A polyketide synthase gene required for biosynthesis of fumonisin mycotoxins in Gibberella fujikuroi mating population A.
Fumonisins are toxins associated with several mycotoxicoses and are produced by the maize pathogen Gibberella fujikuroi mating population A (MP-A). Biochemical analyses indicate that fumonisins are a product of either polyketide or fatty acid biosynthesis. To isolate a putative polyketide synthase (PKS) gene involved in fumonisin biosynthesis, we employed PCR with degenerate PKS primers and a cDNA template prepared from a fumonisin-producing culture of G. fujikuroi. Sequence analysis of the single PCR product and its flanking DNA revealed a gene (FUM5) with a 7.8-kb coding region. The predicted FUM5 translation product was highly similar to bacterial and fungal Type I PKSs. Transformation of a cosmid clone carrying FUM5 into G. fujikuroi enhanced production in three strains and restored wild-type production in a fumonisin nonproducing mutant. Disruption of FUM5 reduced fumonisin production by over 99% in G. fujikuroi MP-A. Together, these results indicate that FUM5 is a PKS gene required for fumonisin biosynthesis.
Mycotoxin Research Unit, National Center for Agricultural Utilization Research, Peoria, Illinois 61604, USA.
R H
RH
Proctor
A E
AE
Desjardins
R D
RD
Plattner
T M
TM
Hohn
D015099:3-Oxoacyl-(Acyl-Carrier-Protein) Synthase / Q000235:genetics; D000595:Amino Acid Sequence; D002264:Carboxylic Acids / Q000378:metabolism*; D017931:DNA Primers; D004271:DNA, Fungal / Q000235:genetics; D037341:Fumonisins; D005800:Genes, Fungal / Q000235:genetics; D005816:Genetic Complementation Test; D005822:Genetic Vectors; D005874:Gibberella / Q000201:enzymology / Q000235:genetics*; D007527:Isoenzymes / Q000235:genetics; D008969:Molecular Sequence Data; D009097:Multienzyme Complexes / Q000235:genetics* / Q000378:metabolism; D016297:Mutagenesis, Site-Directed; D009154:Mutation; D009183:Mycotoxins / Q000096:biosynthesis*; D016133:Polymerase Chain Reaction; D017386:Sequence Homology, Amino Acid; D014170:Transformation, Genetic
D002264:Carboxylic Acids; D017931:DNA Primers; D004271:DNA, Fungal; D037341:Fumonisins; D007527:Isoenzymes; D009097:Multienzyme Complexes; D009183:Mycotoxins; C056934:fumonisin B2; C073063:fumonisin B3; C056933:fumonisin B1; C078182:beta-ketoacyl-acyl carrier protein synthase I; D015099:3-Oxoacyl-(Acyl-Carrier-Protein) Synthase