Dehydroascorbate Influences the Plant Cell Cycle through a Glutathione-Independent Reduction Mechanism

• Published in: Plant physiology (Bethesda) 2004-04, Vol.134 (4), p.1479-1487
• Main Authors: Geert Potters, Nele Horemans, Silvia Bellone, Roland J. Caubergs, Paolo Trost, Guisez, Yves, Asard, Han
• Format: Article
• Language: English
• Subjects: Animal cells; Apoptosis - drug effects; Biological and medical sciences; Biosynthesis; Cell biochemistry; Cell Biology and Signal Transduction; Cell cycle; Cell Cycle - drug effects; Cell Cycle - physiology; Cell growth; Cell kinetics; Cell lines; Cell physiology; Cells, Cultured; Cultured cells; Dehydroascorbic Acid - metabolism; Dehydroascorbic Acid - pharmacology; Fundamental and applied biological sciences. Psychology; Glutathione - metabolism; Glutathione Reductase; Molecular and cellular biology; NADH, NADPH Oxidoreductases - antagonists & inhibitors; NADH, NADPH Oxidoreductases - metabolism; Nitrosourea Compounds - pharmacology; Oxidation-Reduction - drug effects; Oxidative stress; Plant cells; Plant physiology and development; Plant roots; Plants; Plants - drug effects; Plants - genetics; Plants - metabolism; Plasma membrane and permeation; Signal transduction; Synergistic effect; Thioredoxin-Disulfide Reductase
• ISSN: 0032-0889; 1532-2548
• DOI: 10.1104/pp.103.033548

Glutathione is generally accepted as the principal electron donor for dehydroascorbate (DHA) reduction. Moreover, both glutathione and DHA affect cell cycle progression in plant cells. But other mechanisms for DHA reduction have been proposed. To investigate the connection between DHA and glutathione, we have evaluated cellular ascorbate and glutathione concentrations and their redox status after addition of dehydroascorbate to medium of tobacco (Nicotiana tabacum) L. cv Bright Yellow-2 (BY-2) cells. Addition of 1 mM DHA did not change the endogenous glutathione concentration. Total glutathione depletion of BY-2 cells was achieved after 24-h incubation with 1 mM of the glutathione biosynthesis inhibitor L-buthionine sulfoximine. Even in these cells devoid of glutathione, complete uptake and internal reduction of 1 mM DHA was observed within 6 h, although the initial reduction rate was slower. Addition of DHA to a synchronized BY-2 culture, or depleting its glutathione content, had a synergistic effect on cell cycle progression. Moreover, increased intracellular glutathione concentrations did not prevent exogenous DHA from inducing a cell cycle shift. It is therefore concluded that, together with a glutathione-driven DHA reduction, a glutathione-independent pathway for DHA reduction exists in vivo, and that both compounds act independently in growth control.