ARS | Publication request: VeA regulates some secondary metabolism in Fusarium fujikuroi

Submitted to: Meeting Abstract
Publication Type: Abstract
Publication Acceptance Date: March 11, 2009
Publication Date: March 11, 2009
Citation: Wiemann, P., Brown, D.W., Humpf, H., Tudzynski, B. 2009. VeA regulates some secondary metabolism in Fusarium fujikuroi [abstract]. Association for General and Applied Microbiology.

Technical Abstract: Fusarium fujikuroi is a pathogen of rice that causes hyper elongation of seedling stalks and leaves due to the fungal production of gibberellic acids (GAs). During infection of rice or after growth on other cereals, F. fujikuroi may also synthesize other toxins (e.g. fumonisins, fusarin C, and bikaverin) as well as a number of carotenoids. Although some genes responsible for synthesis of some of these secondary metabolites are characterized, our understanding of their regulatory mechanisms is poor or incomplete, at best. In this study, we identified and characterized a gene, called veA, in F. fujikuroi and examined its role as a global regulator of secondary metabolism. A comparison of wild type and veA deletion strains in pathogenicity assays revealed significant less hyper elongation of rice infected with the later strain. To identify genes influenced by VeA in F. fujikuroi, we conducted microarray experiments comparing RNA from the wild type and veA knock-out strains to identify differentially expressed genes. We found that among the down-regulated genes are those involved in sexual development as well as GA and fumonisin synthesis. Up-regulated genes included those involved in bikaverin synthesis. No changes in expression were observed for genes involved in fusarin C or carotenoid production. Northern blot analysis confirmed the microarray data. Examination of veA-regulated genes led to the tentative identification of a putative ortholog of laeA, a critical regulator of secondary metabolism in Aspergillus species. The impact of this gene on Fusarium secondary metabolism is currently under investigation. Our results further prove the cross-species use of the F. verticillioides microarray to elucidate the diverse effects different genes have on the biology of F. fujikuroi.