Identification and expression analysis of putative chemoreception genes from Cyrtorhinus lividipennis (Hemiptera: Miridae) antennal transcriptome

Abstract

Cyrtorhinus lividipennis Reuter (Hemiptera: Miridae) is an important egg predator of planthoppers which are destructive rice pests. The chemosensory genes in the mirid antennae play important roles in mating and prey-seeking behaviors. To gain a better understanding of the olfaction of C. lividipennis, we sequenced the antennal transcriptomes of the predator to identify the key olfaction genes. We identified 18 odorant binding proteins (OBPs), 12 chemosensory proteins (CSPs), 1 Niemann-Pick C2 protein (NPC2), 15 odorant receptors (ORs), 6 ionotropic receptors (IRs), 3 gustatory receptors (GRs) and 3 sensory neuron membrane proteins (SNMPs). Quantitative real-time PCR results showed that the relative transcript levels of three ClivORs (ClivOR6, 7 and 14) in the female antennae were 3 to 6 folds higher than that in the male antennae, indicating these genes were more related to oviposition site selection. The relative transcript levels of ClivCSP8 and ClivOR11 were 2.6 and 2.7 times higher in the male antennae than that of the female, respectively, indicating that these genes might be involved in mate searching. Moreover, the responses of dsorco treated predators to volatiles emitted from infested rice were significantly reduced, indicating these volatiles might serve as crucial cues in the host searching of C. lividipennis.

Analysis of Chemosensory Genes in Full and Hungry Adults of Arma chinensis (Pentatomidae) Through Antennal Transcriptome

“…Previous studies have demonstrated sex-based differences in the chemosensory genes of insects, such as Tessaratoma papillosa (Wu et al, 2017), C. lividipennis (Wang et al, 2018), and A. lucorum (Ji et al, 2013). In insects, the perception of chemical cues, including sex pheromones and plant volatiles, is important to find a conspecific partner and food sources, respectively (Yang et al, 2016;Chang et al, 2017;Wang et al, 2018). In our study, sexual differences were determined in 29 chemosensory genes of A. chinensis, with AchiGR1, AchiGR2, and AchiOBP28 expressed at higher levels in the antennae of females than males regardless of whether the insects were full or hungry.…”

“…In our study, sexual differences were determined in 29 chemosensory genes of A. chinensis , with AchiGR1 , AchiGR2 , and AchiOBP28 expressed at higher levels in the antennae of females than males regardless of whether the insects were full or hungry. The higher-level expression of AchiOBP13 and AchiOBP16 only in full female A. chinensis suggests that these genes encode proteins related to oviposition selection behavior ( Pelosi et al, 2006 ; Wu et al, 2017 ; Wang et al, 2018 ). AchiGRs ( 1 and 2 ), AchiIR6 , and AchiOBPs ( 6–8 , 12 , 20–22 , 28 , and 34 ) were predominantly expressed in full male A. chinensis and may thus be involved in mate searching ( Liu et al, 2012 ; Gu et al, 2014 ; Wang et al, 2018 ) or the recognition of pheromone molecules ( Liu et al, 2015 ).…”

“…However, the number of chemoreceptor genes expressed in A. chinensis antennae and the distinction between genes related to the search for food and the detection of pheromone isomerism are unclear. Insights gained from an elucidation of the olfactory system of A. chinensis can be applied to increase the efficiency of this predator insect in bio-control ( Wang et al, 2017 , 2018 ).…”

“…In this study, next-generation sequencing was used to identify the chemoreception genes of A. chinensis antennae and the sex specificity of those genes in full and hungry male and female A. chinensis ( Wang et al, 2017 , 2018 ), and we assumed that the chemosensory genes would be different between full and hungry adults of A. chinensis ’ antennae. From the datasets of the A. chinensis antennal transcriptome, 38 OBP, 1 CSP, 1 NPC2, 3 OR, 12 IR, 2 GR, and 3 SNMP genes were identified.…”

Frizzled 2 Functions in the Regulation of TOR-Mediated Embryonic Development and Fecundity in Cyrtorhinus lividipennis Reuter

“…C. lividipennis was microinjected with dsRNA as described by Wang et al (2018). In a preliminary study, we evaluated five different dsRNA concentrations, which were designated high (80 and 100 ng), medium (40 and 60 ng), and low (20 ng); 60 ng dsFz2 was selected as an optimum concentration based on the survival rate and RNAi efficiency of C. lividipennis (data not shown).…”