迫条件下大豆优势根瘤菌的QS现象及其调控的固氮效应分子机制奠定理论基础，并有望为酸性土壤上提高豆科作物的产量提供新思路和新方法。

Nitrogen (N)-fixation by rhizobia is one of the key factors for affecting the growth of leguminous crops, and quorum sensing (QS) of rhizobia plays important roles in this process. Up to now, it remains unclear about the quorum sensing of predominant rhizobia and their mediated N-fixation efficiency in the rhizosphere soil of soybeans under aluminum (Al) stress in acidic soil. In this project, Al-tolerant and Al-sensitive soybean genotypes were used as materials to isolate and identify the predominant rhizobia in the rhizosphere soil of the soybeans, to analyze the QS and QS signal components, to analyze soybean nodulation and N-fixation efficiency mediated by rhizobia, and to reveal the multiple index of the growth of two soybean genotypes, with the applications of metagenomics deep-sequencing, C18 reversed-phase thin-layer chromatography analysis, GC-MS, nodulation and N-fixation efficiency analysis, and real-time PCR, etc. Based on these results, we aim to clarify the difference of the QS and the molecular mechanism of QS-mediated N-fixation of the two soybean genotypes. The completion of this project will provide theoretical foundation for deeply understanding the QS and the molecular mechanism of QS-regulated N-fixation under Al stress, and it is also expected to provide new ideas and methods to improve the leguminous crop production in the acidic soils.