Changes in glutathione content during cold acclimation in Cornus sericea and Citrus sinensis

Guy, Charles L.; Carter, John V.; Yelenosky, George; Guy, C.T.

doi:10.1016/0011-2240(84)90082-8

Cited by 38 publications

(21 citation statements)

References 27 publications

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“…decreased temperature [30], 03 [31], UV-light [32], fungal elicitor [33], Cu 2+ [34] and SO2 [35] cause oxidative stress, which is reflected in increased levels of reduced and oxidized glutathione, as well as in a rise in the activity of glutathione reductase. An increase in the GSH level is often preceded by an increase in the level of GSSG.…”

Section: Relationships Between Defensive Metabolismmentioning

confidence: 99%

Nicotinamide, a missing link in the early stress response in eukaryotic cells: A hypothesis with special reference to oxidative stress in plants

Berglund

1994

FEBS Letters

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A hypothesis is presented suggesting that nicotinamide (NIC) is an initial signal substance in the response of eukaryotic cells to conditions which cause DNA-strand breakage, especially in connection with oxidative stress. In the stressed cell, NIC is released as a result of the activity of poly(ADP-ribose)polymerase (PADPRP). PADPRP is known to be activated by DNA-strand breakage, caused by e.g. oxidative stress or mutagens. NIC and its metabolite trigonelline (N-methylnicotinic acid) can induce defensive metabolism at the gene level. Connections between NIC and DNA-methylation are also considered. This hypothesis is discussed in the light of own observations and literature reports.

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Section: Relationships Between Defensive Metabolismmentioning

confidence: 99%

Nicotinamide, a missing link in the early stress response in eukaryotic cells: A hypothesis with special reference to oxidative stress in plants

Berglund

1994

FEBS Letters

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“…The NADPH and GSSG concentrations ranged from 1 to 100 uM and 5 to 200 ,M, respectively. The Km values also were obtained for GR at 5,10,15,20,30, and 40°C using the procedure described by Mahan et al (20), which consisted of a 1 x 5 matrix of GSSG and NADPH, respectively. Initial velocities were calculated over the first 30 s of the assay using 0.04 units of GR.…”

Section: Purification and Analysis Of Glutathione Reductase (Ec 1642)mentioning

confidence: 99%

“…Also, because GR levels are at their lowest during the summer months, the enzyme provides less antioxidant protection during periods of high temperature stress than low temperature stress. Reports ofincreased GSSG levels during exposure to low temperatures, specifically in soybean (25), citrus (15), and cucumber (27), were made using "warm weather plants." Such plants have TKWs for GR that generally range between 22 and 40°C (20) and, therefore, enzyme affinity for GSSG is lower at the temperatures conducive to cold stress.…”

Section: Temperature Versus Km For Glutathione Reductasementioning

confidence: 99%

“…However, some cold-hardened species demonstrate a resistance to photoinhibition that may result from increased metabolism of active oxygen scavengers (16). Cold acclimation has been associated with increased levels of ascorbate (8,11,24), ascorbate peroxidase (11,21,24), dehydroascorbate reductase (11,21), ascorbate free radical reductase (21,24), glutathione (8)(9)(10)15), glutathione reductase (9,10,14,23), and superoxide dismutase (3,24). These metabolites and enzymes are all components of the chloroplast antioxidant system that functions in the scavenging of oxygen free radicals and H202 (1).…”

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confidence: 99%

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Seasonal Variation in the Antioxidant System of Eastern White Pine Needles

Anderson

Chevone²,

Hess³

1992

Plant Physiol.

253

104

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Antioxidant metabolites in eastem white pine (Pinus strobus L.) needles increased two-to fourfold from the summer to the winter season. Antioxidant enzymes in needle tissue increased between 2-and 122-fold during this same period. These seasonal changes were determined by monitoring ascorbate and glutathione concentrations and the activity of ascorbate peroxidase, glutathione reductase (GR), and superoxide dismutase. Levels of antioxidant metabolites and enzymes were observed always to be lowest during the summer, or active growing season, and highest during the winter, or dormant season. These data correlated well with the thermal kinetic window for purified GR obtained from summer needles. The minimum, apparent KmDm for two isoforms of GR (GRA and GRo) occurred at 5 and 10°C, respectively. The upper limit of the thermal kinetic window (200% of the minimum K.) for GRA and GRB was 20 and 250C, respectively, indicating that needle temperatures exceeding 250C may result in impairment of antioxidant metabolism. The needle content and kinetic properties of GR, the increased activities of other enzymes, and the high substrate concentrations observed during the winter are consistent with the protective function this pathway may provide against photooxidative, winter injury.

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“…The most sensitive species have little freezing tolerance (LT502 -2°C) and no significant capacity to undergo cold acclimation (3,34). More hardy species have modest freezing tolerance (LT5o -3 to -6°C) and some capacity to increase freezing tolerance during cold acclimation (1,3,10,12,22). For example, the commercially important sweet orange, C. sinensis, has the ability to increase in freezing tolerance during cold acclimation.…”

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confidence: 99%

Freezing Tolerance of Citrus, Spinach, and Petunia Leaf Tissue

Yelenosky¹,

Guy²

1989

Plant Physiol.

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Seasonal variations in freezing tolerance, water content, water and osmotic potential, and levels of soluble sugars of leaves of field-grown Valencia orange (Citrus sinensis) trees were studied to determine the ability of citrus trees to cold acclimate under natural conditions. Controlled environmental studies of young potted citrus trees, spinach (Spinacia pleracea), and petunia (Petunia hybrids) were carried out to study the water relations during cold acclimation under less variable conditions. During the coolest weeks of the winter, leaf water content and osmotic potential of field-grown trees decreased about 20 to 25%, while soluble sugars increased by 100%. At the same time, freezing tolerance increased from lethal temperature for 50% (LTso) of -2.8 to -3.80C. In contrast, citrus leaves cold acclimated at a constant 100C in growth chambers were freezing tolerant to about -60C. The calculated freezing induced cellular dehydration at the LT5o remained relatively constant for field-grown leaves throughout the year, but increased for leaves of plants cold acclimated at 100C in a controlled environment. Spinach leaves cold acclimated at 50C tolerated increased cellular dehydration compared to nonacclimated leaves. Cold acclimated petunia leaves increased in freezing tolerance by decreasing osmotic potential, but had no capacity to change cellular dehydration sensitivity. The result suggest that two cold acclimation mechanisms are involved in both citrus and spinach leaves and only one in petunia leaves. The common mechanism in all three species tested was a minor increase in tolerance (about -10C) resulting from low temperature induced osmotic adjustment, and the second in citrus and spinach was a noncolligative mechanism that increased the cellular resistance to freeze hydration.During extracellular freezing, ice first forms in the dilute apoplastic solution and a water potential gradient is established between the extracellular ice crystal and the intracellular liquid water. The lower water potential of ice as compared to that of liquid cellular water at the same temperature will cause liquid water to move from the cell to the extracellular ice (19). This process, depending on the temperature and concentration of the cell sap imposes a dehydration stress 'Part of this work was supported by a U.S. Department of Agriculture competitive research grant 85-CRCR-1-1649. University of Florida Agricultural Experiment Station Technical paper 8889. on the cell. When the cellular water potential of the partially dehydrated cell equals that of the extracellular ice, an equilibrium is established and further dehydration will not occur provided the temperature remains constant (15,23). If the temperature further declines or increases, water will flow out of or back into the cell. During such equilibrium freezing a tissue can behave either as an ideal solution or as a nonideal solution (15,23). In nonideal equilibrium freezing, negative wall pressure is believed to reduce the degree of cell dehydration and solute co...

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Changes in glutathione content during cold acclimation in Cornus sericea and Citrus sinensis

Cited by 38 publications

References 27 publications

Nicotinamide, a missing link in the early stress response in eukaryotic cells: A hypothesis with special reference to oxidative stress in plants

Nicotinamide, a missing link in the early stress response in eukaryotic cells: A hypothesis with special reference to oxidative stress in plants

Seasonal Variation in the Antioxidant System of Eastern White Pine Needles

Freezing Tolerance of Citrus, Spinach, and Petunia Leaf Tissue

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