Submitted to: Multicrop Aflatoxin and Fumonisin Elimination and Fungal Genomics Workshop-The Peanut Foundation
Publication Type: Abstract Only
Publication Acceptance Date: 10/19/2007
Publication Date: 12/1/2007
Citation: Chang, P., Wilkinson, J.R., Horn, B.W., Yu, J., Bhatnagar, D., Cleveland, T.E. 2007. Genes Differentially Expressed by Aspergillus flavus Strains After Loss of Aflatoxin Production by Serial Transfers. Multicrop Aflatoxin and Fumonisin Elimination and Fungal Genomics Workshop-The Peanut Foundation, Atlanta, GA. p. 34.
Technical Abstract: Aflatoxins are carcinogenic fungal secondary metabolites produced by Aspergillus flavus and other closely related species. To better understand the molecular events that are associated with aflatoxin production, three separate nonaflatoxigenic A. flavus strains were produced through serial transfers of aflatoxigenic parental strains. The three independent aflatoxigenic/nonaflatoxigenic pairs were compared via transcription profiling by DNA microarray analyses. Cross comparisons identified twenty-two features in common between the aflatoxigenic/nonaflatoxigenic pairs. Physical mapping of the twenty-two features using the A. oryzae whole genome sequence for reference identified sixteen unique genes. Aflatoxin biosynthetic and regulatory gene expression levels were not significantly different between the aflatoxigenic/nonaflatoxigenic pairs, which suggests that the inability to produce aflatoxins is not due to decreased expression of known aflatoxin biosynthetic or regulatory genes. Of the sixteen in common genes, only one gene (hcc) homologous to glutathione S-transferase genes showed higher expression in the nonaflatoxigenic progeny relative to the parental strains. Possible roles of hcc and other identified genes are discussed in relation to regulation of aflatoxin biosynthesis.