Functional and evolutionary characterization of chemosensory protein CSP2 in the whitefly, Bemisia tabaci

Abstract

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 the CSP2 gene in the whitefly Bemisia tabaci using protein expression and the binding affinity spectrum of CSP2 to different types of odor molecules. Moreover, the evolutionary characteristics of the CSP2 gene 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 of B. 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 of B. tabaci to 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 of B. tabaci.

Three chemosensory proteins from the sweet potato weevil, Cylas formicarius, are involved in the perception of host plant volatiles

“…5(C1, C2)). These results, in line with the findings of other studies, indicate that CforCSP1 and CforCSP5 might play olfactory perception by binding and transporting host plant volatiles 40 . On the other hand, CforCSP6 showed strong binding affinities for two ligands (Fig.…”

“…For instance, fluorescent competitive assays and behavioral bioassays showed that the protein, CSP2 can bind to eight volatiles including the homoterpene (E)‐3,8‐dimethyl‐1,4,7‐nonatriene (DMNT). This compound repelled the host selection and oviposition of Bemicia tabaci , which suggested that CSP2 play a mediating role in the responses of B. tabaci to plant volatiles 40 . Further, competitive binding assays of CSP33 protein and H‐tube olfactometer bioassays showed that Cnaphalocrocis medinalis showed significant attraction to nerolidol, but was strongly repelled by β‐ ionone 3 .…”

The Crystal Structure of the Spodoptera litura Chemosensory Protein CSP8

“…Therefore, insecticides specifically targeting key proteins in insects in recognizing these foreign substances could provide alternative biocontrol strategies. CSPs were originally found in the chemosensory system of insects, and it is believed to be involved in the chemo-recognition of different types of environmental chemicals [ 24 ]. Reports had suggested that CSPs can bind plant secondary metabolite molecules [ 25 , 26 ].…”

Expression Profiles and Functional Characterization of Chemosensory Protein 15 (HhalCSP15) in the Brown Marmorated Stink Bug Halyomorpha halys

“…Some specific amino acids located in the hydrophobic cavities may be involved in the process of ligand binding in HhalCSP15 ( Tomaselli et al, 2006 ). For example, in CSPsg4, I76 and W83 are involved in oleamide binding ( Tomaselli et al, 2006 ); in CSP2, Y11 plays a key role in the binding of ( E )-3,8-dimethyl-1,4,7-nonatriene ( Li et al, 2021 ). Molecular docking analyses indicate favorable interactions between HhalCSP15 and its ligands.…”