First Transcriptome and Digital Gene Expression Analysis in Neuroptera with an Emphasis on Chemoreception Genes in Chrysopa pallens (Rambur)

Abstract

Background Chrysopa pallens (Rambur) are the most important natural enemies and predators of various agricultural pests. Understanding the sophisticated olfactory system in insect antennae is crucial for studying the physiological bases of olfaction and also could lead to effective applications of C. pallens in integrated pest management. However no transcriptome information is available for Neuroptera, and sequence data for C. pallens are scarce, so obtaining more sequence data is a priority for researchers on this species.ResultsTo facilitate identifying sets of genes involved in olfaction, a normalized transcriptome of C. pallens was sequenced. A total of 104,603 contigs were obtained and assembled into 10,662 clusters and 39,734 singletons; 20,524 were annotated based on BLASTX analyses. A large number of candidate chemosensory genes were identified, including 14 odorant-binding proteins (OBPs), 22 chemosensory proteins (CSPs), 16 ionotropic receptors, 14 odorant receptors, and genes potentially involved in olfactory modulation. To better understand the OBPs, CSPs and cytochrome P450s, phylogenetic trees were constructed. In addition, 10 digital gene expression libraries of different tissues were constructed and gene expression profiles were compared among different tissues in males and females.ConclusionsOur results provide a basis for exploring the mechanisms of chemoreception in C. pallens, as well as other insects. The evolutionary analyses in our study provide new insights into the differentiation and evolution of insect OBPs and CSPs. Our study provided large-scale sequence information for further studies in C. pallens.

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

“…Comparing with a large amount of studies on pests' olfaction (Vogt et al, 2009;Gu et al, 2013;He and He, 2014;Sparks et al, 2014;Zhou et al, 2014;Liu et al, 2015), studies on natural enemy insects were scarce (Zhang et al, 2009;Li et al, 2013b;Donnell, 2014). Host seeking in insects is strongly mediated by olfaction, which is dependent on chemosensory genes (Zhou, 2010;Rinker et al, 2013).…”

“…The marker of DL2000 (TaKaRa, Dalian, Liaoning, China) were used and the PCR products reviewed single bands of the expected size. The GTPbinding protein gene was selected as the endogenous control to check the integrity of the cDNA templates (Li et al, 2013b). Each reaction was run in three independent biological replicates.…”

“…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).…”

“…A large number of chemosensory genes have been identified from many insects by high-throughput sequencing (Li et al, 2013b;Younus et al, 2014;Zhou et al, 2014). To identify more chemosensory genes of C. sinica, the female-and male-antennal transcriptomes were sequenced in this study.…”

Identification of odorant‐binding and chemosensory protein genes and the ligand affinity of two of the encoded proteins suggest a complex olfactory perception system in Periplaneta americana

“…germanica (Niu et al ., ), D. melanogaster (Vieira et al ., ), Bo. mori (Gong et al ., ), Z. nevadensis (Terrapon et al ., ), Chrysoperla nipponensis (Li et al ., ), R. maderae (Riviere et al ., ), Ap. mellifera (Forêt & Maleszka, ), Lo.…”