入侵我国中南三省(区)草地贪夜蛾的单倍体型和群体遗传结构分析

Haplotype and genetic diversity analysis of Spodoptera frugiperda invading in three provinces of central and southern China

【目的】揭示入侵我国中南三省(区)的草地贪夜蛾Spodoptera frugiperda种群间可能存在的遗传变异,探讨其入侵来源、入侵路线和扩散方式,为制定有效控制和阻击草地贪夜蛾的方案提供理论依据和遗传信息。【方法】利用分子标记技术从线粒体DNA和核DNA角度研究草地贪夜蛾种群的遗传多样性和种群结构。对采集自我国广东、广西和湖南3个省(区)的草地贪夜蛾,利用CO I和Tpi基因片段进行了单倍体型分析,利用9个微卫星标记分析种群间的遗传结构和遗传多样性。【结果】供试样品中,除了湖南张家界群体有2个样品为CO I玉米型单倍体型、1个样品为杂合型,其他群体的个体均为CO I水稻型单倍体型。基于SSR标记的群体遗传分析结果表明,被检测的群体遗传多样性较巴西等国家的美洲群体低,各群体遗传分化不明显。广东东莞群体与湖南张家界群体的遗传距离最近,与广西南宁群体的遗传距离较远。【结论】遗传距离与实际距离之间不一定呈正相关,通过遗传结构的分析有助于推测草地贪夜蛾扩散过程中,天气背景场、地理隔离和人为传播各自所起的作用。入侵湖南省张家界的草地贪夜蛾出现了低频率CO I玉米型和高频率的CO I水稻型单倍体型,说明虫源的非单一性;草地贪夜蛾在入侵地定殖时间较短,目前未形成明显的遗传分化。

【Objective】To reveal possible genetic variation among Spodoptera frugiperda populations in three provinces of central and southern China,trace the invasion source and spread pathway of S.frugiperd,and provide the theoretical basis and genetic information for effectively controlling this insect.【Method】The samples of S.frugiperda were collected from Guangdong,Guangxi and Hunan of China.Haplotype analysis was carried out using CO I and Tpi gene markers.Nine microsatellite(SSR)markers were used to analyze the genetic diversity and genetic structure of S.frugiperda populations.【Results】Expect that two samples of S.frugiperda populations from Zhangjiajie of Hunan were characterized to be CO I corn strain and one sample to be hybrid strain,other samples were CO I rice train.The results of SSR markers showed that lower genetic diversity was detected for each population compared with those in South America populations,and the genetic differentiation across populations was no significant.However,the genetic distance was the nearest between GuangdongDongguan population and Hunan Zhangjiajie population,and the farthest between Guangdong Dongguanpopulation and Guangxi Nanning population.【Conclusion】There is no significant relationship between geneticdistance and geographic distance.The genetic structure analysis helps to speculate on the role of weatherbackground field,geographical isolation and human transmission in the process of S.frugiperda spread.S.frugiperda invading in central-south China might be original from multiple locations.The short time of S.frugiperda colonization in the invasive lands leads to the low genetic diversity.No obvious genetic differentiationhas formed at present.