Date of Award:
5-1-1997
Document Type:
Dissertation
Degree Name:
Doctor of Philosophy (PhD)
Department:
Biology
Committee Chair(s)
Anne J. Anderson
Committee
Anne J. Anderson
Committee
David B. Drown
Committee
Thomas A. Grover
Committee
Bradley R. Kropp
Committee
Lance C. Seefeldt
Abstract
A strain of Trichoderma harzianum (referred to as Tex) and its chemically generated mutant, T95, produced antioxidant enzymes, superoxide dismutase and catalase. The mutant and wild type had similar enzyme activity levels but differed in isozyme patterns and response to exogenous activated oxygen species. Superoxide dismutases had manganese and copper-zinc prosthetic groups, determined by selective inactivation with sodium azide, potassium cyanide, diethyldithiocarbamate, and hydrogen peroxide. Catalases from Tex and T95 were inhibited by 3-amino-1,2,4-triazole. Antioxidant enzymes may be important in survival of T. harzianum and its effective biocontrol of root diseases. In its role as a biocontrol agent, T. harzianum occupies the rhizosphere, where contact with toxic oxygen species from plants, soil microbes, or pesticides may occur. Tex and T95 protected sugar beets from seedling diseases caused by Rhizoctonia solani under laboratory conditions. Both strains colonized the sugar beet rhizosphere under laboratory conditions, higher populations of T95 were recovered than Tex. Field soils in which no disease was established in sugar beets with added virulent R. solani had high populations of naturally occurring Trichoderma species.
Recommended Citation
Pounder, June Inez, "Superoxide Dismutase and Catalase in Trichoderma harzianum, a Biological Control Fungus of Rhizoctonia solani Disease of Sugar Beet" (1997). Biology. 643.
https://digitalcommons.usu.edu/etd_biology/643
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