Evidence for the Participation of Chemosensory Proteins in Response to Insecticide Challenge in Conopomorpha sinensis

Chemosensory proteins (CSPs) are a type of efficient transporters that can bind various hydrophobic compounds. Previous research has shown that the expression levels of some insect CSPs were significantly increased after insecticide treatment. However, the role of CSPs in response to insecticide challenge is unclear. Conopomorpha sinensis is the most destructive borer pest of litchi (Litchi chinensis) and longan (Euphoria longan) in the Asia-Pacific region. Here, we studied the expression patterns and potential functions of 12 CSP genes (CsCSPs) from C. sinensis in response to λ-cyhalothrin exposure. The spatiotemporal distribution of CsCSPs suggested that they were predominantly expressed in the female abdomen, female legs, and male legs. The expression levels of CsCSPs were affected in a time-dependent manner after λ-cyhalothrin treatment in both sexes of C. sinensis adults. Compared to the control group, the expression levels of CsCSP1, CsCSP2, CsCSP9, and CsCSP12 in females were significantly increased by 2-4 times, while only one CsCSP, three CsCSPs, and two CsCSPs were significantly upregulated in males at three time points post-treatment. The sex-biased variance of CSP expression may be related to sex-specific detoxification enzymatic activities and survival rates of C. sinensis in response to insecticide challenge. Homology modeling and molecular docking analyses showed that the binding energy value of CsCSP1-12 to λ-cyhalothrin was negative and the binding energy between CsCSP9 and λ-cyhalothrin was the lowest (-11.35 kJ/mol). Combined with expression alterations of CsCSP1-12, the results indicate that CsCSP1, CsCSP2, CsCSP9, and CsCSP12 were involved in binding and ferrying of λ-cyhalothrin in C. sinensis.