Title: FUMONISIN BIOSYNTHESIS BY FUSARIUM VERTICILLIOIDES IS REGULATED BY A UNIQUE ZN(II)2CYS6 TRANSCRIPTIONAL FACTOR. Authors
Submitted to: Gordon Research Conference Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: June 23, 2006
Publication Date: June 23, 2006
Citation: Brown, D.W., Butchko, R.A., Busman, M., Proctor, R. 2006. Fumonisin biosynthesis by fusarium verticillioides is regulated by a unique zn(ii)2cys6 transcriptional factor [abstract]. Gordon Research Conference on Cellular and Molecular Fungal Biology. Technical Abstract: Fungal toxins are natural products that can negatively effect animal and plant health. The fungal genes involved in toxin synthesis are co-regulated and are often clustered within the genome and encode structural enzymes, regulatory proteins, and/or proteins that provide self protection. Fumonisins are toxins synthesized by Fusarium species that may contaminate maize or maize products, are associated with several animal diseases, and are linked with cancer in animals and humans. The current fumonisin biosynthetic gene cluster includes 16 genes, none of which appear to play a role in regulation. Two unlinked genes (ZFR1 and FCC1), located outside the cluster, have been shown to have an effect on fumonisin production. We identified a new gene (FUM21) located adjacent to the fumonisin polyketide synthase gene, FUM1, and showed that it plays a significant but not absolute role in fumonisin production. FUM21 mutants produce 70% less fumonisin on cracked corn and accumulate significantly less FUM1 and FUM8 transcripts compared to wild-type in a liquid medium. The predicted FUM21 protein includes a Zn(II)2Cys6 DNA binding domain and another domain associated with fungal transcription factors. Transformation of a FUM21 mutant with an intact copy of FUM21 restored wild-type fumonisin production. However, because FUM21 mutants were not completely blocked in fumonisin production, genes located outside the cluster (e.g ZFR1 and FCC1) are likely to also directly regulate fumonisin production.