CPR基因突变对P450介导的禾谷缢管蚜抗药性的影响

P450酶系在昆虫代谢农药中起重要作用，P450还原酶（CPR）和P450在该酶系起核心作用。CPR是昆虫所有参与农药代谢的P450酶的唯一电子供体，其影响P450的代谢活性。大量研究表明，哺乳动物CPR突变显著影响P450对药物的代谢。以往研究显示，CPR和昆虫抗药性相关，但机制不明。申请者发现，禾谷缢管蚜多个抗药性品系均存在抗性相关CPR突变，不同品系突变位点不同，突变频率随抗性水平上升而提高；在此基础上，本项目将研究该虫CPR突变的遗传特性；利用真核表达研究突变对CPR活性及P450农药代谢活性的影响；模拟CPR空间结构，确定各结构域氨基酸组成，结合突变对CPR黄素含量影响及相关分析，明确突变影响P450活性的机理；检测田间种群CPR突变，验证突变与抗性的关系；研究结果可以更全面阐释P450酶系介导昆虫抗药性的机制、建立基于CPR突变的抗性分子标记，这对于该虫综合治理具有重要意义。

The cytochrome P450 monooxygenase (P450) system is involved in the detoxification and metabolism of insecticides in insects. NADPH-cytochrome P450 reductase (CPR) and the cytochrome P450 monooxygenase (P450) are the main and key parts of the system. CPR is the only electron donator of all insect P450s that metabolize insecticides, and affects the activity of the P450s. Previous reports have found that mutations of mammalian CPR can significantly affect the detoxification and metabolism of xenobiotics and endogenous compounds. CPR is considered a vital part of P450-mediated insecticide resistance, though the mechanisms are not known. We found that there are mutations in the CPR gene of different insecticide resistant strains of Rhopalosiphum padi, with varied mutations in different strains. The gene frequencies of the mutations increased with the insecticide resistance levels. Based on the previous research results obtained, we will analyze the inheritance characteristics of the CPR mutations in the resistant strains. Eukaryotic heterologous expression system will be used to investigate the effects of the CPR mutations on its activity as well as on the metabolism of the P450s. The structure of R. padi CPR will be modeled and the key amino acids of the important domains of the enzyme will be confirmed, together with the flavin contents analyses of the recombinant CPR. The correlation between insecticide resistant levels and mutations of CPR will also be investigated in different field populations of the aphid. The results are important for deep understanding of the mechanisms of P450-mediated insecticide resistance, as well as for the development of molecular markers for predicting and monitoring resistance of R. padi, which is important for the insecticide resistance management of the pest.