Molecular characterization of chemosensory protein genes in Bactrocera minax (Diptera: Tephritidae)

Abstract

AbstractChemoreception is of great importance for survival of insects. Chemosensory proteins (CSPs) are believed to be involved in the perireceptor events of chemosensory system in many insect species, but this has not been clarified in the citrus fruit fly, Bactrocera minax, a serious dipteran pest of citrus crops. Previous studies indicated that four CSP genes were identified in many fly speices in Diptera. In the present study, we also identified four CSP genes in B. minax, namely BminCSP1–4, from a transcriptome database. All CSP proteins encoded by these genes bear the typical hallmarks of the CSP family: an N‐terminal signal peptide and the four highly conserved cysteine residues. Phylogenetic analysis comparing with other dipteran CSPs indicated that dipteran CSPs may evolved from three ancestral CSP genes, and revealed the sequence diversities of BminCSPs and showed that BminCSP1–4 are clustered in separate groups, indicating the possibility of their contrasting function in B. minax. Furthermore, the tissue distribution of the four CSP genes in adult B. minax was analyzed by real‐time quantitiative PCR. The results demonstrated that BminCSP3 are significantly transcriptionally enriched in antennae; BminCSP4 expressed primarily in heads; BminCSP1 and BminCSP2 showed high expressions in different tissues, such as antennae, abdomens and wings. Based on these findings, the different implications for the functions of BminCSPs are discussed. This study will offer a significant indication for further functional studies of the CSPs in B. minax.