Chemosensory genes in the antennal transcriptome of two syrphid species, Episyrphus balteatus and Eupeodes corollae (Diptera: Syrphidae)

Abstract

BackgroundPredatory syrphid larvae are an important natural enemy of aphids in cotton agro-ecosystems in China. Their behaviors in prey foraging, localization and oviposition greatly rely on the perception of chemical cues. As a first step to better understand syrphid olfaction at the molecular level, we have performed a systematic identification of their major chemosensory genes.ResultsMale and female antennal transcriptomes of Episyrphus balteatus and Eupeodes corollae were sequenced and assembled using Illumina HiSeq2000 technology. A total of 154 chemosensory genes in E. balteatus transcriptome, including candidate 51 odorant receptors (ORs), 32 ionotropic receptors (IRs), 14 gustatory receptors (GRs), 49 odorant-binding proteins (OBPs), 6 chemosensory proteins (CSPs) and 2 sensory neuron membrane proteins (SNMPs) were identified. In E. corollae transcriptome, we identified 134 genes including 42 ORs, 23 IRs, 16 GRs, 44 OBPs, 7 CSPs and 2 SNMPs. We have provided full-length sequences of the highly conserved co-receptor Orco, IR8a/25a family and carbon dioxide gustatory receptor in both syrphid species. The expression of candidate OR genes in the two syrphid species was evaluated by semi-quantitative reverse transcription PCR. There were no significant differences of transcript abundances in the respective male and female antenna, which is consistent with differentially expressed genes (DEGs) analysis using the FPKM value. The sequences of candidate chemosensory genes were confirmed and phylogenetic analysis was performed.ConclusionsThis research comprehensively analyzed and identified many novel candidate chemosensory genes regarding syrphid olfaction. It provides an opportunity for understanding how syrphid insects use chemical cues to conduct their behaviors among tritrophic interactions of plants, herbivorous insects, and natural enemies in agricultural ecosystems.Electronic supplementary materialThe online version of this article (doi:10.1186/s12864-017-3939-4) contains supplementary material, which is available to authorized users.

Identification and expression analysis of chemosensory genes in the tea green leafhopper, Empoasca onukii Matsuda

“…In consistent with several previous reports Wang, Liu, et al, 2017;Wang, Li, et al, 2017), the results of C-pattern analysis (Supporting Information Figures S4-S6) and motif pattern ( Figure 3) suggested that CSPs are more conservative than OBPs.…”

“…In addition, according to the results of MEME motif analysis, both EonuOBPs and EounCSPs presented several different motif patterns, with the most common one being 1‐3‐5‐2 and 3‐6‐2‐5‐1‐7‐4‐8, respectively. In consistent with several previous reports (Gu et al., ; Wang, Liu, et al., ; Wang, Li, et al., ), the results of C‐pattern analysis (Supporting Information Figures S4–S6) and motif pattern (Figure ) suggested that CSPs are more conservative than OBPs.…”

“…Four CSPs in Bian’s study are missing in the present study, while 17 CSPs are newly identified in our study, this making the total number of CSPs as 28. The number of OBPs in E. onukii (49) was significantly higher than those in some other Hemipteran species, for example, 8 OBPs in B. tabaci (Wang, Liu, et al., ; Wang, Li, et al., ), 10 OBPs in N. lugens (Zhou et al., ), 15 OBPs in A. pisum (Zhou et al., ), 16 OBPs in A. suturalis (Cui et al., ), 33 OBP genes in L. lineolaris (Hull et al., ) and 38 genes in A. lucorum (Yuan et al., ). Empoasca onukii also has 28 CSPs, which are more than the other Hemipteran species.…”

“…Empoasca onukii also has 28 CSPs, which are more than the other Hemipteran species. For instance, A. suturalis has eight CSPs (Cui et al., ), A. gossypii has nine CSPs (Gu, Wu, et al., ) and B. tabaci has 13 CSPs (Wang, Liu, et al., ; Wang, Li, et al., ). Multiple reasons are probably responsible for the different numbers of OBP and CSP genes in diverse insects.…”

“…A CSP protein contains four conserved cysteines in their protein sequence with a similar role as for OBPs (Pelosi et al., ). With the development and improvement of the genome and transcriptome sequencing technique, a large number of OBP and CSP genes have been identified from diverse orders, including Hemiptera (Cui et al., ), Lepidoptera (Yao, Xu, Dong, Lu, & Chen, ), Diptera (Wang, Liu, & Wang, ; Wang, Li, et al., ), Hymenoptera (Zhang, Zhang, Su, Gao, & Guo, ), Orthoptera (Ban et al., ), Isoptera (Krieger & Ross, ) and Coleoptera (Antony et al., ). In the Hemiptera insects, numerous OBP and CSP genes have been identified from diverse families, including Miridae [such as Apolygus lucorum (Yuan et al., ), Adelphocoris lineolatus (Gu et al., ; Sun, Wang, Wang, et al., ), Adelphocoris suturalis (Cui et al., ) and Lygus lineolaris (Hull, Perera, & Snodgrass, )], Aphididae [such as Aphis gossypii (Gu, Wu, et al., ), Sitobion avenae (Xue et al., ), Myzus persicae (Xu et al., ) and Acyrthosiphon pisum (Zhou et al., )], Delphacidae [such as Nilaparvata lugens (Zhou, Sun, Ma, Chen, & Wang, ), Sogatella furcifera (Ming & Peng, ) and Laodelphax striatellus (He, Zhang, Li, Li, & Dong, )] Aleyrodidae (such as Bemisia tabaci ; Wang, Liu, et al., ; Wang, Li, et al., ), Pseudococcidae [such as Phenacoccus solenopsis (Nie et al., )], Pentatomidae [such as Halyomorpha halys (Paula et al., )] and Reduviidae [such as Rhodnius prolixus (Ribeiro et al., )].…”