|Lee, Yin Won|
Submitted to: Gordon Research Conference Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 3/23/2003
Publication Date: N/A
Citation: N/A Interpretive Summary:
Technical Abstract: Fumonisins are mycotoxins that cause several animal diseases, including cancer in rodents. These toxins are produced by the maize pathogen Gibberella moniliformis (anamorph Fusarium verticillioides), several closely related Fusarium species, and at least one isolate of F. oxysporum. G. moniliformis produces predominantly B fumonisins, which are likely formed via the condensation of alanine and a 20-carbon polyketide. In contrast, the isolate of F. oxysporum produces predominantly C fumonisins, which are likely formed via the condensation of glycine and the same 20-carbon polyketide. The FUM8 gene is required for fumonisin production and its predicted protein is highly similar to the yeast sphingolipid biosynthetic enzyme that catalyzes the condensation of serine and palmitic acid. This similarity suggests the FUM8 protein catalyzes the condensation of alanine, or glycine, and the polyketide during fumonisin biosynthesis. To determine whether FUM8 is responsible for the different fumonisin production profiles of G. moniliformis and F. oxysporum, we constructed a hybrid gene consisting of the G. moniliformis FUM8 promoter region fused to the F. oxysporum FUM8 coding region. Transformation of this hybrid gene into G. moniliformis changed the fumonisin profile from predominantly B fumonisins to predominantly C fumonisins when the hybrid gene integrated at FUM8. In contrast, only slight changes in the fumonisin profile occurred when the hybrid gene integrated elsewhere. These results indicate that FUM8 is responsible for B versus C fumonisin production and provide further evidence of a role for FUM8 in the condensation of alanine/glycine and the polyketide during fumonisin biosynthesis.