The metabolic response of Arabidopsis roots to oxidative stress is distinct from that of heterotrophic cells in culture and highlights a complex relationship between the levels of transcripts, metabolites, and flux.
Metabolic adjustments are a significant, but poorly understood, part of the response of plants to oxidative stress. In a previous study (Baxter et al., 2007), the metabolic response of Arabidopsis cells in culture to induction of oxidative stress by menadione was characterized. An emergency survival strategy was uncovered in which anabolic primary metabolism was largely down-regulated in favour of catabolic and antioxidant metabolism. The response in whole plant tissues may be different and we have therefore investigated the response of Arabidopsis roots to menadione treatment, analyzing the transcriptome, metabolome and key metabolic fluxes with focus on primary as well as secondary metabolism. Using a redox-sensitive GFP, it was also shown that menadione causes redox perturbation, not just in the mitochondrion, but also in the cytosol and plastids of roots. In the first 30 min of treatment, the response was similar to the cell culture: there was a decrease in metabolites of the TCA cycle and amino acid biosynthesis and the transcriptomic response was dominated by up-regulation of DNA regulatory proteins. After 2 and 6 h of treatment, the response of the roots was different to the cell culture. Metabolite levels did not remain depressed, but instead recovered and, in the case of pyruvate, some amino acids and aliphatic glucosinolates showed a steady increase above control levels. However, no major changes in fluxes of central carbon metabolism were observed and metabolic transcripts changed largely independently of the corresponding metabolites. Together, the results suggest that root tissues can recover metabolic activity after oxidative inhibition and highlight potentially important roles for glycolysis and the oxidative pentose phosphate pathway.
Lehmann
Martin
M
Max-Planck Institute for Molecular Plant Physiology, Am Mühlenberg 14476, Potsdam-Golm, Germany.
Schwarzländer
Markus
M
Obata
Toshihiro
T
Sirikantaramas
Supaart
S
Burow
Meike
M
Olsen
Carl Erik
CE
Tohge
Takayuki
T
Fricker
Mark D
MD
Møller
Birger Lindberg
BL
Fernie
Alisdair R
AR
Sweetlove
Lee J
LJ
Laxa
Miriam
M
D017360:Arabidopsis / Q000235:genetics* / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism; D002244:Carbon / Q000378:metabolism*; D002478:Cells, Cultured; D020869:Gene Expression Profiling / Q000379:methods; D018506:Gene Expression Regulation, Plant / Q000187:drug effects / Q000502:physiology; D017343:Genes, Plant / Q000502:physiology; D006019:Glycolysis; D010084:Oxidation-Reduction; D018384:Oxidative Stress / Q000187:drug effects / Q000235:genetics; D018517:Plant Roots / Q000378:metabolism*; D018520:Plant Shoots / Q000378:metabolism; D018087:Plastids / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D018749:RNA, Plant / Q000235:genetics / Q000378:metabolism*; D015854:Up-Regulation / Q000187:drug effects / Q000502:physiology; D024483:Vitamin K 3 / Q000494:pharmacology
D029681:Arabidopsis Proteins; D018749:RNA, Plant; D024483:Vitamin K 3; D002244:Carbon