Identification and expression specificity of chemosensory genes in the male reproductive system of Spodoptera exigua

Abstract

Some chemosensory genes are found to be expressed specifically or highly in the male reproductive system, suggesting their importance in male reproductive physiology. In this paper, we identified chemosensory genes expressed in the male reproductive system of the moth pest Spodoptera exigua by transcriptome and proteome sequencing, and further determined expression patterns of these genes regarding antennae and different tissues of the male reproductive system (testes, vas deferens, seminal vesicles, ejaculatory ducts, male accessory glands) by the real-time quantitative PCR (qPCR). Transcriptome analysis showed that 46 chemosensory genes were expressed in the male reproductive system of S. exigua, including 18 odorant binding proteins (OBPs), 12 chemosensory proteins (CSPs), 10 odorant receptors (ORs) and 6 other chemosensory genes. Further qPCR measurements revealed that 14 chemosensory genes were expressed specifically or highly in the male reproductive tissues, relative to that in male antennae. Of the 14 genes, OBP17, OBP22, OBP27 and GR43 were specifically expressed in the testes; OBP20 was specifically expressed in the vas deferens; and PBP4 was specifically expressed in the male accessory glands. In addition, proteome data of the spermatophore confirmed that at least 4 OBPs and one CSP were transmitted from males to females, suggesting their function in the reproductive physiology of mated females. The results provide insights into the functional diversity of chemosensory genes, and bases for exploring functions of these chemosensory genes in male reproductive physiology.