白纹伊蚊ORs基因介导的杀虫剂抗性分子机理研究

The Asian tiger mosquito, Aedes albopictus, is an aggressive, day-time biting insect that is emerging throughout the world as a public health threat following its primary role in recent dengue fever, Japanese encephalitis, Zika virus and Chikungunya outbreaks. Part of its impact on human health is due to its quick and aggressive spread out of its native home range. Mosquito control is the main measure to combat mosquito-borne diseases. Chemical control, because of its killing speed, long-lasting and convenient features, has been the main method in the comprehensive management strategy. Unfortunately, excessive and continuous usage of insecticides induced the development and spread of resistance. Studies have shown that resistant strain can use olfactory identity and avoid pesticides, but the specific mechanism is unknown. Our group previous studies discovered that there were differences in the types and expression of olfactory receptors (ORs) from resistant strains and sensitive strains of Aedes albopictus. Moreover, point mutation occurs in odorant receptor co-receptor (Orco) from wild, sensitive and resistant strains. This research is to: Screen of differentially expressed ORs by transcriptome profiles of insecticide-resistant and sensitive Aedes albopictus; parse process about ORs recognition passed smell; analysis the correlation between the ORs and insecticide resistance level of mosquito, and probe into the forming mechanism of insect resistance. This project will be helpful to clarify mosquito resistance mechanism and the function of olfactory receptors, and to Screen marker genes of new mosquito insecticide resistance by studying the mechanism of olfactory receptor mediated insecticide resistance of mosquito. It is a new method to interfere mosquito behaviors, thus providing a theoretical basis for the effective improvement of chemical prevention and control measures, and laying scientific evidence for the preventive measures.

白纹伊蚊是登革热、乙脑、寨卡等多种病毒性传染病的主要传播媒介，是世界最具侵袭性的蚊种。化学防制是白纹伊蚊综合治理的主要方法。杀虫剂大量、连续使用导致了蚊虫抗药性的发生和发展，已成为蚊媒病防制工作的突出问题。研究显示抗性蚊虫利用嗅觉识别回避杀虫剂，并且课题组前期研究发现溴氰菊酯抗性和敏感品系的白纹伊蚊嗅觉受体(ORs)表达量存在差异，且不同品系的嗅觉受体共表达受体基因存在点突变。本项目通过抗性与敏感品系白纹伊蚊转录组学分析筛选差异表达的嗅觉受体（ORs）；解析ORs识别传递气味过程；研究ORs与蚊虫抗药性水平的相关性，探讨蚊虫抗药性形成的机制。本研究通过ORs介导蚊虫抗药性产生机理的深入研究，有助于明晰蚊虫抗药性机制和ORs的功能，筛选新的蚊虫杀虫剂抗性标记基因，为有效改进化学防控手段提供理论基础，为我国蚊媒病控制措施的制订提供科学依据。

白纹伊蚊是登革热、乙脑、寨卡等多种病毒性传染病的主要传播媒介，是世界最具侵袭性的蚊种。化学防制是白纹伊蚊综合治理的主要方法。杀虫剂大量、连续使用导致了蚊虫抗药性的发生和发展，已成为蚊媒病防制工作的突出问题。我们研究发现溴氰菊酯抗性品系和敏感品系的白纹伊蚊嗅觉受体(ORs)的种类和表达量存在差异，且不同品系的嗅觉受体共表达受体（Orco）基因存在点突变。因此，我们提出疑问ORs是否能够识白纹伊蚊的转录组分析筛选差异表达的ORs；研究Orco基因型与抗性表型的相关性及其对杀虫剂识别信号传递的影响；从异源表达系统（细胞和转基因果蝇）以及蚊虫层面解析配体型嗅觉受体（ORx）与Orco基因共同作用识别传递气味信号，探讨蚊虫抗药性形成的机制。结果表明：通过蚊敏感品系与抗性品系转录组测序比较，共预测白纹伊蚊的ORs 基因182条，其中溴氰菊酯抗性品系和敏感品系差异表达的ORs 基因23条。qPCR检测发现OR58，OR142在敏感种群中表达量较高，其余21条在抗性品系中高表达。通过细胞和转基因果蝇实验发现OR10、OR43、OR58、OR88等嗅觉受体可以识别杀虫剂与蚊虫抗药性密切相关。本项目通过嗅觉受体介导蚊虫抗药性产生机理的深入研究，将有助于明晰蚊虫抗药性机理和嗅觉受体的功能，为有效改进化学防控手段提供理论基础，为我国的媒介控制措施的制订提供科学依据。