College of Plant Protection, Shenyang Agricultural University, Shenyang, Liaoning, China.
PLoS One. 2020 May 14;15(5):e0233133. doi: 10.1371/journal.pone.0233133. eCollection 2020.
The beet armyworm, Spodoptera exigua, is a significant agricultural pest of numerous crops and has caused serious economic losses in China. To effectively control this pest, we analyzed its genetic variation, population genetic structure and demographic history. We used mitochondrial DNA (mtDNA) fragments of the cytochrome oxidase subunit I (COI) and eight nuclear microsatellite loci to investigate genetic diversity and population genetic structure of S. exigua populations at 14 sampling sites in western China. Both mtDNA and microsatellite data indicated low levels of genetic diversity among all populations. A moderate genetic differentiation among some S. exigua populations was detected. Neighbor-joining dendrograms, STRUCTURE, and principal coordinate analysis (PCoA) revealed two genetically distinct groups: the KEL group and the remaining population group. Isolation by distance (IBD) results showed a weak significant correlation between geographic distance and genetic differentiation. Haplotype networks, neutrality testing, and mismatch distribution analysis indicated that the beet armyworm experienced a recent rapid expansion without a recent genetic bottleneck in western China. Thus, the results of this population genetic study can help with the development of strategies for managing this highly migratory pest.
甜菜夜蛾（Spodoptera exigua）是一种重要的农业害虫，对许多作物造成了严重的经济损失。为了有效控制这种害虫，我们分析了其遗传变异、种群遗传结构和种群历史动态。我们使用线粒体 DNA（mtDNA）片段的细胞色素氧化酶亚基 I（COI）和 8 个核微卫星位点，调查了中国西部 14 个采样点的甜菜夜蛾种群的遗传多样性和种群遗传结构。mtDNA 和微卫星数据均表明，所有种群的遗传多样性水平较低。一些甜菜夜蛾种群间存在中度遗传分化。基于邻接法的聚类树、STRUCTURE 和主坐标分析（PCoA）揭示了两个在遗传上明显不同的群体：KEL 群体和其余的种群群体。基于距离的隔离（IBD）结果表明，地理距离与遗传分化之间存在弱显著相关性。单倍型网络、中性检验和不匹配分布分析表明，在中国西部，甜菜夜蛾经历了一次近期的快速扩张，而没有经历近期的遗传瓶颈。因此，这项种群遗传研究的结果有助于制定管理这种高度迁徙性害虫的策略。
