Transcriptome analysis of neuropeptides and G-protein coupled receptors (GPCRs) for neuropeptides in the brown planthopper Nilaparvata lugens

•Transcriptome analysis (RNA-seq) revealed that the brown planthopper Nilaparvata lugens possesses the most comprehensive neuropeptide system yet found in insects.•The gene coding for prothoracicotropic hormone (PTTH) is first identified in hemimetabolous insects.•New type of insect GPCRs such as thyrotropin-releasing hormone receptor-like (TRHRL) is identified from N. lugens.•Our findings demonstrate the power of RNA-seq as a tool for analyzing the neuropeptide-related genes in the absence of whole genome sequence information. The genes encoding neuropeptides, neurohormones and their putative G-protein coupled receptors were identified in the brown planthopper (BPH), Nilaparvata lugens (Stål) by transcriptome analysis (RNA-seq). Forty-eight candidate genes were found to encode neuropeptides or peptide hormones. These include all known insect neuropeptides and neurohormones, with the exception of neuropeptide-like precursor 2 (NPLP2) and trissin. The gene coding for prothoracicotropic hormone (PTTH) was first identified from hemimetabolous insect. A total of 57 putative neuropeptide GPCR genes were identified and phylogenetic analysis showed most of them to be closely related to insect GPCRs. A notable finding was the occurrence of vertebrate hormone receptors, thyrotropin-releasing hormone receptor (TRHR)-like GPCR and parathyroid hormone receptor (PTHR)-like GPCRs. These results suggest that N. lugens possesses the most comprehensive neuropeptide system yet found in insects. Moreover, our findings demonstrate the power of RNA-seq as a tool for analyzing the neuropeptide-related genes in the absence of whole genome sequence information.