R79E Mutation inthe Nicotinic Acetylcholine Receptorβ1 Subunit Drives High-Level Resistance to Neonicotinoid Insecticidesin Bemisia tabaci

The whitefly, Bemisia tabaci, a globally significant pest transmitting over 200 plant viruses, has developed substantial resistance to insecticides, particularly neonicotinoids. Using near-isogenic lines, bulked segregant analysis (BSA), and genetic linkage analysis, we identified a major resistance locus on chromosome 6. The locus harbored dual mutations in the nicotinic acetylcholine receptor (nAChR) β1 subunit gene associated with high-level neonicotinoid resistance. Bioassays using gene-edited Drosophila melanogaster strains revealed that the R79E mutation conferred significant resistance to neonicotinoids. A field population carrying the R79E single mutation and exhibiting high-level resistance was subsequently identified using an optimized hybridization and backcrossing strategy combined with BSA. Furthermore, a six-year resistance monitoring program revealed that R79E is a major contributor to high-level neonicotinoid resistance in B. tabaci field populations. These findings improve our understanding of target-site resistance mechanism in agricultural pests and support the development of molecular tools for resistance monitoring and management.