Functional identification of an FMRFamide-related peptide gene on diapause induction of the migratory locust, Locusta migratoria L.

FMRFamide-related peptides (FaRPs) are a type of neuropeptide, which participate in a variety of physiological processes in insects. Previous study showed that myosuppressin, being a member of FaRPs, initiated pupal diapause in Mamestra brassicae. We presumed that FaRPs genes might play a critical role in photoperiodic diapause induction of L. migratoria. To verify our hypothesis, flrf, a precursor gene of FaRP from L. migratoria, was initially cloned under long and short photoperiods that encoded by flrf gene identified from central nervous system (CNS). Phylogenetic analysis showed that the protein encoded by L. migratoria flrf gene, clustered together with Nilaparvata lugens (Hemiptera: Delphacidae) with 100% bootstrap support, was basically an FMRFamide precursor homologue. We noticed the availability of -RFamide peptides (GSERNFLRFa, DRNFIRFa) under short photoperiod only, which suggested their functions related to photoperiodic diapause induction. RNAi and quantitative real-time PCR (qRT-PCR) results further confirmed that the flrf gene promoted locust's diapause.