title: Endoplasmic reticulum glucosidase II is required for pathogenicity of Ustilago maydis.
abstract: We identified a nonpathogenic strain of Ustilago maydis by tagging mutagenesis. The affected gene, glucosidase1 (gas1), displays similarity to catalytic alpha-subunits of endoplasmic reticulum (ER) glucosidase II. We have shown that Gas1 localizes to the ER and complements the temperature-sensitive phenotype of a Saccharomyces cerevisiae mutant lacking ER glucosidase II. gas1 deletion mutants were normal in growth and mating but were more sensitive to calcofluor and tunicamycin. Mutant infection hyphae displayed significant alterations in the distribution of cell wall material and were able to form appressoria and penetrate the plant surface but arrested growth in the epidermal cell layer. Electron microscopy analysis revealed that the plant-fungal interface between mutant hyphae and the plant plasma membrane was altered compared with the interface of penetrating wild-type hyphae. This may indicate that gas1 mutants provoke a plant response.
authors.affiliation: Max-Planck-Institut für Terrestrische Mikrobiologie, Marburg, Germany.
authors.forename: Jan
authors.initials: J
authors.lastname: Schirawski
authors.forename: Heidi U
authors.initials: HU
authors.lastname: Böhnert
authors.forename: Gero
authors.initials: G
authors.lastname: Steinberg
authors.forename: Karen
authors.initials: K
authors.lastname: Snetselaar
authors.forename: Lubica
authors.initials: L
authors.lastname: Adamikowa
authors.forename: Regine
authors.initials: R
authors.lastname: Kahmann
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D017931:DNA Primers; D004721:Endoplasmic Reticulum / Q000201:enzymology*; D008969:Molecular Sequence Data; D016296:Mutagenesis; D010957:Plasmids; D017386:Sequence Homology, Amino Acid; D014588:Ustilago / Q000201:enzymology* / Q000472:pathogenicity*; D000520:alpha-Glucosidases / Q000737:chemistry / Q000378:metabolism*
chemical_list: D017931:DNA Primers; C034251:4-nitrophenyl-alpha-glucosidase; D000520:alpha-Glucosidases