我国棉花主产区棉蚜对吡虫啉的抗性监测及抗性机理

【目的】由于生长周期短、繁殖率高，棉蚜Aphis gossypii容易对杀虫剂产生抗药性。本研究旨在明确我国棉花主产区棉蚜对吡虫啉的抗性水平及抗性机理。【方法】采用浸叶法测定了北京海淀，河北廊坊和邯郸,山东德州，河南许昌，以及新疆奎屯和阿克苏地区棉蚜对吡虫啉的抗性水平；测定了不同种群棉蚜3种解毒酶（多功能氧化酶、羧酸酯酶、谷胱甘肽S-转移酶）及乙酰胆碱酯酶的活性；并对靶标基因烟碱型乙酰胆碱受体（nAChR）β1亚基基因进行了突变检测。【结果】北京海淀、河南许昌和河北邯郸的棉蚜对吡虫啉敏感；河北廊坊、新疆阿克苏、山东德州及新疆奎屯地区的棉蚜对吡虫啉的抗性倍数(resistance ratio, RR)分别为22.6, 26.3，53.5和61.1倍，为中等水平抗性。酶活力对比研究发现，阿克苏和奎屯地区的棉蚜多功能氧化酶的比活力分别是敏感种群(北京种群)的1.7和1.8倍，羧酸酯酶的比活力分别是敏感种群的1.6和1.7倍，谷胱甘肽S-转移酶的比活力均是敏感种群的1.5倍，但是乙酰胆碱酯酶比活力在棉蚜种群间差异不显著。靶标基因突变检测表明，河北廊坊、新疆阿克苏、山东德州及新疆奎屯棉蚜种群nAChR β1亚基均存在与吡虫啉抗性相关的精氨酸到苏氨酸（R81T）突变。【结论】结果提示，多功能氧化酶、羧酸酯酶和谷胱甘肽S-转移酶活力升高以及nAChR β1亚基R81T突变与棉蚜对吡虫啉的抗性形成相关。

Monitoring and mechanisms of imidacloprid resistance in Aphis gossypii (Hemiptera: Aphidiidae) in the main cotton production areas of China

【Aim】 Aphis gossypii is easy to produce resistance to insecticides because of its short growth cycle and high reproduction rate. This study aims to clarify the levels and mechanisms of imidacloprid resistance in A. gossypii in the main cotton production areas of China. 【Methods】 Different populations of A. gossypii were collected from fields in Haidian of Beijing (BJ), Langfang (LF) and Handan (HD) of Hebei, Dezhou (DZ) of Shandong, Xuchang (XC) of Henan, and Kuitun (KT) and Akesu (AKS) of Xinjiang. Leaf-dipping method was used to determine the resistance levels of A. gossypii to imidacloprid. The activities of three detoxification enzymes ［mixed function oxidase (MFO), carboxylesterase (CarE) and glutathione S-transferase (GST)］ and acetylcholinesterase (AchE) in different A. gossypii populations were assayed. And the mutation of target gene (nAChR β1 subunit gene) was also detected. 【Results】 The BJ, XC and HD populations of A. gossypii were still susceptible to imidacloprid, while the LF, AKS, DZ and KT populations exhibited moderate levels of resistance to imidacloprid, with the resistance ratios of 22.6-, 26.3-, 53.5- and 61.1-fold, respectively. The activities of MFO, CarE and GST in the AKS and KT populations were significantly higher than those in the BJ susceptible population. The activities of MFO, CarE and GST in the AKS population were 1.7-, 1.6- and 1.5-fold, and those in the KT population were 1.8-, 1.7- and 1.5-fold as high as those in the BJ population, respectively. But there was no significant difference in acetylcholinesterase (AchE) activities among the AKS, KT and BJ populations. A single point mutation in the nAChR β1 subunit causing an arginine to threonine substitution (R81T) observed in LF, AKS, DZ and KT populations was associated with the imidacloprid resistance in A. gossypii. 【Conclusion】 The results suggest that enhancement of MFO, CarE and GST activities and the mutation (R81T) of nAChR β1 subunit might confer resistance to imidacloprid in A. gossypii.