Metabolic resistance and the role of <i>CYP6DA2</i> and <i>CYP380C6</i> genes in flupyradifurone resistance in the cowpea aphid (Koch)

The cowpea aphid, Aphis craccivora (Koch), is a significant agricultural pest that globally affects numerous crops, leading to substantial yield losses through both feeding and the transmission of viral diseases. Flupyradifurone has an excellent safety profile and a unique mode of action; resistance to flupyradifurone has been reported in certain aphid species. In the current study, the cross-resistance and resistance mechanisms of A. craccivora to flupyradifurone were investigated. The results revealed that A. craccivora developed a resistance ratio (RR) of 46.6-fold as a result of laboratory selection for 28 consecutive generations. In the flupyradifurone-resistant strain (R-strain), metabolic enzyme determinations indicated significant increases in cytochrome P450 monooxygenase, esterase, and glutathione S-transferase activities. Moreover, quantitative real-time PCR (RT-qPCR) revealed the differential expression of CYP6DA2 and CYP380C6, with CYP6DA2 being upregulated, suggesting its pivotal role in flupyradifurone resistance. Molecular docking studies demonstrated a stronger binding affinity of flupyradifurone to CYP6DA2 than to CYP380C6, further supporting its involvement in detoxification processes. The findings also highlighted moderate cross-resistance to malathion, underscoring the need for insecticide management to mitigate the evolution of resistance. This study provides critical insights into the biochemical mechanisms underlying flupyradifurone resistance in A. craccivora and emphasizes the importance of developing effective resistance management strategies for pest control.