Pheromone-dependent cell cycle arrest in the phytopathogenic fungus ustilago mayids
- Autores: Paola Bardetti
- Directores de la Tesis: Jose Manuel Pérez Martín (dir. tes.)
- Lectura: En la Universidad de Salamanca ( España ) en 2018
- Idioma: español
- Tribunal Calificador de la Tesis: Martí Aldea Malo (presid.), Jaime Correa Bordes (secret.), Andre Fleissner (voc.)
- Programa de doctorado: Programa de Doctorado en Biología Funcional y Genómica por la Universidad de Salamanca
- Materias:
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- Resumen
All living cells use signal transduction pathways to respond to the environmental changes. Signaling cascades are involved in the transmission of an external stimulus to intracellular targets allowing cells to adapt to the new conditions. The comprehension of these signaling pathways is pivotal to understand important mechanisms such as cellular growth, differentiation and cell death. Since Fungi are simple organisms and their internal signals pathways are evolutionary conserved, they represent on of the best model to provide insights into these processes also in higher Eukaryotes. Moreover, in the past decades the knowledge about fungal signaling pathways has increased and it has emerged their importance in determine pathogenicity in human and plant pathogens (Zhao et al. 2007; Perez-Nadales et al. 2014). For this reason these cascades and their intracellular targets are often studied to understand the mechanism of pathogenicity and develop drugs and compounds that can arrest the infection.
Ustilago maydis is a basidiomycota phytopathogen that causes smut disease in Zea mais plant, causing big economic loses (Topp et al. 2002). Thanks to the development of techniques that make easier the genetic and molecular manipulation, nowadays U. maydis represents a good model to study phytopathogenity (Bolker 2001; Kamper 2004; Terfruchte et al. 2014). This fungus has a no pathogenic saprophytic yeast-like phase and a pathogenic phase that is triggered by the mating of two compatible cells in response to pheromone. The fusion results in the formation the infective hyphae that can infect corn plants and cause tumor. In other words, in U. maydis virulence is strictly associated with sexual life and pheromone signal triggers the activation of the virulence program. In order to mate U. maydis needs to form the sexual structures, called conjugative tube and synchronize the cell cycle of both cells in the same phase. In the no-pathogenic ascomycete fungus S. cerevisiae, the mechanism of cell cycle synchronization induced by pheromone is quite well characterized and results in a cell cycle arrest in G1 phase (Chang and Herskowitz 1990). In U.maydis it has been extensively described that a conserved MAPK cascade transmits the pheromone signal, as happens in S. cereviase, but how this cascade is able to govern the arrest of the cell cycle is poorly understood. The aim of this study is to elucidate the mechanism by which the pheromone signal can modulate the cell cycle machinery through the MAPK cascade in a pathogenic fungus.
