Selective and powerful stress gene expression in Arabidopsis in response to malondialdehyde.
The provenance, half-life and biological activity of malondialdehyde (MDA) were investigated in Arabidopsis thaliana. We provide genetic confirmation of the hypothesis that MDA originates from fatty acids containing more than two methylene-linked double bonds, showing that tri-unsaturated fatty acids are the in vivo source of up to 75% of MDA. The abundance of the combined pool of free and reversibly bound MDA did not change dramatically in stress, although a significant increase in the free MDA pool under oxidative conditions was observed. The half-life of infiltrated MDA indicated rapid metabolic turnover/sequestration. Exposure of plants to low levels of MDA using a recently developed protocol powerfully upregulated many genes on a cDNA microarray with a bias towards those implicated in abiotic/environmental stress (e.g. ROF1 and XERO2). Remarkably, and in contrast to the activities of other reactive electrophile species (i.e. small vinyl ketones), none of the pathogenesis-related (PR) genes tested responded to MDA. The use of structural mimics of MDA isomers suggested that the propensity of the molecule to act as a cross-linking/modifying reagent might contribute to the activation of gene expression. Changes in the concentration/localisation of unbound MDA in vivo could strongly affect stress-related transcription.
Gene Expression Laboratory, Plant Molecular Biology, University of Lausanne, Biology Building, 1015 Lausanne, Switzerland.
Hans
H
Weber
Aurore
A
Chételat
Philippe
P
Reymond
Edward E
EE
Farmer
D017360:Arabidopsis / Q000187:drug effects* / Q000235:genetics* / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000235:genetics; D003432:Cross-Linking Reagents / Q000494:pharmacology; D004268:DNA-Binding Proteins / Q000235:genetics; D004355:Drug Stability; D005231:Fatty Acids, Unsaturated / Q000378:metabolism; D015870:Gene Expression / Q000187:drug effects; D017343:Genes, Plant / Q000187:drug effects*; D017930:Genes, Reporter; D006207:Half-Life; D006360:Heat-Shock Proteins / Q000235:genetics; D008315:Malondialdehyde / Q000378:metabolism / Q000494:pharmacology*; D009154:Mutation; D020411:Oligonucleotide Array Sequence Analysis; D030821:Plants, Genetically Modified; D015398:Signal Transduction; D022021:Tacrolimus Binding Proteins
D029681:Arabidopsis Proteins; D003432:Cross-Linking Reagents; D004268:DNA-Binding Proteins; D005231:Fatty Acids, Unsaturated; D006360:Heat-Shock Proteins; C102151:ROF1 protein, Arabidopsis; D008315:Malondialdehyde; D022021:Tacrolimus Binding Proteins