23 results on '"Havaux, Michel"'
Search Results
2. Tocotrienols, the unsaturated forms of vitamin E, can function as antioxidants and lipid protectors in tobacco leaves
- Author
-
Matringe, Michel, Ksas, Brigitte, Rey, Pascal, and Havaux, Michel
- Subjects
Arabidopsis thaliana -- Genetic aspects ,Medical research ,Medicine, Experimental ,Vitamin E ,Tobacco industry ,Biological sciences ,Science and technology - Published
- 2008
3. Zeaxanthin has enhanced antioxidant capacity with respect to all other xanthophylls in Arabidopsis leaves and functions independent of binding to PSII antennae (1)([C][W])
- Author
-
Havaux, Michel, Dall'Osto, Luca, and Bassi, Roberto
- Subjects
Antioxidants -- Evaluation ,Arabidopsis thaliana -- Physiological aspects ,Arabidopsis thaliana -- Genetic aspects ,Arabidopsis thaliana -- Chemical properties ,Genetically modified crops -- Physiological aspects ,Genetically modified crops -- Chemical properties ,Biological sciences ,Science and technology - Published
- 2007
4. Canonical signal recognition particle components can be bypassed for posttranslational protein targeting in chloroplasts ([W])
- Author
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Tzvetkova-Chevolleau, Tzvetelina, Hutin, Claire, Noel, Laurent D., Goforth, Robyn, Carde, Jean-Pierre, Caffarri, Stephano, Sinning, Irmgard, Groves, Matthew, Teulon, Jean-Marie, Hoffman, Neil E., Henry, Ralph, Havaux, Michel, and Nussaume, Laurent
- Subjects
Binding proteins -- Physiological aspects ,Chloroplasts -- Chemical properties ,Chloroplasts -- Genetic aspects ,Plant proteins -- Genetic aspects ,Membrane proteins -- Physiological aspects ,Plant cell membranes -- Chemical properties ,Cellular signal transduction -- Evaluation ,Biological sciences ,Science and technology - Published
- 2007
5. Suppression of both ELIP1 and ELIP2 in Arabidopsis does not affect tolerance to photoinhibition and photooxidative stress (1)
- Author
-
Rossini, Silvia, Casazza, Anna Paola, Engelmann, Enrico C.M., Havaux, Michel, Jennings, Robert C., and Soave, Carlo
- Subjects
Arabidopsis -- Research ,Oxidative stress -- Research ,Plant proteins -- Research ,Biological sciences ,Science and technology - Published
- 2006
6. Vitamin E protects against photoinhibition and photooxidative stress in Arabidopsis thaliana
- Author
-
Havaux, Michel, Eymery, Francoise, Porfirova, Svetlana, Rey, Pascal, and Dormann, Peter
- Subjects
Arabidopsis thaliana -- Research ,Arabidopsis thaliana -- Genetic aspects ,Vitamin E -- Research ,Photosynthesis -- Research ,Plant mechanics -- Research ,Biological sciences ,Science and technology - Published
- 2005
7. Photosynthesis and state transitions in mitochondrial mutants of Chlamydomonas reinhardtii affected in respiration (1)
- Author
-
Cardol, Pierre, Gloire, Geoffrey, Havaux, Michel, Remacle, Claire, Matagne, Rene, and Franck, Fabrice
- Subjects
Chlamydomonas -- Physiological aspects ,Electron transport -- Research ,Photosynthesis research ,Biological sciences ,Science and technology - Published
- 2003
8. Zeaxanthin deficiency enhances the high light sensitivity of an ascorbate-deficient mutant of Arabidopsis (1)
- Author
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Muller-Moule, Patricia, Havaux, Michel, and Niyogi, Krishna K.
- Subjects
Arabidopsis -- Physiological aspects ,Plants -- Photoinhibition ,Plants -- Research ,Biological sciences ,Science and technology - Published
- 2003
9. Chloroplast membrane photostability in chlP transgenic tobacco plants deficient in tocopherols
- Author
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Havaux, Michel, Lutz, Cornelius, and Grimm, Bernhard
- Subjects
Genetically modified plants -- Physiological aspects ,Tobacco (Plant) -- Physiological aspects ,Photosynthesis -- Research ,Adaptation (Physiology) -- Research ,Biological sciences ,Science and technology - Published
- 2003
10. Cyclic electron flow around photosystem I in [C.sub.3] plants. in vivo control by the redox state of chloroplasts and involvement of the NADH-dehydrogenase complex
- Author
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Joet, Thierry, Cournac, Laurent, Peltier, Gilles, and Havaux, Michel
- Subjects
Oxidation-reduction reaction -- Analysis ,Chloroplasts -- Research ,Photosynthesis -- Research ,Biological sciences ,Science and technology - Published
- 2002
11. Photodamage of the photosynthetic apparatus and its dependence on the leaf developmental stage in the npq1 arabidopsis mutant deficient in the xanthophyll cycle enzyme violaxanthin de-epoxidase
- Author
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Havaux, Michel, Bonfils, Jean-Paul, Lutz, Cornelius, and Niyogi, Krishna K.
- Subjects
Energy dissipation -- Research ,Arabidopsis -- Genetic aspects ,Biological sciences ,Science and technology - Published
- 2000
12. A chromodomain protein encoded by the Arabidopsis CAO gene is a plant-specific component of the chloroplast signal recognition particle pathway that is involved in LHCP targeting
- Author
-
Klimyuk, Victor I., Persello-Cartieaux, Fabienne, Havaux, Michel, Contard-David, Pascale, Schuenemann, Danja, Meiherhoff, Karin, Gouet, Patrice, Jones, Jonathan D.G., Hoffman, Neil E., and Nussaume, Laurent
- Subjects
Arabidopsis -- Genetic aspects ,DNA-ligand interactions -- Analysis ,Hydrophobic effect -- Research ,Biological sciences ,Science and technology - Published
- 1999
13. Uncoupling High Light Responses from Singlet Oxygen Retrograde Signaling and Spatial-Temporal Systemic Acquired Acclimation1[OPEN]
- Author
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Carmody, Melanie, Crisp, Peter A., d’Alessandro, Stefano, Ganguly, Diep, Gordon, Matthew, Havaux, Michel, Albrecht-Borth, Verónica, and Pogson, Barry J.
- Subjects
Aldehydes ,Light ,Singlet Oxygen ,Arabidopsis Proteins ,Research Articles - Focus Issue ,Acclimatization ,Arabidopsis ,Plants, Genetically Modified ,Anthocyanins ,Plant Leaves ,Ascorbate Peroxidases ,Gene Expression Regulation, Plant ,Mutation ,Diterpenes ,Reactive Oxygen Species ,Signal Transduction ,Transcription Factors - Abstract
Distinct ROS signaling pathways initiated by singlet oxygen ((1)O2) or superoxide and hydrogen peroxide have been attributed to either cell death or acclimation, respectively. Recent studies have revealed that more complex antagonistic and synergistic relationships exist within and between these pathways. As specific chloroplastic ROS signals are difficult to study, rapid systemic signaling experiments using localized high light (HL) stress or ROS treatments were used in this study to uncouple signals required for direct HL and ROS perception and distal systemic acquired acclimation (SAA). A qPCR approach was chosen to determine local perception and distal signal reception. Analysis of a thylakoidal ascorbate peroxidase mutant (tapx), the (1)O2-retrograde signaling double mutant (ex1/ex2), and an apoplastic signaling double mutant (rbohD/F) revealed that tAPX and EXECUTER 1 are required for both HL and systemic acclimation stress perception. Apoplastic membrane-localized RBOHs were required for systemic spread of the signal but not for local signal induction in directly stressed tissues. Endogenous ROS treatments revealed a very strong systemic response induced by a localized 1 h induction of (1)O2 using the conditional flu mutant. A qPCR time course of (1)O2 induced systemic marker genes in directly and indirectly connected leaves revealed a direct vascular connection component of both immediate and longer term SAA signaling responses. These results reveal the importance of an EXECUTER-dependent (1)O2 retrograde signal for both local and long distance RBOH-dependent acclimation signaling that is distinct from other HL signaling pathways, and that direct vascular connections have a role in spatial-temporal SAA induction.
- Published
- 2016
14. 2-Cysteine Peroxiredoxins and Thylakoid Ascorbate Peroxidase Create a Water-Water Cycle That Is Essential to Protect the Photosynthetic Apparatus under High Light Stress Conditions1
- Author
-
Awad, Jasmin, Stotz, Henrik U., Fekete, Agnes, Krischke, Markus, Engert, Cornelia, Havaux, Michel, Berger, Susanne, and Mueller, Martin J.
- Subjects
Light ,Arabidopsis Proteins ,Arabidopsis ,food and beverages ,Water ,Articles ,Hydrogen Peroxide ,Peroxiredoxins ,respiratory system ,Carbon Dioxide ,Plants, Genetically Modified ,Models, Biological ,Thylakoids ,Plant Leaves ,Oxidative Stress ,Ascorbate Peroxidases ,Gene Expression Regulation, Plant ,Seedlings ,Stress, Physiological ,Mutation ,Cysteine ,Plastids ,Photosynthesis - Abstract
Different peroxidases, including 2-cysteine (2-Cys) peroxiredoxins (PRXs) and thylakoid ascorbate peroxidase (tAPX), have been proposed to be involved in the water-water cycle (WWC) and hydrogen peroxide (H2O2)-mediated signaling in plastids. We generated an Arabidopsis (Arabidopsis thaliana) double-mutant line deficient in the two plastid 2-Cys PRXs (2-Cys PRX A and B, 2cpa 2cpb) and a triple mutant deficient in 2-Cys PRXs and tAPX (2cpa 2cpb tapx). In contrast to wild-type and tapx single-knockout plants, 2cpa 2cpb double-knockout plants showed an impairment of photosynthetic efficiency and became photobleached under high light (HL) growth conditions. In addition, double-mutant plants also generated elevated levels of superoxide anion radicals, H2O2, and carbonylated proteins but lacked anthocyanin accumulation under HL stress conditions. Under HL conditions, 2-Cys PRXs seem to be essential in maintaining the WWC, whereas tAPX is dispensable. By comparison, this HL-sensitive phenotype was more severe in 2cpa 2cpb tapx triple-mutant plants, indicating that tAPX partially compensates for the loss of functional 2-Cys PRXs by mutation or inactivation by overoxidation. In response to HL, H2O2- and photooxidative stress-responsive marker genes were found to be dramatically up-regulated in 2cpa 2cpb tapx but not 2cpa 2cpb mutant plants, suggesting that HL-induced plastid to nucleus retrograde photooxidative stress signaling takes place after loss or inactivation of the WWC enzymes 2-Cys PRX A, 2-Cys PRX B, and tAPX.
- Published
- 2015
15. Thioredoxin m4 Controls Photosynthetic Alternative Electron Pathways in Arabidopsis1[C][W]
- Author
-
Courteille, Agathe, Vesa, Simona, Sanz-Barrio, Ruth, Cazalé, Anne-Claire, Becuwe-Linka, Noëlle, Farran, Immaculada, Havaux, Michel, Rey, Pascal, and Rumeau, Dominique
- Subjects
Chlorophyll ,animal structures ,Chloroplasts ,Light ,Plastoquinone ,Photosynthetic Reaction Center Complex Proteins ,Arabidopsis ,Genes, Plant ,Gene Expression Regulation, Enzymologic ,Electron Transport ,Membranes, Transport, and Bioenergetics ,Chloroplast Proteins ,Thioredoxins ,Gene Expression Regulation, Plant ,Tobacco ,Photosynthesis ,Photosystem I Protein Complex ,Arabidopsis Proteins ,food and beverages ,NADH Dehydrogenase ,Plants, Genetically Modified ,Recombinant Proteins ,Enzyme Activation ,Plant Leaves ,Mutagenesis, Insertional ,Ethylmaleimide ,Oxidation-Reduction - Abstract
In addition to the linear electron flow, a cyclic electron flow (CEF) around photosystem I occurs in chloroplasts. In CEF, electrons flow back from the donor site of photosystem I to the plastoquinone pool via two main routes: one that involves the Proton Gradient Regulation5 (PGR5)/PGRL1 complex (PGR) and one that is dependent of the NADH dehydrogenase-like complex. While the importance of CEF in photosynthesis and photoprotection has been clearly established, little is known about its regulation. We worked on the assumption of a redox regulation and surveyed the putative role of chloroplastic thioredoxins (TRX). Using Arabidopsis (Arabidopsis thaliana) mutants lacking different TRX isoforms, we demonstrated in vivo that TRXm4 specifically plays a role in the down-regulation of the NADH dehydrogenase-like complex-dependent plastoquinone reduction pathway. This result was confirmed in tobacco (Nicotiana tabacum) plants overexpressing the TRXm4 orthologous gene. In vitro assays performed with isolated chloroplasts and purified TRXm4 indicated that TRXm4 negatively controls the PGR pathway as well. The physiological significance of this regulation was investigated under steady-state photosynthesis and in the pgr5 mutant background. Lack of TRXm4 reversed the growth phenotype of the pgr5 mutant, but it did not compensate for the impaired photosynthesis and photoinhibition sensitivity. This suggests that the physiological role of TRXm4 occurs in vivo via a mechanism distinct from direct up-regulation of CEF.
- Published
- 2012
16. Zeaxanthin Has Enhanced Antioxidant Capacity with Respect to All Other Xanthophylls in Arabidopsis Leaves and Functions Independent of Binding to PSII Antennae1[C][W]
- Author
-
Havaux, Michel, Dall'Osto, Luca, and Bassi, Roberto
- Subjects
Chlorophyll ,Light ,Arabidopsis Proteins ,Arabidopsis ,Light-Harvesting Protein Complexes ,food and beverages ,Photosystem II Protein Complex ,macromolecular substances ,Xanthophylls ,eye diseases ,Antioxidants ,Plant Leaves ,Phenotype ,Zeaxanthins ,Mutation ,Chlorophyll Binding Proteins ,Intramolecular Transferases ,Crosses, Genetic ,Research Article - Abstract
The ch1 mutant of Arabidopsis (Arabidopsis thaliana) lacks chlorophyll (Chl) b. Leaves of this mutant are devoid of photosystem II (PSII) Chl-protein antenna complexes and have a very low capacity of nonphotochemical quenching (NPQ) of Chl fluorescence. Lhcb5 was the only PSII antenna protein that accumulated to a significant level in ch1 mutant leaves, but the apoprotein did not assemble in vivo with Chls to form a functional antenna. The abundance of Lhca proteins was also reduced to approximately 20% of the wild-type level. ch1 was crossed with various xanthophyll mutants to analyze the antioxidant activity of carotenoids unbound to PSII antenna. Suppression of zeaxanthin by crossing ch1 with npq1 resulted in oxidative stress in high light, while removing other xanthophylls or the PSII protein PsbS had no such effect. The tocopherol-deficient ch1 vte1 double mutant was as sensitive to high light as ch1 npq1, and the triple mutant ch1 npq1 vte1 exhibited an extreme sensitivity to photooxidative stress, indicating that zeaxanthin and tocopherols have cumulative effects. Conversely, constitutive accumulation of zeaxanthin in the ch1 npq2 double mutant led to an increased phototolerance relative to ch1. Comparison of ch1 npq2 with another zeaxanthin-accumulating mutant (ch1 lut2) that lacks lutein suggests that protection of polyunsaturated lipids by zeaxanthin is enhanced when lutein is also present. During photooxidative stress, alpha-tocopherol noticeably decreased in ch1 npq1 and increased in ch1 npq2 relative to ch1, suggesting protection of vitamin E by high zeaxanthin levels. Our results indicate that the antioxidant activity of zeaxanthin, distinct from NPQ, can occur in the absence of PSII light-harvesting complexes. The capacity of zeaxanthin to protect thylakoid membrane lipids is comparable to that of vitamin E but noticeably higher than that of all other xanthophylls of Arabidopsis leaves.
- Published
- 2007
17. OXI1 and DAD Regulate Light-Induced Cell Death Antagonistically through Jasmonate and Salicylate Levels.
- Author
-
Beaugelin I, Chevalier A, D'Alessandro S, Ksas B, Novák O, Strnad M, Forzani C, Hirt H, Havaux M, and Monnet F
- Subjects
- Apoptosis radiation effects, Arabidopsis cytology, Arabidopsis metabolism, Arabidopsis Proteins metabolism, Biosynthetic Pathways drug effects, Biosynthetic Pathways genetics, Biosynthetic Pathways radiation effects, Cyclopentanes pharmacology, Gene Expression Profiling methods, Gene Expression Regulation, Plant drug effects, Gene Expression Regulation, Plant radiation effects, Light, Mutation, Oxylipins pharmacology, Phospholipases A1 metabolism, Plant Growth Regulators metabolism, Plant Growth Regulators pharmacology, Plant Leaves cytology, Plant Leaves genetics, Plant Leaves metabolism, Protein Serine-Threonine Kinases metabolism, Salicylic Acid pharmacology, Singlet Oxygen metabolism, Apoptosis genetics, Arabidopsis genetics, Arabidopsis Proteins genetics, Cyclopentanes metabolism, Oxylipins metabolism, Phospholipases A1 genetics, Protein Serine-Threonine Kinases genetics, Salicylic Acid metabolism
- Abstract
Singlet oxygen produced from triplet excited chlorophylls in photosynthesis is a signal molecule that can induce programmed cell death (PCD) through the action of the OXIDATIVE STRESS INDUCIBLE 1 (OXI1) kinase. Here, we identify two negative regulators of light-induced PCD that modulate OXI1 expression: DAD1 and DAD2, homologs of the human antiapoptotic protein DEFENDER AGAINST CELL DEATH. Overexpressing OXI1 in Arabidopsis ( Arabidopsis thaliana ) increased plant sensitivity to high light and induced early senescence of mature leaves. Both phenomena rely on a marked accumulation of jasmonate and salicylate. DAD1 or DAD2 overexpression decreased OXI1 expression, jasmonate levels, and sensitivity to photooxidative stress. Knock-out mutants of DAD1 or DAD2 exhibited the opposite responses. Exogenous applications of jasmonate upregulated salicylate biosynthesis genes and caused leaf damage in wild-type plants but not in the salicylate biosynthesis mutant Salicylic acid induction-deficient2 , indicating that salicylate plays a crucial role in PCD downstream of jasmonate. Treating plants with salicylate upregulated the DAD genes and downregulated OXI1 We conclude that OXI1 and DAD are antagonistic regulators of cell death through modulating jasmonate and salicylate levels. High light-induced PCD thus results from a tight control of the relative activities of these regulating proteins, with DAD exerting a negative feedback control on OXI1 expression., (© 2019 American Society of Plant Biologists. All Rights Reserved.)
- Published
- 2019
- Full Text
- View/download PDF
18. Carnosic Acid and Carnosol, Two Major Antioxidants of Rosemary, Act through Different Mechanisms.
- Author
-
Loussouarn M, Krieger-Liszkay A, Svilar L, Bily A, Birtić S, and Havaux M
- Subjects
- Intracellular Membranes drug effects, Intracellular Membranes metabolism, Lipid Peroxidation drug effects, Lipids chemistry, Oxidation-Reduction, Plant Leaves drug effects, Plant Leaves metabolism, Plant Leaves ultrastructure, Reactive Oxygen Species metabolism, Thylakoids drug effects, Thylakoids metabolism, Thylakoids ultrastructure, Time Factors, alpha-Tocopherol pharmacology, Abietanes pharmacology, Antioxidants pharmacology, Rosmarinus metabolism
- Abstract
Carnosic acid, a phenolic diterpene specific to the Lamiaceae family, is highly abundant in rosemary ( Rosmarinus officinalis ). Despite numerous industrial and medicinal/pharmaceutical applications of its antioxidative features, this compound in planta and its antioxidant mechanism have received little attention, except a few studies of rosemary plants under natural conditions. In vitro analyses, using high-performance liquid chromatography-ultraviolet and luminescence imaging, revealed that carnosic acid and its major oxidized derivative, carnosol, protect lipids from oxidation. Both compounds preserved linolenic acid and monogalactosyldiacylglycerol from singlet oxygen and from hydroxyl radical. When applied exogenously, they were both able to protect thylakoid membranes prepared from Arabidopsis ( Arabidopsis thaliana ) leaves against lipid peroxidation. Different levels of carnosic acid and carnosol in two contrasting rosemary varieties correlated with tolerance to lipid peroxidation. Upon reactive oxygen species (ROS) oxidation of lipids, carnosic acid was consumed and oxidized into various derivatives, including into carnosol, while carnosol resisted, suggesting that carnosic acid is a chemical quencher of ROS. The antioxidative function of carnosol relies on another mechanism, occurring directly in the lipid oxidation process. Under oxidative conditions that did not involve ROS generation, carnosol inhibited lipid peroxidation, contrary to carnosic acid. Using spin probes and electron paramagnetic resonance detection, we confirmed that carnosic acid, rather than carnosol, is a ROS quencher. Various oxidized derivatives of carnosic acid were detected in rosemary leaves in low light, indicating chronic oxidation of this compound, and accumulated in plants exposed to stress conditions, in parallel with a loss of carnosic acid, confirming that chemical quenching of ROS by carnosic acid takes place in planta., (© 2017 American Society of Plant Biologists. All Rights Reserved.)
- Published
- 2017
- Full Text
- View/download PDF
19. Uncoupling High Light Responses from Singlet Oxygen Retrograde Signaling and Spatial-Temporal Systemic Acquired Acclimation.
- Author
-
Carmody M, Crisp PA, d'Alessandro S, Ganguly D, Gordon M, Havaux M, Albrecht-Borth V, and Pogson BJ
- Subjects
- Aldehydes metabolism, Anthocyanins metabolism, Arabidopsis Proteins genetics, Arabidopsis Proteins metabolism, Ascorbate Peroxidases genetics, Ascorbate Peroxidases metabolism, Diterpenes metabolism, Gene Expression Regulation, Plant, Light, Mutation, Plant Leaves physiology, Plants, Genetically Modified, Reactive Oxygen Species metabolism, Signal Transduction, Transcription Factors genetics, Transcription Factors metabolism, Acclimatization physiology, Arabidopsis physiology, Singlet Oxygen metabolism
- Abstract
Distinct ROS signaling pathways initiated by singlet oxygen ((1)O2) or superoxide and hydrogen peroxide have been attributed to either cell death or acclimation, respectively. Recent studies have revealed that more complex antagonistic and synergistic relationships exist within and between these pathways. As specific chloroplastic ROS signals are difficult to study, rapid systemic signaling experiments using localized high light (HL) stress or ROS treatments were used in this study to uncouple signals required for direct HL and ROS perception and distal systemic acquired acclimation (SAA). A qPCR approach was chosen to determine local perception and distal signal reception. Analysis of a thylakoidal ascorbate peroxidase mutant (tapx), the (1)O2-retrograde signaling double mutant (ex1/ex2), and an apoplastic signaling double mutant (rbohD/F) revealed that tAPX and EXECUTER 1 are required for both HL and systemic acclimation stress perception. Apoplastic membrane-localized RBOHs were required for systemic spread of the signal but not for local signal induction in directly stressed tissues. Endogenous ROS treatments revealed a very strong systemic response induced by a localized 1 h induction of (1)O2 using the conditional flu mutant. A qPCR time course of (1)O2 induced systemic marker genes in directly and indirectly connected leaves revealed a direct vascular connection component of both immediate and longer term SAA signaling responses. These results reveal the importance of an EXECUTER-dependent (1)O2 retrograde signal for both local and long distance RBOH-dependent acclimation signaling that is distinct from other HL signaling pathways, and that direct vascular connections have a role in spatial-temporal SAA induction., (© 2016 American Society of Plant Biologists. All Rights Reserved.)
- Published
- 2016
- Full Text
- View/download PDF
20. Singlet Oxygen-Induced Cell Death in Arabidopsis under High-Light Stress Is Controlled by OXI1 Kinase.
- Author
-
Shumbe L, Chevalier A, Legeret B, Taconnat L, Monnet F, and Havaux M
- Subjects
- Arabidopsis metabolism, Arabidopsis Proteins metabolism, Cyclopentanes pharmacology, Gene Expression Profiling methods, Gene Expression Regulation, Plant drug effects, Gene Expression Regulation, Plant radiation effects, Light, Models, Genetic, Mutation, Oligonucleotide Array Sequence Analysis, Oxylipins pharmacology, Photosystem II Protein Complex genetics, Photosystem II Protein Complex metabolism, Plant Growth Regulators pharmacology, Protein Serine-Threonine Kinases metabolism, Reverse Transcriptase Polymerase Chain Reaction, Signal Transduction drug effects, Signal Transduction genetics, Signal Transduction radiation effects, Apoptosis genetics, Arabidopsis genetics, Arabidopsis Proteins genetics, Gene Expression Regulation, Plant genetics, Protein Serine-Threonine Kinases genetics, Singlet Oxygen metabolism
- Abstract
Studies of the singlet oxygen ((1)O2)-overproducing flu and chlorina1 (ch1) mutants of Arabidopsis (Arabidopsis thaliana) have shown that (1)O2-induced changes in gene expression can lead to either programmed cell death (PCD) or acclimation. A transcriptomic analysis of the ch1 mutant has allowed the identification of genes whose expression is specifically affected by each phenomenon. One such gene is OXIDATIVE SIGNAL INDUCIBLE1 (OXI1) encoding an AGC kinase that was noticeably induced by excess light energy and (1)O2 stress conditions leading to cell death. Photo-induced oxidative damage and cell death were drastically reduced in the OXI1 null mutant (oxi1) and in the double mutant ch1*oxi1 compared with the wild type and the ch1 single mutant, respectively. This occurred without any changes in the production rate of (1)O2 but was cancelled by exogenous applications of the phytohormone jasmonate. OXI1-mediated (1)O2 signaling appeared to operate through a different pathway from the previously characterized OXI1-dependent response to pathogens and H2O2 and was found to be independent of the EXECUTER proteins. In high-light-stressed plants, the oxi1 mutation was associated with reduced jasmonate levels and with the up-regulation of genes encoding negative regulators of jasmonate signaling and PCD. Our results show that OXI1 is a new regulator of (1)O2-induced PCD, likely acting upstream of jasmonate., (© 2016 American Society of Plant Biologists. All Rights Reserved.)
- Published
- 2016
- Full Text
- View/download PDF
21. 2-cysteine peroxiredoxins and thylakoid ascorbate peroxidase create a water-water cycle that is essential to protect the photosynthetic apparatus under high light stress conditions.
- Author
-
Awad J, Stotz HU, Fekete A, Krischke M, Engert C, Havaux M, Berger S, and Mueller MJ
- Subjects
- Arabidopsis genetics, Arabidopsis radiation effects, Arabidopsis Proteins genetics, Arabidopsis Proteins metabolism, Ascorbate Peroxidases genetics, Carbon Dioxide metabolism, Cysteine metabolism, Light adverse effects, Models, Biological, Mutation, Oxidative Stress, Photosynthesis radiation effects, Plant Leaves genetics, Plant Leaves physiology, Plant Leaves radiation effects, Plants, Genetically Modified, Plastids metabolism, Seedlings genetics, Seedlings physiology, Seedlings radiation effects, Stress, Physiological, Thylakoids enzymology, Arabidopsis physiology, Ascorbate Peroxidases metabolism, Gene Expression Regulation, Plant, Hydrogen Peroxide metabolism, Peroxiredoxins metabolism, Water physiology
- Abstract
Different peroxidases, including 2-cysteine (2-Cys) peroxiredoxins (PRXs) and thylakoid ascorbate peroxidase (tAPX), have been proposed to be involved in the water-water cycle (WWC) and hydrogen peroxide (H2O2)-mediated signaling in plastids. We generated an Arabidopsis (Arabidopsis thaliana) double-mutant line deficient in the two plastid 2-Cys PRXs (2-Cys PRX A and B, 2cpa 2cpb) and a triple mutant deficient in 2-Cys PRXs and tAPX (2cpa 2cpb tapx). In contrast to wild-type and tapx single-knockout plants, 2cpa 2cpb double-knockout plants showed an impairment of photosynthetic efficiency and became photobleached under high light (HL) growth conditions. In addition, double-mutant plants also generated elevated levels of superoxide anion radicals, H2O2, and carbonylated proteins but lacked anthocyanin accumulation under HL stress conditions. Under HL conditions, 2-Cys PRXs seem to be essential in maintaining the WWC, whereas tAPX is dispensable. By comparison, this HL-sensitive phenotype was more severe in 2cpa 2cpb tapx triple-mutant plants, indicating that tAPX partially compensates for the loss of functional 2-Cys PRXs by mutation or inactivation by overoxidation. In response to HL, H2O2- and photooxidative stress-responsive marker genes were found to be dramatically up-regulated in 2cpa 2cpb tapx but not 2cpa 2cpb mutant plants, suggesting that HL-induced plastid to nucleus retrograde photooxidative stress signaling takes place after loss or inactivation of the WWC enzymes 2-Cys PRX A, 2-Cys PRX B, and tAPX., (© 2015 American Society of Plant Biologists. All Rights Reserved.)
- Published
- 2015
- Full Text
- View/download PDF
22. Thioredoxin m4 controls photosynthetic alternative electron pathways in Arabidopsis.
- Author
-
Courteille A, Vesa S, Sanz-Barrio R, Cazalé AC, Becuwe-Linka N, Farran I, Havaux M, Rey P, and Rumeau D
- Subjects
- Arabidopsis genetics, Arabidopsis physiology, Arabidopsis radiation effects, Arabidopsis Proteins metabolism, Chlorophyll metabolism, Chloroplast Proteins genetics, Chloroplast Proteins metabolism, Chloroplasts metabolism, Electron Transport, Enzyme Activation, Ethylmaleimide pharmacology, Gene Expression Regulation, Enzymologic, Gene Expression Regulation, Plant, Genes, Plant, Light, Mutagenesis, Insertional, NADH Dehydrogenase metabolism, Oxidation-Reduction, Photosynthetic Reaction Center Complex Proteins metabolism, Photosystem I Protein Complex genetics, Plant Leaves genetics, Plant Leaves metabolism, Plant Leaves radiation effects, Plants, Genetically Modified genetics, Plants, Genetically Modified metabolism, Plants, Genetically Modified radiation effects, Plastoquinone metabolism, Recombinant Proteins genetics, Recombinant Proteins metabolism, Thioredoxins genetics, Nicotiana genetics, Nicotiana metabolism, Arabidopsis metabolism, Photosynthesis, Photosystem I Protein Complex metabolism, Thioredoxins metabolism
- Abstract
In addition to the linear electron flow, a cyclic electron flow (CEF) around photosystem I occurs in chloroplasts. In CEF, electrons flow back from the donor site of photosystem I to the plastoquinone pool via two main routes: one that involves the Proton Gradient Regulation5 (PGR5)/PGRL1 complex (PGR) and one that is dependent of the NADH dehydrogenase-like complex. While the importance of CEF in photosynthesis and photoprotection has been clearly established, little is known about its regulation. We worked on the assumption of a redox regulation and surveyed the putative role of chloroplastic thioredoxins (TRX). Using Arabidopsis (Arabidopsis thaliana) mutants lacking different TRX isoforms, we demonstrated in vivo that TRXm4 specifically plays a role in the down-regulation of the NADH dehydrogenase-like complex-dependent plastoquinone reduction pathway. This result was confirmed in tobacco (Nicotiana tabacum) plants overexpressing the TRXm4 orthologous gene. In vitro assays performed with isolated chloroplasts and purified TRXm4 indicated that TRXm4 negatively controls the PGR pathway as well. The physiological significance of this regulation was investigated under steady-state photosynthesis and in the pgr5 mutant background. Lack of TRXm4 reversed the growth phenotype of the pgr5 mutant, but it did not compensate for the impaired photosynthesis and photoinhibition sensitivity. This suggests that the physiological role of TRXm4 occurs in vivo via a mechanism distinct from direct up-regulation of CEF.
- Published
- 2013
- Full Text
- View/download PDF
23. Chemical quenching of singlet oxygen by carotenoids in plants.
- Author
-
Ramel F, Birtic S, Cuiné S, Triantaphylidès C, Ravanat JL, and Havaux M
- Subjects
- Arabidopsis genetics, Chlorophyll chemistry, Gene Expression Regulation, Plant, Genes, Plant, Half-Life, Light, Oxidation-Reduction, Oxidative Stress, Photochemical Processes, Photosystem II Protein Complex chemistry, Plant Leaves chemistry, Temperature, Arabidopsis chemistry, Carotenoids chemistry, Singlet Oxygen chemistry
- Abstract
Carotenoids are considered to be the first line of defense of plants against singlet oxygen ((1)O(2)) toxicity because of their capacity to quench (1)O(2) as well as triplet chlorophylls through a physical mechanism involving transfer of excitation energy followed by thermal deactivation. Here, we show that leaf carotenoids are also able to quench (1)O(2) by a chemical mechanism involving their oxidation. In vitro oxidation of β-carotene, lutein, and zeaxanthin by (1)O(2) generated various aldehydes and endoperoxides. A search for those molecules in Arabidopsis (Arabidopsis thaliana) leaves revealed the presence of (1)O(2)-specific endoperoxides in low-light-grown plants, indicating chronic oxidation of carotenoids by (1)O(2). β-Carotene endoperoxide, but not xanthophyll endoperoxide, rapidly accumulated during high-light stress, and this accumulation was correlated with the extent of photosystem (PS) II photoinhibition and the expression of various (1)O(2) marker genes. The selective accumulation of β-carotene endoperoxide points at the PSII reaction centers, rather than the PSII chlorophyll antennae, as a major site of (1)O(2) accumulation in plants under high-light stress. β-Carotene endoperoxide was found to have a relatively fast turnover, decaying in the dark with a half time of about 6 h. This carotenoid metabolite provides an early index of (1)O(2) production in leaves, the occurrence of which precedes the accumulation of fatty acid oxidation products.
- Published
- 2012
- Full Text
- View/download PDF
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