植物乳杆菌LCC-605糖基转移酶基因调控纳米胞外多糖自组装作用机制研究

微生物天然产生的功能性自组装纳米胞外多糖（EPS）是生物医药、食品、生物化工等领域的研究热点，深入研究其高级结构形成的精准调控机制将进一步推进其实际应用。根据前期研究结果及文献报道，申请人发现糖基转移酶（GTF）能够影响植物乳杆菌自组装纳米EPS的合成，但尚缺乏实验证实。本项目以申请人前期获得的产自组装纳米EPS的植物乳杆菌LCC-605为研究对象，构建负向突变株。通过全基因组测序、生物信息学分析，筛选与自组装纳米EPS合成相关的关键GTF编码基因，分析其功能特性；进一步通过基因过表达、基因敲除、基因回补、转录组测序和RT-qPCR等实验阐明其与自组装纳米EPS合成的关系及精准调控机制。通过本项目的实施，将获得参与自组装纳米EPS合成的关键GTF编码基因并阐明其作用机制，为基因工程改造植物乳杆菌、设计多功能EPS，实现其工业化应用提供重要的理论依据。

Functional self-assembled nanoscale exopolysaccharides (EPS) naturally produced by microorganisms are becoming the current research hotspot in the fields of biomedicine, food, and biochemical industry. In-depth study of the precise control mechanism on its high-level structure will greatly advance its practical applications. According to the previous research results and literature reports, we found that glycosyltransferase (GTF) can affect the synthesis of self-assembled nanoscale EPS in Lactobacillus plantarum, which is still unverified by experiment. In this project, taking Lactobacillus plantarum LCC-605 that can produce the self-assembled nanoscale EPS as the research object, negative mutants are constructed. The whole-genome sequencing and bioinformatic analysis are carried out to select the differentially expressed GTF encoding genes and to investigate their functionalities. Furthermore, the relationship between the key GTF encoding genes and the biosynthesis of self-assembled nanoscale EPS and the regulation mechanism are identified through gene overexpression, gene knockout, gene complement, RNA-seq, and RT-qPCR. Through the implementation of this project, key GTF encoding genes involved in the synthesis of self-assembled nanoscale EPS will be obtained and the precise regulation mechanism will be clarified, providing an important theoretical basis for genetic engineering of Lactobacillus plantarum, designing multifunctional EPS, and realizing its industrial utilization.