ARS | Publication request: FOUR CLUSTERED AND COREGULATED GENES ASSOCIATED WITH FUMONISIN BIOSYNTHESIS IN FUSARIUM VERTICILLIOIDES

Submitted to: Fungal Genetics Conference Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: March 18, 2001
Publication Date: N/A

Technical Abstract: Fumonisins are mycotoxins that cause several fatal animal diseases, including cancer in rats and mice. These toxins are produced by the maize pathogen Fusarium verticillioides (syn. F. moniliforme) and can accumulate in maize infected with this fungus. We have identified four F. verticillioides genes (FUM6, FUM7, FUM8, and FUM9) immediately downstream of FUM5, a previously identified polyketide synthase gene that is required for fumonisin biosynthesis. Gene disruption analysis revealed that FUM6 is required for fumonisin production and Northern blot analysis revealed that expression of the four new genes is correlated with fumonisin production. In contrast, the expression of five genes located upstream of FUM5 are not correlated with fumonisin production. Nucleotide sequence analysis indicated that the predicted FUM6 translation product is most similar to cytochrome P450 monooxygenase/reductase fusion proteins, while the predicted products of FUM7, FUM8 and FUM9 are most similar to type III alcohol dehydrogenases, class-II a-aminotransferases and dioxygenases, respectively. These four groups of enzymes catalyze the same general types of reactions expected to be necessary for fumonisin biosynthesis given the chemical structures of the toxins. Together, these data indicate that FUM5, FUM6, FUM7, FUM8, and FUM9 form part of a fumonisin biosynthetic gene cluster in F. verticillioides.