甜菜夜蛾对氯虫苯甲酰胺抗性种群选育及鱼尼丁受体基因表达特征

为明确甜菜夜蛾Spodoptera exigua对氯虫苯甲酰胺的抗性发展及抗性种群中鱼尼丁受体(ryanodine receptor,RyR)基因的表达量变化,室内采用饲料混毒法进行甜菜夜蛾对氯虫苯甲酰胺的抗性选育,荧光定量PCR技术研究了抗性和敏感种群之间RyR基因mRNA表达量的差异。结果表明,室内选育31代后获得一个抗性倍数为105.60倍的甜菜夜蛾抗性种群,其mRNA表达量在甜菜夜蛾不同发育阶段及抗性种群和敏感种群之间均存在差异,以表达量最低的卵期作为对照,抗性种群中1龄幼虫表达量最高,是卵期的154.58倍;其次是雄性成虫,其表达量是卵期的101.51倍;2~5龄幼虫分别是卵期的59.56、35.35、72.99和19.84倍。抗性种群中1、2和4龄幼虫mRNA表达量分别是敏感种群的5.99、2.79和2.14倍,其余阶段低于敏感种群。表明甜菜夜蛾对氯虫苯甲酰胺的抗药性可能主要表现在幼虫阶段,RyR基因的表达量变化与氯虫苯甲酰胺诱导有关。

Selection for resistance in the beet armyworm, Spodoptera exigua to chlorantraniliprole and expression patterns of ryanodine receptor

In order to clarify the resistance development of beet armyworm, Spodoptera exigua to chlorantraniliprole and the expression level of ryanodine receptor (RyR) gene, selection for resistance in S.exigua to chlorantraniliprole was carried out through diet-incorporation bioassays, and the expression levels of RyR gene between the resistant and susceptible populations were analyzed through the quantitative PCR technique. The results showed that a resistant population with 105.60-fold resistance was obtained after selection for 31 generations using chlorantraniliprole and the expression levels varied between the resistant and susceptible populations. The expression of the 1st instar larvae was the highest, with 154.58-fold as compared to the eggs. Significantly higher expression was also observed in male adults with 101.51-fold. The 2nd-5th instar larvae exhibited significantly higher expressions of 59.56, 35.35, 72.99, and 19.84 folds, respectively. As for the resistant population, RyR expression levels of 1st, 2nd and 4th instar larvae were proved to be significantly higher than susceptible population, with 5.99, 2.79, and 2.14 folds, respectively. It is concluded that the resistant response of S. exigua to chlorantraniliprole probably occurred at larval stage and the increased expression of RyR gene was likely related to chlorantraniliprole induction.