ARS | Publication request: FITNESS, PERSISTENCE, AND RESPONSIVENESS OF A GENETICALLY ENGINEERED STRAIN OF TRICHODERMA VIRENS IN SOIL MESOCOSMS

Submitted to: Applied Soil Ecology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: December 17, 2004
Publication Date: July 1, 2005
Citation: Weaver, M.A., Vedenyapina, E., Kenerly, C. 2005. Fitness, persistence, and responsiveness of a genetically engineered strain of trichoderma virens in soil mesocosms. Applied Soil Ecology 29:125-134.

Interpretive Summary: Trichoderma virens is a fungus with demonstrated qualities for the biocontrol of plant disease. This fungus has also been genetically engineered to degrade organophosphate compounds. The genetically engineered fungus and wild type T. virens were incubated in soil and kept at moisture and temperature levels similar to field conditions. After 243 days in soil and without selection pressure the genetically engineered strain still expressed antibiotic resistance and the ability to degrade organophosphates. The two strains were similarly persistent and after long-term incubation in soil they still both rapidly and efficiently colonized freshly added cotton roots.

Technical Abstract: The genetic stability and ecological persistence of a genetically modified (GM) strain of the filamentous fungus, Trichoderma virens, was evaluated over 243 days in soil mesocoms. The GM population declined over time, at rates similar to the wild-type, parental strain (WT), but was still present at the end of the incubation. The presence of the WT strain did not adversely effect the persistence of the GM strain. The GM strain never lost the transgene and still expressed antibiotic resistance and the ability to degrade organophosphate xenobiotics. Even after the long-term incubation both GM and WT strains rapidly and efficiently colonized freshly added substrates, indicating a high level of responsiveness.