甜菜夜蛾是我国蔬菜和其它夏秋作物上的重要害虫，甲维盐是控制此类害虫的主要药剂。前期研究中已建立了对甲维盐具有1200倍抗性的近等基因系（WH-EB），抗性遗传分析表明抗性为多基因控制的不完全显性遗传。鉴于甲维盐作用机制和抗性机理的多样性，本项目拟将抗性品系WH-EB与敏感品系WH-S杂交、回交，建立抗性基因的遗传作图群体，通过高通量测序筛选与抗性基因紧密连锁的SNP标记，构建分子标记连锁图，对抗性基因进行精细定位；然后，通过BAC 文库筛查、染色体步移、基因组的同线性，鉴定出候选的抗性基因；最后，比较抗性和敏感品系在这些基因上的差异，根据基因类型及变异特点，选择相应的方法进行功能验证，以期在分子水平上阐明甜菜夜蛾对甲维盐多因子抗性的分子机理，为这类高效低毒杀虫剂抗性监测预警及合理使用提供理论依据。

Beet armyworm, Spodoptera exigua, is one of the most serious pests of vegetables and other summer/autumn crops. Emamectin benzoate is the major insecticide for its control. We have already selected a pair of near-isogenic lines of S. exigua, one susceptible strain (WH-S) and one resistant strain (WH-EB) which has 1200-fold resistance to emamectin benzoate. Genetic analysis showed that resistance to emamectin benzoate in WH-EB is controlled by incompletely dominant, polygenic factors. Considering multiple target sites of emamectin benzoate, genetic mapping will be employed to identify candidate resistance genes in WH-EB. The resistant strain (WH-EB) will be crossed with the susceptible strain WH-S, and F1 progeny is backcrossed with WH-S. Two mapping groups will be constructed from the backcross progeny. Linkage groups will be identified based on SNP markers originated by RAD-seq. Resistance QTLs will be allocated by fine mapping. With integration of BAC library screen, chromosome walking and synteny among lepidopteran genomes, candidate genes responsible for resistance will be identified. Depending on the nature of candidate genes, adaptive techniques of functional expression will be used to verify causal relationship between candidate genes and resistance. This study aims to elucidate polygenic resistance mechanisms of S. exigua to emamectin benzoate at molecular level, and provide theoretical basis for rational use and further exploitation of this kind of evironment-benign insecticides.