Complementation of an Aspergillus nidulans mutant defective in aflR expression.

Robert A.E. Butchko, Thomas H. Adams, and Nancy P. Keller.


aflR encodes a conserved pathway specific transcription factor that regulates the expression of gene clusters involved in the biosynthesis of aflatoxin by Aspergillus flavus and A. parasiticus and sterigmatocystin (ST) by A. nidulans. We have already shown that aflR expression is developmentally regulated in A. nidulans, mutants that fail to conidiate are also defective in aflR expression. In an effort to more fully understand the regulation of the production of ST by A. nidulans, we have identified A. nidulans mutants that no longer express aflR transcript but retain wild type development. These mutants were easily identified by looking for strains that no longer accumulated the orange colored intermediate in the ST pathway, norsolorinic acid (NOR). One of the mutant strains contained a single locus mutation unlinked to the ST cluster. Transformation of this strain with a wildtype cosmid library returned the strain to NOR production and also restored the production of the green conidia. This preliminary data suggests that the gene responsible for regulating aflR expression is linked to wA. Here we describe the complementation and characterization of one of these mutants.

abstract No: 

Fungal Genet. Newsl. 46 (Supl):

Full conference title: 

Fungal Genetics Conference 20th
    • Fungal Genetics Conference 20th (1999)