Effect of Low Temperature on the Glutathione Status of Plant Cells

Guy, Charles L.; Carter, J.V.

doi:10.1016/b978-0-12-447602-8.50017-9

Cited by 14 publications

(7 citation statements)

References 21 publications

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“…N deprivation can result in a metabolic imbalance of reactive oxygen species (ROS) and an excess of oxygen radicals [ 36 ], while glutathione can quench free radicals and then improve the resistance of the cells to this stress [ 37 ]. Therefore, the increased expression of SAS could play a role in providing glutathione to improve stress resistance arising during N deficiency.…”

Section: Resultsmentioning

confidence: 99%

Proteomics analysis of high lipid-producing strain Mucor circinelloides WJ11: an explanation for the mechanism of lipid accumulation at the proteomic level

et al. 2016

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BackgroundThe oleaginous fungus, Mucor circinelloides, is attracting considerable interest as it produces oil rich in γ-linolenic acid. Nitrogen (N) deficiency is a common strategy to trigger the lipid accumulation in oleaginous microorganisms. Although a simple pathway from N depletion in the medium to lipid accumulation has been elucidated at the enzymatic level, global changes at protein levels upon N depletion have not been investigated. In this study, we have systematically analyzed the changes at the levels of protein expression in M. circinelloides WJ11, a high lipid-producing strain (36 %, lipid/cell dry weight), during lipid accumulation.ResultsProteomic analysis demonstrated that N depletion increased the expression of glutamine synthetase, involved in ammonia assimilation, for the supply of cellular nitrogen but decreased the metabolism of amino acids. Upon N deficiency, many proteins (e.g., fructose-bisphosphate aldolase, glyceraldehyde-3-phosphate dehydrogenase, enolase, pyruvate kinase) involved in glycolytic pathway were up-regulated while proteins involved in the tricarboxylic acid cycle (e.g., isocitrate dehydrogenase, succinyl-CoA ligase, succinate dehydrogenase, fumarate hydratase) were down-regulated, indicating this activity was retarded thereby leading to a greater flux of carbon into fatty acid biosynthesis. Moreover, glucose-6-phosphate dehydrogenase, transaldolase and transketolase, which participate in the pentose phosphate pathway, were up-regulated, leading to the increased production of NADPH, the reducing power for fatty acid biosynthesis. Furthermore, protein and nucleic acid metabolism were down-regulated and some proteins involved in energy metabolism, signal transduction, molecular chaperone and redox homeostasis were up-regulated upon N depletion, which may be the cellular response to the stress produced by the onset of N deficiency.ConclusionN limitation increased those expressions of the proteins involved in ammonia assimilation but decreased that involved in the biosynthesis of amino acids. Upon N deprivation, the glycolytic pathway was up-regulated, while the activity of the tricarboxylic acid cycle was retarded, thus, leading more carbon flux to fatty acid biosynthesis. Moreover, the pentose phosphate pathway was up-regulated, then this would increase the production of NADPH. Together, coordinated regulation of central carbon metabolism upon N limitation, provides more carbon flux to acetyl-CoA and NADPH for fatty acid biosynthesis.Electronic supplementary materialThe online version of this article (doi:10.1186/s12934-016-0428-4) contains supplementary material, which is available to authorized users.

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Section: Resultsmentioning

confidence: 99%

Proteomics analysis of high lipid-producing strain Mucor circinelloides WJ11: an explanation for the mechanism of lipid accumulation at the proteomic level

et al. 2016

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“…Increased levels of glutathione reductase activity were observed in leaf extracts from spinach (Spinacia oleracea L.) in response to frosthardening (4,12). In addition, leaves from both corn (Zea mays L.) and cotton (Gossypium herbaceum L.) exposed to a 75% oxygen concentration showed a 2-to 3-fold increase in glutathione reductase activity within 48 h (9,10).…”

Section: Grmentioning

confidence: 87%

Effect of Water Stress on the Chloroplast Antioxidant System

Gamble¹,

Burke²

1984

Plant Physiol.

135

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The effect of water stress on glutathione reductase and catalase activities was evaluated in leaf blades of field-grown winter wheat (Triticum aestirum L.). Wheat was sown at two seeding rates under both irrigated and dryland conditions. Flag leaves from dryland plants sown at 60 kilograms/hectare showed no change in either glutathione reductase or catalase activities per unit leaf area, while leaves from the basal portion of the canopy exhibited a 273% increase in glutathione reductase activity and a 60% increase in catalase activity. Glutathione reductase activity in dryland plants sown at 120 kilograms/hectare increased 25% in flag leaves and 225% in basal leaves. No change in catalase activity was observed in either flag or basal leaves from these same plants. The increase in glutathione reductase activity in response to water stress was observed when activity was expressed on either a per unit leaf area, protein, or chlorophyll basis. No change in catalase activity was detected when enzyme activity was expressed on a protein basis.The midday closure ofstomates (20) in response to water stress may optimize the water use efficiency of the plant on a daily basis (3), yet result in a reduction in CO2 assimilation at times when peak irradiances are commonly encountered. Because of stomatal closure, CO2 fixation is low while photosynthetic electron transport is operating at normal rates. Under these conditions, limited quantities of NADP are available to accept electrons, therefore oxygen can function as an alternative electron acceptor (6). Although this pseudocyclic pathway for electron transport provides additional ATP (15), it can result in the production of superoxide and H202.Superoxide and H202 are toxic oxygen molecules and upon reaction with chloroplast components can form even more reactive oxygen products such as the hydroxyl radical (7) and singlet oxygen (19). These toxic products produced within the chloroplast must be effectively removed to prevent lipid peroxidation, inhibition of C02-fixation, and the photooxidation of chloroplast pigments.Photosynthetic cells can tolerate elevated oxygen levels because of the presence of several endogenous protective mechanisms including glutathione, ascorbate, carotenoids, and enzymes which effectively scavenge and remove the toxic products before cellular damage occurs (13). Plant cells contain millimolar concentrations of reduced glutathione (GSH) which can prevent the inactivation of enzymes by oxidation of essential thiol groups.Because of the availability of GSH, it can be preferentially oxidized thereby protecting the enzymes from inactivation. GSH can also reduce an oxidized sulthydryl group thereby reactivating certain enzymes. When GSH reacts with oxygen, the glutathione is oxidized to form glutathione disulfide (GSSG). The subsequent re-reduction of GSSG to GSH is catalyzed by the enzyme glutathione reductase in an NADPH-dependent reaction. Glutathione reductase, therefore, plays an essential role in the protection of chloroplasts against oxid...

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“…As antioxidants belong to the plant cryoprotectant pool, they provide reducing power to stabilize the membranes and structures of macromolecules under such conditions as frost, which is favorable for free radical formation. Therefore, it is not surprising that antioxidant activities and concentrations increase toward winter (Levitt, 1972;Esterbauer and Grill, 1978;Guy and Carter, 1982;De Kok and Stulen, 1993;Kunert and Foyer, 1993;Polle et al, 1996). Frost hardiness in bilberry stems from the Abisko treatment was consistently lower in plants grown under enhanced UV-B radiation, and the plants also showed lower ascorbate and glutathione concentrations and lower enzymatic activity of ascorbate peroxidase in September (Taulavuori et al, 1998).…”

Section: Discussionmentioning

confidence: 99%