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Powdery mildew resistance conferred by loss of the ENHANCED DISEASE RESISTANCE1 protein kinase is suppressed by a missense mutation in KEEP ON GOING, a regulator of abscisic acid signaling
- Source :
- Plant physiology. 148(3)
- Publication Year :
- 2008
-
Abstract
- Loss-of-function mutations in the Arabidopsis (Arabidopsis thaliana) ENHANCED DISEASE RESISTANCE1 (EDR1) gene confer enhanced resistance to infection by powdery mildew (Golovinomyces cichoracearum). EDR1 encodes a protein kinase, but its substrates and the pathways regulated by EDR1 are unknown. To identify components of the EDR1 signal transduction pathway(s), we conducted a forward genetic screen for mutations that suppressed edr1-mediated disease resistance. Genetic mapping and cloning of one of these suppressor mutations revealed a recessive missense mutation in the KEEP ON GOING gene (KEG; At5g13530), which we designated keg-4. KEG encodes a multidomain protein that includes a RING E3 ligase domain, a kinase domain, ankyrin repeats, and HERC2-like repeats. The KEG protein has previously been shown to have ubiquitin ligase activity and to negatively regulate protein levels of the transcription factor ABCISIC ACID INSENSITIVE5. KEG mRNA levels were found to be 3-fold higher in edr1 mutant plants compared to wild type. Loss-of-function mutations in KEG are seedling lethal and are hypersensitive to glucose and abscisic acid (ABA). The keg-4 mutation, in contrast, conferred resistance to 6% glucose and suppressed edr1-mediated hypersensitivity to ABA, suggesting that the keg-4 mutation suppresses ABA signaling by altering KEG function. Several ABA-responsive genes were found to be further up-regulated in the edr1 mutant following ABA treatment, and this up-regulation was suppressed by the keg-4 mutation. We conclude that edr1-mediated resistance to powdery mildew is mediated, in part, by enhanced ABA signaling.
- Subjects :
- Physiology
Ubiquitin-Protein Ligases
Mutant
Arabidopsis
Mutation, Missense
Plant Science
medicine.disease_cause
Genes, Plant
Ascomycota
Genetics
medicine
Missense mutation
Arabidopsis thaliana
RNA, Messenger
Protein kinase A
Mutation
biology
Arabidopsis Proteins
Wild type
food and beverages
biology.organism_classification
Ubiquitin ligase
Cell biology
DNA-Binding Proteins
biology.protein
Genetic screen
Abscisic Acid
Signal Transduction
Research Article
Subjects
Details
- ISSN :
- 00320889
- Volume :
- 148
- Issue :
- 3
- Database :
- OpenAIRE
- Journal :
- Plant physiology
- Accession number :
- edsair.doi.dedup.....b18e75704c09339c7d124f262c14588a