家蚕肠道微生物肠球菌（Enterococcus）对产丝量的影响及机制研究

家蚕（Bombyx mori）是我国重要的经济昆虫，人工饲料饲养家蚕具有省力化、有利于防病等诸多优势，是蚕丝产业转型升级的重要途径。然而与传统桑叶喂养相比，人工饲料饲育的家蚕产丝量少、丝蛋白合成效率低的问题一直未得到解决。家蚕对营养物质的吸收利用是影响茧丝产量与质量的重要因素。已有研究证明肠道微生物能够为宿主提供生长所需的营养物质，然而家蚕肠道微生物是否促进家蚕的营养代谢以及对产丝量的影响尚不明确。本项目在对比不同饲养方式的家蚕肠道微生物肠球菌种群变化的基础上，培养、筛选、分离鉴定可能影响茧丝产量的关键差异菌株，回接验证特定菌种、菌株对产丝量等的影响，以代谢组学与细胞分子生物学技术对其可能的蚕丝蛋白合成、作用靶点与调节机制进行初步探究，揭示不同家蚕产业饲养模式下肠道微生物代谢-宿主-丝蛋白合成轴调控的初步机理，为蚕桑产业开发新型微生态制剂与应用提供理论支持。

Bombyx mori is an important economic insect in China. Raising silkworm with artificial diet has many advantages, such as labor-saving and disease-prevention, which is an important way to transform and upgrade the silk industry. However, compared with traditional mulberry leaf feeding, the problems of less silk production and low efficiency of silk protein synthesis in artificial diet have not been solved. The absorption and utilization of nutrients by silkworm is an important factor affecting the quantity and quality of cocoon silk. It has been proved that gut microorganisms can provide nutrients for the host, however, whether intestinal microorganisms promote the nutrient metabolism of silkworm and their effects on cocoon quantity is still unclear. In this project, the key differential strains of Enterococcus which may affect the silk production were screened, isolated and identified from the gut of silkworm on the basis of comparing the difference of intestinal microbiota in silkworm with different rearing methods. Then the isolated Enterococcus strains were re-introduced to silkworm and the effects of them on silk production were verified. Furthermore, the possible mechanisms about silk protein synthesis and its regulation were explored by metabolomics and molecular biology techniques. This project will provide preliminary mechanism of microbe metabolic -host -silk protein synthesis-axis and provide theoretical support for the development and application of novel microecological agents in the silkworm industry.