Wednesday, December 13, 2006 - 1:35 PM

Paratransgenesis: Constructing the enemy within

Rachael Collier, rcollier@agcenter.lsu.edu1, Claudia Husseneder, chusseneder@agcenter.lsu.edu1, Richard Cooper, rcooper@agcenter.lsu.edu2, Lane Foil, lfoil@agcenter.lsu.edu1, and Frederick Enright, fenright@agcenter.lsu.edu2. (1) Louisiana State University Agricultural Center, Entomology, Room 404 Life Sciences Building, Baton Rouge, LA, (2) Louisiana State University Agricultural Center, Veterinary Science, 404 Life Sciences Building, Baton Rouge, LA

Paratransgenesis is the genetic manipulation of a hostís symbiotic microorganisms to achieve an array of objectives, ranging from disease eradication to pest control. The application of paratransgenesis is promising in social insects, because social interactions promote the exchange of microbes naturally between individuals within colonies through mutual feeding and grooming. Within the social insects, termites are known for their close relationship with microbial symbionts. The hind gut of the Formosan subterranean termite (FST) workers provides a refuge for an array of protozoa and bacteria that fulfill important functions in the survival of their hosts, such as cellulose digestion. These symbionts are excellent tools and targets for paratransgenesis. In these studies aimed at the control of FST, the paratransgenesis targets are the termiteís protozoa, which digest cellulose into metabolites subsequently utilized by the termite host. Without their protozoa and the nutrients they supply, termites die. Using microinjection, a technique developed during this study, defaunation of the termite gut has been observed with selected toxins within 72hrs of treatment. The genes of the successful toxins were synthesized and a proto-type gene-shuttle system was constructed to deliver toxins into the termite hind gut. The yeast, Kluyveromyces lactis, has been engineered to secrete toxins and is being used in termite feeding experiments to defaunate termites. It is the ultimate aim of this study to optimize the gene-shuttle for inducible expression within the recently characterized termite specific anaerobic, gram-positive bacterium, Pilibacter termitis, to minimize environmental impacts and achieve efficient colony level control of FST.

Species 1: Isoptera Rhinotermitidae Coptotermes formosanus (Formosan subterranean termite)