atypical resistance gene, RPW8, recruits components of basal defence for powdery mildew resistance in Arabidopsis

• Published in: The Plant journal : for cell and molecular biology 2005-04, Vol.42 (1), p.95-110
• Main Authors: Xiao, S, Calis, O, Patrick, E, Zhang, G, Charoenwattana, P, Muskett, P, Parker, J.E, Turner, J.G
• Format: Article
• Language: English
• Subjects: Agronomy. Soil science and plant productions; Arabidopsis; Arabidopsis - genetics; Arabidopsis - immunology; Arabidopsis Proteins - genetics; Arabidopsis Proteins - physiology; Arabidopsis thaliana; basal resistance; Biological and medical sciences; carboxylic ester hydrolases; disease resistance; DNA-binding proteins; edr1; enhanced disease resistance 1 protein; enhanced disease susceptibility 1 protein; enhanced disease susceptibility 5 protein; Erysiphe cichoracearum; Erysiphe cruciferarum; Erysiphe orontii; ethylene; Fundamental and applied biological sciences. Psychology; gene expression regulation; Gene Expression Regulation, Plant - physiology; Genes; Genetics and breeding of economic plants; hypersensitive response; Immunity, Innate - genetics; jasmonic acid; mitogen-activated protein kinase kinase kinase; Oidium; Oidium lycopersici; Pest resistance; Phenotype; phytoalexin deficient 4 protein; Plant Diseases - microbiology; Plant Leaves - microbiology; Plant Leaves - physiology; plant pathogenic fungi; Plant pathogens; Plant pathology; plant proteins; Plant resistance; Plants, Genetically Modified; powdery mildew; protein kinases; Proteins; resistance gene; resistance mechanisms; RPW8; salicylic acid; Signal Transduction; transcription (genetics); Transcription, Genetic - physiology; transgenic plants; transmembrane proteins; transporters; Varietal selection. Specialized plant breeding, plant breeding aims
• ISSN: 0960-7412; 1365-313X
• DOI: 10.1111/j.1365-313X.2005.02356.x

Genetic studies have identified a number of components of signal transduction pathways leading to plant disease resistance and the accompanying hypersensitive response (HR) following detection of pathogens by plant resistance (R) genes. In Arabidopsis, the majority of R proteins so far characterized belong to a plant superfamily that have a central nucleotide-binding site and C-terminal leucine-rich-repeats (NB-LRRs). Another much less prevalent class comprises RPW8.1 and RPW8.2, two related proteins that possess a putative N-terminal transmembrane domain and a coiled-coil motif, and confer broad-spectrum resistance to powdery mildew. Here we investigated whether RPW8.1 and RPW8.2 engage known pathway(s) for defence signalling. We show that RPW8.1 and RPW8.2 recruit, in addition to salicylic acid and EDS1, the other NB-LRR gene-signalling components PAD4, EDS5, NPR1 and SGT1b for activation of powdery mildew resistance and HR. In contrast, NDR1, RAR1 and PBS3 that are required for function of certain NB-LRR R genes, and COI1 and EIN2 that operate, respectively, in the jasmonic acid and ethylene signalling pathways, do not contribute to RPW8.1 and RPW8.2-mediated resistance. We further demonstrate that EDR1, a gene encoding a conserved MAPKK kinase, exerts negative regulation on HR cell death and powdery mildew resistance by limiting the transcriptional amplification of RPW8.1 and RPW8.2. Our results suggest that RPW8.1 and RPW8.2 stimulate a conserved basal defence pathway that is negatively regulated by EDR1.