Chemosensory Proteins Protect <i>Nilaparvata lugens</i> from Imidacloprid by Sequestering the Insecticide and Facilitating Metabolic Detoxification

The involvement of chemosensory proteins (CSPs) in binding to insecticides has been implicated. However, our understanding of CSP-mediated insecticide resistance remains limited. Herein, 15 CSP genes were identified and characterized from <i>Nilaparvata lugens</i>. Expression analysis identified six CSPs with overexpression in the imidacloprid-resistant strain, whose involvement in imidacloprid resistance was validated by RNA interference. Among them, four CSPs were successfully expressed using a prokaryotic expression system, and their binding affinities to imidacloprid were confirmed through fluorescence competitive binding assays. Knockdown of them impaired the capacity of <i>N. lugens</i> to metabolize imidacloprid and inhibited the activity of metabolic detoxification pathways, while their overexpression in <i>Escherichia coli</i> enhanced bacterial metabolic efficiency toward imidacloprid. Furthermore, the transcriptional regulation of <i>CSP2</i> and <i>CSP15</i> was found to be mediated by AhR/ARNT and CncC/MafK. These findings suggest that the overexpression of CSPs in <i>N. lugens</i> promotes imidacloprid resistance by sequestering the insecticide and enhancing metabolic detoxification.