家蝇对氯菊酯抗性的分子机制研究

PINPOINTING THE MOLECULAR MECHANISMS OF PERMETHRIN RESISTANCE IN THE HOUSEFLY MUSCA DOMESTICA

家蝇是一种重要的病媒生物,可以传播上百种人畜疾病。化学防治是家蝇控制的重要手段,但杀虫剂的重复和广泛使用可导致家蝇产生抗药性。在我国,不少事例显示家蝇对拟除虫菊酯杀虫剂普遍产生了抗药性,但对家蝇种群抗药性的分子机制还缺乏系统了解。本研究以来源于山东济南的家蝇为材料,在明确其对氯菊酯抗性水平的基础上,分析其抗药性的分子机制。结果显示,野外采集未经杀虫剂汰选实验室济南品系(JN)相对于敏感品系(WHO)表现出对氯菊酯近50倍的抗性,而经氯菊酯汰选7代后的JN-Sel品系获得了比JN更高水平的抗性,抗性倍数超过110倍。核酸检测显示JN和JN-Sel品系家蝇钠离子通道的基因型为1014LL敏感纯合型。通过检测8个细胞色素P450基因的表达水平,发现3个P450基因(CYP6A5v2、CYP6A36和CYP6G4)在抗性品系中的表达量高于敏感品系,其中CYP6G4的表达与氯菊酯抗性成正相关,JN品系CYP6G4的表达量是敏感品系的35倍,而在高抗性的JN-Sel品系中的表达量是敏感品系的70倍。研究结果强烈提示CYP6G4的过量表达是JN和JN-Sel品系对氯菊酯抗性的重要机制。

The housefly(Musca domestica)is one of the most important medical pests.The control of housefly mainly relies on the use of insecticides.In China,pyrethroid resistance has been commonly documented in field housefly populations,but the underlying molecular basis has not been well defined.In this study,we investigated the possible mechanisms of permethrin resistance in a field derived(JN),and a permethrin selected housefly strain(JN-Sel),with 48-and 110-fold resistance compared with the WHO strain,respectively.No kdr mutation(1014 F and 1014 H)in the voltage sensitive sodium channel was detected in samples from JN and JN-Sel strains.Three(CYP6 A5 v2,CYP6 A36,and CYP6 G4)of the eight examined CYP genes were observed to be overexpressed in both JN and JN-Sel strains compared with the two susceptible strains(WHO and TJS).Notably,the expression of CYP6 G4 in the field derived colony JN(35 fold),and the permethrin selected JN-Sel strain(70 fold)is much higher than that in the two susceptible strains,indicating that CYP6 G4 might be a major player in permethrin resistance in the two investigated housefly strains.