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United States Department of Agriculture

Agricultural Research Service

Title: 15-Decalonectrin 15-O-Acetyltransferase, Isolation and Characterization of Tri3, a Gene Encoding 15-O-Acetyltransferase from Fusarium Sporotrichioides

item McCormick, Susan
item Hohn, Thomas
item Desjardins, Anne

Submitted to: Applied and Environmental Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: November 8, 1995
Publication Date: N/A

Interpretive Summary: The mold Fusarium is a common contaminant of grain and other livestock feeds. Several species of Fusarium produce trichothecene toxins which cause adverse effects on human and animal health. We identified a gene in Fusarium sporotrichioides that controls one step in the pathway of trichothecene toxins. This gene is closely linked to a gene that controls the production of these toxins. This knowledge will be useful in the development of new strategies for controlling the contamination of food and feed products.

Technical Abstract: An acetyltransferase gene (Tri3) was isolated from Fusarium sporotrichioides by complementation of a previously identified Tri3- mutant, and shown to be closely linked to three other trichothecene biosynthetic pathway genes. Comparison of the Tri3 sequence with its cDNA revealed the presence of four introns. The Tri3 cDNA contains a 1539 bp open reading frame that encodes a protein with a molecular mass of 57,418 Da. Regulation of Tri3 transcription in liquid cultures appeared identical to that of other trichothecene pathway genes. Disruption of the Tri3 gene resulted in the accumulation of deacetylated calonectrins rather than T-2 toxin. The results of whole- cell feeding experiments with Tri3- strains suggested that 15-O- acetylation is blocked. Cell-free feeding experiments confirmed that Tri3- strains are able to acetylate hydroxyls at the C3 and C4 positions but are unable to acetylate a C15 hydroxyl group. Our results show that Tri3 encodes an acetyltransferase that converts 15- deacetylcalonectrin to calonectrin.

Last Modified: 4/19/2015
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