Disruption of TRI101, the gene encoding trichothecene 3-O-acetyltransferase, from Fusarium sporotrichioides

We screened a Fusarium sporotrichioides NRRL 3299 cDNA expression library i n a toxin-sensitive Saccharomyces cerevisiae strain lacking a functional PD R5 gene. Fourteen yeast transformants were identified as resistant to the t richothecene 4,15-diacetoxyscirpenol, and each carried a cDNA encoding the trichothecene 3-O-acetyltransferase that is the F. sporotrichioides homolog of the Fusarium graminearum TRI101 gene. Mutants of F. sporotrichioides NR RL 3299 produced by disruption of TRI101 were altered in their abilities to synthesize T-2 toxin and accumulated isotrichodermol and small amounts of 3,15-didecalonectrin and 3-decalonectrin, trichothecenes that are not obser ved in cultures of the parent strain. Our results indicate that TRI101 conv erts isotrichodermol to isotrichodermin and is required for the biosynthesi s of T-2 toxin.