Identification of candidate chemosensory genes in Mythimna separata by transcriptomic analysis

Abstract
Background: The oriental armyworm, Mythimna separata, is an economically important and common Lepidopteran pest of cereal crops. Chemoreception plays a key role in insect life, such as foraging, oviposition site selection, and
mating partners. To better understand the chemosensory mechanisms in M. separata, transcriptomic analysis of antennae, labial palps, and proboscises were conducted using next-generation sequencing technology to identify members of the major chemosensory related genes.
Results: In this study, 62 putative odorant receptors (OR), 20 ionotropic receptors (IR), 16 gustatory receptors (GR), 38 odorant binding proteins (OBP), 26 chemosensory proteins (CSP), and 2 sensory neuron membrane proteins
(SNMP) were identified in M. separata by bioinformatics analysis. Phylogenetic analysis of these candidate proteins was performed. Differentially expressed genes (DEGs) analysis was used to determine the expressions of all
candidate chemosensory genes and then the expression profiles of the three families of receptor genes were confirmed by real-time quantitative RT-PCR (qPCR).
Conclusions: The important genes for chemoreception have now been identified in M. separata. This study will provide valuable information for further functional studies of chemoreception mechanisms in this important agricultural pest.