神经肽sulfakinin对桔小实蝇觅食和取食行为的调控作用及其药靶潜力

桔小实蝇是严重威胁世界果蔬产业的入侵害虫，行为可塑性是其成功入侵和快速扩张的重要原因，至今其分子生理学机制仍不清楚。我们前期研究发现，神经肽SK及其受体在桔小实蝇中枢神经系统和触角中高表达；敲除SK后，桔小实蝇杂合突变体对多种气味物质的触角电位反应显著下降，且觅食效率和取食频率均显著下降。据此，我们推测SK可能通过嗅觉和味觉关键基因分别调节其觅食和取食行为。因此，本项目拟对桔小实蝇突变体和野生型进行比较组学分析，结合免疫组化技术及桔小实蝇觅食和取食行为测定等技术，明确SK信号系统对桔小实蝇觅食和取食行为的重要调控作用，鉴定调节桔小实蝇嗅觉和味觉敏感性的SK分泌神经元，挖掘与该神经信号系统具有互作潜力的嗅觉和味觉基因，评估该信号系统分子靶标的潜力。研究成果不仅将揭示桔小实蝇强大入侵扩散能力、快速生态适应性的分子生理学机制，还将为靶向实蝇嗅觉和味觉系统开发新型行为控制剂提供新的靶标。

The oriental fruit fly, Bactrocera dorsalis (Hendel), is a destructive invasive pest in tropical and subtropical areas of the world. It causes more and more economic losses to more than 450 species of fruits and vegetables with its expansion to north. The plasticity of foraging and feeding behaviors is an important factor for the successful invasion and rapid expansion of B. dorsalis. However, the molecular physiological mechanism of the plasticity remains largely unknown. In our previous study, we found that a neuropeptide named sulfakinin (SK) and its receptor showed high expression in the central nerve system and antenna. An SK-deletion mutant line was established by using CRISPR/Cas9 system. The mutant flies showed a significant reduction of the EAG response to several odorants including methyl eugenol, β-caryophyllene and benzothiazole, as well as a significant decrease of the foraging efficiency and feeding frequency. Thus, we speculated that SK signaling system probably regulates the foraging and feeding behaviors of the flies by controlling the expression of key olfactory or gustatory genes. In the current project, comparative omics, immunohistochemistry and behavior assays will be employed to demonstrate the important roles that SK signaling played in the foraging and feeding of B. dorsalis. The immunohistochemistry will be applied to identify the SK secreting neurons that are involved in the regulation of foraging and feeding behaviors. The comparative analysis of transcriptomes, proteomes and metabolomes between the mutants and wild-type flies will be conducted to screen the key olfactory or gustatory genes potentially interacting with SK signaling system. An agonist/antagonist high-throughput in vitro screening techniques together with bioassay will be applied to evaluate the potential of the SK signaling system as a molecular target. Our results will not only reveal the molecular mechanisms of the high invasive ability and rapid adaptation of the oriental fruit fly, but also provide potential molecular targets for the development of novel behavior regulating agents against Tephritidae flies targeting its olfaction and taste system.