Receptor interference targeting a GPCR to identify insecticidal peptides against Western flower thrips

Western flower thrips (WFT), Frankliniella occidentalis (Thysanoptera: Thripidae), is a common nursery pest due to its broad host range, short generation time, cryptic size (1–2 mm adult females, 0.6–1.2 mm adult males), high volume of agricultural transport, and ability to transmit plant viruses. Constant reliance on broad-spectrum synthetic pesticides can often result in negative effects on humans and the environment. The need for alternate control tools, particularly those with minimal or no toxicity to non-pests, is a prominent point of discussion in nursery settings impacted by WFT.

Insect neuropeptides (NPs) and G protein-coupled receptors (GPCRs) are often proposed biological targets for next-generation biopesticides. NPs and their GPCRs facilitate many essential biological processes during insect life stages. Bioactive peptides that could interfere with the reception of this signal would also disrupt the processes that depend on this pathway.

We have recently established a novel GPCR-based screening technology called Receptor Interference (Receptor-i) using an insect cell expression system (Sf9) that employs a biopanning technique to screen for peptides against our target receptor in just a couple weeks’ time. Though this technology appears promising in selecting peptides that significantly reduce survival rate of WFT in feeding assays, we have also found that modified peptides derived from WFT’s CAPA peptide, a type of NP, exhibit insecticidal properties, as well. In this study, we will discuss the advantages of different screening methods for discovery of insecticidal compounds targeting our GPCR. We will compare our team’s successes, challenges, and remaining uncertainties of both approaches.