Glutathione depletion due to copper-induced phytochelatin synthesis causes oxidative stress in Silene cucubalus

Journal Article · Sun Mar 01 00:00:00 EST 1992 · Plant Physiology; (United States)

DOI:https://doi.org/10.1104/pp.98.3.853· OSTI ID:7302607

Ric De Vos, C H; Vonk, M J; Vooijs, R; Schat, H ^[1]

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1. Free Univ. of Amsterdam, (Netherlands)

The relation between loss of glutathione due to metal-induced phytochelatin synthesis and oxidative stress was studied in the roots of copper-sensitive and tolerant Silene cucubalus (L.) Wib., resistant to 1 and 40 micromolar Cu, respectively. The amount of nonprotein sulfhydryl compounds other then glutathione was taken as a measure of phytochelatins. At a supply of 20 micromolar Cu, which is toxic for sensitive plants only, phytochelatin synthesis and loss of total glutathione were observed only in sensitive plants within 6 h of exposure. When the plants were exposed to a range of copper concentrations for 3 d, a marked production of phytochelatins in sensitive plants was already observed at 0.5 micromolar Cu, whereas the production in tolerant plants was negligible at 40 micromolar or lower. The highest production in tolerant plants was only 40% of that in sensitive plants. In both varieties, the synthesis of phytochelatins was coupled to a loss of glutathione. Copper at toxic concentrations caused oxidative stress, as was evidenced by both the accumulation of lipid peroxidation products and a shift in the glutathione redox couple to a more oxidized state. Depletion of glutathione by pretreatment with buthionine sulfoximine significantly increased the oxidative damage by copper. At a comparably low glutathione level, cadmium had no effect on either lipid peroxidation or the glutathione redox couple in buthionine sulfoximine-treated plants. These results indicate that copper may specifically cause oxidative stress by depletion of the antioxidant glutathione due to phytochelatin synthesis.

• OSTI ID: 7302607
• Journal Information: Plant Physiology; (United States), Vol. 98:3; ISSN 0032-0889
• Country of Publication: United States
• Language: English

Related Subjects

63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
COPPER
TOXICITY
GLUTATHIONE
BIOCHEMICAL REACTION KINETICS
BIOLOGICAL STRESS
CADMIUM
HERBS
LIPIDS
OXIDATION
ROOTS
SENSITIVITY
THIOLS
CHEMICAL REACTIONS
DRUGS
ELEMENTS
KINETICS
METALS
ORGANIC COMPOUNDS
ORGANIC SULFUR COMPOUNDS
PEPTIDES
PLANTS
POLYPEPTIDES
PROTEINS
RADIOPROTECTIVE SUBSTANCES
REACTION KINETICS
TRANSITION ELEMENTS
560300* - Chemicals Metabolism & Toxicology