Identification of the Short Neuropeptide F and Short Neuropeptide F Receptor Genes and Their Roles of Food Intake in Dendroctonus armandi

SIMPLE SUMMARY: The Chinese white pine beetle, Dendroctonus armandi, is a destructive pest of coniferous forests in the middle Qinling Mountains of China. The short neuropeptide F (sNPF) and short NPF receptor (sNPFR) genes have important roles in a broad range of physiological and behavioral processes. However, the function of sNPF signaling pathway in regulating the food intake of Dendroctonus armandi has been unclear. In this study, we cloned and characterized cDNAs encoding sNPF and sNPF receptor in D. armandi and analyzed their spatiotemporal expression patterns, as well as changes in expression after starvation. Addtionally, sNPF and sNPFR knockdown in beetles using RNA interference significantly increased mortality and reduced their food intake and body weight through changes of a biosynthesis and metabolism pathway. From these results, we conclude that sNPF signaling pathway is important in the feeding control of D. armandi. ABSTRACT: The short neuropeptide F (sNPF) is an essential signaling molecule that is evolutionarily conserved and involved in a broad range of physiological functions in the invertebrates, by interacting with sNPF receptors, which belong to G protein-coupled receptors (GPCR). However, the function of sNPF in regulating the food intake of Dendroctonus armandi has been unclear. In this study, we cloned and characterized cDNAs encoding sNPF and sNPF receptor in the D. armandi and made bioinformatics predictions on the deduced amino acid sequences. They had a high degree of similarity to that of Dendroctonus ponderosa. Quantitative real-time reverse transcription PCR (qRT-PCR) revealed that the transcript levels of both sNPF and sNPFR varied across developmental stages and body parts. In addition, the sNPF and sNPFR expression levels were upregulated in starved beetles, and the expression levels recovered after re-feeding. Furthermore, RNAi knockdown by the injection of sNPF and sNPFR dsRNA into beetles significantly increased mortality and reduced their food intake and body weight, and also caused decrease of glycogen and free fatty acid and increase of trehalose. These results indicate that sNPF signaling pathway plays an important role in the regulation of food intake and provides a potential molecular target for the eco-friendly control strategies of this pest.