TY  - JOUR
AU  - Pastori, GM
AU  - Kiddle, G
AU  - Antoniw, J
AU  - Bernard, S
AU  - Veljović-Jovanović, Sonja
AU  - Verrier, PJ
AU  - Noctor, G
AU  - Foyer, CH
PY  - 2003
UR  - http://rimsi.imsi.bg.ac.rs/handle/123456789/87
AB  - Vitamin C deficiency in the Arabidopsis mutant vtc1 causes slow growth and late flowering. This is not attributable to changes in photosynthesis or increased oxidative stress. We have used the vtc1 mutant to provide a molecular signature for vitamin C deficiency in plants. Using statistical analysis, we show that 171 genes are expressed differentially in vtc1 compared with the wild type. Many defense genes are activated, particularly those that encode pathogenesis-related proteins. Furthermore, transcript changes indicate that growth and development are constrained in vtc1 by the modulation of abscisic acid signaling. Abscisic acid contents are significantly higher in vtc1 than in the wild type. Key features of the molecular signature of ascorbate deficiency can be reversed by incubating vtc1 leaf discs in ascorbate. This finding provides evidence that many of the observed effects on transcript abundance in vtc1 result from ascorbate deficiency. Hence, through modifying gene expression, vitamin C contents not only act to regulate defense and survival but also act via phyto-hormones to modulate plant growth under optimal conditions.
PB  - Amer Soc Plant Biologists, Rockville
T2  - Plant Cell
T1  - Leaf vitamin C contents modulate plant defense transcripts and regulate genes that control development through hormone signaling
EP  - 951
IS  - 4
SP  - 939
VL  - 15
DO  - 10.1105/tpc.010538
ER  - 

@article{
author = "Pastori, GM and Kiddle, G and Antoniw, J and Bernard, S and Veljović-Jovanović, Sonja and Verrier, PJ and Noctor, G and Foyer, CH",
year = "2003",
abstract = "Vitamin C deficiency in the Arabidopsis mutant vtc1 causes slow growth and late flowering. This is not attributable to changes in photosynthesis or increased oxidative stress. We have used the vtc1 mutant to provide a molecular signature for vitamin C deficiency in plants. Using statistical analysis, we show that 171 genes are expressed differentially in vtc1 compared with the wild type. Many defense genes are activated, particularly those that encode pathogenesis-related proteins. Furthermore, transcript changes indicate that growth and development are constrained in vtc1 by the modulation of abscisic acid signaling. Abscisic acid contents are significantly higher in vtc1 than in the wild type. Key features of the molecular signature of ascorbate deficiency can be reversed by incubating vtc1 leaf discs in ascorbate. This finding provides evidence that many of the observed effects on transcript abundance in vtc1 result from ascorbate deficiency. Hence, through modifying gene expression, vitamin C contents not only act to regulate defense and survival but also act via phyto-hormones to modulate plant growth under optimal conditions.",
publisher = "Amer Soc Plant Biologists, Rockville",
journal = "Plant Cell",
title = "Leaf vitamin C contents modulate plant defense transcripts and regulate genes that control development through hormone signaling",
pages = "951-939",
number = "4",
volume = "15",
doi = "10.1105/tpc.010538"
}

Pastori, G., Kiddle, G., Antoniw, J., Bernard, S., Veljović-Jovanović, S., Verrier, P., Noctor, G.,& Foyer, C.. (2003). Leaf vitamin C contents modulate plant defense transcripts and regulate genes that control development through hormone signaling. in Plant Cell
Amer Soc Plant Biologists, Rockville., 15(4), 939-951.
https://doi.org/10.1105/tpc.010538

Pastori G, Kiddle G, Antoniw J, Bernard S, Veljović-Jovanović S, Verrier P, Noctor G, Foyer C. Leaf vitamin C contents modulate plant defense transcripts and regulate genes that control development through hormone signaling. in Plant Cell. 2003;15(4):939-951.
doi:10.1105/tpc.010538 .

Pastori, GM, Kiddle, G, Antoniw, J, Bernard, S, Veljović-Jovanović, Sonja, Verrier, PJ, Noctor, G, Foyer, CH, "Leaf vitamin C contents modulate plant defense transcripts and regulate genes that control development through hormone signaling" in Plant Cell, 15, no. 4 (2003):939-951,
https://doi.org/10.1105/tpc.010538 . .

TY  - JOUR
AU  - Foyer, CH
AU  - Pastori, GM
AU  - Kiddle, G
AU  - Antoniw, J
AU  - Bernard, S
AU  - Veljović-Jovanović, Sonja
AU  - Noctor, G
AU  - Verrier, PJ
PY  - 2002
UR  - http://rimsi.imsi.bg.ac.rs/handle/123456789/76
PB  - Elsevier Science Inc, New York
T2  - Free Radical Biology and Medicine
T1  - Vitamin C contents modulate defence and plant development via transcriptional regulation.
EP  - S170
SP  - S170
VL  - 33
UR  - https://hdl.handle.net/21.15107/rcub_rimsi_76
ER  - 

@article{
author = "Foyer, CH and Pastori, GM and Kiddle, G and Antoniw, J and Bernard, S and Veljović-Jovanović, Sonja and Noctor, G and Verrier, PJ",
year = "2002",
publisher = "Elsevier Science Inc, New York",
journal = "Free Radical Biology and Medicine",
title = "Vitamin C contents modulate defence and plant development via transcriptional regulation.",
pages = "S170-S170",
volume = "33",
url = "https://hdl.handle.net/21.15107/rcub_rimsi_76"
}

Foyer, C., Pastori, G., Kiddle, G., Antoniw, J., Bernard, S., Veljović-Jovanović, S., Noctor, G.,& Verrier, P.. (2002). Vitamin C contents modulate defence and plant development via transcriptional regulation.. in Free Radical Biology and Medicine
Elsevier Science Inc, New York., 33, S170-S170.
https://hdl.handle.net/21.15107/rcub_rimsi_76

Foyer C, Pastori G, Kiddle G, Antoniw J, Bernard S, Veljović-Jovanović S, Noctor G, Verrier P. Vitamin C contents modulate defence and plant development via transcriptional regulation.. in Free Radical Biology and Medicine. 2002;33:S170-S170.
https://hdl.handle.net/21.15107/rcub_rimsi_76 .

Foyer, CH, Pastori, GM, Kiddle, G, Antoniw, J, Bernard, S, Veljović-Jovanović, Sonja, Noctor, G, Verrier, PJ, "Vitamin C contents modulate defence and plant development via transcriptional regulation." in Free Radical Biology and Medicine, 33 (2002):S170-S170,
https://hdl.handle.net/21.15107/rcub_rimsi_76 .

TY  - JOUR
AU  - Noctor, G
AU  - Veljović-Jovanović, Sonja
AU  - Driscoll, S
AU  - Novitskaya, L
AU  - Foyer, CH
PY  - 2002
UR  - http://rimsi.imsi.bg.ac.rs/handle/123456789/74
AB  - Although active oxygen species are produced at high rates in both the chloroplasts and peroxisomes of the leaves Of C-3 plants, most attention has focused on the potentially damaging consequences of enhanced chloroplastic production in stress conditions such as drought. This article attempts to provide quantitative estimates of the relative contributions of the chloroplast electron transport chain and the glycolate oxidase reaction to the oxidative load placed on the photosynthetic leaf cell. Rates of photorespiratory H2O2 production were obtained from photosynthetic and photorespiratory flux rates, derived from steady-state leaf gas exchange measurements at varying irradiance and ambient CO2. Assuming a 10 % allocation of photosynthetic electron flow to the Mehler reaction, photorespiratory H2O2 production would account for about 70 % of total H2O2 formed at all irradiances measured. When chloroplastic CO2 concentration rates are decreased, photorespiration becomes even more predominant in H2O2 generation. At the increased flux through photorespiration observed at lower ambient CO2, the Mehler reaction would have to account for more than 35 % of the total photosynthetic electron flow in order to match the rate of peroxisomal H2O2 production. The potential signalling role of H2O2 produced in the peroxisomes is emphasized, and it is demonstrated that photorespiratory H2O2 can perturb the redox states of leaf antioxidant pools. We discuss the interactions between oxidants, antioxidants and redox changes leading to modified gene expression, particularly in relation to drought, and call attention to the potential significance of photorespiratory H2O2 in signalling and acclimation.
PB  - Oxford Univ Press, Oxford
T2  - Annals of Botany
T1  - Drought and oxidative load in the leaves of C-3 plants: a predominant role for photorespiration?
EP  - 850
SP  - 841
VL  - 89
DO  - 10.1093/aob/mcf096
ER  - 

@article{
author = "Noctor, G and Veljović-Jovanović, Sonja and Driscoll, S and Novitskaya, L and Foyer, CH",
year = "2002",
abstract = "Although active oxygen species are produced at high rates in both the chloroplasts and peroxisomes of the leaves Of C-3 plants, most attention has focused on the potentially damaging consequences of enhanced chloroplastic production in stress conditions such as drought. This article attempts to provide quantitative estimates of the relative contributions of the chloroplast electron transport chain and the glycolate oxidase reaction to the oxidative load placed on the photosynthetic leaf cell. Rates of photorespiratory H2O2 production were obtained from photosynthetic and photorespiratory flux rates, derived from steady-state leaf gas exchange measurements at varying irradiance and ambient CO2. Assuming a 10 % allocation of photosynthetic electron flow to the Mehler reaction, photorespiratory H2O2 production would account for about 70 % of total H2O2 formed at all irradiances measured. When chloroplastic CO2 concentration rates are decreased, photorespiration becomes even more predominant in H2O2 generation. At the increased flux through photorespiration observed at lower ambient CO2, the Mehler reaction would have to account for more than 35 % of the total photosynthetic electron flow in order to match the rate of peroxisomal H2O2 production. The potential signalling role of H2O2 produced in the peroxisomes is emphasized, and it is demonstrated that photorespiratory H2O2 can perturb the redox states of leaf antioxidant pools. We discuss the interactions between oxidants, antioxidants and redox changes leading to modified gene expression, particularly in relation to drought, and call attention to the potential significance of photorespiratory H2O2 in signalling and acclimation.",
publisher = "Oxford Univ Press, Oxford",
journal = "Annals of Botany",
title = "Drought and oxidative load in the leaves of C-3 plants: a predominant role for photorespiration?",
pages = "850-841",
volume = "89",
doi = "10.1093/aob/mcf096"
}

Noctor, G., Veljović-Jovanović, S., Driscoll, S., Novitskaya, L.,& Foyer, C.. (2002). Drought and oxidative load in the leaves of C-3 plants: a predominant role for photorespiration?. in Annals of Botany
Oxford Univ Press, Oxford., 89, 841-850.
https://doi.org/10.1093/aob/mcf096

Noctor G, Veljović-Jovanović S, Driscoll S, Novitskaya L, Foyer C. Drought and oxidative load in the leaves of C-3 plants: a predominant role for photorespiration?. in Annals of Botany. 2002;89:841-850.
doi:10.1093/aob/mcf096 .

Noctor, G, Veljović-Jovanović, Sonja, Driscoll, S, Novitskaya, L, Foyer, CH, "Drought and oxidative load in the leaves of C-3 plants: a predominant role for photorespiration?" in Annals of Botany, 89 (2002):841-850,
https://doi.org/10.1093/aob/mcf096 . .

TY  - JOUR
AU  - Veljović-Jovanović, Sonja
AU  - Noctor, G
AU  - Foyer, CH
PY  - 2002
UR  - http://rimsi.imsi.bg.ac.rs/handle/123456789/72
AB  - We have examined the authenticity of two methods for determination of H2O2 in leaf tissue. We show that the high concentrations of ascorbic acid present in leaf extracts interfere with both techniques. In the chromogenic peroxidase-coupled assay, H2O2 is determined by oxidation of 3-methyl-2-benzothiazoline hydrazone (MBTH) and 3-(dimethylamino) benzoic acid (DMAB). The method yields two phases of absorbance increase as these substrates are oxidized. We show (a) that only the first phase is dependent on extracted H2O2; (b) that the slow phase is due to phenolic-dependent generation of H2O2 during the assay; and (c) that ascorbate inhibits both phases. These effects could explain both the high values and the variable results found in the literature. The chemiluminescence method involves H2O2 enhancement of ferricyanide-induced chemiluminescence of luminol (3-amino-phthal-hydrazide). Chemiluminescence of luminol is strongly inhibited by added ascorbate, suggesting that failure to remove ascorbate from extracts will cause this method to underestimate H2O2. Using the fast phase of the peroxidase-coupled assay to estimate H2O2 in extracts from which ascorbate and phenolic compounds had been removed, we obtained leaf contents of H2O2 within the range of 40-120 nmol g(-1) FW.
PB  - Elsevier France-Editions Scientifiques Medicales Elsevier, Issy-Les-Moulineaux
T2  - Plant Physiology and Biochemistry
T1  - Are leaf hydrogen peroxide concentrations commonly overestimated? The potential influence of artefactual interference by tissue phenolics and ascorbate
EP  - 507
IS  - 6-8
SP  - 501
VL  - 40
DO  - 10.1016/S0981-9428(02)01417-1
ER  - 

@article{
author = "Veljović-Jovanović, Sonja and Noctor, G and Foyer, CH",
year = "2002",
abstract = "We have examined the authenticity of two methods for determination of H2O2 in leaf tissue. We show that the high concentrations of ascorbic acid present in leaf extracts interfere with both techniques. In the chromogenic peroxidase-coupled assay, H2O2 is determined by oxidation of 3-methyl-2-benzothiazoline hydrazone (MBTH) and 3-(dimethylamino) benzoic acid (DMAB). The method yields two phases of absorbance increase as these substrates are oxidized. We show (a) that only the first phase is dependent on extracted H2O2; (b) that the slow phase is due to phenolic-dependent generation of H2O2 during the assay; and (c) that ascorbate inhibits both phases. These effects could explain both the high values and the variable results found in the literature. The chemiluminescence method involves H2O2 enhancement of ferricyanide-induced chemiluminescence of luminol (3-amino-phthal-hydrazide). Chemiluminescence of luminol is strongly inhibited by added ascorbate, suggesting that failure to remove ascorbate from extracts will cause this method to underestimate H2O2. Using the fast phase of the peroxidase-coupled assay to estimate H2O2 in extracts from which ascorbate and phenolic compounds had been removed, we obtained leaf contents of H2O2 within the range of 40-120 nmol g(-1) FW.",
publisher = "Elsevier France-Editions Scientifiques Medicales Elsevier, Issy-Les-Moulineaux",
journal = "Plant Physiology and Biochemistry",
title = "Are leaf hydrogen peroxide concentrations commonly overestimated? The potential influence of artefactual interference by tissue phenolics and ascorbate",
pages = "507-501",
number = "6-8",
volume = "40",
doi = "10.1016/S0981-9428(02)01417-1"
}

Veljović-Jovanović, S., Noctor, G.,& Foyer, C.. (2002). Are leaf hydrogen peroxide concentrations commonly overestimated? The potential influence of artefactual interference by tissue phenolics and ascorbate. in Plant Physiology and Biochemistry
Elsevier France-Editions Scientifiques Medicales Elsevier, Issy-Les-Moulineaux., 40(6-8), 501-507.
https://doi.org/10.1016/S0981-9428(02)01417-1

Veljović-Jovanović S, Noctor G, Foyer C. Are leaf hydrogen peroxide concentrations commonly overestimated? The potential influence of artefactual interference by tissue phenolics and ascorbate. in Plant Physiology and Biochemistry. 2002;40(6-8):501-507.
doi:10.1016/S0981-9428(02)01417-1 .

Veljović-Jovanović, Sonja, Noctor, G, Foyer, CH, "Are leaf hydrogen peroxide concentrations commonly overestimated? The potential influence of artefactual interference by tissue phenolics and ascorbate" in Plant Physiology and Biochemistry, 40, no. 6-8 (2002):501-507,
https://doi.org/10.1016/S0981-9428(02)01417-1 . .

TY  - JOUR
AU  - Veljović-Jovanović, Sonja
AU  - Pignocchi, C
AU  - Noctor, G
AU  - Foyer, CH
PY  - 2001
UR  - http://rimsi.imsi.bg.ac.rs/handle/123456789/65
AB  - Ascorbic acid has numerous and diverse roles in plant metabolism. We have used the vtc-1 mutant of Arabidopsis, which is deficient in ascorbate biosynthesis, to investigate the role of ascorbate concentration in growth, regulation of photosynthesis, and control of the partitioning of antioxidative enyzmes. The mutant possessed 70% less ascorbate in the leaves compared with the wild type. This lesion was associated with a slight increase in total glutathione but no change in the redox state of either ascorbate or glutathione. In vtc-1, total ascorbate in the apoplast was decreased to 23% of the wild-type value. The mutant displayed much slower shoot growth than the wild type when grown in air or at high CO2 (3 mL L-1), where oxidative stress is diminished. Leaves were smaller, and shoot fresh weight and dry weight were lower in the mutant. No significant differences in the light saturation curves for CO, assimilation were found in air or at high CO2, suggesting that the effect on growth was not due to decreased photosynthetic capacity in the mutant. Analysis of chlorophyll a fluorescence quenching revealed only a slight effect on non-photochemical energy dissipation. Hydrogen peroxide contents were similar in the leaves of the vtc-1 mutant and the wild type. Total leaf peroxidase activity was increased in the mutant and compartment-specific differences in ascorbate peroxidase (APX) activity were observed. In agreement with the measurements of enzyme activity, the expression of cytosolic APX was increased, whereas that for chloroplast APX isoforms was either unchanged or slightly decreased. These data implicate ascorbate concentration in the regulation of the compartmentalization of the antioxidant system in Arabidopsis.
PB  - Oxford Univ Press Inc, Cary
T2  - Plant Physiology
T1  - Low ascorbic acid in the vtc-1 mutant of arabidopsis is associated with decreased growth and intracellular redistribution of the antioxidant system
EP  - 435
IS  - 2
SP  - 426
VL  - 127
DO  - 10.1104/pp.127.2.426
ER  - 

@article{
author = "Veljović-Jovanović, Sonja and Pignocchi, C and Noctor, G and Foyer, CH",
year = "2001",
abstract = "Ascorbic acid has numerous and diverse roles in plant metabolism. We have used the vtc-1 mutant of Arabidopsis, which is deficient in ascorbate biosynthesis, to investigate the role of ascorbate concentration in growth, regulation of photosynthesis, and control of the partitioning of antioxidative enyzmes. The mutant possessed 70% less ascorbate in the leaves compared with the wild type. This lesion was associated with a slight increase in total glutathione but no change in the redox state of either ascorbate or glutathione. In vtc-1, total ascorbate in the apoplast was decreased to 23% of the wild-type value. The mutant displayed much slower shoot growth than the wild type when grown in air or at high CO2 (3 mL L-1), where oxidative stress is diminished. Leaves were smaller, and shoot fresh weight and dry weight were lower in the mutant. No significant differences in the light saturation curves for CO, assimilation were found in air or at high CO2, suggesting that the effect on growth was not due to decreased photosynthetic capacity in the mutant. Analysis of chlorophyll a fluorescence quenching revealed only a slight effect on non-photochemical energy dissipation. Hydrogen peroxide contents were similar in the leaves of the vtc-1 mutant and the wild type. Total leaf peroxidase activity was increased in the mutant and compartment-specific differences in ascorbate peroxidase (APX) activity were observed. In agreement with the measurements of enzyme activity, the expression of cytosolic APX was increased, whereas that for chloroplast APX isoforms was either unchanged or slightly decreased. These data implicate ascorbate concentration in the regulation of the compartmentalization of the antioxidant system in Arabidopsis.",
publisher = "Oxford Univ Press Inc, Cary",
journal = "Plant Physiology",
title = "Low ascorbic acid in the vtc-1 mutant of arabidopsis is associated with decreased growth and intracellular redistribution of the antioxidant system",
pages = "435-426",
number = "2",
volume = "127",
doi = "10.1104/pp.127.2.426"
}

Veljović-Jovanović, S., Pignocchi, C., Noctor, G.,& Foyer, C.. (2001). Low ascorbic acid in the vtc-1 mutant of arabidopsis is associated with decreased growth and intracellular redistribution of the antioxidant system. in Plant Physiology
Oxford Univ Press Inc, Cary., 127(2), 426-435.
https://doi.org/10.1104/pp.127.2.426

Veljović-Jovanović S, Pignocchi C, Noctor G, Foyer C. Low ascorbic acid in the vtc-1 mutant of arabidopsis is associated with decreased growth and intracellular redistribution of the antioxidant system. in Plant Physiology. 2001;127(2):426-435.
doi:10.1104/pp.127.2.426 .

Veljović-Jovanović, Sonja, Pignocchi, C, Noctor, G, Foyer, CH, "Low ascorbic acid in the vtc-1 mutant of arabidopsis is associated with decreased growth and intracellular redistribution of the antioxidant system" in Plant Physiology, 127, no. 2 (2001):426-435,
https://doi.org/10.1104/pp.127.2.426 . .

TY  - JOUR
AU  - Noctor, G
AU  - Veljović-Jovanović, Sonja
AU  - Foyer, CH
PY  - 2000
UR  - http://rimsi.imsi.bg.ac.rs/handle/123456789/59
AB  - Photosynthesis has a high capacity for production of hydrogen peroxide (H2O2), but the intracellular levels of this relatively weak oxidant are controlled by the antioxidant system, comprising a network of enzymatic and non-enzymatic components that notably includes reactions linked to the intracellular ascorbate and glutathione pools, Mutants and transformed plants with specific decreases in key components offer the opportunity to dissect the complex system that maintains redox homeostasis. Since H2O2 is a signal-transducing molecule relaying information on intracellular redox state, the pool size must be rigorously controlled within each compartment of the cell. This review focuses on compartment-specific differences in the stringency of redox coupling between ascorbate and glutathione, and the significance this may have for the flexibility of the control of gene expression that is linked to photosynthetic H2O2 production.
PB  - Royal Soc, London
T2  - Philosophical Transactions of the Royal Society B-Biological Sciences
T1  - Peroxide processing in photosynthesis: antioxidant coupling and redox signalling
EP  - 1475
IS  - 1402
SP  - 1465
VL  - 355
DO  - 10.1098/rstb.2000.0707
ER  - 

@article{
author = "Noctor, G and Veljović-Jovanović, Sonja and Foyer, CH",
year = "2000",
abstract = "Photosynthesis has a high capacity for production of hydrogen peroxide (H2O2), but the intracellular levels of this relatively weak oxidant are controlled by the antioxidant system, comprising a network of enzymatic and non-enzymatic components that notably includes reactions linked to the intracellular ascorbate and glutathione pools, Mutants and transformed plants with specific decreases in key components offer the opportunity to dissect the complex system that maintains redox homeostasis. Since H2O2 is a signal-transducing molecule relaying information on intracellular redox state, the pool size must be rigorously controlled within each compartment of the cell. This review focuses on compartment-specific differences in the stringency of redox coupling between ascorbate and glutathione, and the significance this may have for the flexibility of the control of gene expression that is linked to photosynthetic H2O2 production.",
publisher = "Royal Soc, London",
journal = "Philosophical Transactions of the Royal Society B-Biological Sciences",
title = "Peroxide processing in photosynthesis: antioxidant coupling and redox signalling",
pages = "1475-1465",
number = "1402",
volume = "355",
doi = "10.1098/rstb.2000.0707"
}

Noctor, G., Veljović-Jovanović, S.,& Foyer, C.. (2000). Peroxide processing in photosynthesis: antioxidant coupling and redox signalling. in Philosophical Transactions of the Royal Society B-Biological Sciences
Royal Soc, London., 355(1402), 1465-1475.
https://doi.org/10.1098/rstb.2000.0707

Noctor G, Veljović-Jovanović S, Foyer C. Peroxide processing in photosynthesis: antioxidant coupling and redox signalling. in Philosophical Transactions of the Royal Society B-Biological Sciences. 2000;355(1402):1465-1475.
doi:10.1098/rstb.2000.0707 .

Noctor, G, Veljović-Jovanović, Sonja, Foyer, CH, "Peroxide processing in photosynthesis: antioxidant coupling and redox signalling" in Philosophical Transactions of the Royal Society B-Biological Sciences, 355, no. 1402 (2000):1465-1475,
https://doi.org/10.1098/rstb.2000.0707 . .