title: Cross-talk of the biotrophic pathogen Claviceps purpurea and its host Secale cereale.
abstract: The economically important Ergot fungus Claviceps purpurea is an interesting biotrophic model system because of its strict organ specificity (grass ovaries) and the lack of any detectable plant defense reactions. Though several virulence factors were identified, the exact infection mechanisms are unknown, e.g. how the fungus masks its attack and if the host detects the infection at all.
  
  
  
  We present a first dual transcriptome analysis using an RNA-Seq approach. We studied both, fungal and plant gene expression in young ovaries infected by the wild-type and two virulence-attenuated mutants. We can show that the plant recognizes the fungus, since defense related genes are upregulated, especially several phytohormone genes. We present a survey of in planta expressed fungal genes, among them several confirmed virulence genes. Interestingly, the set of most highly expressed genes includes a high proportion of genes encoding putative effectors, small secreted proteins which might be involved in masking the fungal attack or interfering with host defense reactions. As known from several other phytopathogens, the C. purpurea genome contains more than 400 of such genes, many of them clustered and probably highly redundant. Since the lack of effective defense reactions in spite of recognition of the fungus could very well be achieved by effectors, we started a functional analysis of some of the most highly expressed candidates. However, the redundancy of the system made the identification of a drastic effect of a single gene most unlikely. We can show that at least one candidate accumulates in the plant apoplast. Deletion of some candidates led to a reduced virulence of C. purpurea on rye, indicating a role of the respective proteins during the infection process.
  
  
  
  We show for the first time that- despite the absence of effective plant defense reactions- the biotrophic pathogen C. purpurea is detected by its host. This points to a role of effectors in modulation of the effective plant response. Indeed, several putative effector genes are among the highest expressed genes in planta.
authors.affiliation: Institut für Biologie und Biotechnologie der Pflanzen, Westfälische Wilhelms-Universität, D-48143, Münster, Germany.
authors.forename: Birgitt
authors.initials: B
authors.lastname: Oeser
authors.affiliation: Institut für Biologie und Biotechnologie der Pflanzen, Westfälische Wilhelms-Universität, D-48143, Münster, Germany.
authors.forename: Sabine
authors.initials: S
authors.lastname: Kind
authors.affiliation: Institut für Biologie und Biotechnologie der Pflanzen, Westfälische Wilhelms-Universität, D-48143, Münster, Germany.
authors.forename: Selma
authors.initials: S
authors.lastname: Schurack
authors.affiliation: Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), Gatersleben, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Schmutzer
authors.affiliation: Institut für Biologie und Biotechnologie der Pflanzen, Westfälische Wilhelms-Universität, D-48143, Münster, Germany.
authors.forename: Paul
authors.initials: P
authors.lastname: Tudzynski
authors.affiliation: Institut für Biologie und Biotechnologie der Pflanzen, Westfälische Wilhelms-Universität, D-48143, Münster, Germany. Janinehinsch@gmail.com.
authors.forename: Janine
authors.initials: J
authors.lastname: Hinsch
mesh_terms: D002967:Claviceps / Q000235:genetics* / Q000378:metabolism; D060467:Disease Resistance / Q000235:genetics; D035264:Flowers / Q000235:genetics / Q000378:metabolism / Q000382:microbiology*; D015966:Gene Expression Regulation, Fungal; D018506:Gene Expression Regulation, Plant; D005800:Genes, Fungal; D017343:Genes, Plant; D054884:Host-Pathogen Interactions; D010935:Plant Diseases / Q000382:microbiology*; D012434:Secale / Q000235:genetics / Q000378:metabolism / Q000382:microbiology*; D059467:Transcriptome; D037521:Virulence Factors / Q000235:genetics
chemical_list: D037521:Virulence Factors
keywords: Biotrophic pathogen; Claviceps purpurea; Effectors; Host-pathogen interaction; Transcriptome