ARS | Publication request: Novel regulation of Fumonisin biosynthesis by Fusarium verticillioides via a Zn(II)2Cys6 transcriptional factor

Submitted to: World Mycotoxin Forum, the Third Conference
Publication Type: Abstract
Publication Acceptance Date: November 6, 2006
Publication Date: November 6, 2006
Citation: Brown, D.W., Butchko, R.A., Busman, M., Proctor, R. 2006. Novel regulation of Fumonisin biosynthesis by Fusarium verticillioides via a Zn(II)2Cys6 transcriptional factor [abstract]. World Mycotoxin Fourth Conference. Poster 1.

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 fumonisin biosynthetic gene cluster includes 16 genes, none of which appear to play a role in regulation. We identified a new gene (FUM21) located adjacent to the cluster and show that it plays a significant but not absolute role in fumonisin production. Fum21 mutants produce no fumonsin after 10 days, and 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. The observation that fum21 mutants are not completely blocked in fumonisin production suggests that genes located outside the cluster may also directly regulate fumonisin production.