Submitted to: ARS Workshop on Fusarium Toxins Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: September 26, 1995
Publication Date: N/A
Technical Abstract: Fumonisin mycotoxins are produced by Gibberella fujikuroi (Fusarium moniliforme) mating population A, a major pathogen of maize and sorghum worldwide. Our multidisciplinary research team is identifying fumonisin biosynthetic genes by both classical meiotic and molecular genetic methods. Meiotic analysis of naturally occurring fumonisin production mutants has identified three putative fumonisin biosynthetic loci. Fum1, which can control the ability to produce fumonisins, has been localized by marker-based mapping to one end of chromosome 1. Fum2 and fum3 appear to control hydroxylation of carbon-10 and carbon-5, respectively. Allelism tests indicate that fum1, fum2 and fum3 are tightly linked and may constitute a gene cluster on chromosome 1. This finding is not unexpected because genes that control biosynthesis of aflatoxins and trichothecenes in several fungal species have recently been found to be organized in complex clusters. When marker-based mapping has localized the position of the fumonisin biosynthetic genes to a particular chromosomal region or regions, the genes will be identified by complementation of function via DNA-mediated transformation. Understanding fumonisin biosynthesis and its genetic regulation should facilitate development of measures to control fumonisin contamination.