Identification of a motor protein required for filamentous growth in Ustilago maydis . Abstract Signal transduction and morphogenesis in Ustilago maydis Pathogenic microorganisms have developed many different strategies to attack plants and animals and to survive as parasites within their hosts. Common themes of pathogenic development are signalling reactions and morphogenetic transitions to recognize the appropriate host and to propagate within plant or animal tissue. We use the phytopathogenic fungus Ustilago maydis as a model system to study the role of these processes during infection. Within these tumors masses of black spores are produced and eventually released.
Haploid cells grow vegetatively by budding and are non-pathogenic.
Cells secrete specific pheromones that are recognized by receptors present on the surface of cells of opposite mating type. After fusion, the infectious dikaryon is formed which now grows as a filamentous hypha. For the completion of sexual development the fungus is dependent on its host plant in which division of nuclei, karyogamy and spore formation occurs. Upon germination of the diploid spores meiosis occurs and haploid cells are released that again can grow saprophytically. The contributions of each mating-type locus have been dissected by genetic and molecular analysis.