A narrow host-range and lack of persistence in two non-target insect species of a bacterial symbiont exploited to deliver insecticidal RNAi in Western Flower Thrips

Miranda M A Whitten; Qi Xue; Clauvis Nji Tizi Taning; Reuben James; Guy Smagghe; Ricardo Del Sol; Matthew Hitchings; Paul Dyson

doi:10.3389/finsc.2023.1093970

A narrow host-range and lack of persistence in two non-target insect species of a bacterial symbiont exploited to deliver insecticidal RNAi in Western Flower Thrips

Front Insect Sci. 2023 Mar 8:3:1093970. doi: 10.3389/finsc.2023.1093970. eCollection 2023.

Authors

Miranda M A Whitten¹, Qi Xue², Clauvis Nji Tizi Taning², Reuben James¹, Guy Smagghe², Ricardo Del Sol¹, Matthew Hitchings¹, Paul Dyson¹

Affiliations

¹ Institute of Life Science, Swansea University Medical School, Singleton Park, Swansea, United Kingdom.
² Department of Plants and Crops, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium.

Abstract

Introduction: Insecticidal RNAi is a targeted pest insect population control measure. The specificity of insecticidal RNAi can theoretically be enhanced by using symbiotic bacteria with a narrow host range to deliver RNAi, an approach termed symbiont-mediated RNAi (SMR), a technology we have previously demonstrated in the globally-invasive pest species Western Flower Thrips (WFT).

Methods: Here we examine distribution of the two predominant bacterial symbionts of WFT, BFo1 and BFo2, among genome-sequenced insects. Moreover, we have challenged two non-target insect species with both bacterial species, namely the pollinating European bumblebee, Bombus terrestris, and an insect predator of WFT, the pirate bug Orius laevigatus.

Results: Our data indicate a very limited distribution of either symbiont among insects other than WFT. Moreover, whereas BFo1 could establish itself in both bees and pirate bugs, albeit with no significant effects on insect fitness, BFo2 was unable to persist in either species.

Discussion: In terms of biosafety, these data, together with its more specific growth requirements, vindicate the choice of BFo2 for delivery of RNAi and precision pest management of WFT.

Keywords: European bumblebee; Western flower Thrips; host-range; pirate bug; symbiotic bacteria.

Grants and funding

This study was partly supported by a grant from UKRI (BBSRC grant ref. BB/R006148/1) to PD, and in part by the Special Research Fund of Ghent University and Research Foundation Flanders (FWO). CT is recipient of a senior postdoctoral fellowship from FWO (grant number 12V5722N). QX is recipient of a doctoral grant provided by the China Scholarship Council (CSC).