A paratransgenic strategy to block transmission of Xylella fastidiosa from the glassy-winged sharpshooter Homalodisca vitripennis

Thomas A. Miller,Lourival D. Possani,Arinder K. Arora,Ravi V. Durvasula,Kendra N. Pesko,Verónica Quintero-Hernández

doi:10.1186/s12896-018-0460-z

Abstract

BackgroundArthropod-borne diseases remain a leading cause of human morbidity and mortality and exact an enormous toll on global agriculture. The practice of insecticide-based control is fraught with issues of excessive cost, human and environmental toxicity, unwanted impact on beneficial insects and selection of resistant insects. Efforts to modulate insects to eliminate pathogen transmission have gained some traction and remain future options for disease control.ResultsHere, we report a paratransgenic strategy that targets transmission of Xylella fastidiosa, a leading bacterial pathogen of agriculture, by the Glassy-Winged Sharpshooter (GWSS), Homalodisca vitripennis. Earlier, we identified Pantoea agglomerans, a bacterial symbiont of the GWSS as the paratransgenic control agent. We genetically engineered P. agglomerans to express two antimicrobial peptides (AMP)-melittin and scorpine-like molecule (SLM). Melittin and SLM were chosen as the effector molecules based on in vitro studies, which showed that both molecules have anti-Xylella activity at concentrations that did not kill P. agglomerans. Using these AMP-expressing strains of P. agglomerans, we demonstrated disruption of pathogen transmission from insects to grape plants below detectable levels.ConclusionThis is the first report of halting pathogen transmission from paratransgenically modified insects. It is also the first demonstration of paratransgenic control in an agriculturally important insect vector.

Highlights

Arthropod-borne diseases remain a leading cause of human morbidity and mortality and exact an enormous toll on global agriculture
We recently identified Pantoea agglomerans as a symbiotic bacterium of H. vitripennis and, using an EPA-approved non-pathogenic variant of Pantoea, reported both paratransgenic manipulation and a field-applicable strategy to target Glassy-Winged Sharpshooter (GWSS) with engineered bacteria [15]
scorpine-like molecule (SLM) is an antimicrobial peptides (AMP) found in the venom gland transcriptome of the scorpion Vaejovis mexicanus [17]

Summary

Introduction

Arthropod-borne diseases remain a leading cause of human morbidity and mortality and exact an enormous toll on global agriculture. We report the paratransgenic manipulation of an agricultural pest, Homalodisca vitripennis (the Glassy-Winged Sharpshooter), to block transmission of the bacterial pathogen, Xylella fastidiosa, to grape plants. We recently identified Pantoea agglomerans as a symbiotic bacterium of H. vitripennis and, using an EPA-approved non-pathogenic variant of Pantoea, reported both paratransgenic manipulation and a field-applicable strategy to target GWSS with engineered bacteria [15]. Using this platform, we have engineered lines of P. agglomerans that secrete antimicrobial peptides (AMP) that kill X. fastidiosa and report here, for the first time, a pathogen-refractory H. vitripennis that is unable to infect target plants

Methods

Results

Discussion

Conclusion