title: The pep4 gene encoding proteinase A is involved in dimorphism and pathogenesis of Ustilago maydis.
abstract: Vacuole proteases have important functions in different physiological processes in fungi. Taking this aspect into consideration, and as a continuation of our studies on the analysis of the proteolytic system of Ustilago maydis, a phytopathogenic member of the Basidiomycota, we have analysed the role of the pep4 gene encoding the vacuolar acid proteinase PrA in the pathogenesis and morphogenesis of the fungus. After confirmation of the location of the protease in the vacuole using fluorescent probes, we obtained deletion mutants of the gene in sexually compatible strains of U. maydis (FB1 and FB2), and analysed their phenotypes. It was observed that the yeast to mycelium dimorphic transition induced by a pH change in the medium, or the use of a fatty acid as sole carbon source, was severely reduced in Δpep4 mutants. In addition, the virulence of the mutants in maize seedlings was reduced, as revealed by the lower proportion of plants infected and the reduction in size of the tumours induced by the pathogen, when compared with wild-type strains. All of these phenotypic alterations were reversed by complementation of the mutant strains with the wild-type gene. These results provide evidence of the importance of the pep4 gene for the morphogenesis and virulence of U. maydis.
authors.affiliation: Departamento de Microbiología, Escuela Nacional de Ciencias Biológicas del Instituto Politécnico Nacional, México, 11340, Distrito Federal, Mexico.|Departamento de Ingeniería Genética, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Unidad Irapuato, 36821, Irapuato, Mexico.
authors.forename: Cinthia V
authors.initials: CV
authors.lastname: Soberanes-Gutiérrez
authors.affiliation: Departamento de Microbiología, Escuela Nacional de Ciencias Biológicas del Instituto Politécnico Nacional, México, 11340, Distrito Federal, Mexico.
authors.forename: Margarita
authors.initials: M
authors.lastname: Juárez-Montiel
authors.affiliation: Departamento de Microbiología, Escuela Nacional de Ciencias Biológicas del Instituto Politécnico Nacional, México, 11340, Distrito Federal, Mexico.
authors.forename: Omar
authors.initials: O
authors.lastname: Olguín-Rodríguez
authors.affiliation: Departamento de Microbiología, Escuela Nacional de Ciencias Biológicas del Instituto Politécnico Nacional, México, 11340, Distrito Federal, Mexico.
authors.forename: César
authors.initials: C
authors.lastname: Hernández-Rodríguez
authors.affiliation: Departamento de Ingeniería Genética, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Unidad Irapuato, 36821, Irapuato, Mexico.
authors.forename: José
authors.initials: J
authors.lastname: Ruiz-Herrera
authors.affiliation: Departamento de Microbiología, Escuela Nacional de Ciencias Biológicas del Instituto Politécnico Nacional, México, 11340, Distrito Federal, Mexico.
authors.forename: Lourdes
authors.initials: L
authors.lastname: Villa-Tanaca
mesh_terms: D016282:Aspartic Acid Endopeptidases / Q000235:genetics*; D005800:Genes, Fungal; D008969:Molecular Sequence Data; D014588:Ustilago / Q000235:genetics / Q000472:pathogenicity*; D014774:Virulence; D003313:Zea mays / Q000382:microbiology
chemical_list: D016282:Aspartic Acid Endopeptidases; C022442:aspergillopepsin II
keywords: Ustilago maydis; fungal dimorphism; plant pathogenesis; proteinase A; vacuole proteinases