棉铃虫是重要的多食性农业害虫，其广泛的寄主范围和对各种类型杀虫剂的抗性已成为有效控制该害虫的主要障碍。细胞色素P450（简称P450）被认为在棉铃虫对植物防御性次生物质和化学杀虫剂的代谢解毒中起着至关重要的作用，但其中的生物化学本质与进化机制至今没有得到清楚地阐明。项目组拟采用生物化学与分子生物学的研究手段，选择棉铃虫抗药性相关的8个CYP9A亚家族P450基因为研究系统，在明确这些基因的序列特征和时空表达模式的基础上，剖析它们对26种活性与结构不同但相关的化合物的催化活性,以期查明这些P450在植物次生物质和杀虫剂代谢解毒中的作用,揭示同源P450基因功能分化的进化意义，预测决定底物特异性的关键位点。研究结果有助于在分子水平上阐明棉铃虫对有毒化学环境胁迫适应性的机理，为有效防控棉铃虫提供新思路。棉铃虫P450离体反应体系的建立可为新制剂开发、杀虫剂代谢途径和抗性风险分析提供研究平台。

The cotton bollworm (Helicoverpa armigera) is a very important polyphagous pest that may cause serious yield losses in many economically important crops. The outbreak of this pest is largely due to its capacity in the detoxification of plant toxins and insecticides. Cytochrome P450s of this pest have been long recognized as very important enzymes in such detoxication process, resulting in rapid evolution of resistance to various classes of pesticides and wide adaptation to a broad range of host plants. However, as of today, only few of the many co-existed cytochrome P450s responsible for xenobiotics detoxification have been rudimentarily functionally characterized in this pest. In this study, we attempt to explore the potential involvement of eight CYP9A genes from H. armigera in the metabolism of plant toxins and pyrethroid insecticides by using approaches of gene recombinant expression and metabolism assay, and probe the amino acids determining their substrate specificity. We believe that the results to be obtained in this project will provide better insights into the molecular basis of host plant adaptation and insecticide resistance, and will be helpful for the development of effective control strategies. The successful establishment of completely lepidoptera-specific P450 monoxygenase systems will be useful for evaluating the metabolic pathway and resistance risk of the currently available or used insecticides, and for developing new control agents.