Odorant-Binding and Chemosensory Proteins in Anthonomus eugenii (Coleoptera: Curculionidae) and Their Tissue Expression

Abstract

The pepper weevil Anthonomus eugenii is one of the most damaging pests to the pepper crop. To offer alternative management strategies to insecticides, several studies have identified the semiochemicals that are involved in the pepper weevil’s aggregation and mating behavior; however, there is no information on its perireceptor molecular mechanism, to date. In this study, bioinformatics tools were used to functionally annotate and characterize the A. eugenii head transcriptome and their probable coding proteins. We identified twenty-two transcripts belonging to families related to chemosensory processes, seventeen corresponding to odorant-binding proteins (OBP), and six to chemosensory proteins (CSP). All results matched with closely related Coleoptera: Curculionidae homologous proteins. Likewise, twelve OBP and three CSP transcripts were experimentally characterized by RT-PCR in different female and male tissues. The results by sex and tissue display the different expression patterns of the AeugOBPs and AeugCSPs; some are present in both sexes and all tissues, while others show expressions with higher specificity, which suggests diverse physiological functions in addition to chemo-detection. This study provides information to support the understanding of odor perception in the pepper weevil.

Antennal Transcriptome Evaluation and Analysis for Odorant-Binding Proteins, Chemosensory Proteins, and Suitable Reference Genes in the Leaf Beetle Pest Diorhabda rybakowi Weise (Coleoptera: Chrysomelidae)

“…The number of OBPs in D. rybakowi was lower than previously reported, but eleven OBPs were found in Podabrus annulatus, which was the same as in previous reports [54]. Furthermore, upon comparing CSP numbers in D. rybakowi with those in other Coleoptera species, there were differences in twelve CSP genes in H. axyridis and C. bowringi, respectively [11,12], but similar CSP genes were found in Hylamorpha elegans (four CSPs), A. eugenii (six CSPs) [14], and C. maculatus (seven CSPs) [13,55]. The differences in the number of OBPs and CSPs may be due to the variation in the chemical environment of different species, where these species have evolved for a long time [56].…”

“…Soluble proteins, odorant-binding proteins (OBPs), and chemosensory proteins (CSPs) selectively bind and transport odorant molecules to the surface of olfactory neurons in the membrane, and odorant receptors convert captured chemicals into nerve impulses transmitted to the brain for regulation of various insect behavior [9,10]. OBPs and CSPs are the most important olfactory proteins, and only about 20 Coleoptera species have been identified, such as Harmonia axyridis [11], Colaphellus bowringi [12], Callosobruchus maculatus [13], Anthonomus eugenii [14], Ophraella communa [15], and Galeruca daurica [16]. OBPs generally have six highly conserved cysteines and three disulfide bridges.…”