|Howell, Charles - Charlie|
Submitted to: Material Und Organismen
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/16/1999
Publication Date: N/A
Interpretive Summary: The biocontrol fungus Trichoderma virens is capable of controlling decay of wood blocks by white and brown rot fungi when it is applied prior to infection by the pathogens. However when mutants of the biocontrol agent deficient for production of the antibiotic gliotoxin are used, only the brown rot fungi are controlled. This indicates the gliotoxin is involved in nprotection against brown rot fungi but not against those causing white rot
Technical Abstract: Trichoderma (Gliocladium) virens has shown good antagonism against decay fungi in agar medium and in wood blocks. Gliotoxin produced by T. virens is associated with biocontrol of some plant diseases, but its importance to biocontrol of wood-attacking fungi is unknown. We investigated the ability of gliotoxin-producing [GLT+] isolates of T. virens and gliotoxin-deficient t[GLT-] mutants of T. virens to inhibit growth of wood-attacking fungi in agar medium and to prevent decay in wood. The brown-rot fungi Postia placenta and Neolentinus lepideus and the white-rot fungi Trametes versicolor and Phlebia brevispora were completely inhibited by the GLT+ isolate and the GLT- mutants in agar medium. The GLT+ isolate also completely inhibited the growth of the brown-rot fungus Gloeophyllum trabeum and the white-rot fungus Irpex lacteus, but the GLT- mutants caused lesser inhibition. The GLT+ isolate and GLT- mutants were ineffective in preventing growth of mold fungi, but both inhibited stain fungi in dual agar culture. Pretreatment of wood blocks with the GLT+ isolate or GLT- mutant prevented decay by the brown-rot fungi. Although the GLT+ isolate prevented decay by the white-rot fungi, the GLT- mutants did not. G. virens [GL-21] was grown on a sulfur-containing medium at pH 3.5 to enhance antibiotic production in culture filtrates. However, inhibition of growth of decay fungi on agar medium containing culture filtrates was not enhanced. Decay was reduced in blocks treated with the culture filtrates but not completely stopped. The filtrates were also ineffective in preventing growth of mold and stain fungi on wood.