亚致死质量浓度联苯肼酯对截形叶螨解毒酶系的影响
Effect of sublethal concentrations of bifenazate on detoxifying enzymes in Tetranychus truncatus
尚素琴；薛玉丽
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DOI：10.7679/j.issn.2095-1353.2019.084
作者单位：甘肃农业大学植物保护学院，甘肃省农作物病虫害生物防治工程实验室，兰州 730070；甘肃农业大学植物保护学院，甘肃省农作物病虫害生物防治工程实验室，兰州 730070
中文关键词：截形叶螨；联苯肼酯；致死中浓度LC50；解毒酶；比活力；酶动力常数
英文关键词：Tetranychus truncatus; bifenazate; lethal concentration; detoxifying enzymes; specific activity; kinetic parameters of enzymology
中文摘要：【目的】 明确联苯肼酯的亚致死质量浓度对截形叶螨Tetranychus truncatus解毒酶系的影响，从而为进一步揭示截形叶螨的代谢抗性及联苯肼酯的科学使用提供理论依据和指导。【方法】 采用叶片浸渍法测定了联苯肼酯对截形叶螨雌成螨的LC50，应用毒力回归方程计算截形叶螨雌成螨死亡率为10%和30%时联苯肼酯的亚致死质量浓度LC10和LC30，并处理截形叶螨雌成螨，以甲醇水溶液作为对照，测定并分析其体内羧酸酯酶（CarE）、谷胱甘肽S-转移酶（GSTs）、多功能氧化酶（MFO）的比活力及酶动力学常数（米氏常数Km和最大反应速率Vmax）的变化。【结果】 比活力与对照相比，LC10、LC30处理后，截形叶螨雌成螨体内CarE、GSTs和MFO的比活力均显著升高（P<0.05），且LC30处理组CarE、GSTs（除24 h外）比活力显著高于LC10（P<0.05）。酶动力学常数：体内CarE的Km显著减小或无明显变化（P<0.05），Vmax显著增大（P<0.05），即CarE与底物亲和力增大，反应速率加快；而GSTs和MFO的Km显著增大或无明显变化（P<0.05），Vmax均显著减小（P<0.05），说明GSTs和MFO与底物亲和力低，反应速率降低。
英文摘要：[Objectives] To determine the effect of sublethal concentrations of bifenazate on detoxifying enzymes in Tetranychus truncatus, further understanding of the mechanism underlying resistance to bifenazate in this species and improve the application of bifenazate. [Methods] The LC50 of bifenazate to adult female T. truncatus was tested using the leaf-dipping method and sublethal concentrations corresponding to 10% and 30% mortality (LC10 and LC30) calculated from the virulence regression equation. The specific activity, and two constants of kinetic parameters, Michaelis constant (Km) and Maximal velocity (Vmax), of carboxylesterase (CarE), glutathione s-transferase (GSTs) and multifunctional oxidase (MFO), were tested and analyzed after treating T. truncatus with LC10 and LC30 doses of bifenazate. [Results] Specific activities of CarE, GSTs and MFO were all significantly increased (P<0.05) by exposure to LC10 and LC30 doses of bifenazate. The specific activities of CarE and GSTs in the LC30 treatment group were generally significantly higher than those of the LC10 treatment group (P<0.05). The Km value of CarE either decreased significantly, or had no significant change (P<0.05), whereas that of GSTs and MFO increased significantly, or had no significant change (P<0.05). The Vmax value of CarE increased significantly (P < 0.05), indicating that CarE has a high substrate affinity and catalytic rate. Conversely, the Vmax value of GSTs and MFO decreased significantly (P < 0.05), indicating low substrate affinity. [Conclusion] Bifenazate can induce the activity of detoxification enzymes in T. truncatus and CarE plays a key role in the detoxification of bifenaazate in this species.