title: Lipid-induced filamentous growth in Ustilago maydis.
abstract: The phytopathogenic fungus Ustilago maydis is obligately dependent on infection of maize to complete the sexual phase of its life cycle. Mating interactions between haploid, budding cells establish an infectious filamentous cell type that invades the host, induces large tumours and eventually forms large masses of black spores. The ability to switch from budding to filamentous growth is therefore critical for infection and completion of the life cycle, although the signals that influence the transition have not been identified from the host or the environment. We have found that growth in the presence of lipids promotes a filamentous phenotype that resembles the infectious cell type found in planta. In addition, the ability of the fungus to respond to lipids is dependent on both the cAMP signalling pathway and a Ras/MAPK pathway; these pathways are known to regulate mating, filamentous growth and pathogenesis in U. maydis. Overall, these results lead us to hypothesize that lipids may represent one of the signals that promote and maintain the filamentous growth of the fungus in the host environment.
authors.affiliation: Department of Microbiology and Immunology, and Faculty of Agricultural Sciences, The University of British Columbia, 237-6174 University Blvd, Vancouver, BC, V6T 1Z3, Canada.
authors.forename: Jana
authors.initials: J
authors.lastname: Klose
authors.forename: Mário Moniz
authors.initials: MM
authors.lastname: de Sá
authors.forename: James W
authors.initials: JW
authors.lastname: Kronstad
mesh_terms: D002455:Cell Division / Q000502:physiology*; D048429:Cell Size; D000242:Cyclic AMP / Q000378:metabolism; D005947:Glucose / Q000378:metabolism; D008049:Lipase / Q000378:metabolism; D050356:Lipid Metabolism; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D010641:Phenotype; D015398:Signal Transduction / Q000502:physiology; D014280:Triglycerides / Q000378:metabolism; D014588:Ustilago / Q000166:cytology / Q000378:metabolism / Q000502:physiology*
chemical_list: D014280:Triglycerides; D000242:Cyclic AMP; D020928:Mitogen-Activated Protein Kinases; D008049:Lipase; D005947:Glucose