The Formosan subterranean termite is one of the most destructive and costly invasive pests nationally and internationally. Economic loss due to Formosan termite treatment, damage repair, and demolition of structures ranges in the billions of dollars worldwide. In addition to urban structures and agriculture, this invasive pest species is known to damage military structures and training facilities in temperate, tropical, and subtropical regions. These wood-destroying insects are a major concern for the Department of Defense (DoD) because it has billions of dollars invested in wooden structures and products. Invasive termites are easily transported around the world with movement of wooden material. Demand is increasing for the development of new environmentally friendly, fast, and cost-effective termite control technologies.
The objective of this SERDP Exploratory Development (SEED) project was to engineer microbes, which live naturally in the termite gut but are modified to express genes detrimental to termites, as an alternative to conventional chemical and bait treatments for termite control. Development of such an approach can reduce the considerable termite damage to military installations, reduce the risk of spreading invasive termites with military movements, and lower DoD's costs for termite control and damage repair.
The initial phase of this project involved the development of methods to test the efficacy of lytic peptides against protozoa. Three species of protozoa from the termite gut were cultured in vitro and used to test lytic peptide activity anaerobically. A microinjection system was then developed, and small volumes of different lytic peptides were injected into the hindgut of termite workers to stimulate defaunation. Those lytic peptides were subsequently used to construct a prototype paratransgenesis system for killing termites. The paratransgenesis system was tested using a commercially available yeast as the host. Termite workers were fed yeast expressing the lytic peptides previously shown to cause defaunation, and the effect on termite workers was observed.
Using paratransgenesis, genetically fortified indigenous species-specific microorganisms can be created that are able to avoid immune detection and carry detrimental gene products for insect control. This project established a proof of concept that layed out the path for developing an environmentally- and user-friendly product. Follow-on work is likely to yield a high payoff and lead to reduced costs of termite control and pesticide use. Paratransgenesis is likely to lead to a paradigm shift in termite control. (SEED Project Completed - 2008)