Identification and expression profiles of putative chemosensory protein genes in Cnaphalocrocis medinalis (Lepidoptera: Pyralidae)

Insect chemosensory proteins (CSPs) are small, water-soluble proteins which can bind and transport hydrophobic odorants through sensillum lymph to activate odorant receptors, thus play important roles in the olfactory recognition. In the present study, by searching the transcriptome data sets, a total of 22 candidate CSP genes were identified from Cnaphalocrocis medinalis , a serious lepidopteran rice pest in Asia. CSP proteins encoded by these genes showed typical characteristics: an N-terminal signal peptide, four conserved cysteine residues and the pattern of cysteine spacing. The expression profiles of these putative CSP genes were investigated using real-time quantitative PCR. The results showed that five genes ( CmedCSP4 , CmedCSP8 , CmedCSP11 , CmedCSP18 and CmedCSP21 ) were expressed primarily in antennae, suggesting their involvement in olfactory processes; whilst other genes are mainly expressed in non-olfactory tissues, such as abdomen and legs, indicating a broader physiological function for these CSPs. The findings will lead to a better understanding of the molecular mechanisms of chemoreception in C. medinalis .