茶尺蠖产卵引诱信息素降解酶的鉴定及功能研究

蛾类昆虫高度灵敏的嗅觉系统对其识别产卵信息素、定位产卵位点至关重要。在嗅觉信号的传递通路中，气味受体被激活后，产卵信息素的及时清除有助于快速恢复嗅觉神经元的敏感性。本项目拟以茶树重要害虫茶尺蠖为研究对象，基于前期成功鉴定雌蛾酯类产卵信息素的研究基础，拟重点研究触角高表达的羧酸酯酶CXEs，以期鉴定茶尺蠖产卵信息素降解酶OPDEs并阐明其在雌蛾偏好产卵中的生理功能。首先，利用荧光定量PCR分析触角酯酶CXEs的底物诱导表达谱；其次，通过原位杂交、免疫组化和单感器记录研究CXEs在茶尺蠖雌蛾产卵信息素敏感感器中的定位。最后，结合体外酶动力学及活体水平RNAi系统的阐明CXEs的底物谱、功能进化及在降解茶尺蠖产卵信息素中的生理功能。研究结果一方面有助于解析昆虫嗅觉信号降解的分子机制，同时也为探索利用OPDEs靶向调控茶尺蠖产卵行为，研发相应的绿色防控技术提供科学依据。

The sophisticated olfactory system plays important roles for lepidopteran moth species to detect oviposition-attractant pheromones and locate oviposition sites. In the olfactory cues transduction pathway, the rapid degradation of oviposition pheromones is crucial to restore the sensitivity of the sensory neuron after their activations of odorant receptors. In the current project proposal, we mainly focus on the antennal enriched carboxylesterases (CXEs) with particular interests to identify and functionally characterize the oviposition-attractant pheromone degrading enzymes, OPDEs related to E. obliqua oviposition behaviors. First, quantitative real-time PCR experiment is used to evaluate the CXEs transcript level variations under the exposure to the oviposition-attractant pheromones. Next, the chemosensillum localization of CXEs in female oviposition pheromones-sensitive sensilla will be studied by using in situ hybridizations, immunocytochemistry and the single sensillum recording assay. Finally, enzyme activities and kinetic estimations in vitro in combination with RNA interference in vivo are employed to investigate the substrate spectrum, functional evolution and the physiological roles of CXEs in degrading the oviposition-attractant pheromones of female E. obliqua moth. The results would provide new insights on the molecular mechanisms of insect olfactory cue degradation, which in turn help to develop the new environmentally friendly pest-management strategies to regulate female E. obliqua egg-laying behaviors through RNAi with CXEs as target.