吡虫啉对异迟眼蕈蚊抗性筛选及其对解毒酶活性的影响

Effects of Imidacloprid on Resistance Selection and Activity of Detoxifying Enzyme in Bradysia difformis Frey

异迟眼蕈蚊是一种食用菌的主要害虫。为探讨该虫对吡虫啉的抗性风险及生化机制,在室内采用吡虫啉对异迟眼蕈蚊进行抗性筛选并进行抗性现实遗传力(h2)分析,测定吡虫啉亚致死剂量(LC10、LC20和LC40)处理下异迟眼蕈蚊解毒酶活性。结果表明,抗性筛选21代后异迟眼蕈蚊抗性倍数为4.09倍,该虫对吡虫啉处于敏感性下降水平。异迟眼蕈蚊对吡虫啉的抗性现实遗传力(h2)为0.0913,当选择压力在80%~90%时,预测异迟眼蕈蚊抗性增长10倍需要15.9~20.1代。随着吡虫啉亚致死剂量的增加,敏感品系和抗性品系异迟眼蕈蚊的多功能氧化酶O-脱甲基和羧酸酯酶活性逐渐上升,均在LC40处理48 h达到峰值,此时多功能氧化酶O-脱甲基活性分别较空白对照上升了63.81%和119.42%,羧酸酯酶活性分别较空白对照上升了18.40%和48.13%。综上,异迟眼蕈蚊对吡虫啉产生抗性的风险较低,多功能氧化酶和羧酸酯酶活性的增强与异迟眼蕈蚊对吡虫啉产生代谢抗性有密切关系。

Bradysia difformis is one of the main pests of edible fungi.In order to investigate the resistance risk and biochemical mechanism of B.difformis to imidacloprid,resistance selection and realized heritability(h2)of B.difformis to imidacloprid were analyzed in the laboratory,and the detoxifying enzyme activities of treated with sublethal doses of imidacloprid(LC10,LC20 and LC40)were determined.The results showed that the resistance ratio of B.difformis was 4.09 times after 21 generations of resistant selection,and resistance level of B.difformis was sensitivity drop to imidacloprid.The realized heritability(h2)of B.difformis to imidacloprid was 0.0913,it would take 15.9—20.1 generations to achieve 10-fold resistance under the selection pressure of 80%to 90%.With the increase of the sublethal dose of imidacloprid,the activities of mixed function oxidase O-demethylation and carboxylesterase in susceptible strain and resistant strain of B.difformis increased gradually,and both reached the peak value at 48 h after LC40 treatment,at this time,the activities of mixed function oxidase O-demethylation in susceptible strain and resistant strain increased by 63.81%and 119.42%,and the activities of carboxylesterase in susceptible strain and resistant strain increased by 18.40%and 48.13%,respectively,compared with blank control.These results indicated that the resistance risk of B.difformis to imidacloprid was low,and the enhanced activities of mixed function oxidase and carboxylesterase were closely related to the metabolic resistance of B.difformis to imidacloprid.