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Biological Control of Sclerotium rolfsii and Verticillium dahliae by Talaromyces flavus Is Mediated by Different Mechanisms

October 1997 , Volume 87 , Number  10
Pages  1,054 - 1,060

Lea Madi , Talma Katan , Jaacov Katan , and Yigal Henis

Department of Plant Pathology and Microbiology, The Hebrew University of Jerusalem, Faculty of Agricultural, Food and Environmental Quality Sciences, Rehovot 76100, Israel; Department of Plant Pathology, ARO, The Volcani Center, P.O. Box 6, Bet Dagan 50250, Israel

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Accepted for publication 5 July 1997.

Ten wild-type strains and two benomyl-resistant mutants of Talaromyces flavus were examined for their ability to secrete the cell wall-degrading enzymes chitinase, β-1,3-glucanase, and cellulase, to parasitize sclerotia of Sclerotium rolfsii, to reduce bean stem rot caused by S. rolfsii, and to secrete antifungal substance(s) active against Verticillium dahliae. The benomyl-resistant mutant BenRTF1-R6 overproduced extracellular enzymes and exhibited enhanced antagonistic activity against S. rolfsii and V. dahliae compared to the wild-type strains and other mu tants. Correlation analyses between the extracellular enzymatic activities of different isolates of T. flavus and their ability to antagonize S. rolfsii indicated that mycoparasitism by T. flavus and biological control of S rolfsii were related to the chitinase activity of T. flavus. On the other hand, production of antifungal compounds and glucose-oxidase activity may play a role in antagonism of V. dahliae by retardation of germination and hyphal growth and melanization of newly formed microsclerotia.

Additional keyword: antibiosis.

© 1997 The American Phytopathological Society