The effect of chlorogenic acid, a potential botanical insecticide, on gene transcription and protein expression of carboxylesterases in the armyworm (Mythimna separata)

Chlorogenic acid (CGA) is a potential botanical insecticide metabolite that naturally occurs in various plants. Our previous studies revealed CGA is sufficient to control the armyworm Mythimna separata. In this study, we conducted a proteomic analysis of saliva collected from M. separata following exposure to CGA and found that differentially expressed proteins (DEPs) treated with CGA for 6 h and 24 h were primarily enriched in glutathione metabolism and the pentose phosphate pathway. Notably, we observed six carboxylesterase (CarE) proteins that were enriched at both time points. Additionally, these corresponding genes were expressed at levels 5.05 to 130.25 times higher in our laboratory-selected resistance strains. We also noted a significant increase in the enzyme activity of carboxylesterase following treatments with varying CGA concentrations. Finally, we confirmed that knockdown of MsCarE14, MsCarE28, and MsCCE001h decreased the susceptibility to CGA in resistance strain, indicating three CarE genes play crucial roles in CGA detoxification. This study presents the first report on the salivary proteomics of M. separata, offering valuable insights into the role of salivary proteins. Moreover, the determination of CarE mediated susceptibility change to CGA provides new targets for agricultural pest control and highlights the potential insecticide resistance mechanism for pest resistance management.