Identification of chemosensory gene families in Rhyzopertha dominica (Coleoptera: Bostrichidae)

Chemoreception is a key process for insects. Odorant messages diffuse through the air and are translated into physiological signals by chemosensory receptor neurons in sensilla that are mainly located on insect antennae. We sequenced the antenna transcriptome of Rhyzopertha dominica (Fabricius) (Coleoptera: Bostrichidae), which is a serious pest of stored grains throughout regions with warm climates, and performed transcriptome analysis on R. dominica antennae. We obtained 57 million 90-base pair-long reads that we assembled into 37 877 unigenes with a mean size of 1007 base pairs. Predicted protein sequences were matched with Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae) (79.1%), Dendroctonus ponderosae Hopkins (Coleoptera: Curculionidae) (1.7%), Megachile rotundata (Fabricius) (Hymenoptera: Megachilidae) (1.3%), Acyrthosiphon pisum Harris (Hemiptera: Aphididae) (1.2%), and other (16.7%) homologues. In chemosensory gene families, we identified transcripts that encoded the following putative genes: 12 odorant-binding proteins (OBPs), four pheromone-binding proteins (PBPs), eight chemosensory proteins (CSPs), five sensory neuron membrane proteins (SNMPs), six odorant receptors, and eight ionotropic receptors. The diversity of the predicted OBPs, PBPs, and CSPs are also discussed. These findings will advance our understanding of olfaction process by this pest.