ARS | Publication request: FUMONISIN MYCOTOXIN BIOSYNTHESIS IN FUSARIUM VERTICILLIOIDES

Submitted to: Society of Industrial Microbiology Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: August 15, 2002
Publication Date: August 15, 2002
Citation: Proctor, R., Plattner, R.D., Desjardins, A.E., Butchko, R.A., Brown, D.W. 2002. Fumonisin mycotoxin biosynthesis in fusarium verticillioides. Society of Industrial Microbiology Annual Meeting.

Technical Abstract: Fumonsins are mycotoxins produced by the maize pathogen Fusarium verticillioides. These toxins are of concern because of their association with cancer in experimental rodents and the epidemiological correlation between consumption of fumonisin-contaminated maize and human esophageal cancer. We have sequenced a 75-kb region of F. verticillioides DNA and identified a putative fumonisin biosynthetic gene cluster that consists of 15 genes. Expression of cluster genes was correlated with fumonisin production, while expression of genes on either side of the cluster was not. To date, we have disrupted 8 of the cluster genes to determine whether they are required for fumonisin biosynthesis. Disruption of three genes, encoding a polyketide synthase, an aminotransferase, and a cytochrome P450 monooxygenase (P450), blocked fumonisin production but did not lead to accumulation of obvious biosynthetic intermediates. Disruption of a fourth gene, encoding a P450, resulted in accumulation of only fumonisins without a C-10 hydroxyl. In contrast, disruption of four other genes, encoding an ABC transporter, two longevity assurance factors, and a P450, did not alter fumonisin production. Thus, some cluster genes are required for production while others are not. Efforts are underway to determine whether those genes not required are nevertheless involved in fumonisin biosynthesis.