自然界中昆虫与细菌共生现象广泛存在。内共生菌可以向寄主提供必要的营养物质、调控寄主生殖方式、增强寄主对环境的适应力以及对病原菌或天敌的抵抗力。本项目以重大农业入侵害虫烟粉虱Bemisia tabaci及其次生共生菌Rickettsia为研究对象，利用昆虫生理学、PCR、荧光原位杂交、扫描电镜以及MLST分型等分子生态学技术，研究以烟粉虱为代表的刺吸式昆虫体内Rickettsia次生共生菌通过寄主植物、寄生蜂及两性交配途径进行水平传播的过程及其分子机制，验证“昆虫共生菌三种水平传播途径”假说。本项目的预期研究成果，可以诠释“次生共生菌在自然界中普遍存在”以及“次生共生菌与昆虫寄主之间存在非协同进化关系”的原因，丰富人类对共生菌传播机制的认知；也可为今后利用Rickettsia、Wolbachia等昆虫内共生菌开展农业昆虫的控害保益、探索烟粉虱等重大农业害虫的新型防控策略与技术提供重要参考。

Innumerable species of insects are associated with various intracellular bacterial endosymbionts. These endsoymbionts usually provide essential nutrients under limited or unbalanced diets to their hosts, manipulating host reproductive systems through a variety of strategies, and can also increasing the defensive ability of their host against thermal stress, natural enemies and pathogens. Earlier studies revealed that secondary endosymbionts are maternally inherited and vertical transmitted among different generations, however, the occurrence of closely related stains of maternally transmitted endosymbionts in distantly related arthropod species indicated that a means of horizontal transmission might exist...Here, we focus the interactions of the most devastating invasive pest, whitefly Bemisia tabaci, and its endosymbiont Rickettsia. The horizontal transmission routes of Rickettsia between different whitefly populations, including host plant mediated, parastitoid mediated and sex mating are investigated, using PCR, FISH, transmission electron microscope and multiple gene analysis and insect physiology methods. ..The expected findings will benefit us to deeply understand the transmission approach of endosymbionts, to verify our hypothesis of “plant, parasitoid and sex mating behavior mediated horizontal transmission of endosymbionts”, will also help us to evaluate the pros and cons of endosymbionts in pest management. Results are expected to be much significant in the exploration and development of novel strategies for pest prevention and integrated control.