Identification and expression profiling of five chemosensory protein genes in the whitefly MED, Bemisia tabaci

Insect chemosensory proteins (CSPs) are small, water-soluble proteins involved in detection and recognition of chemical cues and semiochemicals. A better understanding of CSPs and their function could aid in the development of pest control strategies that are based on chemosensory regulation. We screened our unpublished transcriptome data of Bemisia tabaci and identified five CSP genes (BtabCSPs) including two novel BtabCSPs viz. BtabCSP4 and BtabCSP5. Phylogenetic analysis of amino acid sequences of the proteins encoded by these genes revealed that BtabCSPs are distinct from CSPs of other hemipterans. Quantitative PCR analysis showed differential expression of these genes in different stages. In the adult stage, BtabCSP1, 2 and 4 had significantly higher expression than BtabCSP3 and 5 respectively. On the other hand, BtabCSP2 and 5 were relatively highly expressed in stage of pseudopupae compared to BtabCSP1, 3 and 4. In the third instar BtabCSP3, 4 and 5 exhibited higher expression compared to other CSP genes. Expression of all CSP genes was relatively low in the first and second instars compared to later developmental stages. The identification of novel BtabCSPs and the expression profiling of CSP genes in general may help facilitate development of pest management strategies based on disruption of CSP-driven behaviors.