甜菜夜蛾对虫酰肼抗性的生化机制

为了解甜菜夜蛾Spodoptera exigua (Hübner)对虫酰肼的抗性生化机制, 采用活体测定法测定了甜菜夜蛾虫酰肼敏感种群、汰选种群和武汉自然种群体内解毒酶［羧酸酯酶（CarE）和谷胱甘肽-S-转移酶（GSTs)］、保护酶［过氧化氢酶(CAT)、 过氧化物酶（POD）和超氧化物歧化酶（SOD) ］以及与表皮形成相关的表皮酚氧化酶(PO)和几丁质酶的活性。结果表明: 汰选种群和自然种群CarE比活力分别是敏感种群的1.20和2.67倍, GSTs比活力分别是敏感种群的2.34和0.96倍。汰选种群CarE的Km值与敏感种群相比差异显著, 但V_max值无明显差异; 自然种群Km值和V_max值与敏感种群、汰选种群均存在极显著差异。酯酶同工酶电泳酶谱在迁移率、谱带数目、酶带染色深浅等方面均存在明显差异, 分析结果与CarE活力测定、酶动力学研究结果相符。与敏感种群相比, 汰选种群CAT和POD比活力差异不显著, SOD比活力显著增高; 自然种群3种酶比活力均显著增高; 自然种群和汰选种群均是SOD酶活力的变化较CAT和POD明显。汰选种群PO和几丁质酶比活力比敏感种群分别上升了37.64%和27.37%, 自然种群比活力分别上升了59.63%和60.29%。自然种群和汰选种群PO酶动力学常数均与敏感种群存在显著差异。

Biochemical mechanisms of beet armyworm (Spodoptera exigua) resistance to tebufenozide

In order to explore the biochemical mechanisms of the beet armyworm, Spodoptera exigua (Hübner), resistance to tebufenozide, activities of detoxifying enzymes including carboxylesterase (CarE) and glutathione-S-transferases (GSTs), protective enzymes including catalase (CAT), peroxidase (POD) and superoxide (SOD), and phenoloxidase (PO) and chitinase were tested in vivo in the susceptible population, selected population and natural population in Wuhan. The results showed that CarE activities of the selected population and natural population were 1.20- and 2.67-fold, and GSTs activities were 2.3- and 0.9-fold, respectively, compared with the susceptible population. There were significant differences in Km values of the CarE but no significant differences in V_max values between the selected population and susceptible population. Compared with the selected population and susceptible population, the natural population had highly significant differences in K_m and V_max values of the CarE. PAGE results of the esterase isozymes also proved that the CarE activities and kinetic constants had changed dramatically. There were no significant differences in CAT and POD activities between the selected population and susceptible population, but SOD activity of the selected population increased obviously. Meanwhile the activities of the three enzymes in natural population also increased remarkably. The changes of SOD activities were more significant than those of CAT and POD activities. The PO and chitinase activities of the selected population increased 37.64% and 27.37%, respectively, and that of the natural population increased 59.63% and 60.29%, respectively, compared with the susceptible population. The kinetic constants of PO in the natural population and selected population had significant differences from those in the susceptible population. Refs. In Chinese