101
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Suda Y, Yoshikawa T, Okuda Y, Tsunemoto M, Tanaka S, Ikeda K, Miyasaka H, Watanabe M, Sasaki K, Harada K, Bamba T, Hirata K. Isolation and characterization of a novel antistress gene from Chlamydomonas sp. W80. J Biosci Bioeng 2009; 107:352-4. [DOI: 10.1016/j.jbiosc.2008.12.019] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2008] [Revised: 12/18/2008] [Accepted: 12/19/2008] [Indexed: 10/21/2022]
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102
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Generation of selectable marker-free transgenic tomato resistant to drought, cold and oxidative stress using the Cre/loxP DNA excision system. Transgenic Res 2009. [PMID: 19263233 DOI: 10.1007/s11248–009–9251–6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/29/2022]
Abstract
The aim of this research was to generate selectable marker-free transgenic tomato plants with improved tolerance to abiotic stress. An estradiol-induced site-specific DNA excision of a selectable marker gene using the Cre/loxP DNA recombination system was employed to develop transgenic tomato constitutively expressing AtIpk2 beta, an inositol polyphosphate 6-/3-kinase gene from Arabidopsis thaliana. Transgenic tomato plants containing a selectable marker were also produced as controls. The expression of AtIpk2 beta conferred improved resistance to drought, cold and oxidative stress in both sets of transgenic tomato plants. These results demonstrate the feasibility of using this Cre/loxP-based marker elimination strategy to generate marker-free transgenic crops with improved stress tolerance.
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103
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Generation of selectable marker-free transgenic tomato resistant to drought, cold and oxidative stress using the Cre/loxP DNA excision system. Transgenic Res 2009; 18:607-19. [PMID: 19263233 DOI: 10.1007/s11248-009-9251-6] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2008] [Accepted: 02/03/2009] [Indexed: 10/21/2022]
Abstract
The aim of this research was to generate selectable marker-free transgenic tomato plants with improved tolerance to abiotic stress. An estradiol-induced site-specific DNA excision of a selectable marker gene using the Cre/loxP DNA recombination system was employed to develop transgenic tomato constitutively expressing AtIpk2 beta, an inositol polyphosphate 6-/3-kinase gene from Arabidopsis thaliana. Transgenic tomato plants containing a selectable marker were also produced as controls. The expression of AtIpk2 beta conferred improved resistance to drought, cold and oxidative stress in both sets of transgenic tomato plants. These results demonstrate the feasibility of using this Cre/loxP-based marker elimination strategy to generate marker-free transgenic crops with improved stress tolerance.
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104
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Ding S, Lu Q, Zhang Y, Yang Z, Wen X, Zhang L, Lu C. Enhanced sensitivity to oxidative stress in transgenic tobacco plants with decreased glutathione reductase activity leads to a decrease in ascorbate pool and ascorbate redox state. PLANT MOLECULAR BIOLOGY 2009; 69:577-92. [PMID: 19043665 DOI: 10.1007/s11103-008-9440-3] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2008] [Accepted: 11/20/2008] [Indexed: 05/03/2023]
Abstract
To investigate the possible mechanisms of glutathione reductase (GR) in protecting against oxidative stress, we obtained transgenic tobacco (Nicotiana tabacum) plants with 30-70% decreased GR activity by using a gene encoding tobacco chloroplastic GR for the RNAi construct. We investigated the responses of wild type and transgenic plants to oxidative stress induced by application of methyl viologen in vivo. Analyses of CO(2) assimilation, maximal efficiency of photosystem II photochemistry, leaf bleaching, and oxidative damage to lipids demonstrated that transgenic plants exhibited enhanced sensitivity to oxidative stress. Under oxidative stress, there was a greater decrease in reduced to oxidized glutathione ratio but a greater increase in reduced glutathione in transgenic plants than in wild type plants. In addition, transgenic plants showed a greater decrease in reduced ascorbate and reduced to oxidized ascorbate ratio than wild type plants. However, there were neither differences in the levels of NADP and NADPH and in the total foliar activities of monodehydroascorbate reductase and dehydroascorbate reductase between wild type and transgenic plant. MV treatment induced an increase in the activities of GR, ascorbate peroxidase, superoxide dismutase, and catalase. Furthermore, accumulation of H(2)O(2) in chloroplasts was observed in transgenic plants but not in wild type plants. Our results suggest that capacity for regeneration of glutathione by GR plays an important role in protecting against oxidative stress by maintaining ascorbate pool and ascorbate redox state.
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Affiliation(s)
- Shunhua Ding
- Institute of Botany, Chinese Academy of Sciences, 100093, Beijing, China
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105
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Ogawa T, Ishikawa K, Harada K, Fukusaki E, Yoshimura K, Shigeoka S. Overexpression of an ADP-ribose pyrophosphatase, AtNUDX2, confers enhanced tolerance to oxidative stress in Arabidopsis plants. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2009; 57:289-301. [PMID: 18798872 DOI: 10.1111/j.1365-313x.2008.03686.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
Mutant pqr-216 from an Arabidopsis activation-tagged line showed a phenotype of increased tolerance to oxidative stress after treatment with 3 mum paraquat (PQ). Based on the phenotype of transgenic plants overexpressing the genes flanking the T-DNA insert, it was clear that enhanced expression of a Nudix (nucleoside diphosphates linked to some moiety X) hydrolase gene, AtNUDX2 (At5g47650), was responsible for the tolerance. It has been reported that the AtNUDX2 protein has pyrophosphatase activities towards both ADP-ribose and NADH (Ogawa et al., 2005). Interestingly, the pyrophosphatase activity toward ADP-ribose, but not NADH, was increased in pqr-216 and Pro(35S):AtNUDX2 plants compared with control plants. The amount of free ADP-ribose was lower in the Pro(35S):AtNUDX2 plants, while the level of NADH was similar to those in control plants under both normal conditions and oxidative stress. Depletion of NAD(+) and ATP resulting from activation of poly(ADP-ribosyl)ation under oxidative stress was observed in the control Arabidopsis plants. Such alterations in the levels of these molecules were significantly suppressed in the Pro(35S):AtNUDX2 plants. The results indicate that overexpression of AtNUDX2, encoding ADP-ribose pyrophosphatase, confers enhanced tolerance of oxidative stress on Arabidopsis plants, resulting from maintenance of NAD(+) and ATP levels by nucleotide recycling from free ADP-ribose molecules under stress conditions.
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Affiliation(s)
- Takahisa Ogawa
- Department of Advanced Bioscience, Faculty of Agriculture, Kinki University, 3327-204 Nakamachi, Nara 631 8505, Japan
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106
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Cao Y, Yang Y, Zhang H, Li D, Zheng Z, Song F. Overexpression of a rice defense-related F-box protein gene OsDRF1 in tobacco improves disease resistance through potentiation of defense gene expression. PHYSIOLOGIA PLANTARUM 2008; 134:440-52. [PMID: 18573188 DOI: 10.1111/j.1399-3054.2008.01149.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
F-box proteins play important roles in plant growth/development and responses to environmental stimuli through targeting substrates into degradation machinery. A rice defense-related F-box protein gene, OsDRF1, was cloned and identified during a course of study aimed at elucidating the molecular basis of induced immunity in rice. OsDRF1 encodes a protein of 328 amino acids, containing a highly conserved F-box domain. Expression of OsDRF1 was induced upon treatment with benzothiadiazole (BTH), a chemical inducer of defense responses in rice. Moreover, in BTH-treated rice seedlings, expression of OsDRF1 was further induced by infection with Magnaporthe grisea, the rice blast fungus, compared with those in water-treated seedlings. OsDRF1 was also upregulated in rice seedlings after treatment with ABA. Overexpression of OsDRF1 in transgenic tobacco resulted in enhanced disease resistance against tomato mosaic virus (ToMV) and Pseudomonas syringae pv. tabaci and strengthened expression of defense-related genes after salicylic acid treatment or ToMV infection. Root elongation of the OsDRF1-overexpressing transgenic seedlings was significantly inhibited by ABA, indicating that overexpression of OsDRF1 resulted in increased ABA sensitivity. The results suggest that OsDRF1 plays a role in disease resistance via upregulating defense-related gene expression and that OsDRF1 may also be involved in the response to ABA.
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Affiliation(s)
- Yifei Cao
- State Key Laboratory for Rice Biology, Institute of Biotechnology, Zhejiang University-Huajiachi Campus, Hangzhou, Zhejiang 310029, China
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107
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Maruta T, Yonemitsu M, Yabuta Y, Tamoi M, Ishikawa T, Shigeoka S. Arabidopsis phosphomannose isomerase 1, but not phosphomannose isomerase 2, is essential for ascorbic acid biosynthesis. J Biol Chem 2008; 283:28842-51. [PMID: 18755683 PMCID: PMC2661998 DOI: 10.1074/jbc.m805538200] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2008] [Revised: 08/25/2008] [Indexed: 11/06/2022] Open
Abstract
We studied molecular and functional properties of Arabidopsis phosphomannose isomerase isoenzymes (PMI1 and PMI2) that catalyze reversible isomerization between D-fructose 6-phosphate and D-mannose 6-phosphate (Man-6P). The apparent K(m) and V(max) values for Man-6P of purified recombinant PMI1 were 41.3+/-4.2 microm and 1.89 micromol/min/mg protein, respectively, whereas those of purified recombinant PMI2 were 372+/-13 microm and 22.5 micromol/min/mg protein, respectively. Both PMI1 and PMI2 were inhibited by incubation with EDTA, Zn(2+), Cd(2+), and L-ascorbic acid (AsA). Arabidopsis PMI1 protein was constitutively expressed in both vegetative and reproductive organs under normal growth conditions, whereas the PMI2 protein was not expressed in any organs under light. The induction of PMI1 expression and an increase in the AsA level were observed in leaves under continuous light, whereas the induction of PMI2 expression and a decrease in the AsA level were observed under long term darkness. PMI1 showed a diurnal expression pattern in parallel with the total PMI activity and the total AsA content in leaves. Moreover, a reduction of PMI1 expression through RNA interference resulted in a substantial decrease in the total AsA content of leaves of knockdown PMI1 plants, whereas the complete inhibition of PMI2 expression did not affect the total AsA levels in leaves of knock-out PMI2 plants. Consequently, this study improves our understanding of the molecular and functional properties of Arabidopsis PMI isoenzymes and provides genetic evidence of the involvement of PMI1, but not PMI2, in the biosynthesis of AsA in Arabidopsis plants.
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Affiliation(s)
- Takanori Maruta
- Department of Advanced Bioscience, Faculty of Agriculture, Kinki University, 3327-204 Nakamachi, Nara 631-8505, Japan
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108
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Abstract
Thiol/selenol peroxidases are ubiquitous nonheme peroxidases. They are divided into two major subfamilies: peroxiredoxins (PRXs) and glutathione peroxidases (GPXs). PRXs are present in diverse subcellular compartments and divided into four types: 2-cys PRX, 1-cys PRX, PRX-Q, and type II PRX (PRXII). In mammals, most GPXs are selenoenzymes containing a highly reactive selenocysteine in their active site while yeast and land plants are devoid of selenoproteins but contain nonselenium GPXs. The presence of a chloroplastic 2-cys PRX, a nonselenium GPX, and two selenium-dependent GPXs has been reported in the unicellular green alga Chlamydomonas reinhardtii. The availability of the Chlamydomonas genome sequence offers the opportunity to complete our knowledge on thiol/selenol peroxidases in this organism. In this article, Chlamydomonas PRX and GPX families are presented and compared to their counterparts in Arabidopsis, human, yeast, and Synechocystis sp. A summary of the current knowledge on each family of peroxidases, especially in photosynthetic organisms, phylogenetic analyses, and investigations of the putative subcellular localization of each protein and its relative expression level, on the basis of EST data, are presented. We show that Chlamydomonas PRX and GPX families share some similarities with other photosynthetic organisms but also with human cells. The data are discussed in view of recent results suggesting that these enzymes are important scavengers of reactive oxygen species (ROS) and reactive nitrogen species (RNS) but also play a role in ROS signaling.
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109
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Nishizawa A, Yabuta Y, Shigeoka S. Galactinol and raffinose constitute a novel function to protect plants from oxidative damage. PLANT PHYSIOLOGY 2008; 147:1251-63. [PMID: 18502973 PMCID: PMC2442551 DOI: 10.1104/pp.108.122465] [Citation(s) in RCA: 618] [Impact Index Per Article: 38.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2008] [Accepted: 05/20/2008] [Indexed: 05/17/2023]
Abstract
Galactinol synthase (GolS) is a key enzyme in the synthesis of raffinose family oligosaccharides that function as osmoprotectants in plant cells. In leaves of Arabidopsis (Arabidopsis thaliana) plants overexpressing heat shock transcription factor A2 (HsfA2), the transcription of GolS1, -2, and -4 and raffinose synthase 2 (RS2) was highly induced; thus, levels of galactinol and raffinose increased compared with those in wild-type plants under control growth conditions. In leaves of the wild-type plants, treatment with 50 mum methylviologen (MV) increased the transcript levels of not only HsfA2, but also GolS1, -2, -3, -4, and -8 and RS2, -4, -5, and -6, the total activities of GolS isoenzymes, and the levels of galactinol and raffinose. GolS1- or GolS2-overexpressing Arabidopsis plants (Ox-GolS1-11, Ox-GolS2-8, and Ox-GolS2-29) had increased levels of galactinol and raffinose in the leaves compared with wild-type plants under control growth conditions. High intracellular levels of galactinol and raffinose in the transgenic plants were correlated with increased tolerance to MV treatment and salinity or chilling stress. Galactinol and raffinose effectively protected salicylate from attack by hydroxyl radicals in vitro. These findings suggest the possibility that galactinol and raffinose scavenge hydroxyl radicals as a novel function to protect plant cells from oxidative damage caused by MV treatment, salinity, or chilling.
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Affiliation(s)
- Ayako Nishizawa
- Department of Advanced Bioscience, Faculty of Agriculture, Kinki University, 3327-204 Nakamachi, Nara 631-8505, Japan
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110
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Hoque MA, Banu MNA, Nakamura Y, Shimoishi Y, Murata Y. Proline and glycinebetaine enhance antioxidant defense and methylglyoxal detoxification systems and reduce NaCl-induced damage in cultured tobacco cells. JOURNAL OF PLANT PHYSIOLOGY 2008; 165:813-24. [PMID: 17920727 DOI: 10.1016/j.jplph.2007.07.013] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/28/2007] [Revised: 07/23/2007] [Accepted: 07/23/2007] [Indexed: 05/04/2023]
Abstract
Salt stress impairs reactive oxygen species (ROS) and methylglyoxal (MG) detoxification systems, and causes oxidative damage to plants. Up-regulation of the antioxidant and glyoxalase systems provides protection against NaCl-induced oxidative damage in plants. Thiol-disulfide contents, glutathione content and its associated enzyme activities involved in the antioxidant defense and glyoxalase systems, and protein carbonylation in tobacco Bright Yellow-2 cells grown in suspension culture were investigated to assess the protection offered by proline and glycinebetaine against salt stress. Salt stress increased protein carbonylation, contents of thiol, disulfide, reduced (GSH) and oxidized (GSSG) forms of glutathione, and the activity of glutathione-S-transferase and glyoxalase II enzymes, but decreased redox state of both thiol-disulfide and glutathione, and the activity of glutathione peroxidase and glyoxalase I enzymes involved in the ROS and MG detoxification systems. Exogenous application of proline or glycinebetaine resulted in a reduction of protein carbonylation, and in an increase in glutathione redox state and activity of glutathione peroxidase, glutathione-S-transferase and glyoxalase I under salt stress. Neither proline nor glycinebetaine, however, had any direct protective effect on NaCl-induced GSH-associated enzyme activities. The present study, therefore, suggests that both proline and glycinebetaine provide a protective action against NaCl-induced oxidative damage by reducing protein carbonylation, and enhancing antioxidant defense and MG detoxification systems.
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Affiliation(s)
- Md Anamul Hoque
- Graduate School of Natural Science and Technology, Okayama University, Okayama 700-8530, Japan
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111
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Morgan MJ, Lehmann M, Schwarzländer M, Baxter CJ, Sienkiewicz-Porzucek A, Williams TCR, Schauer N, Fernie AR, Fricker MD, Ratcliffe RG, Sweetlove LJ, Finkemeier I. Decrease in manganese superoxide dismutase leads to reduced root growth and affects tricarboxylic acid cycle flux and mitochondrial redox homeostasis. PLANT PHYSIOLOGY 2008; 147:101-14. [PMID: 18337490 PMCID: PMC2330298 DOI: 10.1104/pp.107.113613] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2007] [Accepted: 03/03/2008] [Indexed: 05/18/2023]
Abstract
Superoxide dismutases (SODs) are key components of the plant antioxidant defense system. While plastidic and cytosolic isoforms have been extensively studied, the importance of mitochondrial SOD at a cellular and whole-plant level has not been established. To address this, transgenic Arabidopsis (Arabidopsis thaliana) plants were generated in which expression of AtMSD1, encoding the mitochondrial manganese (Mn)SOD, was suppressed by antisense. The strongest antisense line showed retarded root growth even under control growth conditions. There was evidence for a specific disturbance of mitochondrial redox homeostasis in seedlings grown in liquid culture: a mitochondrially targeted redox-sensitive green fluorescent protein was significantly more oxidized in the MnSOD-antisense background. In contrast, there was no substantial change in oxidation of cytosolically targeted redox-sensitive green fluorescent protein, nor changes in antioxidant defense components. The consequences of altered mitochondrial redox status of seedlings were subtle with no widespread increase of mitochondrial protein carbonyls or inhibition of mitochondrial respiratory complexes. However, there were specific inhibitions of tricarboxylic acid (TCA) cycle enzymes (aconitase and isocitrate dehydrogenase) and an inhibition of TCA cycle flux in isolated mitochondria. Nevertheless, total respiratory CO2 output of seedlings was not decreased, suggesting that the inhibited TCA cycle enzymes can be bypassed. In older, soil-grown plants, redox perturbation was more pronounced with changes in the amount and/or redox poise of ascorbate and glutathione. Overall, the results demonstrate that reduced MnSOD affects mitochondrial redox balance and plant growth. The data also highlight the flexibility of plant metabolism with TCA cycle inhibition having little effect on overall respiratory rates.
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Affiliation(s)
- Megan J Morgan
- Department of Plant Sciences, University of Oxford, Oxford OX1 3RB, United Kingdom
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112
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Usadel B, Bläsing OE, Gibon Y, Poree F, Höhne M, Günter M, Trethewey R, Kamlage B, Poorter H, Stitt M. Multilevel genomic analysis of the response of transcripts, enzyme activities and metabolites in Arabidopsis rosettes to a progressive decrease of temperature in the non-freezing range. PLANT, CELL & ENVIRONMENT 2008; 31:518-47. [PMID: 18088337 DOI: 10.1111/j.1365-3040.2007.01763.x] [Citation(s) in RCA: 117] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
This paper characterizes the transcriptional and metabolic response of a chilling-tolerant species to an increasingly large decrease of the temperature. Arabidopsis Col-0 was grown at 20 degrees C and transferred to 17, 14, 12, 10 or 8 degrees C for 6 and 78 h, before harvesting the rosette and profiling >22 000 transcripts, >20 enzyme activities and >80 metabolites. Most parameters showed a qualitatively similar response across the entire temperature range, with the amplitude increasing as the temperature decreased. Transcripts typically showed large changes after 6 h, which were often damped by 78 h. Genes were induced for sucrose, proline, raffinose, tocopherol and polyamine synthesis, phenylpropanoid and flavonoid metabolism, fermentation, non-phosphorylating mitochondrial electron transport, RNA processing, and protein synthesis, targeting and folding. Genes were repressed for carbonic anhydrases, vacuolar invertase, and ethylene and jasmonic acid signalling. While some enzyme activities and metabolites changed rapidly, most changed slowly. After 6 h, there was an accumulation of phosphorylated intermediates, a shift of partitioning towards sucrose, and a perturbation of glycine decarboxylation and nitrogen metabolism. By 78 h, there was an increase of the overall protein content and many enzyme activities, a general increase of carbohydrates, organic and amino acids, and an increase of many stress-responsive metabolites including raffinose, proline, tocopherol and polyamines. When the responses of transcripts and metabolism were compared, there was little agreement after 6 h, but considerable agreement after 78 h. Comparison with the published studies indicated that much, but not all, of the response was orchestrated by the CBF programme. Overall, our results showed that transcription and metabolism responded in a continuous manner across a wide range of temperatures. The general increase of enzyme activities and metabolites emphasized the positive and compensatory nature of this response.
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Affiliation(s)
- Björn Usadel
- Max-Planck-Institute for Molecular Plant Physiology, Am Mühlenberg 1, 14476, Golm, Germany
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113
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Yang L, Tang R, Zhu J, Liu H, Mueller-Roeber B, Xia H, Zhang H. Enhancement of stress tolerance in transgenic tobacco plants constitutively expressing AtIpk2beta, an inositol polyphosphate 6-/3-kinase from Arabidopsis thaliana. PLANT MOLECULAR BIOLOGY 2008; 66:329-43. [PMID: 18165921 PMCID: PMC2238787 DOI: 10.1007/s11103-007-9267-3] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2007] [Accepted: 11/14/2007] [Indexed: 05/18/2023]
Abstract
Inositol phosphates (IPs) and their turnover products have been implicated to play important roles in stress signaling in eukaryotic cells. In higher plants genes encoding inositol polyphosphate kinases have been identified previously, but their physiological functions have not been fully resolved. Here we expressed Arabidopsis inositol polyphosphate 6-/3-kinase (AtIpk2beta) in two heterologous systems, i.e. the yeast Saccharomyces cerevisiae and in tobacco (Nicotiana tabacum), and tested the effect on abiotic stress tolerance. Expression of AtIpk2beta rescued the salt-, osmotic- and temperature-sensitive growth defects of a yeast mutant strain (arg82Delta) that lacks inositol polyphosphate multikinase activity encoded by the ARG82/IPK2 gene. Transgenic tobacco plants constitutively expressing AtIpk2beta under the control of the Cauliflower Mosaic Virus 35S promoter were generated and found to exhibit improved tolerance to diverse abiotic stresses when compared to wild type plants. Expression patterns of various stress responsive genes were enhanced, and the activities of anti-oxidative enzymes were elevated in transgenic plants, suggesting a possible involvement of AtIpk2beta in plant stress responses.
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Affiliation(s)
- Lei Yang
- National Key Laboratory of Plant Molecular Genetics, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 300 Fenglin Road, Shanghai, 200032 China
| | - Renjie Tang
- National Key Laboratory of Plant Molecular Genetics, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 300 Fenglin Road, Shanghai, 200032 China
| | - Jinqi Zhu
- National Key Laboratory of Plant Molecular Genetics, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 300 Fenglin Road, Shanghai, 200032 China
| | - Hua Liu
- National Key Laboratory of Plant Molecular Genetics, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 300 Fenglin Road, Shanghai, 200032 China
| | - Bernd Mueller-Roeber
- University of Potsdam, Karl-Liebknecht-Str. 24-25, Haus 20, 14476 Potsdam-Golm, Germany
| | - Huijun Xia
- Key Laboratory of MOE for Plant Developmental Biology, College of Life Sciences, Wuhan University, Wuhan, 430072 China
| | - Hongxia Zhang
- National Key Laboratory of Plant Molecular Genetics, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 300 Fenglin Road, Shanghai, 200032 China
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114
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Schenk PM, Thomas-Hall SR, Stephens E, Marx UC, Mussgnug JH, Posten C, Kruse O, Hankamer B. Second Generation Biofuels: High-Efficiency Microalgae for Biodiesel Production. BIOENERGY RESEARCH 2008; 1:20-43. [PMID: 0 DOI: 10.1007/s12155-008-9008-8] [Citation(s) in RCA: 759] [Impact Index Per Article: 47.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
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115
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Wang X, Ma Y, Huang C, Wan Q, Li N, Bi Y. Glucose-6-phosphate dehydrogenase plays a central role in modulating reduced glutathione levels in reed callus under salt stress. PLANTA 2008; 227:611-23. [PMID: 17952457 DOI: 10.1007/s00425-007-0643-7] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/04/2007] [Accepted: 09/28/2007] [Indexed: 05/24/2023]
Abstract
In the present study, we investigated the role of glucose-6-phosphate dehydrogenase (G6PDH) in regulating the levels of reduced form of glutathione (GSH) to the tolerance of calli from two reed ecotypes, Phragmites communis Trin. dune reed (DR) and swamp reed (SR), in a long-term salt stress. G6PDH activity was higher in SR callus than that of DR callus under 50-150 mM NaCl treatments. In contrast, at higher NaCl concentrations (300-600 mM), G6PDH activity was lower in SR callus. A similar profile was observed in GSH contents, glutathione reductase (GR) and glutathione peroxidase (GPX) activities in both salt-stressed calli. After G6PDH activity and expression were reduced in glycerol treatments, GSH contents and GR and GPX activity decreased strongly in both calli. Simultaneously, NaCl-induced hydrogen peroxide (H2O2) accumulation was also abolished. Exogenous application of H2O2 increased G6PDH, GR, and GPX activities and GSH contents in the control conditions and glycerol treatment. Diphenylene iodonium (DPI), a plasma membrane (PM) NADPH oxidase inhibitor, which counteracted NaCl-induced H(2)O(2) accumulation, decreased these enzymes activities and GSH contents. Furthermore, exogenous application of H2O2 abolished the N-acetyl-L: -cysteine (NAC)-induced decrease in G6PDH activity, and DPI suppressed the effect of buthionine sulfoximine (BSO) on induction of G6PDH activity. Western-blot analyses showed that G6PDH expression was stimulated by NaCl and H2O2, and blocked by DPI in DR callus. Taken together, G6PDH activity involved in GSH maintenance and H2O2 accumulation under salt stress. And H2O2 regulated G6PDH, GR, and GPX activities to maintain GSH levels. In the process, G6PDH plays a central role.
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Affiliation(s)
- Xiaomin Wang
- Key Laboratory of Arid and Grassland Agroecology (Ministry of Education), School of Life Sciences, Lanzhou University, Lanzhou Gansu 730000, People's Republic of China
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116
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Shibagaki N, Grossman A. The State of Sulfur Metabolism in Algae: From Ecology to Genomics. SULFUR METABOLISM IN PHOTOTROPHIC ORGANISMS 2008. [DOI: 10.1007/978-1-4020-6863-8_13] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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117
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RoyChoudhury A, Roy C, Sengupta DN. Transgenic tobacco plants overexpressing the heterologous lea gene Rab16A from rice during high salt and water deficit display enhanced tolerance to salinity stress. PLANT CELL REPORTS 2007; 26:1839-59. [PMID: 17554543 DOI: 10.1007/s00299-007-0371-2] [Citation(s) in RCA: 87] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2007] [Revised: 04/16/2007] [Accepted: 04/23/2007] [Indexed: 05/15/2023]
Abstract
The full length Rab16A, from the indica rice Pokkali, was introduced into tobacco by Agrobacterium-mediated transformation. The transgene was stably integrated into the genome and they originated from different lines of integration. Expression of Rab16A transcript driven by its own promoter (stress inducible) in T2 progenies, only when triggered by salinity/ABA/PEG (Polyethylene glycol)-mediated dehydration, but not at the constitutive level, led to the stress-induced accumulation of RAB16A protein in the leaves of transgenic plants. The selected independent transgenic lines showed normal growth, morphology and seed production as the WT plants without any yield penalty under stress conditions. They exhibited significantly increased tolerance to salinity, sustained growth rates under stress conditions; with concomitant increased osmolyte production like reducing sugars, proline and higher polyamines. They also showed delayed development of damage symptoms with better antioxidative machinery and more favorable mineral balance, as reflected by reduced H2O2 levels and lipid peroxidation, lesser chlorophyll loss as well as lesser accumulation of Na+ and greater accumulation of K+ in 200 mM NaCl. These findings establish the potential role of Rab16A gene in conferring salt tolerance without affecting growth and yield, as well as pointing to the fact that the upstream region of Rab16A behaves as an efficient stress-inducible promoter. Our result also suggests the considerable potential of Group 2 lea genes as molecular tools for genetic engineering of plants towards stress tolerance.
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Affiliation(s)
- Aryadeep RoyChoudhury
- Department of Botany, Bose Institute, 93/1, Acharya Prafulla Chandra Road, Kolkata 700009, West Bengal, India
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118
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Yoshimura K, Ogawa T, Ueda Y, Shigeoka S. AtNUDX1, an 8-oxo-7,8-dihydro-2'-deoxyguanosine 5'-triphosphate pyrophosphohydrolase, is responsible for eliminating oxidized nucleotides in Arabidopsis. PLANT & CELL PHYSIOLOGY 2007; 48:1438-49. [PMID: 17804481 DOI: 10.1093/pcp/pcm112] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Cellular DNA, RNA and their precursor nucleotides are at high risk of being oxidized by reactive oxygen species. An oxidized base, 8-oxo-7,8-dihydro-2'-(deoxy)guanosine, can pair with both adenine and cytosine, and thus would cause both replicational and translational errors. Previously, we have reported that an Arabidopsis Nudix hydrolase, AtNUDX1, acts to hydrolyze an oxidized deoxyribonucleotide, 8-oxo-7,8-dihydro-2'-deoxyguanosine 5'-triphosphate (8-oxo-dGTP). Here we showed that 8-oxo-dGTP pyrophosphohydrolase activity is not exhibited by any other Arabidopsis Nudix hydrolase. AtNUDX1 acted on an oxidized ribonucleotide, 8-oxo-GTP, with high affinity (K(m) 28.1 microM). In a transcriptional mutational analysis using the lacZ reporter gene, the phenotypic suppression of the lacZ amber mutation in a mutT-deficient Escherichia coli strain caused by the misincorporation of 8-oxo-GTP into the mRNA was significantly diminished by expression of AtNUDX1. These findings suggest that AtNUDX1 prevents transcriptional errors in vivo. A confocal microscopic analysis using a green fluorescent protein (GFP) fusion protein demonstrated that AtNUDX1 is distributed in the cytosol, where the main pool of nucleotides in the cells exists. The level of 8-oxo-guanosine in genomic DNA was significantly increased in knockout nudx1 plants compared with wild-type plants under normal and oxidative stress (3 microM paraquat) conditions. The results obtained here indicate that AtNUDX1 functions in cellular defense against oxidative DNA and RNA damage through the sanitization of their precursor pools in the cytosol in Arabidopsis cells.
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Affiliation(s)
- Kazuya Yoshimura
- Department of Food and Nutritional Science, College of Bioscience and Biotechnology, Chubu University, 1200 Matsumoto-cho, Kasugai, Aichi, 487-8501 Japan
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119
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Hema R, Senthil-Kumar M, Shivakumar S, Chandrasekhara Reddy P, Udayakumar M. Chlamydomonas reinhardtii, a model system for functional validation of abiotic stress responsive genes. PLANTA 2007; 226:655-70. [PMID: 17431668 DOI: 10.1007/s00425-007-0514-2] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2006] [Accepted: 03/13/2007] [Indexed: 05/02/2023]
Abstract
Stress tolerance is a multigenic character and there are many stress responsive genes, which are stress specific. Although many of these have been cloned, their functional significance remains fragmentary. Hence it is important to identify the relevant stress genes involved in altering the metabolism for adaptation. Overexpression is one of the several approaches and Chlamydomonas is a suitable system to study the functional relevance of stress genes. Stress responses can only be assessed on prior exposure to sublethal induction stress. In this study the acclimation response of Chlamydomonas was assessed for different abiotic stresses using physiological screens like chlorophyll stability, membrane damage, cell viability, accumulation of free radicals, survival and recovery growth. We demonstrate that Chlamydomonas responds to diverse stresses and is a potential system to study the relevance of stress genes. The relevance of choline oxidase A (codA), a key enzyme in glycinebetaine biosynthesis, was examined by developing transformants expressing codA gene from Arthrobacter globiformis. Southern positive transformants showed enhanced accumulation of glycinebetaine. The transformants also showed enhanced growth under salinity, high light coupled with methylviologen-induced oxidative stress, high temperature and cold stress. However the transgenics were not tolerant to PEG-mediated simulated osmotic stress, LiCl, menadione and UV stress. Increased cell survival and decreased chlorophyll degradation in transformants under acclimated conditions further confirmed the relevance of codA in imparting stress tolerance. Our results indicated that the relevance of stress responsive genes can be efficiently validated for diverse abiotic stresses using Chlamydomonas system.
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Affiliation(s)
- R Hema
- Department of Crop Physiology, University of Agricultural Sciences, GKVK, Bangalore 560 065, India
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120
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Tanaka S, Suda Y, Ikeda K, Ono M, Miyasaka H, Watanabe M, Sasaki K, Hirata K. A novel gene with antisalt and anticadmium stress activities from a halotolerant marine green alga Chlamydomonas sp. W80. FEMS Microbiol Lett 2007; 271:48-52. [PMID: 17391362 DOI: 10.1111/j.1574-6968.2007.00696.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
A novel gene with antistress activities against both salt (NaCl) and cadmium stresses was isolated from the cDNA library of halotolerant green alga Chlamydomonas sp. strain W80 by a functional expression screening with Escherichia coli. The C-terminal region of this protein is responsible for the antistress activity, because N-terminal truncated clone of this gene retains the antistress activity, and the C-terminal truncated clone loses the activity. In the C-terminal region, there is a histidine and aspartic acid-rich domain (HD-rich domain).
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Affiliation(s)
- Satoshi Tanaka
- The Kansai Electric Power Co, Environmental Research Center, Kyoto, Japan
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121
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Abstract
Glutathione peroxidases (GPXs, EC 1.11.1.9) were first discovered in mammals as key enzymes involved in scavenging of activated oxygen species (AOS). Their efficient antioxidant activity depends on the presence of the rare amino-acid residue selenocysteine (SeCys) at the catalytic site. Nonselenium GPX-like proteins (NS-GPXs) with a Cys residue instead of SeCys have also been found in most organisms. As SeCys is important for GPX activity, the function of the NS-GPX can be questioned. Here, we highlight the evolutionary link between NS-GPX and seleno-GPX, particularly the evolution of the SeCys incorporation system. We then discuss what is known about the enzymatic activity and physiological functions of NS-GPX. Biochemical studies have shown that NS-GPXs are not true GPXs; notably they reduce AOS using reducing substrates other than glutathione, such as thioredoxin. We provide evidence that, in addition to their inefficient scavenging action, NS-GPXs act as AOS sensors in various signal-transduction pathways.
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122
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Tardif G, Kane NA, Adam H, Labrie L, Major G, Gulick P, Sarhan F, Laliberté JF. Interaction network of proteins associated with abiotic stress response and development in wheat. PLANT MOLECULAR BIOLOGY 2007; 63:703-18. [PMID: 17211514 DOI: 10.1007/s11103-006-9119-6] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2006] [Accepted: 11/22/2006] [Indexed: 05/13/2023]
Abstract
Wheat is the most widely adapted crop to abiotic stresses and considered an excellent system to study stress tolerance in spite of its genetic complexity. Recent studies indicated that several hundred genes are either up- or down-regulated in response to stress treatment. To elucidate the function of some of these genes, an interactome of proteins associated with abiotic stress response and development in wheat was generated using the yeast two-hybrid GAL4 system and specific protein interaction assays. The interactome is comprised of 73 proteins, generating 97 interactions pairs. Twenty-one interactions were confirmed by bimolecular fluorescent complementation in Nicotiana benthamiana. A confidence-scoring system was elaborated to evaluate the significance of the interactions. The main feature of this interactome is that almost all bait proteins along with their interactors were interconnected, creating a spider web-like structure. The interactome revealed also the presence of a "cluster of proteins involved in flowering control" in three- and four-protein interaction loops. This network provides a novel insight into the complex relationships among transcription factors known to play central roles in vernalization, flower initiation and abscisic acid signaling, as well as associations that tie abiotic stress with other regulatory and signaling proteins. This analysis provides useful information in elucidating the molecular mechanism associated with abiotic stress response in plants.
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Affiliation(s)
- Guylaine Tardif
- Institut Armand-Frappier, Institut national de la recherche scientifique, 531 boulevard des Prairies, Laval, Québec, Canada, H7V 1B7
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123
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Navrot N, Collin V, Gualberto J, Gelhaye E, Hirasawa M, Rey P, Knaff DB, Issakidis E, Jacquot JP, Rouhier N. Plant glutathione peroxidases are functional peroxiredoxins distributed in several subcellular compartments and regulated during biotic and abiotic stresses. PLANT PHYSIOLOGY 2006; 142:1364-79. [PMID: 17071643 PMCID: PMC1676047 DOI: 10.1104/pp.106.089458] [Citation(s) in RCA: 227] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
We provide here an exhaustive overview of the glutathione (GSH) peroxidase (Gpx) family of poplar (Populus trichocarpa). Although these proteins were initially defined as GSH dependent, in fact they use only reduced thioredoxin (Trx) for their regeneration and do not react with GSH or glutaredoxin, constituting a fifth class of peroxiredoxins. The two chloroplastic Gpxs display a marked selectivity toward their electron donors, being exclusively specific for Trxs of the y type for their reduction. In contrast, poplar Gpxs are much less specific with regard to their electron-accepting substrates, reducing hydrogen peroxide and more complex hydroperoxides equally well. Site-directed mutagenesis indicates that the catalytic mechanism and the Trx-mediated recycling process involve only two (cysteine [Cys]-107 and Cys-155) of the three conserved Cys, which form a disulfide bridge with an oxidation-redox midpoint potential of -295 mV. The reduction/formation of this disulfide is detected both by a shift on sodium dodecyl sulfate-polyacrylamide gel electrophoresis or by measuring the intrinsic tryptophan fluorescence of the protein. The six genes identified coding for Gpxs are expressed in various poplar organs, and two of them are localized in the chloroplast, with one colocalizing in mitochondria, suggesting a broad distribution of Gpxs in plant cells. The abundance of some Gpxs is modified in plants subjected to environmental constraints, generally increasing during fungal infection, water deficit, and metal stress, and decreasing during photooxidative stress, showing that Gpx proteins are involved in the response to both biotic and abiotic stress conditions.
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Affiliation(s)
- Nicolas Navrot
- Unité Mixte de Recherche Institut National de la Recherche Agronomique-Université Henri Poincaré 1136, Université Henri Poincaré, 54506 Vandoeuvre cedex, France
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124
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Iqbal A, Yabuta Y, Takeda T, Nakano Y, Shigeoka S. Hydroperoxide reduction by thioredoxin-specific glutathione peroxidase isoenzymes of Arabidopsis thaliana. FEBS J 2006; 273:5589-97. [PMID: 17096689 DOI: 10.1111/j.1742-4658.2006.05548.x] [Citation(s) in RCA: 81] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Arabidopsis thaliana contains eight glutathione peroxidase (GPX) homologs (AtGPX1-8). Four mature GPX isoenzymes with different subcellular distributions, AtGPX1, -2, -5 and -6, were overexpressed in Escherichia coli and characterized. Interestingly, these recombinant proteins were able to reduce H2O2, cumene hydroperoxide, phosphatidylcholine and linoleic acid hydroperoxides using thioredoxin but not glutathione or NADPH as an electron donor. The reduction activities of the recombinant proteins with H2O2 were 2-7 times higher than those with cumene hydroperoxide. Km values for thioredoxin and H2O2 were 2.2-4.0 and 14.0-25.4 microM, respectively. These finding suggest that GPX isoenzymes may function to detoxify H2O2 and organic hydroperoxides using thioredoxin in vivo and may also be involved in regulation of the cellular redox homeostasis by maintaining the thiol/disulfide or NADPH/NADP balance.
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Affiliation(s)
- Aqib Iqbal
- Department of Applied Biological Chemistry, Osaka Prefecture University, Sakai, Japan
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125
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Meyer AJ, Hell R. Glutathione homeostasis and redox-regulation by sulfhydryl groups. PHOTOSYNTHESIS RESEARCH 2005; 86:435-57. [PMID: 16315075 DOI: 10.1007/s11120-005-8425-1] [Citation(s) in RCA: 93] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2005] [Accepted: 06/06/2005] [Indexed: 05/05/2023]
Abstract
Continuous control of metabolism and developmental processes is a key feature of live cells. Cysteine thiol residues of proteins are both exceptionally useful in terms of structural and regulatory aspects, but at the same time exceptionally vulnerable to oxidation. Conserved cysteines thus are highly important for the function of metabolic enzymes and for signaling processes underlying responses to environmental factors. The underlying mechanism for the central role of thiol-mediated redox control in cellular metabolism is the ability of the cysteine-thiols to reversibly change their redox state followed by changes of structural, catalytic or regulatory functions. The cellular glutathione/glutathione disulfide redox buffer is present in cells at millimolar concentrations and forms one major basis of redox homeostasis by which protein thiols can maintain their redox state or oxidized protein thiols can be reverted to their reduced state. Besides acting as redox buffer, glutathione also acts as an electron donor for both scavenging of reactive oxygen, e.g. from photosynthesis and respiration, and metabolic reactions such as reduction of hydroperoxides and lipidperoxides or sulfate assimilation. The central role of glutathione is further emphasized by its involvement in signaling processes and the crosstalk of redox signaling processes with other means of signaling including protein glutathionylation and control of transcription factors. The present review aims at highlighting the key functions of glutathione in thiol-mediated redox control and its interplay with other protein-thiol-based redox systems.
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Affiliation(s)
- Andreas J Meyer
- Heidelberg Institute of Plant Sciences, University of Heidelberg, Im Neuenheimer Feld 360, 69120 Heidelberg, Germany.
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126
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Luo H, Song F, Zheng Z. Overexpression in transgenic tobacco reveals different roles for the rice homeodomain gene OsBIHD1 in biotic and abiotic stress responses. JOURNAL OF EXPERIMENTAL BOTANY 2005; 56:2673-82. [PMID: 16105854 DOI: 10.1093/jxb/eri260] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
The rice OsBIHD1 gene encodes a transcriptional factor belonging to the homeodomain class. It had previously been shown to be activated by treatment with benzothiadiazole, a chemical inducer of disease resistance, and in an incompatible interaction between rice and the blast fungus. To allow a better understanding of the function of OsBIHD1 in plant disease resistance response, the OsBIHD1 gene in tobacco was overexpressed by Agrobacterium-mediated leaf disc transformation with a construct containing the OsBIHD1 ORF under control of the 35S promoter. Overexpression of the rice OsBIHD1 gene in some of the transgenic tobacco lines led to some morphological abnormalities in the top buds and roots. The transgenic tobacco plants showed an elevated level of defence-related PR-1 gene expression and enhanced disease resistance against infection by tomato mosaic virus, tobacco mosaic virus, and Phytophthora parasitica var. nicotianae. However, the transgenic tobacco plants overexpressing OsBIHD1 showed enhanced sensitivity to salt and oxidative stress as compared with the wild-type plants. The results suggested that the OsBIHD1 protein may be positively involved in activating expression of the defence-related genes in disease resistance responses, and is also important in rice development and abiotic stress tolerance.
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Affiliation(s)
- Hongli Luo
- Institute of Biotechnology, Zhejiang University, Hangzhou, Zhejiang 310029, PR China
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127
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Vinocur B, Altman A. Recent advances in engineering plant tolerance to abiotic stress: achievements and limitations. Curr Opin Biotechnol 2005; 16:123-32. [PMID: 15831376 DOI: 10.1016/j.copbio.2005.02.001] [Citation(s) in RCA: 610] [Impact Index Per Article: 32.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Abiotic stresses, especially salinity and drought, are the primary causes of crop loss worldwide. Plant adaptation to environmental stresses is dependent upon the activation of cascades of molecular networks involved in stress perception, signal transduction, and the expression of specific stress-related genes and metabolites. Consequently, engineering genes that protect and maintain the function and structure of cellular components can enhance tolerance to stress. Our limited knowledge of stress-associated metabolism remains a major gap in our understanding; therefore, comprehensive profiling of stress-associated metabolites is most relevant to the successful molecular breeding of stress-tolerant crop plants. Unraveling additional stress-associated gene resources, from both crop plants and highly salt- and drought-tolerant model plants, will enable future molecular dissection of salt-tolerance mechanisms in important crop plants.
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Affiliation(s)
- Basia Vinocur
- The Robert H Smith Institute of Plant Sciences and Genetics in Agriculture and the Otto Warburg Center for Agricultural Biotechnology, The Hebrew University of Jerusalem, PO Box 12, Rehovot 76100, Israel
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128
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Abstract
A reduced form of glutathione (GSH) is considered to protect the cell from oxidative damage, based on its redox buffering action and abundance in the cell. However, in plants, the high redox potential molecule ascorbate exists at comparable or higher concentrations and is used for scavenging hydrogen peroxide as an electron donor. Recently, examples that cannot be explained simply by the antioxidant activity of GSH have been increasing in number. This article summarizes the recent findings on the glutathione-associated events in plants, in particular, growth and development including cell differentiation, cell death and senescence, pathogen resistance, and enzymatic regulation.
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Affiliation(s)
- Ken'ichi Ogawa
- Research Institute for Biological Sciences Okayama, Okayama, Japan.
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129
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Herbette S, Menn AL, Rousselle P, Ameglio T, Faltin Z, Branlard G, Eshdat Y, Julien JL, Drevet JR, Roeckel-Drevet P. Modification of photosynthetic regulation in tomato overexpressing glutathione peroxidase. Biochim Biophys Acta Gen Subj 2005; 1724:108-18. [PMID: 15921856 DOI: 10.1016/j.bbagen.2005.04.018] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2004] [Revised: 04/21/2005] [Accepted: 04/21/2005] [Indexed: 11/22/2022]
Abstract
To investigate the function of glutathione peroxidase (GPX) in plants, we produced transgenic tomato plants overexpressing an eukaryotic selenium-independent GPX (GPX5). We show here that total GPX activity was increased by 50% in transgenic plants, when compared to control plants transformed with the binary vector without the insert (PZP111). A preliminary two-dimensional electrophoretic protein analysis of the GPX overexpressing plants showed notably a decrease in the accumulation of proteins identified as rubisco small subunit 1 and fructose-1,6-bisphosphate aldolase, two proteins involved in photosynthesis. These observations, together with the fact that in standard culture conditions, GPX-overexpressing plants were not phenotypically distinct from control plants prompted us to challenge the plants with a chilling treatment that is known to affect photosynthesis activity. We found that upon chilling treatment with low light level, photosynthesis was not affected in GPX-overexpressing plants while it was in control plants, as revealed by chlorophyll fluorescence parameters and fructose-1,6-biphosphatase activity. These results suggest that overexpression of a selenium-independent GPX in tomato plants modifies specifically gene expression and leads to modifications of photosynthetic regulation processes.
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130
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Finkemeier I, Goodman M, Lamkemeyer P, Kandlbinder A, Sweetlove LJ, Dietz KJ. The mitochondrial type II peroxiredoxin F is essential for redox homeostasis and root growth of Arabidopsis thaliana under stress. J Biol Chem 2005; 280:12168-80. [PMID: 15632145 DOI: 10.1074/jbc.m413189200] [Citation(s) in RCA: 160] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Peroxiredoxins (Prx) have recently moved into the focus of plant and animal research in the context of development, adaptation, and disease, as they function both in antioxidant defense by reducing a broad range of toxic peroxides and in redox signaling relating to the adjustment of cell redox and antioxidant metabolism. At-PrxII F is one of six type II Prx identified in the genome of Arabidopsis thaliana and the only Prx that is targeted to the plant mitochondrion. Therefore, it might be assumed to have functions similar to the human 2-Cys Prx (PRDX3) and type II Prx (PRDX5) and yeast 1-Cys Prx that likewise have mitochondrial localizations. This paper presents a characterization of PrxII F at the level of subcellular distribution, activity, and reductive regeneration by mitochondrial thioredoxin and glutaredoxin. By employing tDNA insertion mutants of A. thaliana lacking expression of AtprxII F (KO-AtPrxII F), it is shown that under optimal environmental conditions the absence of PrxII F is almost fully compensated for, possibly by increases in activity of mitochondrial ascorbate peroxidase and glutathione-dependent peroxidase. However, a stronger inhibition of root growth in KO-AtPrxII F seedlings as compared with wild type is observed under stress conditions induced by CdCl2 as well as after administration of salicylhydroxamic acid, an inhibitor of cyanide-insensitive respiration. Simultaneously, major changes in the abundance of both nuclear and mitochondria-encoded transcripts were observed. These results assign a principal role to PrxII F in antioxidant defense and possibly redox signaling in plants cells.
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Affiliation(s)
- Iris Finkemeier
- Department of Plant Physiology and Biochemistry, University of Bielefeld, 33501 Bielefeld, Germany
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131
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Ohara K, Kokado Y, Yamamoto H, Sato F, Yazaki K. Engineering of ubiquinone biosynthesis using the yeast coq2 gene confers oxidative stress tolerance in transgenic tobacco. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2004; 40:734-43. [PMID: 15546356 DOI: 10.1111/j.1365-313x.2004.02246.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Ubiquinone (UQ), an electron carrier in the respiratory chain ranging from bacteria to humans, shows antioxidative activity in vitro, but its physiological role in vivo is not yet clarified in plants. UQ biosynthesis was modified by overexpressing the yeast gene coq2, which encodes p-hydroxybenzoate:polyprenyltransferase, to increase the accumulation of UQ-6 in yeast and UQ-10 in tobacco. The yeast and tobacco transgenic lines showed about a three- and six-fold increase in UQ, respectively. COQ2 polypeptide, the localization of which was forcibly altered to the endoplasmic reticulum, had the same or a greater effect as mitochondria-localized COQ2 on the increase in UQ in both the yeast and tobacco transformants, indicating that the UQ intermediate is transported from the endoplasmic reticulum to the mitochondria. Plants with a high UQ level are more resistant to oxidative stresses caused by methyl viologen or high salinity. This is attributable to the greater radical scavenging ability of the transgenic lines when compared with the wild type.
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Affiliation(s)
- Kazuaki Ohara
- Laboratory of Plant Gene Expression, Research Institute for Sustainable Humanosphere, Kyoto University, Uji 611-0011, Japan
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132
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Tanaka S, Ikeda K, Miyasaka H. Isolation of a new member of group 3 late embryogenesis abundant protein gene from a halotorelant green alga by a functional expression screening with cyanobacterial cells. FEMS Microbiol Lett 2004. [DOI: 10.1111/j.1574-6968.2004.tb09624.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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