Chemosensory Protein 10 (CSP10) Is Involved in Resistance to Chlorantraniliprole in Spodoptera frugiperda

Spodoptera frugiperda, an economically important agricultural pest, has developed high resistance to chlorantraniliprole, yet mechanisms beyond metabolic detoxification and target-site mutations remain unclear. Chemosensory proteins (CSPs) have emerged as novel contributors to insecticide resistance via direct sequestration. Here, the transcript abundance of 22 CSPs was evaluated in susceptible (SS) and chlorantraniliprole-resistant (CAP-RR) strains of S. frugiperda using transcriptomics and RT-qPCR. Results showed that CSP10 was notably upregulated in the CAP-RR strain and inducible by the insecticide exposure. RNAi-mediated silencing of CSP10 significantly increased larval susceptibility to chlorantraniliprole. Fluorescence binding assays confirmed strong affinity between CSP10 and chlorantraniliprole. Molecular docking and dynamics further revealed the binding interaction primarily via van der Waals forces. Site-directed mutagenesis coupled with computational alanine scanning revealed Phe6, Ile17, Tyr21, Val25, and Phe38 as critical residues for the interaction. Collectively, our findings establish CSP10 as a key mediator of chlorantraniliprole resistance, offering a promising target for resistance management strategies.