title: Transcriptomic analysis of Ustilago maydis infecting Arabidopsis reveals important aspects of the fungus pathogenic mechanisms.
abstract: Transcriptomic and biochemical analyses of the experimental pathosystem constituted by Ustilago maydis and Arabidopsis thaliana were performed. Haploid or diploid strains of U. maydis inoculated in A. thaliana plantlets grew on the surface and within the plant tissues in the form of mycelium, inducing chlorosis, anthocyanin formation, malformations, necrosis and adventitious roots development, but not teliospores. Symptoms were more severe in plants inoculated with the haploid strain which grew more vigorously than the diploid strain. RNA extracted at different times post-infection was used for hybridization of one-channel microarrays that were analyzed focusing on the fungal genes involved in the general pathogenic process, biogenesis of the fungal cell wall and the secretome. In total, 3,537 and 3,299 genes were differentially expressed in the haploid and diploid strains, respectively. Differentially expressed genes were related to different functional categories and many of them showed a similar regulation occurring in U. maydis infecting maize. Our data suggest that the haploid strain behaves as a necrotrophic pathogen, whereas the diploid behaves as a biotrophic pathogen. The results obtained are evidence of the usefulness of the U. maydis-A. thaliana pathosystem for the analysis of the pathogenic mechanisms of U. maydis.
authors.affiliation: Departamento de Ingeniería Genética; Unidad Irapuato; Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional; Irapuato, Gto México.
authors.forename: Domingo
authors.initials: D
authors.lastname: Martínez-Soto
authors.forename: Angélica M
authors.initials: AM
authors.lastname: Robledo-Briones
authors.forename: Andrés A
authors.initials: AA
authors.lastname: Estrada-Luna
authors.forename: José
authors.initials: J
authors.lastname: Ruiz-Herrera
mesh_terms: D017360:Arabidopsis / Q000254:growth & development / Q000382:microbiology*; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism; D020869:Gene Expression Profiling; D015966:Gene Expression Regulation, Fungal; D005800:Genes, Fungal / Q000235:genetics; D006031:Glycosylation; D054884:Host-Pathogen Interactions / Q000235:genetics*; D010935:Plant Diseases / Q000382:microbiology*; D011134:Polysaccharides / Q000096:biosynthesis; D014588:Ustilago / Q000235:genetics / Q000472:pathogenicity*; D014774:Virulence / Q000235:genetics
chemical_list: D005656:Fungal Proteins; D011134:Polysaccharides
keywords: Arabidopsis thaliana; Ustilago maydis; experimental pathosystem; microarrays; necrotrophic fungus; plant virulence