Submitted to: Toxic Microorganisms Symposium Proceedings
Publication Type: Proceedings
Publication Acceptance Date: June 21, 1995
Publication Date: N/A
Interpretive Summary: Many fungi that infect plants produce toxins that are harmful to animals and humans who eat contaminated feed and food. We have used a variety of genetic analyses to show that some of these fungal toxins play an important role in causing yield losses and other disease symptoms in the infected plants themselves. These results may help guide plant breeders in producing disease resistant plants.
Technical Abstract: All Fusarium species that produce fumonisin or trichothecene mycotoxins are plant pathogens. The acute phytotoxicity of both fumonisins and trichothecenes and their occurrence in plant tissues also suggest that these mycotoxins play a role in the pathogenesis of Fusarium diseases on plants. A variety of genetic approaches are being used to investigate the biosynthesis of these mycotoxins and their role in the pathogenicity of F. moniliforme, F. sambucinum, F. sporotrichioides and F. graminearum on a number of plant species, including corn, parsnip, potato and wheat. Meiotic recombinational analysis has shown a correlation between fumonisin production and pathogenicity of F. moniliforme on corn seedlings. Trichothecene gene disruptants have been used to demonstrate that trichothecenes play a role in pathogenicity of F. sambucinum and F. sporotrichioides on parsnip root, but not in pathogenicity of F. sambucinum on potato tubers. Trichothecene gene disruptants have also been used to demonstrate that trichothecenes play a role in the ability of F. graminearum to cause wheat seedling blight in the growth chamber and to cause head scab in the growth chamber and in the field. These genetic analyses indicate that fumonisins and trichothecenes are neither necessary nor sufficient for pathogenicity, but that they generally do increase the extent of disease produced.