D3033: Identification of bioactive peptides using a GPCR system for western flower thrips

Western flower thrips (WFT), Frankliniella occidentalis (Thysanoptera: Thripidae) is a common polyphagous pest with a broad host range that has persistently plagued the global nursery industry due to its short generation time, cryptic size (1–2mm adult females, 0.6–1.2 mm adult males), high volume of agricultural transport, and ability to transmit devastating plant viruses. The use of broad-spectrum synthetic pesticides often results in negative effects on the environment and human health, as well as WFT developing insecticide resistance. Therefore, we need to develop thrips-specific management strategies using biological targets that are less environmentally toxic, such as bioactive peptides.

Insect neuropeptides (NPs) and G protein-coupled receptors (GPCRs) are often proposed biological targets for next-generation biopesticides because NPs and their GPCRs facilitate many essential biological processes, such as water regulation, anti-diuresis, and desiccation during insect life stages. We have recently established a novel GPCR-based screening technology called Receptor Interference (Receptor-i) using an insect cell expression system, and have successfully screened short peptides against insect pests.

In this study, we identified various bioactive peptides, including natural and modified peptide ligands for the thrips GPCR, tested the activation affinities using an insect cell-based in vitro assay, and conducted direct injection and live feeding assays with WFT adults. Here, we present the progress we have made in developing a method to characterize the binding relationship of bioactive peptides to the GPCR, and evaluating their toxicity to the WFT.