Overexpression of the ABCG Gene Cluster Contributed to Multi-Insecticide Resistance in Plutella xylostella (L.)

The diamondback moth, Plutella xylostella (L.) (Lepidoptera: Plutellidae), has evolved pronounced resistance to nearly all major classes of insecticides, posing a persistent threat to global agricultural productivity. Although ATP-binding cassette (ABC) transporters are known to contribute to multiple insecticide resistance, their functional significance in P. xylostella remains inadequately elucidated. A genome-wide association study (GWAS) comparing resistant and susceptible strains revealed a genomically clustered trio of ABCG genes (PxABCG4, PxABCG8, PxABCG9) on chromosome 12 that was strongly correlated with the resistance phenotype. Functional characterization through RNAi and CRISPR/Cas9 confirmed that PxABCG4 and PxABCG9 contribute to resistance against indoxacarb, chlorantraniliprole, and beta-cypermethrin. PxABCG8 was implicated in resistance to chlorantraniliprole and beta-cypermethrin in P. xylostella. Furthermore, molecular docking analyses demonstrated high-affinity binding between insecticides and PxABCG4, PxABCG8, and PxABCG9. These findings establish that this ABCG gene cluster constitutes a genetic basis of broad-spectrum insecticide resistance in P. xylostella and provides new insights for understanding the functions of ABCG genes in insects.