Regulation of fumonisin biosynthesis in Gibberella fujikuroi
Abstract
Fumonisins are a group of mycotoxins produced in corn kernels by the plant pathogenic fungus Gibberella fujikuroi. Fumonisins cause various mycotoxicoses in animals by inhibiting sphingolipid metabolism. Information about the biosynthesis and regulation of fumonisins is incomplete. The data obtained from this research indicate that fumonisin B1 (FB1) is predominantly produced in endosperm of corn kernel and that FB1 biosynthesis is inhibited by nitrogen metabolite repression. I isolated a mutant of G. fujikuroi that failed to produce FB1 when grown on corn. The mutant, FT536, contained a disrupted gene, FIC1 (Fumonisin Inhibited on Corn), which encodes a putative 319-amino-acid polypeptide that has high similarity to UME3, a cyclin C of Saccharomyces cerevisiae. FIC1 is required for conidiation and expression of FB1 biosynthetic genes during growth on corn kernels. Subtraction EST libraries were constructed from wildtype and FT536 grown on corn. DNA sequence analysis of 800 ESTs indicated that FIC1 affects expression of a specific set of genes in G. fujikuroi .
Degree
Ph.D.
Advisors
Woloshuk, Purdue University.
Subject Area
Plant pathology
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