Differential Expression Patterns in Chemosensory and Non-Chemosensory Tissues of Putative Chemosensory Genes Identified by Transcriptome Analysis of Insect Pest the Purple Stem Borer Sesamia inferens (Walker)

Abstract

BackgroundA large number of insect chemosensory genes from different gene subfamilies have been identified and annotated, but their functional diversity and complexity are largely unknown. A systemic examination of expression patterns in chemosensory organs could provide important information.Methodology/Principal FindingsWe identified 92 putative chemosensory genes by analysing the transcriptome of the antennae and female sex pheromone gland of the purple stem borer Sesamia inferens, among them 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). The transcriptome analyses were validated and quantified with a detailed global expression profiling by Reverse Transcription-PCR for all 92 transcripts and by Quantitative Real Time RT-PCR for selected 16 ones. 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 were expressed in non-chemosensory tissues, and some CSP transcripts were antenna-biased expression. Furthermore, no chemosensory transcript is specific to female sex pheromone gland and very few are found in the heads.ConclusionOur study revealed that there are a large number of chemosensory genes expressed in S. inferens, and some of them displayed unusual expression profile in non-chemosensory tissues. 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.

Molecular identification and sex distribution of two chemosensory receptor families in Athetis lepigone by antennal transcriptome analysis

“…Consistent with other moths (Bengtsson et al, 2012;Feng et al, 2015;Zhang et al, 2013Zhang et al, , 2015, the AlepORco gene also displayed a very high mRNA abundance. Many previous studies showed that ORco could act as a chaperone and dimerization partner for other ORs, forming a ligand gated ion channel to specific ligands (Krieger et al, 2003(Krieger et al, , 2005Nakagawa et al, 2005;Xu and Leal, 2013), and ORco was more highly conserved in insects than other ORs (Krieger et al, 2003;Leal, 2013;Robertson et al, 2003;Vogt, 2005), thus it required more ORco transcripts to activate different ORs.…”

“…In the present study, we sequenced and analyzed the antennal transcriptome of A. lepigone. Among the 45,301 unigenes, only 42.17% genes had homologous matches to the entries in NCBI non-redundant (nr) protein database, and only 29.90% could be annotated to one or more GO term, which is similar to other lepidopteran species (Grosse-Wilde et al, 2011;Liu et al, 2012;Zhang et al, 2013), indicating that a large number of A. lepigone genes are either non-coding or homologous with genes that do not have any GO term. Importantly, we first obtained 80 novel genes involved in the mechanism of odorant perception in A. lepigone, which provided a basis for elucidation of the molecular mechanisms of odorant perception and determined a large Fig.…”

“…Based on the research, RT-PCR method successfully analyzed the tissue expression of chemosensory genes in many insects (Latorre-Estivalis et al, 2016;Olivier et al, 2011;Patch et al, 2009;Tanaka et al, 2009;Zhang et al, 2013); therefore, we also used the method to investigate all of the AlepOR and AlepIR genes in female and male antennae, and used glyceraldehyde-3-phosphate dehydrogenase (GAPDH) as a reference gene.…”

Identification and expression pattern of candidate olfactory genes in Chrysoperla sinica by antennal transcriptome analysis

“…Consequently, the female-and male-antennal transcriptomes of C. sinica were sequenced in this study. A total of 14 Gb of C. sinica antennae transcriptome data was obtained, which is larger than that from many other insects (Grosse-Wilde et al, 2011;Glaser et al, 2013;Zhang et al, 2013;Cao et al, 2014a;Cao et al, 2014b). After extensive sequencing and assembly, 19 CSPs, 12 OBPs, 36 ORs, and 64 IRs, were identified.…”

“…Since the first insect ORs were discovered in the fruit fly (Clyne et al, 1999;Vosshall et al, 1999), multiple homologs have been identified (Robertson and Wanner, 2006;Bohbot et al, 2007;Engsontia et al, 2008;Li et al, 2013b;Zhang et al, 2013;Cao et al, 2014b). ORs play a key role in detecting odorants and triggering the transduction of chemical signals to electric signals (Liu et al, 2013).…”