Development of RNAi methods to control the harlequin bug, Murgantia histrionica

• Published in: Archives of insect biochemistry and physiology 2020-08, Vol.104 (4), p.e21690-n/a
• Main Authors: Howell, Jeffrey L., Mogilicherla, Kanakachari, Gurusamy, Dhandapani, Palli, Subba Reddy
• Format: Article
• Language: English
• Subjects: Adenosine triphosphatase; Adults; Apoptosis; Control methods; Double-stranded RNA; dsRNA; Feeding; G protein-coupled receptors; Gene expression; Gene silencing; Genes; Host plants; IAP; Insects; Interference; Localization; Mortality; Murgantia histrionica; Mustard; Nuclease; Nymphs; pest control; Pests; Post-transcription; Protein phosphatase; Proteins; Ribonucleic acid; RNA; RNA-mediated interference; RNAi; Saliva; Seedlings; Serine; Signal recognition particle; stink bug; Threonine
• ISSN: 0739-4462; 1520-6327
• DOI: 10.1002/arch.21690

The harlequin bug (HB), Murgantia histrionica, is a major pest of cabbage family plants throughout its range in the United States. RNA interference (RNAi) is a posttranscriptional gene silencing mechanism that is showing promise as a biopesticide due to the ability to target species‐specific genes necessary for growth and/or survival with synthetic double‐stranded RNA (dsRNA). In the present study, dsRNA stability assays revealed that nucleases present in the saliva of harlequin bugs did not rapidly degrade dsRNA. We tracked the movement and localization of radioactively labeled dsRNA in both mustard plant seedlings and harlequin bug nymphs that fed on treated host plants. Movement of 32P‐labeled‐dsRNA from soil to plant and plant to insect was detected. The efficacy of RNAi in inducing mortality in harlequin bug adults and nymphs injected or fed with dsRNA targeting inhibitor of apoptosis (IAP), ATPase N2B (ATPase), serine/threonine‐protein phosphatase PP1‐β catalytic subunit (PP1), signal recognition particle 54 kDa protein (SRP), and G protein-coupled receptor 161-like (GPCR) genes was evaluated. Injection of dsRNA targeting candidate genes into adults caused between 40% and 75% mortality and induced significant knockdown of target gene expression. Feeding dsRNA targeting the IAP gene to nymphs by plant‐mediated and droplet feeding methods induced knockdown of the target gene and caused 40–55% mortality. These findings suggest that RNAi may be a viable approach for managing this pest. Setup for Murgantia histrionica nymph's feeding assay. Greenhouse‐grown two‐week‐old mustard seedlings were inserted in 2 ml Eppendorf tubes containing 300 μl of nuclease‐free water with 20 μg of double‐stranded RNA (dsRNA; 20 μg each day for 3 days), fixed to a solid support and placed in magenta jars. About 20 μg of dsRNA targeting five different target genes (IAP, ATPase, PP1, GPCR, and SRP) was fed to 2nd instar M. histrionica nymphs (four nymphs per group). The dsGFP was used as a control. Research Highlights Feeding double‐stranded RNA to harlequin bug, Murgantia histrionica nymphs induced knockdown of target gene expression and mortality. RNA interference could be a viable approach for managing harlequin bugs.