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United States Department of Agriculture

Agricultural Research Service

Title: Isolation and Characterization of the Trichothecene Pathway Gene Encoding Tri7 from Fusarium Sporotrichioides

Authors
item Hohn, Thomas
item MCCORMICK, SUSAN

Submitted to: Fungal Genetics Conference Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: March 26, 1995
Publication Date: N/A

Technical Abstract: The biosynthesis of trichothecene mycotoxins occurs via a complex pathway involving multiple isomerization, oxygenation, and esterification reactions. At least four trichothecene pathway genes are known to be closely linked in Fusarium sporotrichioides. Our efforts to further characterize the trichothecene pathway gene cluster have resulted in the identification of a fifth pathway gene (Tri7) located 898 bp upstream from Tri3. The Tri7 gene encodes a protein of 399 amino acids with no significant homology to sequences present in the protein databases. Comparison of the cDNA and genomic sequences revealed the presence of a single intron of 52 bp. Hydropathy analysis predicts the presence of several membrane spanning regions indicating that TRI7 is most likely an integral membrane protein. Disruption of Tri7 results in an altered trichothecene production phenotype characterized by the accumulation of HT-2 toxin but does not alter the expression of other pathway enzymes. Regulation of Tri7 transcription is similar to that of other pathway genes. Efforts are underway to determine the function of the Tri7 gene product.

Last Modified: 9/29/2014
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