Sequence variability in the FUM1 gene of Fusarium verticillioides strains.

Fumonisins are mycotoxins, produced mainly by Fusarium verticillioides, that are potentially carcinogenic to humans and toxic to animals. Synthesis of these toxins is directed by a cluster of 15 genes, among which FUM1 is the largest; it encodes a polyketide synthase. This enzyme probably catalyzes the synthesis of a polyketide that forms a large portion of the fumonisin structure. In this study, 27 strains possessing the FUM1 gene, as determined by polymerase chain reaction, were analyzed. A portion of the FUM1 gene was amplified and sequenced from 6 of 27 Brazilian strains isolated from corn and sorghum. The sequence similarity for the six F. verticillioides strains was almost 100%.