Large number of putative chemosensory genes identified by transcriptomic analysis in the purple stem borer Sesamia inferens (Walker)

Abstract: By analysing the transcriptome of the antennae and female sex pheromone gland, 92 putative chemosensory genes were identified in the purple stem borer Sesamin inferens. Of these genes 87 are novel in this species, including 24 transcripts encoding for odorant binding proteins (OBPs), 24 for chemosensory proteins (CSPs), 2 for sensory neuron membrane proteins (SNMPs), 39 for odorant receptors (ORs) and 3 for ionotropic receptors (IRs). A further comprehensive examination was conducted on the expression profile of these genes regarding to different tissues and life stages by Reverse Transcription-PCR (RT-PCR) for all 92 genes and by Quantitative Real Time RT-PCR (qRT-PCR) for selected 16 genes. Among the chemosensory gene subfamilies, CSP transcripts are most widely and evenly expressed in different tissues and stages, OBP transcripts showed a clear antenna bias and most of OR transcripts are only detected in adult antennae. Our results also revealed that some OR transcripts, such as the transcripts of SNMP2 and 2 IRs are expressed in non-chemosensory tissues, and some CSP transcripts are antenna-specifically expressed. Furthermore, no chemosensory transcript is specific to female sex pheromone gland and very few are found in the heads. The identification of a large set of putative chemosensory genes of each subfamily from a single insect species, together with their different expression profiles provide further information in understanding the functions of these chemosensory genes in S. inferens as well as other insects.

Keywords: transcriptomic analysis; chemosensory gene; antenna; female pheromone gland; tissue expression

 

Correspondence: Shuang-Lin Dong, E-mail: sldong@njau.edu.cn

Fundings: This work was supported by grants from the Agricultural Ministry (201203036), the National Natural Science Foundation (31071978), and the Zhejiang Provincial Natural Foundation (Y3100384) of China.