Submitted to: Tottori International Symposium on Host Specific Toxins Molecular Genetics O
Publication Type: Proceedings
Publication Acceptance Date: August 29, 1997
Publication Date: N/A
Technical Abstract: Trichothecene toxins are produced by Fusarium species in food and feed grains worldwide and represent an important economic problem for agriculture. F. graminearum is the major source of trichothecene contamination in the U.S. and the causative agent of Wheat Head Scab (WHS). Recently, it was shown that trichothecene-deficient mutants of F. graminearum display significantly reduced levels of virulence on wheat. Based on these results, trichothecenes appear to be examples of fungal toxins that can function as virulence factors without strong host selectivity. Biosynthesis of trichothecenes is complex, and at least ten pathway genes have been identified within a gene cluster spanning a 23 Kb region of DNA in F. sporotrichioides. Recent investigations of the trichothecene pathway gene cluster have provided new information concerning the transcriptional regulation of pathway gene expression (TRI6) and the transport of pathway products (TRI12). A trichothecene resistance gene (TRI+) has also been identified in F. sporotrichioides. Expression of TRI+ or other microbial trichothecene resistance genes in wheat may provide a means for further investigating the importance of trichothecenes in Fusarium WHS.