An Ustilago maydis gene involved in H2O2 detoxification is required for virulence.
The fungus Ustilago maydis is a biotrophic pathogen of maize (Zea mays). In its genome we have identified an ortholog of YAP1 (for Yeast AP-1-like) from Saccharomyces cerevisae that regulates the oxidative stress response in this organism. yap1 mutants of U. maydis displayed higher sensitivity to H(2)O(2) than wild-type cells, and their virulence was significantly reduced. U. maydis yap1 could partially complement the H(2)O(2) sensitivity of a yap1 deletion mutant of S. cerevisiae, and a Yap1-green fluorescent protein fusion protein showed nuclear localization after H(2)O(2) treatment, suggesting that Yap1 in U. maydis functions as a redox sensor. Mutations in two Cys residues prevented accumulation in the nucleus, and the respective mutant strains showed the same virulence phenotype as Deltayap1 mutants. Diamino benzidine staining revealed an accumulation of H(2)O(2) around yap1 mutant hyphae, which was absent in the wild type. Inhibition of the plant NADPH oxidase prevented this accumulation and restored virulence. During the infection, Yap1 showed nuclear localization after penetration up to 2 to 3 d after infection. Through array analysis, a large set of Yap1-regulated genes were identified and these included two peroxidase genes. Deletion mutants of these genes were attenuated in virulence. These results suggest that U. maydis is using its Yap1-controlled H(2)O(2) detoxification system for coping with early plant defense responses.
Molina
Lázaro
L
Max Planck Institute for Terrestrial Microbiology, D-35043 Marburg, Germany.
Kahmann
Regine
R
D000595:Amino Acid Sequence; D003545:Cysteine / Q000378:metabolism; D005656:Fungal Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D017353:Gene Deletion; D015966:Gene Expression Regulation, Fungal / Q000187:drug effects; D005800:Genes, Fungal; D005816:Genetic Complementation Test; D006861:Hydrogen Peroxide / Q000378:metabolism* / Q000494:pharmacology; D008658:Inactivation, Metabolic; D050296:Microbial Viability / Q000187:drug effects; D008969:Molecular Sequence Data; D019255:NADPH Oxidases / Q000037:antagonists & inhibitors; D020411:Oligonucleotide Array Sequence Analysis; D018384:Oxidative Stress / Q000187:drug effects; D009195:Peroxidase / Q000235:genetics; D017434:Protein Structure, Tertiary; D021381:Protein Transport / Q000187:drug effects; D017382:Reactive Oxygen Species / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000187:drug effects / Q000254:growth & development; D017386:Sequence Homology, Amino Acid; D014588:Ustilago / Q000166:cytology / Q000187:drug effects / Q000235:genetics* / Q000472:pathogenicity*; D014774:Virulence / Q000187:drug effects
D005656:Fungal Proteins; D017382:Reactive Oxygen Species; D006861:Hydrogen Peroxide; D009195:Peroxidase; D019255:NADPH Oxidases; D003545:Cysteine