烟粉虱体内共生菌Hamiltonella与Cardinium在宿主防御致病真菌中的作用及机理

During long-term evolution, some symbionts have become helpful in insect resisting pathogenic fungi. Bemisia tabaci (Gennadius) harbors various symbionts. Hamiltonella and Cardinium are the most abundant strains in B. tabaci. However, the effects of them on B. tabaci resisting important pathogenic fungi, for example Paecilomyces fumosoroseus, are still unknown. In this project, we plan to compare the pathogenicity and sublethal effects of P. fumosoroseus on different B. tabaci lines based on the establishment of high virulent P. fumosoroseus strain and B. tabaci lines which are singly infected with Hamiltonella or Cardinium, doubly infected with both Hamiltonella and Cardinium, and symbiont-free. Also, we analyze the relationship between incidence of P. fumosoroseus and infection rate of Hamiltonella and Cardinium in natural B. tabaci populations, revealing the effects of the two symbionts on B. tabaci resisting P. fumosoroseus. Furthermore, to underly the mechanism of symbiont-associated anti-pathogenic effects, we will compare the density and distribution of Hamiltonella and Cardinium with different effects, and analyze the tissue lesion and the immune effector expression in sick B. tabaci. The results will be important to further elucidate the co-evolutionary relationship between B. tabaci and symbionts, as well as to develop accurate and efficient biological control strategies of B. tabaci.

在长期进化过程中，一些共生菌具有了帮助宿主防御致病真菌的功能。烟粉虱体内共生菌种类丰富，其中Hamiltonella与Cardinium是我国烟粉虱中的优势共生菌，然而它们在烟粉虱防御玫烟色拟青霉等重要致病真菌中的作用尚不明确。本项目在已建立了单感染Hamiltonella、单感染Cardinium、双感染Hamiltonella与Cardinium以及不感染共生菌的烟粉虱品系，且已分离获得玫烟色拟青霉高致病力株系的基础上，比较真菌对不同品系致病力差异，分析烟粉虱自然种群中两种共生菌携带率与玫烟色拟青霉感染率的相关性，以明确两种共生菌在烟粉虱防御致病真菌中的作用。并通过比较防御功能不同的共生菌株系在烟粉虱体内含量和分布差异，分析共生菌对感病烟粉虱组织病变及免疫效应因子表达的影响等，揭示共生菌的作用机理。研究结果有助于进一步阐释烟粉虱与共生菌的协同进化关系和制定精准高效的烟粉虱生物防治策略。