N-酰基高丝氨酸内酯（AHL）类信号系统是细菌群体感应（Quorum sensing，QS）中最为普遍的信号系统。AHL类信号系统主要分为两类：传统的（脂肪酰侧链）和新型的（芳香酰与氨基酰侧链）AHL信号系统。目前，对于新型AHL信号系统的研究还相对较浅，对新型AHL信号系统的调控网络也不够清晰。前期研究发现，新型AHL信号系统同源基因大量存在于根围细菌之中。本课题将对根围益生细菌包西氏菌OK403（Bosea sp. OK403）的新型AHL信号系统进行研究。前期工作中，已经完成了OK403信号合成酶bosI和转录调控因子bosR的敲除工作，构建了信号特异性的报告菌株，并进行了信号分子的初步分离工作。本项目将进行信号分子鉴定，化学合成信号分子，解析信号合成机制和生理功能调控机制；讨论植物根围分泌物与植物益生细菌群体感应的关系，为探索根围细菌群落的群体感应体系提供线索和打下基础。

N-acyl-homoserine lactone (AHL) is the most common quorum-sensing signal produced by bacteria, which includes two categories: traditional AHL (fatty acyl side chain) and new type AHL signal (aromatic acid or branched amino acid side chain). To date, the research on the new AHL signal system is limited, and the regulatory network is not clear. In previous studies, new AHL signal system seems epidemic in the rhizosphere proteobacteria. In this study, we focus on the investigation of the new AHL signal system produced by rhizosphere bacteria Bosea sp. OK403. In our preliminary work, the signal synthase bosI and the transcriptional regulator bosR in strain OK403 has been knockout, the signal specific reporter strain has been constructed, and finished the first round signal purification. In this project, we will identify signal molecule, synthesize the signal molecules, figure out signal synthesis mechanism and regulation mechanism. Furthermore, relationship between bacterial quorum sensing and plant rhizosphere will be discussed. Findings in this study will provide clues to explore the quorum sensing of rhizosphere bacterial community.