葡萄球菌调控豆天蛾幼虫苏氨酸合成机制研究

豆天蛾（Clanis bilineata）幼虫（俗称“豆丹”）营养价值高，富含蛋白质和人体必需氨基酸等，是重要的资源昆虫。如何提高虫体必需氨基酸含量是当前豆丹产业化面临的新挑战。研究表明，昆虫肠道微生物能通过转氨酶调节虫体氨基酸合成。本项目开展肠道葡萄球菌调控豆丹苏氨酸（第一限制氨基酸）合成机制研究。首先，分析肠道葡萄球菌属群落结构与多样性，明确肠道优势菌株（种），预测苏氨酸合成通路关键基因及其功能；其次，抗生素处理去除豆丹优势菌株，明确优势菌株对必需氨基酸组成与含量、谷氨酰胺合成酶活性以及苏氨酸合成相关基因表达的影响，并通过RNAi技术验证基因功能。本项目的实施有助于明确豆丹肠道优势菌株，阐明其调控宿主苏氨酸合成的机制，研究结果可为探索肠道细菌与豆天蛾的共生关系提供科学依据和理论基础，并服务于豆丹产业化的应用实践，满足市场对高品质豆丹的消费需求。

Clanis bilineata larvae (commonly known as "Doudan") are important resource insects with high nutritional value, rich in protein and essential amino acids for human body. How to increase the content of larvae essential amino acids is a new challenge for the industrialization of Doudan. Studies have shown that the intestinal microorganism of insects can regulate the synthesis of amino acids through transaminase. This study focused on the mechanism of Staphylococcus regulating the synthesis of threonine, which is the first restricted amino acid in Doudan. Firstly, the community structure and diversity of intestinal Staphylococcus in Doudan were analyzed, the dominant strains (species) were identified, and the key genes of threonine synthesis pathway and their functions were predicted. Secondly, the dominant strains of Doudan above were removed by antibiotic treatment, and the effects of the dominant strains on the composition and content of essential amino acids, glutamine synthetase activity and the key gene expression in threonine synthesis were determined, and the gene functions were verified by RNAi technology. The implementation of this project will help identify Doudan intestinal superiority strains, to clarify the mechanism of threonine synthesis regulated by it, the results could provide the scientific evidence and theoretical basis to explore the symbiosis between intestinal bacteria and Clanis bilineata, and serve to Doudan industrialization application practice, and also meet consumers’ demand for high quality Doudan.