Abstract:

【Aim】 Chemosensory proteins (CSPs) are soluble carrier proteins that may play multiple roles in insects. The objective of this study is to assembly the antennal transcriptomes of Oedaleus asiaticus, one of the most important grasshopper pests in northern China, to identify the chemosensory protein genes, and to analyze their tissue expression profiles. 【Methods】 The antennal transcriptomes of the O. asiaticus adults were sequenced and assembled by RNA-Seq. The CSP genes were identified by screening the transcriptome data, and their expression levels in  different adult tissues (antenna, head without antennae and mouthparts, labrum, labium without labial palps, labial palp, maxillary palp, thorax, tarsus, wing, and abdomen) were analyzed by qPCR. 【Results】 The antennal transcriptomes of the O. asiaticus adults were successfully assembled. A total of 61 629 unigenes with a mean length of 733 nt were obtained, and the total length and N50 were 45 175 449 nt and 1 130 nt, respectively. Among them, 26 064 unigenes (42.29%) were annotated to six databases (NR, NT, Swiss-Prot, KEGG, COG and GO). A total of 17 putative CSP genes were identified by blasting, cDNA cloning and sequencing. BlastP best hit results and phylogenetic analysis both showed that the putative OasiCSPs were most closely related to LmigCSPs from Locusta migratoria and SgreCSPs from Schistocerca gregaria. qPCR analysis howed that there were significant differences in the expression levels of eight different SP genes in different adult tissues. Especially, OasiCSP8 was much highly expressed in the abial palps and maxillary palps, and OasiCSP11 and OasiCSP13 had the highest expression evels in the antenna. OasiCSP15 had much higher expression levels in chemosensory tissues antenna, labrum, labium without labial palps, labial palp, maxillary palp, and tarsus) han in non-chemosensory tissues (head without antenna and mouthpart, thorax, wing, and abdomen). However, OasiCSP12 had similar expression distribution in nearly all the tested tissues.【Conclusion】 The results suggest that OasiCSPs might play multiple roles in the hemosensory process and development of O. asiaticus. Our findings provide a foundation for the further functional studies of these CSPs in O. asiaticus.

Key words: Oedaleus asiaticus, antenna, transcriptome, chemosensory protein, expression profile