title: CPMK2, an SLT2-homologous mitogen-activated protein (MAP) kinase, is essential for pathogenesis of Claviceps purpurea on rye: evidence for a second conserved pathogenesis-related MAP kinase cascade in phytopathogenic fungi.
abstract: Cpmk2, encoding a mitogen-activated protein (MAP) kinase from the ascomycete Claviceps purpurea, is an orthologue of SLT2 from Saccharomyces cerevisiae, the first isolated from a biotrophic, non-appressorium-forming pathogen. Deletion mutants obtained by a gene replacement approach show impaired vegetative properties (no conidiation) and a significantly reduced virulence, although they retain a limited ability to colonize the host tissue. Increased sensitivity to protoplasting enzymes indicates that the cell wall structure of the mutants may be altered. As the phenotypes of these mutants are similar to those observed in strains of the rice pathogen, Magnaporthe grisea, that have been deprived of their MAP kinase gene mps1, the ability of cpmk2 to complement the defects of delta mps1 was investigated. Interestingly, the C. purpurea gene, under the control of its own promoter, was able to complement the M. grisea mutant phenotype: transformants were able to sporulate and form infection hyphae on onion epidermis and were fully pathogenic on barley leaves. This indicates that, despite the differences in infection strategies, which include host and organ specificity, mode of penetration and colonization of host tissue, CPMK2/MPS1 defines a second MAP kinase cascade (after the Fus3p/PMK1 cascade) essential for fungal pathogenicity.
authors.affiliation: Institut für Botanik Westfälische Wilhelms-Universität, Münster, Germany.
authors.forename: Géraldine
authors.initials: G
authors.lastname: Mey
authors.forename: Katrin
authors.initials: K
authors.lastname: Held
authors.forename: Jan
authors.initials: J
authors.lastname: Scheffer
authors.forename: Klaus B
authors.initials: KB
authors.lastname: Tenberge
authors.forename: Paul
authors.initials: P
authors.lastname: Tudzynski
mesh_terms: D002967:Claviceps / Q000201:enzymology* / Q000235:genetics / Q000472:pathogenicity*; D003001:Cloning, Molecular; D005656:Fungal Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D015966:Gene Expression Regulation, Fungal; D020043:Genes, Essential; D005816:Genetic Complementation Test; D020935:MAP Kinase Signaling System; D020928:Mitogen-Activated Protein Kinases / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism; D009154:Mutation; D010935:Plant Diseases / Q000382:microbiology; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics*; D012434:Secale / Q000382:microbiology*; D017386:Sequence Homology, Amino Acid; D014170:Transformation, Genetic
chemical_list: D005656:Fungal Proteins; D029701:Saccharomyces cerevisiae Proteins; D020928:Mitogen-Activated Protein Kinases; C072724:SLT2 protein, S cerevisiae