THE TRI11 GENE OF FUSARIUM-SPOROTRICHIOIDES ENCODES A CYTOCHROME-P-450 MONOOXYGENASE REQUIRED FOR C-15 HYDROXYLATION IN TRICHOTHECENE BIOSYNTHESIS

Several genes in the trichothecene biosynthetic pathway of Fusarium sp orotrichiodes have been shown to reside in a gene cluster. Sequence an alysis of a cloned DNA fragment located 3.8 kb downstream from TRI5 ha s led to the identification of the TRI11 gene. The nucleotide sequence of TRI11 predicts a polypeptide of 492 residues (M-r = 55,579) with s ignificant similarity to members of the cytochrome P-450 superfamily. TRI11 is most similar to several fungal cytochromes P-450 (23 to 27% i dentity) but is sufficiently distinct to define a new cytochrome P-450 gene family, designated CYP65A1. Disruption of TRI11 results in an al tered trichothecene production phenotype characterized by the accumula tion of isotrichodermin, a trichothecene pathway intermediate. The evi dence suggests that TRI11 encodes a C-15 hydroxylase involved in trich othecene biosynthesis.