The cAMP Signaling and MAP Kinase Pathways in Plant Pathogenic Fungi

The key components of the well conserved cyclic AMP signaling and MAP kinase pathways have been functionally characterized in the corn smut Ustilago maydis, rice blast fungus Magnaporthe grisea, and a few other fungal pathogens. In general, the cAMP signaling and the MAP kinase cascade homologous to the yeast pheromone response pathway are required for plant penetration and invasive growth. For the other two MAP kinase pathways, yeast Slt2 homologs also are essential for plant infection but the function of HOG1 homologs varies among plant pathogenic fungi. In addition to pathogenesis, fungal pathogens also use these pathways to regulate various developmental and differentiation processes, such as mating, stress response, and hyphal fusion