Identification and expression profiles of candidate chemosensory receptors in Histia rhodope (Lepidoptera: Zygaenidae)

Abstract

Insect olfaction and vision play important roles in survival and reproduction. Diurnal butterflies mainly rely on visual cues whereas nocturnal moths rely on olfactory signals to locate external resources. Histia rhodope Cramer (Lepidoptera: Zygaenidae) is an important pest of the landscape tree Bischofia polycarpa in China and other Southeast Asian regions. As a diurnal moth, H. rhodope represents a suitable model for studying the evolutionary shift from olfactory to visual communication. However, only a few chemosensory soluble proteins have been characterized and information on H. rhodope chemoreceptor genes is currently lacking. In this study, we identified 45 odorant receptors (ORs), nine ionotropic receptors (IRs), eight gustatory receptors (GRs) and two sensory neuron membrane proteins (SNMPs) from our previously acquired H. rhodope antennal transcriptomic data. The number of chemoreceptors of H. rhodope was less compared with that found in many nocturnal moths. Some specific chemoreceptors such as OR co-receptor (ORco), ionotropic receptors co-receptor, CO2 receptors, sugar receptors and bitter receptors were predicted by phylogenetic analysis. Notably, two candidate pheromone receptors (PRs) were identified within a novel PR lineage. qRT-PCR results showed that almost all tested genes (22/24) were predominantly expressed in antennae, indicating that they may be important in olfactory function. Among these antennae-enriched genes, six ORs, five IRs and two GRs displayed female-biased expression, while two ORs displayed male-biased expression. Additionally, HrhoIR75q.2 and HrhoGR67 were more highly expressed in heads and legs. This study enriches the olfactory gene inventory of H. rhodope and provides the foundation for further research of the chemoreception mechanism in diurnal moths.

Identification and Expression Analysis of Chemosensory Genes in the Antennal Transcriptome of Chrysanthemum Aphid Macrosiphoniella sanborni

“…By comparing and analyzing the amino acid sequences of ORs, it has been found that the homology of ORs among different insects is very low, and ORs among the same kind of insects are also dispersed, which may be related to ORs’ participation in recognition of odorants [ 43 ]. This study supports the evidence from previous observations that ORCO has high homology among different species, and an insect usually contains only one ORCO [ 44 ]. Compared with ORs, IRs only have three transmembrane domains.…”

The Structure and Function of Ionotropic Receptors in Drosophila

“…IRs are conserved across protostome species and bioinformatic analyses of IR genes have been performed in many species (Benton et al, 2009 ; Croset et al, 2010 ; Bengtsson et al, 2012 ; Glaser et al, 2013 ; Poivet et al, 2013 ; Rytz et al, 2013 ; Cao et al, 2014 ; Groh-Lunow et al, 2014 ; Liu et al, 2014 , 2017 , 2018 ; Missbach et al, 2014 ; Ahmed et al, 2016 ; Dippel et al, 2016 ; Macharia et al, 2016 ; van Schooten et al, 2016 ; Cicconardi et al, 2017 ; Latorre-Estivalis et al, 2017 ; Yang et al, 2017 , 2020 ; Zbinden et al, 2017 ; Harrison et al, 2018 ; Kozma et al, 2018 ; Matthews et al, 2018 ; Robertson et al, 2018 , 2019 ; Rojas et al, 2018 ; Andersson et al, 2019 ; Lei et al, 2019 ; Li et al, 2019 ; Ma et al, 2019 ; Xu et al, 2019 ; Balart-García et al, 2020 ; Sun et al, 2020 ; Wu et al, 2020 ; Yin et al, 2020 ). However, the functional studies of IRs in non-model organisms are largely lacking.…”