Submitted to: Society of Industrial Microbiology Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: August 9, 1996
Publication Date: N/A
Technical Abstract: Trichothecenes constitute a large and structurally diverse family of sesquiterpenoid mycotoxins. Studies on the biosynthesis of trichothecenes by Fusarium sporotrichioides have revealed that many of the trichothecene pathway genes are present in a gene cluster. Evidence for a gene cluster initially came from the identification of a cosmid clone (Cos9-1) carrying the trichodiene synthase gene (Tri5) that was able to complement two different trichothecene deficient mutants. Subsequently, seven additional pathway genes (Tri3, Tri4, Tri6, Tri7, Tri8, Tri9, and Tri11) have been identified within a 20.5 Kb region that includes Tri5. The involvement of these genes in trichothecene biosynthesis has been confirmed by gene disruption experiments. Biochemical and genetic studies have determined that Tri4 and Tri11 encode P450 monooxygenases, Tri3 encodes a transacetylase, and Tri6 encodes a transcriptional factor that serves as a positive regulator of pathway gene expression. The levels of pathway gene mRNAs are greatly reduced in mutants lacking a functional Tri6 gene. These results indicate that trichothecene pathway genes are closely linked and that their expression is coordinately regulated.