Arabidopsis DMR6 encodes a putative 2OG-Fe(II) oxygenase that is defense-associated but required for susceptibility to downy mildew.
The Arabidopsis mutant downy mildew resistant 6 (dmr6) carries a recessive mutation that results in the loss of susceptibility to Hyaloperonospora parasitica. Here we describe the map-based cloning of DMR6 (At5g24530), which was found to encode a 2-oxoglutarate (2OG)-Fe(II) oxygenase of unknown function. DMR6 transcription is locally induced during infections with both compatible and incompatible H. parasitica isolates. High DMR6 transcript levels were also observed in constitutive defense mutants and after treatment with salicylic acid analog BTH, suggesting that DMR6 has a role during plant defense. Expression analysis of dmr6 mutants, using DNA microarrays and quantitative PCR, showed the enhanced expression of a subset of defense-associated genes, including DMR6 itself, suggesting dmr6-mediated resistance results from the activation of plant defense responses. Alternatively, resistance could be caused by the accumulation of a toxic DMR6 substrate, or by the absence of a DMR6 metabolic product that is required for H. parasitica infection.
van Damme
Mireille
M
Plant-Microbe Interactions, Department of Biology, Science Faculty, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands.
Huibers
Robin P
RP
Elberse
Joyce
J
Van den Ackerveken
Guido
G
D017360:Arabidopsis / Q000235:genetics* / Q000382:microbiology; D029681:Arabidopsis Proteins / Q000235:genetics*; D001483:Base Sequence; D017931:DNA Primers; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D007658:Ketone Oxidoreductases / Q000235:genetics*; D020411:Oligonucleotide Array Sequence Analysis; D009868:Oomycetes / Q000502:physiology*; D030821:Plants, Genetically Modified; D016133:Polymerase Chain Reaction; D011401:Promoter Regions, Genetic; D014158:Transcription, Genetic
D029681:Arabidopsis Proteins; D017931:DNA Primers; D007658:Ketone Oxidoreductases; C023096:2-oxoglutarate synthase