双歧杆菌具有维持肠道菌群微生态平衡、增强机体免疫力、降低胆固醇和调节血脂等功能，常用于发酵乳制品的生产。氧敏感性是制约双歧杆菌产业化应用开发急需突破的关键瓶颈问题，尽管目前对双歧杆菌耐氧机制在细胞和酶等水平上已有一定的了解，但缺乏在RNA水平上的机理解析，双歧杆菌中调控耐氧功能的small RNA（sRNA）尚未见研究报道。本项目以实验室筛选的一株动物双歧杆菌AR668及其耐氧驯化菌株为研究对象，通过比较基因组和转录组学分析，筛选出动物双歧杆菌中与调控耐氧相关潜在的sRNA；构建动物双歧杆菌Crispr/cas9基因编辑系统，高效敲除这些潜在的sRNA，鉴定出具有调控耐氧功能的sRNA；利用生物信息学分析预测其潜在的调控基因，并通过转录组测序、分子互作和凝胶迁移等实验确定其调控靶点，解析调控途径及其调控网络，阐明sRNA调控耐氧功能具体分子机制，为解决双歧杆菌氧敏感性提供理论指导。

Bifidobacteria have probiotic health functions such as maintaining microecological balance of intestinal flora, enhancing immunity, reducing cholesterol and regulating blood lipid and blood pressure, which are widely applied in the fermented dairy products. However, the oxygen sensitivity of Bifidobacteria is a limitation for its application and development. Although the mechanism of oxygen tolerance in Bifidobacteria has been understood, there is no study on the mechanism at RNA level. There is also no report on the small RNA (sRNA) regulating oxygen tolerance in Bifidobacteria. In this project, a bifidobacterium animal strain AR668 and its oxygen-tolerant strain will select as the research objects. Potential sRNAs related to regulating oxygen-tolerance in Bifidobacterium animal will be screened through comparative genomic and transcriptome analysis. The Crispr/cas9 gene editing system of Bifidobacterium animal will be constructed for rapid and efficient knockout of these potential sRNAs and identifying sRNA regulating oxygen tolerance. The potential regulatory genes, regulatory pathway and regulatory network of oxygen-tolerance sRNA will predict and analyze by bioinformatics analysis and transcriptome sequencing, molecular interaction and gel migration, The molecular mechanism of oxygen tolerance function provides theoretical guidance for solving the oxygen sensitivity of Bifidobacteria.