Characterization of candidate odorant‐binding proteins and chemosensory proteins in the tea geometrid Ectropis obliqua Prout (Lepidoptera: Geometridae)

Abstract

Insects rely heavily on their sophisticated chemosensory systems to locate host plants and find conspecific mates. Although the molecular mechanisms of odorant recognition in many Lepidoptera species have been well explored, limited information has been reported on the geometrid moth Ectropis obliqua Prout, an economically important pest of tea plants. In the current study, we first attempted to identify and characterize the putative olfactory carrier proteins, including odorant-binding proteins (OBPs) and chemosensory proteins (CSPs). By analyzing previously obtained transcriptomic data of third-instar larvae, five OBPs and 14 CSPs in E. obliqua were identified. Sequence alignment, conserved motif identification, and phylogenetic analysis suggested that candidate proteins have typical characteristics of the insect OBP or CSP family. The expression patterns regarding life stages and different tissues were determined by quantitative real-time PCR. The results revealed that four transcripts (OBP2, OBP4 and CSP8, CSP10) had larvae preferential expression profiles and nine candidate genes (PBP1, OBP1 and CSP2, CSP4, CSP5, CSP6, CSP7, CSP11, and CSP13) were adult-biased expressed. Further specific tissue expression profile evaluation showed that OBP1, OBP2, OBP4, and PBP1 were highly expressed at olfactory organs, implying their potential involvement in chemical cue detection, whereas CSPs were ubiquitously detected among all of the tested tissues and could be associated with multiple physiological functions. This study provided a foundation for understanding the physiological functions of OBPs and CSPs in E. obliqua and will help pave the way for the development of a new environmental friendly pest management strategy against the tea geometrid moth.

Comparison of male antennal morphology and sensilla physiology for sex pheromone olfactory sensing between sibling moth species: Ectropis grisescens and Ectropis obliqua (Geometridae)

“…We consider that the OSNs population coding accounts for OR function and expression. However, to date, only a few studies of the expression of relevant candidate olfactory genes have been carried out in E. grisescens and E. obliqua (Li et al, ; Sun et al, ). Further comparative studies of function, response profiles, and expression patterns of ORs between the two species are required.…”

“…For E. obliqua , the components are Z3,epo6,Z9–18:H, Z3,Z6,Z9–18:H, and (Z,Z)‐3,9‐ cis ‐6,7‐epoxy‐nonadecadiene (Z3,epo6,Z9–19:H) at a ratio of 4:2:4 (Luo, Li, Cai, Bian, & Chen, ). Several studies have focused on volatile analytical chemistry, behavior, antennal morphology, and molecular biology of olfactory receptors (ORs) and genetic analysis of candidate olfactory binding proteins of the two species (Li et al, ; Luo et al, ; Ma, Bian, et al, ; Ma, Xiao, et al, ; Sun et al, ; Zhang et al, ), but no experiments have investigated sensillum physiology.…”

Identification and expression patterns of chemosensory proteins in the black-back prominent moth, Clostera restitura (Lepidoptera: Notodontidae)

“…The multi-tissue expression pattern of CSPs indicate they may also have other functions, apart from chemo sensation (Tegoni et al, 2004). In fact, with the development of genome and transcriptome sequencing, recent studies have demonstrated that CSPs do contribute to other physiological processes Kang, 2016;Zhang et al, 2017;Ting et al, 2018;Zeng et al, 2018). As carrier proteins, CSPs bind with small molecules, for instance nutrients, toxic compounds, hormones and semiochemicals, (Pelosi et al, 2017).…”

Expression patterns and colocalization of two sensory neurone membrane proteins in Ectropis obliqua Prout, a geometrid moth pest that uses Type‐II sex pheromones

“…The reference genes Eoblβ-actin (Ma et al, 2016) and EoblGAPDH (Sun, Mao et al, 2017) were previously demonstrated to be suitable for estimating relative expression levels of E. obliqua olfactory genes; therefore, we selected them as housekeeping genes to normalize EoblSNMP1-2 gene expression and to correct for sample-to-sample variation. Negative controls were nontemplate reactions (sterilized H 2 O instead of cDNA).…”

“…Negative controls were nontemplate reactions (sterilized H 2 O instead of cDNA). The reference genes Eoblβ-actin (Ma et al, 2016) and EoblGAPDH (Sun, Mao et al, 2017) were previously demonstrated to be suitable for estimating relative expression levels of E. obliqua olfactory genes; therefore, we selected them as housekeeping genes to normalize EoblSNMP1-2 gene expression and to correct for sample-to-sample variation. The amplification efficiencies of the target and reference genes were assessed by examining the variation of ΔCt (Ct target -Ct reference) with template gradient dilution (Livak & Schmittgen, 2001).…”