Deep sequencing of antennal transcriptome from Callosobruchus chinensis to characterize odorant binding protein and chemosensory protein genes

The sophisticated olfactory system of insects has a key role in their growth and reproduction, and elucidating the molecular mechanisms of this system in economically important insect species will be useful for development of new and effective insecticides. Callosobruchus chinensis (Linnaeus) (Coleoptera, Bruchidae) is a destructive pest of stored food, and is widely distributed around the world. However, our understanding at the molecular level of the olfactory mechanism in this beetle is limited. In the present study, antennal transcriptomic data was obtained using Illumina sequencing, and a total of 69,847 unigenes was assembled. Bioinformatics analyses identified a set of putative olfactory genes, including 21 odorant binding proteins (OBPs) and five chemosensory proteins (CSPs). We constructed phylogenetic trees of these OBPs and CSPs together with those from other insect species, and found high orthology with coleopteran species. The expression levels of OBPs and CSPs were estimated by the reads per kilobase per million mapped reads (RPICM) method. Our results provide the foundation to identify other chemoreception-related genes. It is to be hoped that some of these genes will be potential targets for developing novel behavioral blocker compounds and pesticides to interfere with the olfactory system of C chinensis and help reduce population densities. (C) 2017 Elsevier Ltd. All rights reserved.