title: MgHog1 regulates dimorphism and pathogenicity in the fungal wheat pathogen Mycosphaerella graminicola.
abstract: The dimorphic ascomycete pathogen Mycosphaerella graminicola switches from a yeastlike form to an infectious filamentous form that penetrates the host foliage through stomata. We examined the biological function of the mitogen-activated protein kinase-encoding gene MgHog1 in M. graminicola. Interestingly, MgHog1 mutants were unable to switch to filamentous growth on water agar that mimics the nutritionally poor conditions on the foliar surface and, hence, exclusively developed by a yeastlike budding process. Consequently, due to impaired initiation of infectious germ tubes, as revealed by detailed in planta cytological analyses, the MgHog1 mutants failed to infect wheat leaves. We, therefore, conclude that MgHog1 is a new pathogenicity factor involved in the regulation of dimorphism in M. graminicola. Furthermore, MgHog1 mutants are osmosensitive, resistant to phenylpyrrole and dicarboximide fungicides, and do not melanize.
authors.affiliation: Plant Research International B.V., Wageningen University and Research Centre (WUR), PO. Box 16, 6700 AA, Wageningen, The Netherlands.
authors.forename: Rahim
authors.initials: R
authors.lastname: Mehrabi
authors.forename: Lute-Harm
authors.initials: LH
authors.lastname: Zwiers
authors.forename: Maarten A
authors.initials: MA
authors.lastname: de Waard
authors.forename: Gert H J
authors.initials: GH
authors.lastname: Kema
mesh_terms: D001203:Ascomycota / Q000201:enzymology / Q000235:genetics* / Q000254:growth & development / Q000472:pathogenicity; D025141:Drug Resistance, Fungal / Q000235:genetics; D020224:Expressed Sequence Tags; D005800:Genes, Fungal; D020928:Mitogen-Activated Protein Kinases / Q000235:genetics* / Q000502:physiology; D008969:Molecular Sequence Data; D009154:Mutation; D009997:Osmotic Pressure; D014908:Triticum / Q000382:microbiology; D014774:Virulence / Q000235:genetics
chemical_list: D020928:Mitogen-Activated Protein Kinases