The metabolic response of heterotrophic Arabidopsis cells to oxidative stress.
To cope with oxidative stress, the metabolic network of plant cells must be reconfigured either to bypass damaged enzymes or to support adaptive responses. To characterize the dynamics of metabolic change during oxidative stress, heterotrophic Arabidopsis (Arabidopsis thaliana) cells were treated with menadione and changes in metabolite abundance and (13)C-labeling kinetics were quantified in a time series of samples taken over a 6 h period. Oxidative stress had a profound effect on the central metabolic pathways with extensive metabolic inhibition radiating from the tricarboxylic acid cycle and including large sectors of amino acid metabolism. Sequential accumulation of metabolites in specific pathways indicated a subsequent backing up of glycolysis and a diversion of carbon into the oxidative pentose phosphate pathway. Microarray analysis revealed a coordinated transcriptomic response that represents an emergency coping strategy allowing the cell to survive the metabolic hiatus. Rather than attempt to replace inhibited enzymes, transcripts encoding these enzymes are in fact down-regulated while an antioxidant defense response is mounted. In addition, a major switch from anabolic to catabolic metabolism is signaled. Metabolism is also reconfigured to bypass damaged steps (e.g. induction of an external NADH dehydrogenase of the mitochondrial respiratory chain). The overall metabolic response of Arabidopsis cells to oxidative stress is remarkably similar to the superoxide and hydrogen peroxide stimulons of bacteria and yeast (Saccharomyces cerevisiae), suggesting that the stress regulatory and signaling pathways of plants and microbes may share common elements.
Baxter
Charles J
CJ
Department of Plant Sciences, University of Oxford, Oxford OX1 3RB, United Kingdom.
Redestig
Henning
H
Schauer
Nicolas
N
Repsilber
Dirk
D
Patil
Kiran R
KR
Nielsen
Jens
J
Selbig
Joachim
J
Liu
Junli
J
Fernie
Alisdair R
AR
Sweetlove
Lee J
LJ
D017360:Arabidopsis / Q000166:cytology / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000145:classification / Q000235:genetics / Q000378:metabolism; D002247:Carbon Isotopes / Q000032:analysis; D002952:Citric Acid Cycle; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant; D007700:Kinetics; D008954:Models, Biological; D020411:Oligonucleotide Array Sequence Analysis; D018384:Oxidative Stress; D012333:RNA, Messenger / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects; D013997:Time Factors; D024483:Vitamin K 3 / Q000494:pharmacology
D029681:Arabidopsis Proteins; D002247:Carbon Isotopes; D012333:RNA, Messenger; D024483:Vitamin K 3