菜蛾盘绒茧蜂多分DNA病毒microRNA调控寄主免疫的研究

Polydnaviruses (PDVs), obligate mutualists of parasitoid wasps, function as suppressing the immune responses to ensure the successful development of wasp offspring. At present, the researches on PDVs mainly focus on the regulation of host immune by their encoded proteins，while the immunoregulatory effects of PDV non-coding RNAs in the parasitic process are not clear. In this study, we will carry out a comprehensive analysis of the miRNAs of Cotesia vestalis bracovirus (CvBV), a PDV of C. vestalis (Haliday) that parasitizes the diamondback moth Plutella xylostella (Linnaeus), to figure out the immunoregulatory effects of CvBV microRNAs (miRNAs) during parasitism. Firstly, we try to screen out the CvBV miRNAs involved in P. xylostella immune by authenticating the interaction between miRNAs and immune-related target genes. Secondly, we try to figure out the roles of the target genes of CvBV miRNAs in the immune response of P. xylostella through their expression dynamics and functions. Finally, we try to identify the biological functions of CvBV miRNAs in the parasitic process. The results will not only reveal the new mechanism of PDV regulation of host immunity, but also lay the foundation for the development of genetically modified crops with insecticidal effects and provide genetic materials.

多分DNA病毒（polydnavirus，PDV）是寄生蜂专性共生的特殊病毒，能够帮助寄生蜂抑制寄主免疫反应，是寄生蜂成功寄生的重要寄生因子。目前国内外关于PDV的研究主要集中在其编码的毒性蛋白对寄主免疫的调控，而对于PDV非编码RNA在寄生过程中的免疫调控作用并不清楚。本项目以小菜蛾的优势寄生蜂（菜蛾盘绒茧蜂）所携带的多分DNA病毒（CvBV）为对象，通过鉴定CvBV miRNA在小菜蛾免疫相关基因上的靶标位点，筛选参与调控小菜蛾免疫的CvBV miRNA；通过对相关靶基因蛋白表达动态及相关功能的研究，明确进CvBV miRNA靶基因参与小菜蛾免疫的途径；探究过表达和干扰CvBV miRNA对小菜蛾免疫的影响，明确CvBV miRNA在寄生过程中的生物学功能。研究成果不仅将揭示PDV调控寄主免疫的新机制，还将为具有抑虫、杀虫作用的转基因农作物研发奠定基础和提供基因材料。

多分DNA病毒（polydnavirus，PDV）作为寄生蜂的专性共生病毒，是重要的寄生因子，能够帮助寄生蜂抑制寄主免疫。目前关于PDV的研究主要集中在其编码的毒性蛋白对寄主免疫的调控，而对于PDV编码的miRNA在寄生过程中的免疫调控作用并不清楚。本项目以小菜蛾的优势寄生蜂（菜蛾盘绒茧蜂）所携带的多分DNA病毒（CvBV）为对象，系统分析了CvBV所有编码miRNA的靶标基因，筛选出其中两个和免疫相关的靶标。即Cve-miR-novel20-5p和Cve-miR-novel21-5p分别靶向小菜蛾Psh和API5基因，进而影响小菜蛾抗菌肽的产生和引起血细胞的调亡。本研究表明，CvBV可以通过不同的miRNA跨物种调控寄主的免疫。