Genome-wide analysis of odorant-binding proteins and chemosensory proteins in the sweet potato whitefly, Bemisia tabaci.

Odorant-binding proteins (OBPs) and chemosensory proteins (CSPs) of insects are thought to play roles in olfactory recognition affecting host choice, copulation, reproduction and other behaviors. Previous descriptions of OBPs and CSPs in the whitefly Bemisia tabaci often provided no or incomplete genetic information. In this study, we present a genome-wide and transcriptome-wide investigation of the OBPs and CSPs in B. tabaci MEAM1 (Middle East-Asia Minor1 species). Eight OBP and 19 CSP genes were identified that covered all previous sequences. Phylogenetic analyses showed that the CSP genes had a lineage-specific expansion (BtabBCSP1, BtabBCSP3, BtabBCSP13, BtabBCSP17, BtabBCSP18 and BtabBCSP19). Expression profiling of OBPs and CSPs by transcriptome sequencing and quantitative real-time polymerase chain reaction (qPCR) revealed that expression patterns differed among developmental stages of B. tabaci MEAM1. Five OBP genes and 11 CSP genes significantly differed between males and females; four of the 19 CSP genes were highly expressed in adults, while two were highly expressed in nymphs. The expression profiles of the OBP and CSP genes in different tissues of B. tabaci MEAM1 adults were analyzed by qPCR. Four OBP genes found in B. tabaci MEAM1 were highly expressed in the head. Conversely, only two CSPs were enriched in the head, while the other six CSPs were specifically expressed in other tissues. Our results provide a foundation for future research on OBPs and CSPs in B. tabaci.