Conserved loci and tandem arrays of P450s facilitate evolution of insecticide resistance in noctuid moths

Noctuid moths are major agricultural pests causing extensive crop damage worldwide. Their enhanced insecticide resistance is largely attributed to expansions and variations of cytochrome P450 genes, which play a pivotal role in adapting to environmental pressures. In this study, we analyzed genomic data from eight noctuid species and four representative Lepidopteran species to explore the evolutionary patterns and functional diversification of P450s. Our results reveal substantial expansions in the CYP3 and CYP4 subfamilies in noctuids, primarily driven by gene duplications forming extensive tandem arrays. Synteny analysis identified two conserved P450 loci across all examined Lepidopteran species; notably, noctuid species exhibit significant expansions at these loci—including a 20-gene cluster in Spodoptera frugiperda and an 18-gene cluster in S. littoralis. Phylogenetic analyses indicate that these expansions are lineage-specific to noctuids. Furthermore, molecular docking of P450s from these loci with nine pesticides suggests that these gene expansions may confer resistance to pyrethroids. Our findings provide crucial insights into the molecular mechanisms underlying noctuid adaptation and resistance, with important implications for developing more sustainable pest management strategies.