ARS | Publication request: TRICHOTHECENE TOXIN PRODUCTION AND VIRULENCE OF FUSARIUM GRAMINEARUM ON WHEAT

Submitted to: Molecular Plant Microbe International Symposium
Publication Type: Abstract Only
Publication Acceptance Date: July 19, 1996
Publication Date: N/A

Technical Abstract: Trichothecenes are a family of fungal toxins that inhibit protein synthesis in eukaryotic cells. There is a growing body of evidence to indicate that trichothecenes enhance the virulence of some Fusarium species. To determine whether trichothecenes contribute to the virulence of Fusarium graminearum, the causal agent of head blight (scab) of wheat, we examined the virulence of two trichothecene deficient mutants of the fungus on field-grown wheat. The mutants were generated via transformation-mediated disruption of Tri5, a gene encoding the enzyme that catalyzes the first step in trichothecene biosynthesis. To confirm that any reduced virulence of the mutants was due specifically to Tri5 disruption, rather than a nonspecific effect of transformation, we also examined the virulence of trichothecene-producing revertants derived from a mutant. Wheat was inoculated by injecting spore suspensions into a single floret per head and disease was assessed via symptoms, yield, and grain quality. The trichothecene-deficient mutants were markedly less virulent than their wild-type, trichothecene producing progenitor. In contrast, the trichothecene producing revertants were as virulent as the wild-type progenitor. These results indicate that the ability to produce trichothecenes contributes to the virulence of F. graminearum on wheat.