Molecular Characterization and Expression Profiling of Chemosensory Proteins in Male Eogystia hippophaecolus (Lepidoptera: Cossidae)

Abstract

Abstract Eogystia hippophaecolus Hua, Chou, Fang et Chen (Lepidoptera: Cossidae) is a notorious carpenterworm pest of sea buckthorn, Hippophae rhamnoides L. (Elaeagnaceae). Chemosensory proteins (CSPs) are thought to be responsible for initial biochemical recognition during olfactory perception by the insect. We examined the structure, function, and expression profiles of these proteins in four structures (e.g., antennae, labipalp, legs, and external genitalia) of male adults. Molecular weight, isoelectric point, hydrophilicity and hydrophobicity of proteins, and signal peptide prediction of 18 E. hippophaecolus CSPs (EhipCSPs) were investigated via software. Expression profiles in the four male structures were analyzed by fluorescence quantitative real-time polymerase chain reaction. Bioinformatics analysis showed that most EhipCSPs are low-molecular-weight proteins with hydrophobic regions and a high proportion of alpha-helices, consistent with the general characteristics of insect CSPs. Eight EhipCSPs (EhipCSP2, EhipCSP5, EhipCSP7, and EhipCSP13–17) were predominantly expressed in the labipalp (P < 0.01), and three (EhipCSP6, EhipCSP8, and EhipCSP9) were predominantly expressed in legs (P < 0.01). We speculate that these proteins may be related to contact sensations, host recognition, and other functions. Two EhipCSPs (EhipCSP4 and EhipCSP11) were highly expressed in the external genitalia (P < 0.01), suggesting that they may be involved in spousal positioning or mating activities. Most EhipCSPs were differentially expressed in the four structures, with wide overall expression, indicating an important role in olfactory recognition in multiple tissues. Our findings establish the foundation for further investigation of EhipCSPs and potential development of nonpesticide control measures.