共生菌Wolbachia促进宿主灰飞虱产卵的分子机制研究

The small brown planthopper (Laodelphax striatellus, SBPH) is an important agricultural pest around the world. The difficulty in controlling SBPH is closely related to the endosymbiont Wolbachia. Wolbachia-infected females of SBPH produced about 30% more eggs than uninfected females. Wolbachia bacteria, potentially an important factor in the outbreak of SBPH, affect host reproduction by secreting effector proteins that act on the host germ cells. We have previously identified four genes associated with meiotic differentiation of germline nuclei. From the prespective of Wolbachia-increased fecundity in SBPH, this project will further investigate the target factors of meiotic differentiation and the effector proteins secreted by Wolbachia. The aim of this project is to explore the molecular mechanism of Wolbachia-increased fecundity in SBPH from gene, protein and cell levels by using RNAi, immunofluorescence staining, and DNA-protein pull down approaches. The results may lead to ways in which Wolbachia can be used to control SBPH, are helpful to reduce the use of pesticides, and of great significance for rice safety production and environmental protection.

灰飞虱作为危害世界粮食产业的主要害虫，其防治困难与体内共生菌Wolbachia密切相关。共生菌Wolbachia分泌“武器”--效应蛋白，作用宿主灰飞虱生殖细胞，使灰飞虱产卵量增加约30%，是灰飞虱暴发的潜在重要因素。本项目将从共生菌Wolbachia促进宿主灰飞虱产卵这一现象出发，在已获得4个卵巢细胞减数分裂差异表达生殖因子的基础上，拟通过显微注射RNAi干扰、免疫组化以及DNA-protein pull down等手段，确定共生菌Wolbachia促进灰飞虱产卵的细胞减数分裂靶标因子，及其所分泌的效应蛋白。从基因、蛋白以及细胞水平，揭示共生菌Wolbachia促进宿主灰飞虱产卵的分子机制。研究结果有助于开发利用共生菌Wolbachia进行灰飞虱生物防治，减少农药的使用，对粮食安全生产、生态环境保护具有重要意义。

灰飞虱严重危害我国粮食生产，其防治困难与体内共生菌Wolbachia密切相关。研究表明，自然界灰飞虱100%感染共生菌Wolbachia，Wolbachia促进宿主灰飞虱产卵，感染Wolbachia的灰飞虱产卵量比不感染灰飞虱高约30%。本项目从此现象出发，通过对感染及不感染Wolbachia的灰飞虱卵巢进行转录组测序，获得4个灰飞虱卵巢细胞分裂差异表达生殖因子Cdc20，CDK1，CycB及APC1。从生物学、细胞学及分子生物学等角度，揭示Wolbachia通过共同调控灰飞虱卵巢细胞分裂因子Cdc20，CDK1及CycB，促进卵巢生殖细胞分裂从而促进灰飞虱产卵的分子机制。. 本项目探索了Wolbachia抑制新宿主传播病毒的作用。通过胚胎显微注射技术将Wolbachia转入新宿主白纹伊蚊体内，发现Wolbachia能在新宿主白纹伊蚊体内高效垂直传播。运用激光共聚焦显微技术，Western-blot以及荧光定量PCR技术等，对不感染、自然感染及转染Wolbachia的白纹伊蚊传播寨卡病毒（ZIKV）能力进行比较发现，Wolbachia显著地提高白纹伊蚊卵巢中抗菌肽及免疫因子的表达，同时显著地抑制ZIKV进入白纹伊蚊卵巢内。研究结果表明，胚胎显微注射 Wolbachia显著地抑制宿主白纹伊蚊垂直传播ZIKV病毒。. 综上所述，本项目通过分子生物学技术揭示了Wolbachia促进宿主产卵及抑制新宿主垂直传播病毒的分子机制，结果有助于开发利用Wolbachia进行生物防治，减少农药的使用，对粮食安全生产、生态环境保护以及人类健康具有重要意义。