寄生蜂PDVs对寄主小菜蛾脑神经肽的调控

We use the diamondback moth, Plutella xylostella, and its two solitary parasitoids, Cotesia vestalis (Braconidae) and Diadegma semiclausum (Ichneumonidae), as a model system to examine the regulation patterns of major neuropeptides, such as PTTH, allatotropin, allatostatin and bursicon, of host larvae by two types of polydnaviruses, Cotesia vestalis bracovirus (CvBV) and Diadegma semiclausum ichnovirus (DsIV) and the molecular mechanism underlined. Firstly we will characterize the genes and gene transcripts of these neuropeptides at different developmental stages of host larvae and their localization in brain cells. Secondly we will examine the impact on the expression of these neuropeptides by CvBV and DsIV. Lastly, we will identify the key genes and their products of CvBV and DsIV that are interacted with these neuropeptides in host brain and the possible regulating pathways where they are involved. The results will not only reveal the regulation mechanism of different types of polydnaviruses on host physiology, but also provide us a profound base for understanding mechanism underlying the co-regulation of polydnaviruses and other parasitiod-associated factors on host physiology, and for developing new techniques for sustainable management of insect pests.

以携带不同类型多DNA病毒（PDVs）的2种内寄生蜂（菜蛾盘绒茧蜂和半闭弯尾姬蜂）寄生同一寄主（小菜蛾）为研究体系，在分析和鉴定寄主小菜蛾与变态发育相关的主要脑神经肽（促前胸腺激素PTTH、咽侧体活化激素allatotropin、咽侧体抑制肽allatostatin、糅化激素bursicon等）的基础上，研究菜蛾盘绒茧蜂病毒（CvBV）和半闭弯尾姬蜂病毒（DsIV）对寄主主要脑神经肽表达的影响，鉴定CvBV和DsIV中影响主要脑神经肽基因表达的关键基因及他们的产物，分析其功能及其影响的信号途径，从而提出不同类型PDVs(CvBV和DsIV)调控寄主小菜蛾生长发育的途径和模式，解析不同类型PDVs作用的分子机制，开辟寄生蜂PDVs调控寄主的分子机理研究的新领域，为最终阐明PDVs与其它寄生因子协同发挥作用调控寄主生理的机制及发展持续控制害虫的新技术奠定扎实的基础。

本项目以小菜蛾及其携带PDVs的寄生蜂--菜蛾盘绒茧蜂及半闭弯尾姬蜂为研究体系，5年来完成了项目的计划任务。分析和鉴定了寄主小菜蛾与变态发育相关的主要脑神经肽，如促前胸腺激素PTTH、咽侧体抑制肽allatostatin、糅化激素bursicon等及其在小菜蛾幼虫不同发育阶段的转录规律、脑神经细胞的定位、原核表达及功能验证，同时还预测、克隆和研究了脑神经肽核心启动子及其对应受体基因的功能。检测分析了寄生和注射菜蛾盘绒茧蜂病毒（CvBV）和半闭弯尾姬蜂病毒（DsIV）对小菜蛾主要脑神经肽表达的影响。更新了菜蛾盘绒茧蜂病毒（CvBV）基因组、完成了半闭弯尾姬蜂病毒（DsIV）基因组的测序，明确了PDV复制、组装、整合到寄主基因组的机制；在预测、克隆和研究了两类PDVs的潜在转录因子基因的基础上，克隆和分析了它们的转录动态。构建PDVs中PTP等关键功能基因的表达载体、获得了重组蛋白和抗体并进行了组织定位，研究了它们对小菜蛾神经肽及其信号通路的影响，揭示了寄生蜂不同类型PDVs(CvBV和DsIV)调控寄主发育及生理的途径和模式。此外，我们还发现了寄生蜂PDVs编码的miRNA能跨物种调控小菜蛾幼虫的蜕皮激素信号途径而达到调控小菜蛾的幼虫发育，提出了miRNA跨物种调控的新机制。一些阶段性研究结果在Nature Communications, PLos Pathogens, PLos Genetics, Frontiers in Microbiology, BMC Genomics, Developmental and Comparative Immunology, Pest Management Science, Insect Molecular Biology, Insect Science, Journal of Insect Physiology, Journal of Integrative Agriculture等刊物上发表。