基于稳定同位素示踪及高通量测序技术解析家蚕肠道菌群多样性及代谢功能

昆虫肠道共生菌不但在宿主生长发育、免疫调控和抑制病原体上起重要作用，同时也是有待深入开发的资源宝库。然而由于肠道微生态系统的错综复杂性，往往很难用传统的方法将肠道菌群物种组成及其生理功能直接耦合分析，限制了对昆虫肠道共生微生物这一重要生物资源的研究利用。为了探索新技术与新方法在昆虫肠道菌群研究中的应用，本项目拟以重要资源昆虫，同时也是鳞翅目常用模式生物家蚕为研究对象，利用新一代高通量测序技术和稳定同位素示踪技术相结合的手段（即Pyro-SIP），解析家蚕肠道核心菌群构成，揭示其演变特征，以及通过13C标记底物重构肠道微生物的代谢途径，提供微生物参与家蚕生理功能的直接证据,为通过调节肠道微生态来提高家蚕生长与生产性能提供理论基础与技术指导。鳞翅目昆虫肠道结构简单，便于实验操作，本研究也为应用Pyro-SIP先进技术探讨其他更为复杂的肠道菌群提供了参考依据,将加快昆虫来源的生物资源的开发利用。

Microbes that live inside insects not only play critical roles in host nutrition, physiology, immune regulation and disease suppression, but also are valuable bioresources. Despite Lepidoptera (butterflies and moths) are one of the most diverse insect taxa, their microbial symbionts are little-studied. Because of the complexity of the gut ecosystem, traditional research approaches are difficult to directly link the identification of microbes with their functions in situ, limiting the deciphering of microbial roles in the host. To investigate the application of new methods and new technologies in the study of gut microbiota, here by coupling the Next Generation Sequencing technology (Pyrosequencing) and stable isotope labeling (SIP) approach, namely Pyro-SIP, we plan to study the biodiversity and activity of core gut microbiotas across the holometabolous life cycle of the silkworm Bombyx mori, an important economic insect and also a common research model in the Lepidoptera order. This systematic survey of microbial communities residing in the lepidopteran gut lumen will not only conduct microbial inventories of B. mori, but also reveal its dynamic change. Furthermore, feeding larvae with the 13C labeled compounds will indicate the active gut members involved in food digestion, energy metabolism and so on. These information can assist the development of novel strategies in the silkworm breeding and disease suppression. The validation of the Pyro-SIP approach in the research of the insect gut microbiota in a lepidopteran insect provides a foundation for future studies of microbial symbiosis in other important insect groups too.