Title: MICROARRAY EVIDENCE FOR GENE CLUSTERS INVOLVED IN POLYKETIDE BIOSYNTHESIS IN THE FUMONISIN-PRODUCING FUNGUS FUSARIUM VERTICILLIOIDES Authors
Submitted to: Mycological International Conference Proceedings
Publication Type: Proceedings
Publication Acceptance Date: July 11, 2006
Publication Date: September 27, 2006
Citation: Proctor, R., Butchko, R.A., Brown, D.W., Busman, M., Plattner, R.D. 2006. Microarray evidence for gene clusters involved in polyketide biosynthesis in the fumonisin-producing fungus fusarium verticillioides. Mycological International Conference. p. 35. Technical Abstract: Fusarium verticillioides can cause stalk and ear rot of maize, and can produce the polyketide-derived mycotoxins fumonisins in infected kernels. Although the genetics and biochemistry of fumonisin biosynthesis is relatively well understood in F. verticillioides, little is known about the biosynthesis of other secondary metabolites produced by this fungus. A previously reported genomic sequence analysis (Kroken et al, 2003) identified 15 polyketide synthase (PKS) genes in F. verticillioides. We are characterizing these genes to determine which polyketide metabolites are synthesized by the corresponding PKS enzymes, whether the polyketide metabolites contribute to pathogenesis of F. verticillioides, and whether the PKS genes are located within gene clusters. For the latter objective, we are using microarray analysis to examine changes in expression of the PKS genes and genes adjacent to them. This analysis indicates that the fusarin PKS gene, PKS10, and eight contiguous genes on one side of it, exhibit similar increases in expression over time in liquid GYAM medium. Likewise, PKS10 and the same eight genes exhibit relatively high levels of expression on whole maize kernels but low levels of expression on maize embryo tissue after four days of growth. In contrast, other genes in the same chromosomal region do not exhibit such changes or differences in expression. Together the data suggest that PKS10 and eight genes adjacent to it are members of a fusarin gene cluster.