共生菌在昆虫生态学和进化中起着重要的作用。然而昆虫与共生菌互作的研究多集中在细菌基因组进化、寄主生态和代谢互补等方面，对于昆虫免疫系统调控共生菌在其体内稳定的分子机制仍不清楚。申请人以褐飞虱和次生共生菌A. nilaparvatae为研究对象，首先克隆了IMD通路的重要基因Relish，通过RNAi干扰其表达明确IMD通路调控的抗菌肽基因AMPs；其次发现抑制PGRP-LC、Relish和AMPs等IMD通路相关基因的表达，可显著降低A. nilaparvatae在褐飞虱不同组织中的含量；最后为揭示IMD通路调控A. nilaparvatae含量的分子机制，我们拟通过酵母双杂交、pull-down和免疫共定位等技术探究AMPs与A. nilaparvatae外膜蛋白及GroEL蛋白间的互作关系。该结果可为揭示昆虫与共生菌在免疫方面的互作机制和开发针对褐飞虱的新型防控策略提供理论依据。

Long-term associations between bacteria and insects are widely represented in nature and play an important role in adaptation and evolution. Insect endosymbiosis has been largely studied with regards to bacterial genome evolution, host ecology, and metabolic complementation. In contrast, data on the molecular processes that orchestrate host immune system interactions with symbionts remain scarce. In this proposal, we cloned a key gene Relish in Nilaparvata lugens IMD pathway and interfere with RNAi for identification downstream genes. The titer of Arsenophonus nilaparvatae in different tissues of N. lugens was significant reduction when IMD pathway related genes included PGRP-LC, Relish and downstream genes was interfered by RNAi. To investigate the mechanism that IMD pathway maintains A. nilaparvatae homeostasis, yeast-two hybrid, pull-down and immunocolocalization will be employed to identify the interaction between AMPs and outer membrane protein, GroEL of A. nilaparvatae. This result will facilitate the identification of relationship between insects and symbionts in immunity, thus providing a translational foundation for the development of novel control strategies that target major insect pests and disease vectors.