Population genomics of biotype adaptation in soybean aphid (Aphis glycines)

Host plant resistant (HPR) crop varieties have the potential to offer economic and environmentally sound control for a variety of agricultural pest species. However, the rapid adaptation of pests to overcome HPR poses significant challenges to the implementation and long-term efficacy of these varieties. The mechanisms of adaptation to HPR are poorly understood in many crop/pest interactions, and are completely unknown in most. Understanding the genetic mechanisms of pest adaptation may allow for better prediction of the HPR efficacy and the implementation of more robust evolutionary control tactics to limit adaptive potential. Here we utilize genotyping-by-sequencing (GBS) to perform a single nucleotide polymorphism (SNP) based genome scan of HPR-adapted and non-adapted populations of soybean aphid (Aphis glycines) from across the species North American range. Using FST-based outlier tests we identified genomic regions exhibiting signatures of selection, suggesting association with biotypic adaptation. This work represents a first step toward the identification of the genes and underlying mechanisms that mediate soybean aphid adaptation to HPR crop varieties.