Pep1, a Secreted Effector Protein of Ustilago maydis, Is Required for Successful Invasion of Plant Cells

Doehlemann, G., van der Linde, K., Amann, D., Schwammbach, D., Hof, A., Mohanty, A., Jackson, D. P., Kahmann, R. (February 2009) Pep1, a Secreted Effector Protein of Ustilago maydis, Is Required for Successful Invasion of Plant Cells. Plos Pathogens, 5 (2). e1000290. ISSN 1553-7366

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Abstract

The basidiomycete Ustilago maydis causes smut disease in maize. Colonization of the host plant is initiated by direct penetration of cuticle and cell wall of maize epidermis cells. The invading hyphae are surrounded by the plant plasma membrane and proliferate within the plant tissue. We identified a novel secreted protein, termed Pep1, that is essential for penetration. Disruption mutants of pep1 are not affected in saprophytic growth and develop normal infection structures. However, Delta pep1 mutants arrest during penetration of the epidermal cell and elicit a strong plant defense response. Using Affymetrix maize arrays, we identified 116 plant genes which are differentially regulated in Delta pep1 compared to wild type infections. Most of these genes are related to plant defense. By in vivo immunolocalization, live-cell imaging and plasmolysis approaches, we detected Pep1 in the apoplastic space as well as its accumulation at sites of cell-to-cell passages. Site-directed mutagenesis identified two of the four cysteine residues in Pep1 as essential for function, suggesting that the formation of disulfide bridges is crucial for proper protein folding. The barley covered smut fungus Ustilago hordei contains an ortholog of pep1 which is needed for penetration of barley and which is able to complement the U. maydis Delta pep1 mutant. Based on these results, we conclude that Pep1 has a conserved function essential for establishing compatibility that is not restricted to the U. maydis / maize interaction.

Item Type: Paper
Uncontrolled Keywords: CORN SMUT FUNGUS corn smut fungus DISEASE RESISTANCE disease resistance PATHOGENIC DEVELOPMENT pathogenic development VIRULENCE virulence FACTOR factor RXLR EFFECTORS effectors FLAX RUST flax rust INHIBITOR inhibitor GENE DEFENSE TOMATO tomatoe
Subjects: diseases & disorders
organism description > plant > maize
bioinformatics > genomics and proteomics > Mapping and Rendering > Micro Array Data Rendering
bioinformatics > genomics and proteomics > genetics & nucleic acid processing > protein structure, function, modification > protein expression
CSHL Authors:
Communities: CSHL labs > Jackson lab
Depositing User: CSHL Librarian
Date: 6 February 2009
Date Deposited: 03 Apr 2012 20:21
Last Modified: 13 Mar 2018 18:34
PMCID: PMC2631132
Related URLs:
URI: https://repository.cshl.edu/id/eprint/25903

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