Characterization and Expression Profiling of Neuropeptides and G-Protein-Coupled Receptors (GPCRs) for Neuropeptides in the Asian Citrus Psyllid, Diaphorina citri (Hemiptera: Psyllidae)

Neuropeptides are endogenous active substances that widely exist in multicellular biological nerve tissue and participate in the function of the nervous system, and most of them act on neuropeptide receptors. In insects, neuropeptides and their receptors play important roles in controlling a multitude of physiological processes. In this project, we sequenced the transcriptome from twelve tissues of the Asian citrus psyllid, Diaphorina citri Kuwayama. A total of 40 candidate neuropeptide genes and 42 neuropeptide receptor genes were identified. Among the neuropeptide receptor genes, 35 of them belong to the A-family (or rhodopsin-like), four of them belong to the B-family (or secretin-like), and three of them are leucine-rich repeat-containing G-protein-coupled receptors. The expression profile of the 82 genes across developmental stages was determined by qRT-PCR. Our study provides the first investigation on the genes of neuropeptides and their receptors in D. citri, which may play key roles in regulating the physiology and behaviors of D. citri.