Assessment of genetically engineered Trabulsiella odontotermitis as a 'Trojan Horse' for paratransgenesis in termites.

Jennifer Delatte,Chinmay Vijay Tikhe,Thomas M Martin,Andréa Howells,Claudia Husseneder

doi:10.1186/s12866-016-0822-4

Jennifer Delatte, Chinmay Vijay Tikhe + Show 3 more

Open Access

https://doi.org/10.1186/s12866-016-0822-4

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Abstract

BackgroundThe Formosan subterranean termite, Coptotermes formosanus is an invasive urban pest in the Southeastern USA. Paratransgenesis using a microbe expressed lytic peptide that targets the termite gut protozoa is currently being developed for the control of Formosan subterranean termites. In this study, we evaluated Trabulsiella odontotermitis, a termite-specific bacterium, for its potential to serve as a ‘Trojan Horse’ for expression of gene products in termite colonies.ResultsWe engineered two strains of T. odontotermitis, one transformed with a constitutively expressed GFP plasmid and the other engineered at the chromosome with a Kanamycin resistant gene using a non- disruptive Tn7 transposon. Both strains were fed to termites from three different colonies.Fluorescent microscopy confirmed that T. odontotermitis expressed GFP in the gut and formed a biofilm in the termite hindgut. However, GFP producing bacteria could not be isolated from the termite gut after 2 weeks. The feeding experiment with the chromosomally engineered strain demonstrated that T. odontotermitis was maintained in the termite gut for at least 21 days, irrespective of the termite colony. The bacteria persisted in two termite colonies for at least 36 days post feeding. The experiment also confirmed the horizontal transfer of T. odontotermitis amongst nest mates.ConclusionOverall, we conclude that T. odontotermitis can serve as a ‘Trojan Horse’ for spreading gene products in termite colonies. This study provided proof of concept and laid the foundation for the future development of genetically engineered termite gut bacteria for paratransgenesis based termite control.Electronic supplementary materialThe online version of this article (doi:10.1186/s12866-016-0822-4) contains supplementary material, which is available to authorized users.

Highlights

The Formosan subterranean termite, Coptotermes formosanus is an invasive urban pest in the Southeastern USA
We were able to retrieve engineered T. odontotermitis via culture from the termite gut thereby confirming that the strain was ingested by the termites; we were not able to visually detect GFP expression in the termite gut [22]
A termite specific bacterium, T. odontotermitis can be engineered with a plasmid and at chromosome level using a non-disruptive Tn7 transposon based method to express foreign proteins in the termite gut

Summary

Introduction

The Formosan subterranean termite, Coptotermes formosanus is an invasive urban pest in the Southeastern USA. The Formosan subterranean termite (FST), Coptotermes formosanus, is an invasive urban pest from China and is estimated to cause an economic loss of $1 billion annually in the US [5]. This termite species forms large underground colonies with tunnels and galleries; and, in a mature colony, the number of individual termites can reach more than a million [6, 7]. Workers forage, digest the food, and feed the rest of the colony via stomodeal and proctodeal food exchange known as trophallaxis [1]

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