Data from: Implementing an evolutionary framework for understanding genetic relationships of phenotypically defined insect biotypes in the invasive soybean aphid (Aphis glycines)

Adaptive evolution of pest insects in response to the introduction of resistant cultivars is well documented and commonly results in virulent (i.e. capable of feeding upon resistant cultivars) insect populations being labeled as distinct biotypes. Phenotypically defined, biotypes frequently remain evolutionarily indistinct, resulting in ineffective application of virulence control measures and shorter durability of resistant cultivars. Here we utilize an evolutionary framework to discern the genetic relationship between biotypes of the soybean aphid (Aphis glycines, Matsumura). The soybean aphid is invasive in North America, and is among the most destructive pests of commercial soybean on the continent. Attempts to breed host-plant resistant soybean have been hampered by the emergence of virulent aphid biotypes that are unaffected by the plant’s resistance mechanism(s). Comparative population genetic analysis of virulent and avirulent (i.e. unable to feed on resistant cultivars) biotypes found populations to be genetically indistinguishable across biotype and geographic distance, with high rates of inter-population immigration and admixture. The lack of genetic distinction between biotypes coupled with elevated genotypic diversity within all populations suggested virulence has a non-genetic based or includes a gene complex that is widely distributed throughout soybean aphid populations, which undergo regular dispersal and unimpeded sexual recombination.

害虫针对抗虫品种（resistant cultivars）的引入所产生的适应性进化已有充分的文献记载，其常见结果是：能够在抗虫品种上取食的致毒型（virulent）昆虫种群被归类为独特的生物型（biotype）。通过表型特征定义的生物型往往在进化层面难以区分，这导致毒力防控措施应用失效，并缩短了抗虫品种的使用寿命。本研究借助进化分析框架，解析大豆蚜（Aphis glycines, Matsumura）不同生物型间的遗传关系。大豆蚜是北美入侵性害虫，也是该地区商业大豆生产中破坏性最强的害虫之一。培育抗寄主大豆的尝试因致毒型蚜虫生物型的出现而受阻，这类生物型不受植物抗性机制的影响。对致毒型与无毒型（avirulent，即无法在抗虫品种上取食的）生物型开展群体遗传比较分析后发现，无论生物型类别与地理距离如何，各群体在遗传层面均无显著差异，且种群间存在高频的迁入与遗传混合。不同生物型间缺乏遗传区分度，加之所有群体的基因型多样性均较高，这表明致毒特性要么基于非遗传基础，要么包含一个广泛分布于大豆蚜种群中的基因复合体——这类种群会定期扩散并进行不受阻碍的有性重组。