Ztf1, an Ustilago maydis transcription factor involved in virulence

Abstract

Ustilago maydis (DC.) Cda., the causal agent of common corn smut, is considered an important model to analyze fundamental problems of fungal development and virulence. In this work, we proceeded to analyze the characteristics and role in Zea mays and Arabidopsis thaliana virulence of the UMAG_02301 gene encoding an important and conserved transcription factor (ZTF1) that is over-expressed in the experimental pathosystem U. maydis/A. thaliana. Mutants in this gene were deficient in virulence to both, A. thaliana and Z. mays, and affected in the yeast-to-mycelium dimorphic transition induced by use of a fatty acid as carbon source, but not by acid pH. In addition, it was observed that the gene was positively or negatively regulated by different kinds of stress. The observation that the gene is involved in virulence to both, its natural host, maize, and the experimental host, A. thaliana, is evidence of the usefulness of the U. maydis/A. thaliana pathosystem for the study of the virulence mechanisms of the fungus.