Nuclear Activity of MLA Immune Receptors Links Isolate-Specific and Basal Disease-Resistance Responses

• Published in: Science (American Association for the Advancement of Science) 2007-02, Vol.315 (5815), p.1098-1103
• Main Authors: Shen, Qian-Hua, Saijo, Yusuke, Mauch, Stefan, Biskup, Christoph, Bieri, Stéphane, Keller, Beat, Seki, Hikaru, Ülker, Bekir, Somssich, Imre E, Schulze-Lefert, Paul
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; Arabidopsis - genetics; Arabidopsis - immunology; Arabidopsis - metabolism; Arabidopsis - microbiology; Arabidopsis Proteins - genetics; Arabidopsis Proteins - metabolism; Ascomycota - growth & development; Ascomycota - immunology; Barley; Biochemistry; Biological and medical sciences; Botany; Cell Nucleus - metabolism; Cytoplasm - metabolism; Epidermal cells; Fluorescence; Fundamental and applied biological sciences. Psychology; Fungal plant pathogens; Fungal Proteins - metabolism; Hordeum - genetics; Hordeum - immunology; Hordeum - metabolism; Hordeum - microbiology; Hordeum vulgare; Immunity, Innate; Immunology; Infections; Inoculation; Molecular Sequence Data; Mutation; Pathogens; Pathology, epidemiology, host-fungus relationships. Damages, economic importance; Phytopathology. Animal pests. Plant and forest protection; Plant cells; Plant Diseases - immunology; Plant Diseases - microbiology; Plant pathology; Plant Proteins - chemistry; Plant Proteins - genetics; Plant Proteins - metabolism; Plants, Genetically Modified; Plasmids; Protein Structure, Tertiary; Proteins; Receptors; Receptors, Immunologic - chemistry; Receptors, Immunologic - genetics; Receptors, Immunologic - metabolism; Receptors, Pattern Recognition - metabolism; Recombinant Fusion Proteins - metabolism; Research Article; Transcription Factors - genetics; Transcription Factors - metabolism; Two-Hybrid System Techniques
• ISSN: 0036-8075; 1095-9203
• DOI: 10.1126/science.1136372

Plant immune responses are triggered by pattern recognition receptors that detect conserved pathogen-associated molecular patterns (PAMPs) or by resistance (R) proteins recognizing isolate-specific pathogen effectors. We show that in barley, intracellular mildew A (MLA) R proteins function in the nucleus to confer resistance against the powdery mildew fungus. Recognition of the fungal avirulence A10 effector by MLA10 induces nuclear associations between receptor and WRKY transcription factors. The identified WRKY proteins act as repressors of PAMP-triggered basal defense. MLA appears to interfere with the WRKY repressor function, thereby de-repressing PAMP-triggered basal defense. Our findings reveal a mechanism by which these polymorphic immune receptors integrate distinct pathogen signals.