Molecular Evolutionary Mechanisms of CYP6ER1vA -Type Variant Associated with Resistance to Neonicotinoid Insecticides in Field Populations of Nilaparvata lugens .

The evolution of insecticide resistance has threatened the control of Nilaparvata lugens . Research on mechanisms behind neonicotinoid resistance in N. lugens remains incomplete. This study examined P450-mediated resistance to neonicotinoids in a resistant N. lugens strain (XA-2017-3G). The overexpression of CYP6ER1 in the XA-2017-3G strain plays a role in neonicotinoid resistance, as confirmed by RNA interference. Phenotypic analyses of CYP6ER1 -mediated resistance in strains, including laboratory-susceptible, field-collected, and imidacloprid-laboratory further-selected strains, revealed that the vA-type/vL-type genotype exhibited greater resistance to neonicotinoids compared to the vA-type/vA-type genotype. The mRNA expression levels of CYP6ER1vA -type were closely correlated with the levels of neonicotinoid resistance in N. lugens strains, in which CYP6ER1vA -type overexpression is in part attributed to increased copy numbers of CYP6ER1 . CYP6ER1vA -type-mediated neonicotinoid resistance was further confirmed by a CYP6ER1vA -type transgenic Drosophila melanogaster line. Taken together, our findings strongly suggest that the overexpression of CYP6ER1vA -type, which can be partially attributed to copy number variations, plays a crucial role in N. lugens resistance to neonicotinoids.