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通过增效剂生物测定和生化分析,探讨了采自福建省的B型烟粉虱Bemisia tabaci6个田间种群对毒死蜱和敌敌畏抗性的生化机制。结果表明:与敏感品系SUD-S相比,6个田间种群对毒死蜱和敌敌畏分别具有54.53~78.43倍和6.23~11.25倍的抗性。TPP、PBO和DEM对毒死蜱的增效比分别为3.61~24.94倍、1.14~1.76倍和1.04倍,对敌敌畏的增效比分别为1.67~2.64倍、1.33~1.65倍和1.09倍,表明羧酸酯酶的解毒代谢在烟粉虱对毒死蜱的抗性中起着重要作用。烟粉虱抗性种群乙酰胆碱酯酶的Km值是敏感品系的1.83~4.0倍,Vmax值是敏感品系的0.34~0.62倍;敏感品系乙酰胆碱酯酶的活性在底物浓度大于1.0mmol/L时受抑制,抗性种群乙酰胆碱酯酶的活性在底物浓度大于16mmol/L时受抑制;抗性种群乙酰胆碱酯酶对敌敌畏和毒死蜱的敏感度分别比敏感品系低119.92~161.33倍和10.11~14.24倍,表明烟粉虱田间抗性种群乙酰胆碱酯酶可能已发生了变构,由变构引起的乙酰胆碱酯酶不敏感是烟粉虱田间种群对毒死蜱和敌敌畏产生抗性的重要原因。结果提示,乙酰胆碱酯酶不敏感性和羧酸酯酶的解毒代谢在烟粉虱对毒死蜱的抗性中均起着重要作用,而乙酰胆碱酯酶不敏感性在对敌敌畏的抗性中起重要的作用,多功能氧化酶和谷胱甘肽S转移酶在烟粉虱对毒死蜱和敌敌畏抗性中所起的作用不大。
The biochemical mechanism of resistance to chlorpyrifos and dichlorvos in six field populations of Bemisia tabaci B collected from Fujian province was investigated by potentiometric bioassay and biochemical analysis. The results showed that compared with the susceptible strain SUD-S, the six field populations were 54.53-78.43-fold and 6.23- 11.25-fold more resistant to chlorpyrifos and dichlorvos, respectively. The synergistic ratios of TPP, PBO and DEM to chlorpyrifos were 3.61 ~ 24.94 folds, 1.14-1.76 folds and 1.04 folds respectively, and the synergistic ratios against dichlorvos were 1.67-2.64 folds, 1.33-1.65 folds and 1.09 folds respectively, indicating that the carboxylic acid Detoxification of esterases plays an important role in the resistance of whitefly to chlorpyrifos. The Km value of acetylcholinesterase in resistant population of B. tabaci was 1.83 ~ 4.0 times that of the susceptible strain, and the Vmax value was 0.34 ~ 0.62 times that of the susceptible strain. The activity of acetylcholinesterase in sensitive strain was higher than 1.0 mmol / L The activities of acetylcholinesterase (AChE) of the resistant and resistant populations were inhibited when the substrate concentration was more than 16mmol / L. The susceptibility of the resistant population to acetylcholinesterase and chlorpyrifos was 119.92-161.33 and 10.11-14.24 times lower than that of the susceptible strain, respectively. This indicates that the acetylcholinesterase may have undergone allosteric transformation in the field population of Bemisia tabaci (Gennadius). The insensitivity of acetylcholinesterase (AchE) induced by allosteric change is an important reason for the resistance of Bemisia tabaci population to chlorpyrifos and dichlorvos. The results suggest that the insensitivity of acetylcholinesterase and the detoxification metabolism of carboxylesterase play an important role in the resistance of B. tabaci to chlorpyrifos, whereas the insensitivity of acetylcholinesterase plays an important role in the resistance to dichlorvos The role of multifunctional oxidase and glutathione S-transferase in Bemisia tabaci chlorpyrifos and dichlorvos resistance play a small role.