Functional and evolutionary characterization of chemosensory proteinCSP2in the whitefly,Bemisia tabaci

BACKGROUND Chemosensory proteins (CSPs) are thought to play essential roles in insect chemical communication, but their exact physiological functions remain unclear. RESULTS In this study, we investigated the functions of theCSP2gene in the whiteflyBemisia tabaciusing protein expression and the binding affinity spectrum of CSP2 to different types of odor molecules. Moreover, the evolutionary characteristics of theCSP2gene were studied. The data obtained using binding assay showed that the CSP2 protein can bind to a broad range of plant volatiles including the homoterpene (E)-3,8-dimethyl-1,4,7-nonatriene (DMNT) and its analogs. In addition, using a behavioral experimental approach we identified that DMNT can repel the selection and oviposition ofB. tabaci. Furthermore, protein structure modeling, molecular docking analyses and a functional mutation experiment were carried out resulting in the final identification of key amino acid residue Y11, which displayed important roles in the binding of CSP2 to DMNT. The results also showed that Y11 is located in the pocket region where CSP2 has a pi-alkyl interaction with DMNT. Meanwhile, comparative and evolutionary analyses indicated that CSP2 shared a high sequence similarity with CSPs of other insect family members such as Sternorrhyncha and Auchenorrhyncha including aphids, whiteflies and planthoppers. CONCLUSION These results suggested that CSP2 likely contributes to mediating responses ofB. tabacito plant volatiles, which may play a pivotal role in its feeding and oviposition preferences. Moreover, these findings could provide key information for exploring efficiency monitoring and integrated pest management strategies ofB. tabaci.

Automated summary

This study investigated the functions of the CSP2 gene in the whitefly Bemisia tabaci, revealing its binding affinity to various plant volatiles and identifying key amino acid residue Y11 essential for binding to DMNT. Furthermore, CSP2 showed high sequence similarity with CSPs of other insect family members, highlighting its potential role in mediating responses to plant volatiles and implications for pest management strategies.