亚致死浓度甲维盐胁迫对甜菜夜蛾幼虫解毒酶系活力及其相关基因表达量的影响

为明晰几种重要解毒酶在甜菜夜蛾针对甲维盐抗性形成过程中的可能作用,本文研究分析了甲维盐处理后甜菜夜蛾幼虫体内主要解毒酶活力及其对应基因表达量的变化趋势。结果表明,在甲维盐(剂量为:LC5、LC20、LC50)胁迫72 h后,甜菜夜蛾体内多功能氧化酶(MFO)比活力及Se CYP450表达量均较对照极显著上升(P0.01),且二者均随着处理浓度的增大而先上升后下降。同时,谷胱甘肽S-转移酶(GST)的比活力也呈现出相同的变化趋势。而Se GSTs与Se GSTs1在胁迫后的表达趋势与GST比活力的并不一致,Se GSTs表达量随着处理浓度的上升而极显著升高(P0.01),而Se GSTs1则随着处理浓度的上升而下降。在3个亚致死浓度甲维盐处理下,酯酶(EST)比活力均被显著抑制(P0.05),同样的趋势也反映在Se Car E表达量的显著变化上(P0.05)。此外,MFO、EST的比活力变化趋势与其对应基因Se CYP450、Se Car E表达谱之间存在极显著相关性(P0.01);而GST活力只与Se GSTs表达量具有极显著相关性(P0.01),与Se GSTs1表达量之间则不存在显著相关性。因此,MFO、GST及其相关基因Se CYP450、Se GSTs、Se GSTs1有可能参与到甜菜夜蛾对甲维盐抗药性的演化过程中。

Activities of Detoxification Enzymes and Expressions of Related Genes in Spodoptera exigua Larvae Treated with Sublethal Concentrations of Emamectin Benzoate

To clarify the role of several important enzymatic detoxification steps in the formation of resistance against emamectin benzoate in Spodoptera exigua, the detoxifying enzyme activities and the expression of related genes were analyzed in S. exigua larvae treated with emamectin benzoate. When 3rd instar larvae of S. exigua were treated with emamectin benzoate at induction doses of LC₅, LC₂₀ and LC₅₀ for 72 h, the mixed-function oxidase(MFO) activity and the expression of SeCYP450 genes were significantly increased(P＜0.01). The changes in activity or expression all increased at first and then decreased following the increasing doses of emamectin benzoate. The change in glutathione-S-transferase(GST) activity of S. exigua was similar to that for MFO, while the expression trends for SeGSTs and SeGSTs1 were different from the GST activity. Compared with the control, the expression of SeGSTs significantly increased in S. exigua treated with increasing induction doses of emamectin benzoate (P＜0.01), while expression of SeGSTs1 decreased. The esterase activities of S. exigua treated with three induction doses of emamectin benzoate all significantly decreased(P＜0.05), as did the expression of SeCarE(P＜0.05). Correlation analysis indicated that there was significant correlation between MFO, esterase activities and the expression of the corresponding genes SeCYP450 and SeCarE, respectively(P＜0.01). There was significant correlation between GST activities and SeGSTs expressions (P＜0.01), but no significant correlation between GST activities and SeGSTs1 expressions(P＞0.01). The MFO, GST and their related genes SeCYP450, SeGSTs and SeGSTs1 might be involves the evolution of resistance to emamectin benzoate in S. exigua larvae.