ddRAD Sequencing Identifies Pesticide Resistance-Related Loci and Reveals New Insights into Genetic Structure of Bactericera cockerelli as a Plant Pathogen Vector

Abstract

(1) Background: Many hemipteran insects transmit plant pathogens that cause devastating crop diseases, while pest management frequently relies primarily on insecticide applications. These intense insecticide applications lead to the development of insecticide resistance, as was the case for potato psyllid, Bactericera cockerelli (Hemiptera: Triozidae), a vector of Candidatus Liberibacter solanacearum, which causes zebra chip disease in potato. (2) Methods: Here, we use double-digest restriction site-associated DNA (ddRAD) to genotype eight psyllid populations (one susceptible and seven resistant to neonicotinoid insecticides). (3) Results: Association tests identified over 400 loci that were strongly segregated between susceptible and resistant populations. Several loci were located within genes involved in insecticide resistance, gene regulation, fertility, and development. Moreover, we explored the genetic structure of these eight populations and discovered that routinely utilized haplotyping was not an accurate predictor of population structure. Pairwise comparisons of the fixation index (FST) of populations of the same haplotype were not different from pairwise FST of populations that belonged to different haplotypes. (4) Conclusions: Our findings suggest that neonicotinoid insecticide resistance has a genetic basis, most likely as a result of similar selection pressure. Furthermore, our results imply that using a single maternally inherited gene marker to designate genetic lineages for potato psyllids should be re-evaluated.

Biology, Ecology, and Management of the Potato Psyllid, Bactericera cockerelli (Hemiptera: Triozidae), and Zebra Chip Disease in Potato

“…However, differences in the transmission efficiency of Lso have not been observed (122). Despite these among-haplotype differences, haplotype characterizations are less accurate predictors of population structure relative to using a broader range of molecular markers such as genome-wide single nucleotide polymorphisms (SNPs) (43,65).…”

Population Genomics for Insect Conservation

“…In the Colorado potato beetle, Leptinotarsa decemlineata, genome resequencing showed repeated selection on insecticide resistance from standing variation, involving similar pathways but different genes (162). In the psyllid Bactericera cockerelli, insecticide resistance was associated with more than 400 loci (163). A full genome scan in the aphid Myzus persicae revealed a high diversity of resistance mutations segregating in global populations (164).…”