生物膜具有抵抗环境胁迫和机体免疫防御功能，其形成过程会直接影响菌体的生存能力。群体感应作为菌体间交流的一种机制，其调控细菌生物膜形成过程是近年来研究的热点，但多集中于病原菌及有害菌。乳酸菌作为食品工业和人体肠道中重要的微生物，群体感应调控其生物膜形成机制的研究尚不明确。本研究从LuxS/AI-2群体感应系统出发，通过研究外界环境因子的刺激、群体感应系统的变化，掌握植物乳杆菌生物膜形成的规律及与AI-2活性的相关性。通过敲除luxS基因、转录组学分析及基因回补和外源添加AI-2来探究LuxS/AI-2群体感应系统调控植物乳杆菌生物膜的分子机制，提高生物膜的生成量和结构的稳定性。同时，验证生物被膜状态下植物乳杆菌抗环境胁迫的能力和益生特性。最终，期望建立有效调控形成稳定生物膜结构的方法，为植物乳杆菌在被膜态下更好地抵抗环境胁迫，发挥益生特性奠定基础，同时为有益菌生物膜的研究开辟新思路。

Biofilms have the abilities of resisting environmental stresses and against the body's immune defense, which directly affect the viability of bacteria. Quorum sensing which is defined as a mechanism of bacterial cell communication regulate the biofilm formation has come into people's horizon in recent years, though mainly focus on pathogenic microorganisms and harmful bacteria. As the important microorganism in the food industry and human intestinal tract, the mechanism of biofilm formation in lactic acid bacteria is still not clear. The project aims to explore the change law of the biofilm formation and the relationship between biofilm and AI-2 activity under external environmental factors stimulation from the perspective of LuxS/AI-2 QS system. The molecular mechanism of LuxS/AI-2 QS system, which regulates biofilm formation of Lactobacillus plantarum would be detected by deleting luxS gene, transcriptomics analysis, genetic complementation and addition exogenous AI-2, and thus improving the biofilm formation and its structural stability. Meanwhile, the ability to resist environmental stresses and probiotic properties of Lactobacillus plantarum under the bacterial biofilm condition would be verified. The project expects to establish an effective regulation method which can form a stable biofilm structure. The results of whole project contribute to lay a foundation to resist environmental stresses and exert its probiotic properties under the bacterial biofilm condition in Lactobacillus plantarum. At the same time, it provides new ideas for the research of beneficial microbial biofilms.