ARS | Publication request: Characterization of polyketide synthase genes in the genus Fusarium

Submitted to: Meeting Abstract
Publication Type: Abstract
Publication Acceptance Date: June 5, 2007
Publication Date: September 16, 2007
Citation: Proctor, R., Butchko, R.A., Brown, D.W., Busman, M. 2007. Characterization of polyketide synthase genes in the genus Fusarium [abstract]. XV European Mycological Congress. p. 282.

Technical Abstract: Fusarium verticillioides is a stalk and ear rot pathogen of maize and can produce the fumonisin mycotoxins. Although the genetics and biochemistry of fumonisin biosynthesis is relatively well understood, little is known about the biosynthesis of other secondary metabolites produced by F. verticillioides, and whether the regulatory mechanisms that affect fumonisin production also affect biosynthesis of other secondary metabolites. To begin to address such issues, we are characterizing 14 F. verticillioides polyketide synthase (PKS) genes that were identified in the genome sequence of this fungus (Kroken et al, 2003 PNAS 100:15670-15675). Some of these genes appear to be located in gene clusters. For example, PKS10, which is required for the biosynthesis of fusarin mycotoxins, and eight contiguous genes adjacent to it, exhibit similar changes in expression over time in liquid GYAM medium. These same nine genes also exhibit relatively high expression on whole maize kernels and low expression on embryo tissue. The predicted functions of some of these genes are consistent with enzymatic activities predicted to be required for fusarin biosynthesis. Five of the F. verticillioides PKS genes are also present in the genome sequences of F. graminearum, F. oxysporum and N. haematococca; Southern blot analysis of 42 other species detected three of the five PKS genes in all species examined, and two of the genes in all but three to five species. In contrast, other F. verticillioides PKS genes were detected in only some species that are closely related to F. verticillioides.