入侵云南草地贪夜蛾种群对5种常用Bt蛋白的敏感性评价

草地贪夜蛾Spodoptera frugiperda(J. E. Smith)是原分布于美洲大陆热带和亚热带地区的一种重要玉米害虫。在当地,种植抗虫转基因玉米是防控草地贪夜蛾危害的主要手段。该虫于2019年1月入侵我国云南省,为明确入侵我国云南的草地贪夜蛾种群对常用Bt蛋白的敏感性水平,本文通过饲料表面涂抹法测定了瑞丽草地贪夜蛾幼虫对Cry1Ab、Cry1Ac、Cry1F、Cry2Ab以及Vip3A等5种Bt蛋白的敏感性。结果表明:几种常用Bt蛋白对瑞丽草地贪夜蛾致死作用顺序为Vip3A>Cry1Ab>Cry1F>Cry2Ab>Cry1Ac,对草地贪夜蛾抑制生长发育的顺序为Cry1Ab>Cry1F>Vip3A>Cry1Ac>Cry2Ab。此外,与美国相对敏感种群比较,云南瑞丽草地贪夜蛾种群对Cry1Ab、Cry1Ac、Cry1F、Cry2Ab和Vip3A的敏感性指标在0.28～3.76之间,表明该入侵种群对此5种Bt蛋白均未产生抗性。此研究可为将来建立以转Bt基因玉米作为防控草地贪夜蛾的技术体系提供依据。

Susceptibility evaluation of invaded Spodoptera frugiperdapopulation in Yunnan province to five Bt proteins

The fall armyworm, Spodoptera frugiperda (J. E. Smith), is a native major pest of corn in the tropical subtropical regions of the American continent. Planting transgenic hybrid maize expressing insecticidal protein is the main tool for fall armyworm control in this area. Since January 2019, it has invaded the western part of Yunnan province. In order to determine the susceptibility difference of this invaded fall armyworm population in Ruili of Yunnan province to five Bt proteins, we conducted the susceptibility bioassay to Cry1Ab, Cry1Ac, Cry1F, Cry2Ab and Vip3A by using artificial diet overlay method. Based on the LC50 and GIC50 values, the descending order of lethal was ranked as follows: Vip3A>Cry1Ab>Cry1F>Cry2Ab>Cry1Ac, and the descending order of growth inhibition was ranked as follows: Cry1Ab>Cry1F>Vip3A>Cry1Ac>Cry2Ab. Compared with susceptible strain of fall armyworm population from USA, the sensitivity indexes of the invaded population to Cry1Ab, Cry1Ac, Cry1F, Cry2Ab, and Vip3A proteins ranged from 0.28-3.76, indicating that this invaded population has not significantly developed to resistance to these five Bt proteins. This study will help to construct the strategy of planting transgenic Bt corn for controlling fall armyworm as one of main tactics in the future.