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Fortunato S, Nigro D, Lasorella C, Marcotuli I, Gadaleta A, de Pinto MC. The Role of Glutamine Synthetase (GS) and Glutamate Synthase (GOGAT) in the Improvement of Nitrogen Use Efficiency in Cereals. Biomolecules 2023; 13:1771. [PMID: 38136642 PMCID: PMC10742212 DOI: 10.3390/biom13121771] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2023] [Revised: 12/06/2023] [Accepted: 12/07/2023] [Indexed: 12/24/2023] Open
Abstract
Cereals are the most broadly produced crops and represent the primary source of food worldwide. Nitrogen (N) is a critical mineral nutrient for plant growth and high yield, and the quality of cereal crops greatly depends on a suitable N supply. In the last decades, a massive use of N fertilizers has been achieved in the desire to have high yields of cereal crops, leading to damaging effects for the environment, ecosystems, and human health. To ensure agricultural sustainability and the required food source, many attempts have been made towards developing cereal crops with a more effective nitrogen use efficiency (NUE). NUE depends on N uptake, utilization, and lastly, combining the capability to assimilate N into carbon skeletons and remobilize the N assimilated. The glutamine synthetase (GS)/glutamate synthase (GOGAT) cycle represents a crucial metabolic step of N assimilation, regulating crop yield. In this review, the physiological and genetic studies on GS and GOGAT of the main cereal crops will be examined, giving emphasis on their implications in NUE.
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Affiliation(s)
- Stefania Fortunato
- Department of Biosciences, Biotechnology and Environment, University of Bari Aldo Moro, Via Orabona 4, 70125 Bari, Italy; (S.F.)
| | - Domenica Nigro
- Department of Soil, Plant and Food Sciences, University of Bari Aldo Moro, Via Orabona 4, 70125 Bari, Italy; (D.N.); (I.M.)
| | - Cecilia Lasorella
- Department of Biosciences, Biotechnology and Environment, University of Bari Aldo Moro, Via Orabona 4, 70125 Bari, Italy; (S.F.)
| | - Ilaria Marcotuli
- Department of Soil, Plant and Food Sciences, University of Bari Aldo Moro, Via Orabona 4, 70125 Bari, Italy; (D.N.); (I.M.)
| | - Agata Gadaleta
- Department of Soil, Plant and Food Sciences, University of Bari Aldo Moro, Via Orabona 4, 70125 Bari, Italy; (D.N.); (I.M.)
| | - Maria Concetta de Pinto
- Department of Biosciences, Biotechnology and Environment, University of Bari Aldo Moro, Via Orabona 4, 70125 Bari, Italy; (S.F.)
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Gao Y, Zhang Y, Ji X, Wang J, Suo N, Liu J, Huo X. Identification of Dioscorea opposite Thunb. CDPK gene family reveals that DoCDPK20 is related to heat resistance. PeerJ 2023; 11:e16110. [PMID: 37744230 PMCID: PMC10517659 DOI: 10.7717/peerj.16110] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2023] [Accepted: 08/25/2023] [Indexed: 09/26/2023] Open
Abstract
Temperature affects the growth and yield of yam (Dioscorea opposite Thunb.), and calcium-dependent protein kinases (CDPKs) play an important role in the plant stress response. However, there has been a lack of system analyses of yam's CDPK gene family. In this study, 29 CDPK transcriptome sequences with complete open reading frames (ORFs) were identified from yam RNA sequencing data. The sequences were classified into four groups (I-VI) using phylogenetic analysis. Two DoCDPK genes were randomly selected from each group and the gene patterns of yam leaves were determined using quantitative real-time PCR (qRT-PCR) under high and low temperature stress in order to show their unique functions in mediating specific responses. Among them, DoCDPK20 was significantly induced in high temperatures. The pPZP221-DoCDPK20 was transformed into tobacco leaves using an agrobacterium-mediated method. Under high temperature stress, DoCDPK20 overexpression reduced photosynthesis and improved heat tolerance in transgenic tobacco. Our research offers meaningful perspectives into CDPK genes and new avenues for the genetic engineering and molecular breeding of yam.
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Affiliation(s)
- Yuanli Gao
- Inner Mongolia Agricultural University, Hohhot, China
| | - Yanfang Zhang
- Inner Mongolia Agricultural University, Hohhot, China
| | - Xiang Ji
- Inner Mongolia Agricultural University, Hohhot, China
| | - Jinxin Wang
- Inner Mongolia Agricultural University, Hohhot, China
| | - Ningning Suo
- Inner Mongolia Agricultural University, Hohhot, China
| | - Jiecai Liu
- Inner Mongolia Agricultural University, Hohhot, China
| | - Xiuwen Huo
- Inner Mongolia Agricultural University, Hohhot, China
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El-aty MSA, Abo-youssef MI, Bahgt MM. Genetic diversity Analysis using molecular markers of some rice varieties for Physiological, biochemical and yield Traits under water deficit condition.. [DOI: 10.21203/rs.3.rs-3111398/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/02/2023]
Abstract
Abstract
Rice is a major staple food crop all over the world. Recent climate change trends forecast an increase in drought severity, necessitating the creation of novel drought-tolerant rice cultivars in order to continue rice production in this ecosystem. This study was carried out at the experimental farm of the rice research and training center (RRTC) using the randomized complete block design (RCBD) to assess the impact of water scarcity on eight rice varieties by identifying differences in physiological and biochemical responses among drought-sensitive and resistant rice varieties, in addition applying two PCR-based molecular marker systems ISSR and SCoT to assess the genetic diversity among the studied rice varieties. The results revealed that, Water shortage stress significantly reduced relative water content, total chlorophyll content, grain yield, and yield characteristics. while, it significantly raised proline content and antioxidant enzyme activity (CAT, APX, and SOD). The combined analysis of variance demonstrated that the mean squares for environments, varieties, and their interaction were highly significant for all investigated traits, suggesting that the germplasm used in the study had significant genetic diversity from one environment (normal irrigation) to another (water deficit) and could rank differently in both of them. Mean performance data showed that, Puebla and Hispagran varieties were selected as the most favourable varieties for most physiological and biochemical parameters studied, as well as yield traits which recorded the highest desirable values under both irrigation treatments. They were recommended for use in rice hybrid breeding programmes for water scarcity tolerance. Genetic Similarity and Cluster Analysis revealed that, the both molecular markers exhibited comparable genetic diversity values but a higher level of polymorphism was represented by ISSR. This indicates the high efficiency of both markers in discriminating the tested varieties. The dendrogram generated by ISSR and SCoT markers combined data divided the varieties into two major clusters. Cluster I consisted of the genotype Sakha 106. Cluster II retained seven varieties, which were further divided into two sub-clusters; Sakha 101, Sakha 105, Sakha 106, Sakha 107 constituted the first subgroup, while Giza 177, Hispagran, and Puebla formed the second one.
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Yao Z, Rao Z, Hou S, Tian C, Liu CY, Yang X, Zhu G. The appropriate expression and coordination of glycolate oxidase and catalase are vital to the successful construction of the photorespiratory metabolic pathway. FRONTIERS IN PLANT SCIENCE 2022; 13:999757. [PMID: 36388585 PMCID: PMC9647076 DOI: 10.3389/fpls.2022.999757] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/21/2022] [Accepted: 09/20/2022] [Indexed: 06/16/2023]
Abstract
Photorespiration has emerged as a hotspot in the evolution of photosynthesis owing to the energy loss during the process. To ensure the physiological functions of photorespiration such as light protection, H2O2 signaling, and stress resistance, separate the photorespiration glycolic acid flow, and minimize photorespiration loss, a balance must be maintained during the construction of photorespiratory metabolic branch. In this study, glycolate oxidase (GLO) and catalase (CAT) were introduced into potato (Solanum tuberosum) chloroplasts through the expression of fusion protein. Through the examination of phenotypic characteristics, photosynthesis, anatomical structure, and enzyme activity, the efficiency of the photorespiration pathway was demonstrated. The results showed that certain transgenic lines plants had shorter plant height and deformed leaves and tubers in addition to the favorable photosynthetic phenotypes of thicker leaves and larger and denser mesophyll cells. By Diaminobenzidine (DAB) staining analysis of the leaves, the intermediate H2O2 could not be decomposed in time to cause biomass decline and malformation, and the excessive glycolate shunt formed by the overexpression of the fusion protein affected other important physiological activities. Hence, the appropriate and coordinated expression of glycolate oxidase and catalase is essential for the establishment of photorespiration pathways in chloroplasts.
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Affiliation(s)
- Zhen Yao
- College of Horticulture and Gardening, Yangtze University, Jingzhou, China
| | - Zelai Rao
- College of Horticulture and Gardening, Yangtze University, Jingzhou, China
- School of Finance and Economics, Jimei University, Xiamen, China
| | - ShuWang Hou
- College of Horticulture and Gardening, Yangtze University, Jingzhou, China
| | - Changwei Tian
- College of Horticulture and Gardening, Yangtze University, Jingzhou, China
| | - Chun-Yan Liu
- College of Horticulture and Gardening, Yangtze University, Jingzhou, China
| | - Xiulan Yang
- Department of Medicine, Yangtze University, Jingzhou, China
| | - Guicai Zhu
- College of Horticulture and Gardening, Yangtze University, Jingzhou, China
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Nitrogen assimilation in plants: current status and future prospects. J Genet Genomics 2021; 49:394-404. [PMID: 34973427 DOI: 10.1016/j.jgg.2021.12.006] [Citation(s) in RCA: 72] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2021] [Revised: 11/30/2021] [Accepted: 12/23/2021] [Indexed: 11/24/2022]
Abstract
Nitrogen (N) is the driving force for crop yields, however, excessive N application in agriculture not only increases production cost, but also causes severe environmental problems. Therefore, comprehensively understanding the molecular mechanisms of N use efficiency (NUE) and breeding crops with higher NUE is essential to tackle these problems. NUE of crops is determined by N uptake, transport, assimilation, and remobilization. In the process of N assimilation, nitrate reductase (NR), nitrite reductase (NiR), glutamine synthetase (GS), and glutamine-2-oxoglutarate aminotransferase (GOGAT, also known as glutamate synthase) are the major enzymes. NR and NiR mediate the initiation of inorganic N utilization, and GS/GOGAT cycle converts inorganic N to organic N, playing a vital role in N assimilation and the final NUE of crops. Besides, asparagine synthetase (ASN), glutamate dehydrogenase (GDH), and carbamoylphosphate synthetase (CPSase) are also involved. In this review, we summarize the function and regulation of these enzymes reported in three major crops, rice, maize, wheat, also in the model plant Arabidopsis, and we highlight their application in improving NUE of crops via manipulating N assimilation. Anticipated challenges and prospects toward fully understanding the function of N assimilation and further exploring the potential for NUE improvement are discussed.
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Ancín M, Larraya L, Florez-Sarasa I, Bénard C, Fernández-San Millán A, Veramendi J, Gibon Y, Fernie AR, Aranjuelo I, Farran I. Overexpression of thioredoxin m in chloroplasts alters carbon and nitrogen partitioning in tobacco. JOURNAL OF EXPERIMENTAL BOTANY 2021; 72:4949-4964. [PMID: 33963398 PMCID: PMC8219043 DOI: 10.1093/jxb/erab193] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Accepted: 04/27/2021] [Indexed: 06/02/2023]
Abstract
In plants, there is a complex interaction between carbon (C) and nitrogen (N) metabolism, and its coordination is fundamental for plant growth and development. Here, we studied the influence of thioredoxin (Trx) m on C and N partitioning using tobacco plants overexpressing Trx m from the chloroplast genome. The transgenic plants showed altered metabolism of C (lower leaf starch and soluble sugar accumulation) and N (with higher amounts of amino acids and soluble protein), which pointed to an activation of N metabolism at the expense of carbohydrates. To further delineate the effect of Trx m overexpression, metabolomic and enzymatic analyses were performed on these plants. These results showed an up-regulation of the glutamine synthetase-glutamate synthase pathway; specifically tobacco plants overexpressing Trx m displayed increased activity and stability of glutamine synthetase. Moreover, higher photorespiration and nitrate accumulation were observed in these plants relative to untransformed control plants, indicating that overexpression of Trx m favors the photorespiratory N cycle rather than primary nitrate assimilation. Taken together, our results reveal the importance of Trx m as a molecular mediator of N metabolism in plant chloroplasts.
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Affiliation(s)
- María Ancín
- Institute for Multidisciplinary Applied Biology (IMAB), Dpto. Agronomía, Biotecnología y Alimentación, Universidad Publica de Navarra (UPNA), Campus Arrosadia, 31006 Pamplona, Spain
| | - Luis Larraya
- Institute for Multidisciplinary Applied Biology (IMAB), Dpto. Agronomía, Biotecnología y Alimentación, Universidad Publica de Navarra (UPNA), Campus Arrosadia, 31006 Pamplona, Spain
| | - Igor Florez-Sarasa
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, Am Mühlenberg 1, 14476 Potsdam-Golm, Germany
- Centre for Research in Agricultural Genomics (CRAG) CSIC-IRTA-UAB-UB, Campus UAB Bellaterra, 08193 Barcelona, Spain
| | - Camille Bénard
- UMR 1332 Biologie du Fruit et Pathologie and Plateforme Metabolome Bordeaux, INRA, Bordeaux University, 33882 Villenave d’Ornon, France
| | - Alicia Fernández-San Millán
- Institute for Multidisciplinary Applied Biology (IMAB), Dpto. Agronomía, Biotecnología y Alimentación, Universidad Publica de Navarra (UPNA), Campus Arrosadia, 31006 Pamplona, Spain
| | - Jon Veramendi
- Institute for Multidisciplinary Applied Biology (IMAB), Dpto. Agronomía, Biotecnología y Alimentación, Universidad Publica de Navarra (UPNA), Campus Arrosadia, 31006 Pamplona, Spain
| | - Yves Gibon
- UMR 1332 Biologie du Fruit et Pathologie and Plateforme Metabolome Bordeaux, INRA, Bordeaux University, 33882 Villenave d’Ornon, France
| | - Alisdair R Fernie
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, Am Mühlenberg 1, 14476 Potsdam-Golm, Germany
| | - Iker Aranjuelo
- Instituto de Agrobiotecnología, CSIC-Gobierno de Navarra, Avda. Pamplona 123, 31192 Mutilva, Spain
| | - Inmaculada Farran
- Institute for Multidisciplinary Applied Biology (IMAB), Dpto. Agronomía, Biotecnología y Alimentación, Universidad Publica de Navarra (UPNA), Campus Arrosadia, 31006 Pamplona, Spain
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Wang J, Chen W, Wang H, Li Y, Wang B, Zhang L, Wan X, Li M. Transcription factor CsDOF regulates glutamine metabolism in tea plants (Camellia sinensis). PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2021; 302:110720. [PMID: 33288026 DOI: 10.1016/j.plantsci.2020.110720] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Revised: 09/09/2020] [Accepted: 10/12/2020] [Indexed: 06/12/2023]
Abstract
Glutamine plays a critical role in ammonium assimilation, and contributes substantially to the taste and nutritional quality of tea. To date, little research has been done on glutamine synthesis in tea plants. Here, a zinc finger protein CsDOF and a glutamine synthetase (GS)-encoding gene CsGS2 from tea plant (Camellia sinensis cv 'Shuchazao') were characterized, and their role in glutamine biosynthesis was determined using transient suppression assays in tea leaves and overexpression in Arabidopsis thaliana. The expression patterns of CsDOF and CsGS2, the GS activity and the glutamine content of photosynthetic tissues (leaf and bud) were significantly induced by shade. Suppressing the expression of CsDOF resulted in downregulated expression of CsGS2 and reduction of the leaf glutamine content. Moreover, in CsDOF-silenced plants, the expression of CsDOF and the glutamine content under shade treatment were higher than in natural light. The glutamine content and CsGS2 transcript level were also decreased in tea leaves when CsGS2 was suppressed, while they were higher under shade treatment than in natural light in CsGS2-silenced plants. In addition, the glutamine content and GS2 transcript level were increased when CsDOF and CsGS2 was overexpressed in Arabidopsis thaliana, respectively. In binding analyses, CsDOF directly bound to an AAAG motif in the promoter of CsGS2, and promotes its activity. The study shed new light on the molecular mechanism by which CsDOF activates CsGS2 gene expression and contributes to glutamine biosynthesis in tea plants.
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Affiliation(s)
- Jinhe Wang
- State Key Laboratory of Crop Biology, College of Horticulture Science and Engineering, Shandong Agricultural University, Taian, Shandong, 271018, China
| | - Wenzhen Chen
- State Key Laboratory of Crop Biology, College of Horticulture Science and Engineering, Shandong Agricultural University, Taian, Shandong, 271018, China
| | - Hanyue Wang
- State Key Laboratory of Crop Biology, College of Horticulture Science and Engineering, Shandong Agricultural University, Taian, Shandong, 271018, China
| | - Yuanda Li
- State Key Laboratory of Crop Biology, College of Horticulture Science and Engineering, Shandong Agricultural University, Taian, Shandong, 271018, China
| | - Biao Wang
- State Key Laboratory of Crop Biology, College of Horticulture Science and Engineering, Shandong Agricultural University, Taian, Shandong, 271018, China
| | - Lixia Zhang
- State Key Laboratory of Crop Biology, College of Horticulture Science and Engineering, Shandong Agricultural University, Taian, Shandong, 271018, China
| | - Xiaochun Wan
- State Key Laboratory of Tea Plant Biology and Utilization, Anhui Agricultural University, Hefei, Anhui, 230036, China.
| | - Min Li
- State Key Laboratory of Crop Biology, College of Horticulture Science and Engineering, Shandong Agricultural University, Taian, Shandong, 271018, China.
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Ferreira S, Moreira E, Amorim I, Santos C, Melo P. Arabidopsis thaliana mutants devoid of chloroplast glutamine synthetase (GS2) have non-lethal phenotype under photorespiratory conditions. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2019; 144:365-374. [PMID: 31622939 DOI: 10.1016/j.plaphy.2019.10.009] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Revised: 10/04/2019] [Accepted: 10/08/2019] [Indexed: 06/10/2023]
Abstract
Chloroplast located Glutamine Synthetase (GS2) is believed to play a major role in the reassimilation of ammonium generated by photorespiration, being GS2 knockout mutants unable to grow under photorespiratory conditions (low-CO2 atmosphere) in the species characterized so far (Barley, Lotus). To investigate the importance of GS2 in A. thaliana nitrogen metabolism mutant plants devoid of this GS isoenzyme were characterized. It was shown that GS2 mutants although smaller, slightly chlorotic and with the nitrogen metabolism impaired, were able to grow and complete their life cycle under ordinary air conditions. Surprisingly, GS2 mutants were more tolerant to salt stress than wild-type plants. The lack of GS2 seems to be compensated by higher expression of some GS cytosolic isogenes, namely GLN1;2 and GLN1;3 and by glutamate dehydrogenase, whose activity and expression is enhanced in the GS2 mutant plants and might account for the increased tolerance to salt stress. Under conditions that minimize photorespiration (CO2-enriched atmosphere) plant growth and ammonium assimilation impairment is less evident in the GS2 mutant plants and is accompanied by an adjustment of levels of expression of the cytosolic isogenes, with an increase in the expression of GLN1;3 and a decrease in the expression of the GLN1;1 and GLN1;2. Altogether the results confirm a major role of GS2 in the assimilation of ammonium released during photorespiration, but suggest a redundancy of activity with cytosolic GSs and GDH and further support the involvement of the chloroplastic isoenzyme in primary nitrogen assimilation and plant growth and development in A. thaliana.
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Affiliation(s)
- Sónia Ferreira
- Department of Biology, Faculty of Sciences of the University of Porto, Rua do Campo Alegre s/n, 4169-007, Porto, Portugal.
| | - Emanuel Moreira
- Department of Biology, Faculty of Sciences of the University of Porto, Rua do Campo Alegre s/n, 4169-007, Porto, Portugal.
| | - Isabel Amorim
- Department of Biology, Faculty of Sciences of the University of Porto, Rua do Campo Alegre s/n, 4169-007, Porto, Portugal; GreenUPorto - Research Centre on Sustainable Agri-food Production & Department of Biology, Faculty of Sciences of the University of Porto, Rua do Campo Alegre s/n, 4169-007, Porto, Portugal.
| | - Conceição Santos
- Department of Biology, Faculty of Sciences of the University of Porto, Rua do Campo Alegre s/n, 4169-007, Porto, Portugal; LAQV/REQUIMTE, Department of Biology, Faculty of Sciences of the University of Porto, Rua do Campo Alegre s/n, 4169-007, Porto, Portugal.
| | - Paula Melo
- Department of Biology, Faculty of Sciences of the University of Porto, Rua do Campo Alegre s/n, 4169-007, Porto, Portugal; GreenUPorto - Research Centre on Sustainable Agri-food Production & Department of Biology, Faculty of Sciences of the University of Porto, Rua do Campo Alegre s/n, 4169-007, Porto, Portugal.
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Wang Y, Feng Y, Liu X, Zhong M, Chen W, Wang F, Du H. Response of Gracilaria lemaneiformis to nitrogen deprivation. ALGAL RES 2018. [DOI: 10.1016/j.algal.2018.07.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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James D, Borphukan B, Fartyal D, Ram B, Singh J, Manna M, Sheri V, Panditi V, Yadav R, Achary VMM, Reddy MK. Concurrent Overexpression of OsGS1;1 and OsGS2 Genes in Transgenic Rice ( Oryza sativa L.): Impact on Tolerance to Abiotic Stresses. FRONTIERS IN PLANT SCIENCE 2018; 9:786. [PMID: 29977247 PMCID: PMC6021690 DOI: 10.3389/fpls.2018.00786] [Citation(s) in RCA: 64] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2017] [Accepted: 05/23/2018] [Indexed: 05/18/2023]
Abstract
Glutamine synthetase (GS) is a key enzyme involved in the nitrogen metabolism of higher plants. Abiotic stresses have adverse effects on crop production and pose a serious threat to global food security. GS activity and expression is known to be significantly modulated by various abiotic stresses. However, very few transgenic overexpression studies of GS have studied its impact on abiotic stress tolerance. GS is also the target enzyme of the broad spectrum herbicide Glufosinate (active ingredient: phosphinothricin). In this study, we investigated the effect of concurrent overexpression of the rice cytosolic GS1 (OsGS1;1) and chloroplastic GS2 (OsGS2) genes in transgenic rice on its tolerance to abiotic stresses and the herbicide Glufosinate. Our results demonstrate that the co-overexpression of OsGS1;1 and OsGS2 isoforms in transgenic rice plants enhanced its tolerance to osmotic and salinity stress at the seedling stage. The transgenic lines maintained significantly higher fresh weight, chlorophyll content, and relative water content than wild type (wt) and null segregant (ns) controls, under both osmotic and salinity stress. The OsGS1;1/OsGS2 co-overexpressing transgenic plants accumulated higher levels of proline but showed lower electrolyte leakage and had lower malondialdehyde (MDA) content under the stress treatments. The transgenic lines showed considerably enhanced photosynthetic and agronomic performance under drought and salinity stress imposed during the reproductive stage, as compared to wt and ns control plants. The grain filling rates of the transgenic rice plants under reproductive stage drought stress (64.6 ± 4.7%) and salinity stress (58.2 ± 4.5%) were significantly higher than control plants, thereby leading to higher yields under these abiotic stress conditions. Preliminary analysis also revealed that the transgenic lines had improved tolerance to methyl viologen induced photo-oxidative stress. Taken together, our results demonstrate that the concurrent overexpression of OsGS1;1 and OsGS2 isoforms in rice enhanced physiological tolerance and agronomic performance under adverse abiotic stress conditions, apparently acting through multiple mechanistic routes. The transgenic rice plants also showed limited tolerance to the herbicide Glufosinate. The advantages and limitations of glutamine synthetase overexpression in crop plants, along with future strategies to overcome these limitations for utilization in crop improvement have also been discussed briefly.
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Affiliation(s)
- Donald James
- Crop Improvement Group, International Centre for Genetic Engineering and Biotechnology, New Delhi, India
| | - Bhabesh Borphukan
- Crop Improvement Group, International Centre for Genetic Engineering and Biotechnology, New Delhi, India
| | - Dhirendra Fartyal
- Crop Improvement Group, International Centre for Genetic Engineering and Biotechnology, New Delhi, India
- Department of Biotechnology, Uttarakhand Technical University, Dehradun, India
| | - Babu Ram
- Crop Improvement Group, International Centre for Genetic Engineering and Biotechnology, New Delhi, India
- Department of Biotechnology, Uttarakhand Technical University, Dehradun, India
| | - Jitender Singh
- Crop Improvement Group, International Centre for Genetic Engineering and Biotechnology, New Delhi, India
- National Institute of Plant Genome Research, New Delhi, India
| | - Mrinalini Manna
- Crop Improvement Group, International Centre for Genetic Engineering and Biotechnology, New Delhi, India
| | - Vijay Sheri
- Crop Improvement Group, International Centre for Genetic Engineering and Biotechnology, New Delhi, India
| | - Varakumar Panditi
- Crop Improvement Group, International Centre for Genetic Engineering and Biotechnology, New Delhi, India
| | - Renu Yadav
- Crop Improvement Group, International Centre for Genetic Engineering and Biotechnology, New Delhi, India
| | - V. Mohan M. Achary
- Crop Improvement Group, International Centre for Genetic Engineering and Biotechnology, New Delhi, India
| | - Mallireddy K. Reddy
- Crop Improvement Group, International Centre for Genetic Engineering and Biotechnology, New Delhi, India
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Havé M, Marmagne A, Chardon F, Masclaux-Daubresse C. Nitrogen remobilization during leaf senescence: lessons from Arabidopsis to crops. JOURNAL OF EXPERIMENTAL BOTANY 2017; 68:2513-2529. [PMID: 27707774 DOI: 10.1093/jxb/erw365] [Citation(s) in RCA: 68] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
As a result of climate changes, land use and agriculture have to adapt to new demands. Agriculture is responsible for a large part of the greenhouse gas (GHG) emissions that have to be urgently reduced in order to protect the environment. At the same time, agriculture has to cope with the challenges of sustainably feeding a growing world population. Reducing the use of the ammonia-nitrate fertilizers that are responsible for a large part of the GHGs released and that have a negative impact on carbon balance is one of the objectives of precision agriculture. One way to reduce N fertilizers without dramatically affecting grain yields is to improve the nitrogen recycling and remobilization performances of plants. Mechanisms involved in nitrogen recycling, such as autophagy, are essential for nutrient remobilization at the whole-plant level and for seed quality. Studies on leaf senescence and nutrient recycling provide new perspectives for improvement. The aim of this review is to give an overview of the mechanisms involved in nitrogen recycling and remobilization during leaf senescence and to present the different approaches undertaken to improve nitrogen remobilization efficiency using both model plants and crop species.
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Affiliation(s)
- Marien Havé
- INRA-AgroParisTech, Institut Jean-Pierre Bourgin, UMR1318, ERL CNRS 3559, Saclay Plant Sciences, Versailles, France
| | - Anne Marmagne
- INRA-AgroParisTech, Institut Jean-Pierre Bourgin, UMR1318, ERL CNRS 3559, Saclay Plant Sciences, Versailles, France
| | - Fabien Chardon
- INRA-AgroParisTech, Institut Jean-Pierre Bourgin, UMR1318, ERL CNRS 3559, Saclay Plant Sciences, Versailles, France
| | - Céline Masclaux-Daubresse
- INRA-AgroParisTech, Institut Jean-Pierre Bourgin, UMR1318, ERL CNRS 3559, Saclay Plant Sciences, Versailles, France
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Asad MAU, Lavoie M, Song H, Jin Y, Fu Z, Qian H. Interaction of chiral herbicides with soil microorganisms, algae and vascular plants. THE SCIENCE OF THE TOTAL ENVIRONMENT 2017; 580:1287-1299. [PMID: 28003051 DOI: 10.1016/j.scitotenv.2016.12.092] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/06/2016] [Revised: 12/13/2016] [Accepted: 12/13/2016] [Indexed: 06/06/2023]
Abstract
Chiral herbicides are often used in agriculture as racemic mixtures, although studies have shown that the fate and toxicity of herbicide enantiomers to target and non-target plants can be enantioselective and that herbicide toxicity can be mediated by only one enantiomer. If one enantiomer is active against the target plant, the use of enantiomer-rich herbicide mixtures instead of racemic herbicides could decrease the amount of herbicide applied to a crop and the cost of herbicide application, as well as unintended toxic herbicide effects in the environment. Such a change in the management of herbicide applications requires in-depth knowledge and a critical analysis of the fate and effects of herbicide enantiomers in the environment. This review article first synthesizes the current state of knowledge on soil and plant biodegradation of herbicide enantiomers. Second, we discuss our understanding of the biochemical toxicity mechanisms associated with both enantiomers in target and non-target plants gained from state-of-the-art genomic, proteomic and metabolomic tools. Third, we present the emerging view on the "side effects" of herbicides in the root microbiome and their repercussions on target or non-target plant metabolism. Although our review of the literature indicates that the toxicity of herbicide enantiomers is highly variable depending on plant species and herbicides, we found general trends in the enantioselective toxic effects of different herbicides in vascular plants and algae. The present study will be helpful for pesticide risk assessments as well as for the management of applying enriched-enantiomer herbicides.
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Affiliation(s)
- Muhammad Asad Ullah Asad
- College of Biotechnological and Bioengineering, Zhejiang University of Technology, Hangzhou 310032, PR China
| | - Michel Lavoie
- Quebec-Ocean and Takuvik Joint International Research Unit, Université Laval, Québec G1VOA6, Canada
| | - Hao Song
- College of Environment, Zhejiang University of technology, Hangzhou 310032, PR China
| | - Yujian Jin
- College of Biotechnological and Bioengineering, Zhejiang University of Technology, Hangzhou 310032, PR China
| | - Zhengwei Fu
- College of Biotechnological and Bioengineering, Zhejiang University of Technology, Hangzhou 310032, PR China
| | - Haifeng Qian
- College of Environment, Zhejiang University of technology, Hangzhou 310032, PR China.
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13
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Ferreira MJ, Vale D, Cunha L, Melo P. Role of the C-terminal extension peptide of plastid located glutamine synthetase from Medicago truncatula: Crucial for enzyme activity and needless for protein import into the plastids. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2017; 111:226-233. [PMID: 27951492 DOI: 10.1016/j.plaphy.2016.11.015] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2016] [Revised: 11/22/2016] [Accepted: 11/22/2016] [Indexed: 06/06/2023]
Abstract
Glutamine synthetase (GS), a key enzyme in plant nitrogen metabolism, is encoded by a small family of highly homologous nuclear genes that produce cytosolic (GS1) and plastidic (GS2) isoforms. Compared to GS1, GS2 proteins have two extension peptides, one at the N- and the other at the C-terminus, which show a high degree of conservation among plant species. It has long been known that the N-terminal peptide acts as a transit peptide, targeting the protein to the plastids however, the function of the C-terminal extension is still unknown. To investigate whether the C-terminal extension influences the activity of the enzyme, we produced a C-terminal truncated version of Medicago truncatula GS2a in Escherechia coli and studied its catalytic properties. The activity of the truncated protein was found to be lower than that of MtGS2a and with less affinity for glutamate. The importance of the C-terminal extension for the protein import into the chloroplast was also assessed by transient expression of fluorescently-tagged MtGS2a truncated at the C-terminus, which was correctly detected in the chloroplast. The results obtained in this work demonstrate that the C-terminal extension of M. truncatula GS2a is important for the activity of the enzyme and does not contain crucial information for the import process.
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Affiliation(s)
- Maria João Ferreira
- Departamento de Biologia, Faculdade de Ciências da Universidade do Porto, Rua do Campo Alegre, s/n, 4169-007 Porto, Portugal
| | - Diogo Vale
- Departamento de Biologia, Faculdade de Ciências da Universidade do Porto, Rua do Campo Alegre, s/n, 4169-007 Porto, Portugal
| | - Luis Cunha
- Departamento de Biologia, Faculdade de Ciências da Universidade do Porto, Rua do Campo Alegre, s/n, 4169-007 Porto, Portugal
| | - Paula Melo
- BioISI-Biosystems & Integrative Sciences Institute, Departamento de Biologia, Faculdade de Ciências, Universidade do Porto, Rua Campo Alegre s/n, 4169-007 Porto, Portugal.
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14
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Diaz-Mendoza M, Velasco-Arroyo B, Santamaria ME, González-Melendi P, Martinez M, Diaz I. Plant senescence and proteolysis: two processes with one destiny. Genet Mol Biol 2016; 39:329-38. [PMID: 27505308 PMCID: PMC5004835 DOI: 10.1590/1678-4685-gmb-2016-0015] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2016] [Accepted: 05/10/2016] [Indexed: 01/03/2023] Open
Abstract
Senescence-associated proteolysis in plants is a complex and controlled process,
essential for mobilization of nutrients from old or stressed tissues, mainly leaves,
to growing or sink organs. Protein breakdown in senescing leaves involves many
plastidial and nuclear proteases, regulators, different subcellular locations and
dynamic protein traffic to ensure the complete transformation of proteins of high
molecular weight into transportable and useful hydrolysed products. Protease
activities are strictly regulated by specific inhibitors and through the activation
of zymogens to develop their proteolytic activity at the right place and at the
proper time. All these events associated with senescence have deep effects on the
relocation of nutrients and as a consequence, on grain quality and crop yield. Thus,
it can be considered that nutrient recycling is the common destiny of two processes,
plant senescence and, proteolysis. This review article covers the most recent
findings about leaf senescence features mediated by abiotic and biotic stresses as
well as the participants and steps required in this physiological process, paying
special attention to C1A cysteine proteases, their specific inhibitors, known as
cystatins, and their potential targets, particularly the chloroplastic proteins as
source for nitrogen recycling.
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Affiliation(s)
- Mercedes Diaz-Mendoza
- Centro de Biotecnología y Genómica de Plantas, Universidad Politécnica de Madrid, Madrid, Spain
| | - Blanca Velasco-Arroyo
- Centro de Biotecnología y Genómica de Plantas, Universidad Politécnica de Madrid, Madrid, Spain
| | - M Estrella Santamaria
- Centro de Biotecnología y Genómica de Plantas, Universidad Politécnica de Madrid, Madrid, Spain
| | - Pablo González-Melendi
- Centro de Biotecnología y Genómica de Plantas, Universidad Politécnica de Madrid, Madrid, Spain
| | - Manuel Martinez
- Centro de Biotecnología y Genómica de Plantas, Universidad Politécnica de Madrid, Madrid, Spain
| | - Isabel Diaz
- Centro de Biotecnología y Genómica de Plantas, Universidad Politécnica de Madrid, Madrid, Spain
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15
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Kaminski KP, Kørup K, Andersen MN, Sønderkær M, Andersen MS, Kirk HG, Nielsen KL. Cytosolic glutamine synthetase is important for photosynthetic efficiency and water use efficiency in potato as revealed by high-throughput sequencing QTL analysis. TAG. THEORETICAL AND APPLIED GENETICS. THEORETISCHE UND ANGEWANDTE GENETIK 2015; 128:2143-2153. [PMID: 26163769 PMCID: PMC4624824 DOI: 10.1007/s00122-015-2573-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2015] [Accepted: 06/23/2015] [Indexed: 05/29/2023]
Abstract
WUE phenotyping and subsequent QTL analysis revealed cytosolic GS genes importance for limiting N loss due to photorespiration under well-watered and well-fertilized conditions. Potato (Solanum tuberosum L.) closes its stomata at relatively low soil water deficits frequently encountered in normal field conditions resulting in unnecessary annual yield losses and extensive use of artificial irrigation. Therefore, unraveling the genetics underpinning variation in water use efficiency (WUE) of potato is important, but has been limited by technical difficulties in assessing the trait on individual plants and thus is poorly understood. In this study, a mapping population of potatoes has been robustly phenotyped, and considerable variation in WUE under well-watered conditions was observed. Two extreme WUE bulks of clones were identified and pools of genomic DNA from them as well as the parents were sequenced and mapped to reference potato genome. Following a novel data analysis approach, two highly resolved QTLs were found on chromosome 1 and 9. Interestingly, three genes encoding isoforms of cytosolic glutamine synthase were located in the QTL at chromosome 1 suggesting a major contribution of this enzyme to photosynthetic efficiency and thus WUE in potato. Indeed, Glutamine synthetase enzyme activity of leaf extracts was measured and found to be correlated with contrasting WUE phenotypes.
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Affiliation(s)
- Kacper Piotr Kaminski
- Department of Chemistry and Bioscience, Aalborg University, Fredrik Bajers Vej 7H, 9220, Aalborg Øst, Denmark.
- Department of Biotechnology, Chemistry and Environmental Engineering, Aalborg University, Fredrik Bajers Vej 7H, 9220, Aalborg Øst, Denmark.
| | - Kirsten Kørup
- Department of Agroecology, Faculty of Science and Technology, Aarhus University, Blichers Allé 20, 8830, Tjele, Denmark.
| | - Mathias Neumann Andersen
- Department of Agroecology, Faculty of Science and Technology, Aarhus University, Blichers Allé 20, 8830, Tjele, Denmark.
| | - Mads Sønderkær
- Department of Chemistry and Bioscience, Aalborg University, Fredrik Bajers Vej 7H, 9220, Aalborg Øst, Denmark.
| | - Mette Sondrup Andersen
- Department of Chemistry and Bioscience, Aalborg University, Fredrik Bajers Vej 7H, 9220, Aalborg Øst, Denmark.
| | - Hanne Grethe Kirk
- Danish Potato Breeding Foundation, Grindstedvej 55, 7184, Vandel, Denmark.
| | - Kåre Lehmann Nielsen
- Department of Chemistry and Bioscience, Aalborg University, Fredrik Bajers Vej 7H, 9220, Aalborg Øst, Denmark.
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16
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Sankar R, Prasath BB, Nandakumar R, Santhanam P, Shivashangari KS, Ravikumar V. Growth inhibition of bloom forming cyanobacterium Microcystis aeruginosa by green route fabricated copper oxide nanoparticles. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2014; 21:14232-14240. [PMID: 25074832 DOI: 10.1007/s11356-014-3362-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/04/2014] [Accepted: 07/17/2014] [Indexed: 06/03/2023]
Abstract
The cyanobacterium Microcystis aeruginosa can potentially proliferate in a wide range of freshwater bionetworks and create extensive secondary metabolites which are harmful to human and animal health. The M. aeruginosa release toxic microcystins that can create a wide range of health-related issues to aquatic animals and humans. It is essential to eliminate them from the ecosystem with convenient method. It has been reported that engineered metal nanoparticles are potentially toxic to pathogenic organisms. In the present study, we examined the growth inhibition effect of green synthesized copper oxide nanoparticles against M. aeruginosa. The green synthesized copper oxide nanoparticles exhibit an excitation of surface plasmon resonance (SPR) at 270 nm confirmed using UV-visible spectrophotometer. The dynamic light scattering (DLS) analysis revealed that synthesized nanoparticles are colloidal in nature and having a particle size of 551 nm with high stability at -26.6 mV. The scanning electron microscopy (SEM) analysis shows that copper oxide nanoparticles are spherical, rod and irregular in shape, and consistently distributed throughout the solution. The elemental copper and oxide peak were confirmed using energy dispersive x-ray analysis (EDAX). Fourier-transform infrared (FT-IR) spectroscopy indicates the presence of functional groups which is mandatory for the reduction of copper ions. Besides, green synthesized copper oxide nanoparticles shows growth inhibition against M. aeruginosa. The inhibition efficiency was 31.8 % at lower concentration and 89.7 % at higher concentration of copper oxide nanoparticles, respectively. The chlorophyll (a and b) and carotenoid content of M. aeruginosa declined in dose-dependent manner with respect to induction of copper oxide nanoparticles. Furthermore, we analyzed the mechanism behind the cytotoxicity of M. aeruginosa induced by copper oxide nanoparticles through evaluating membrane integrity, reactive oxygen species (ROS), and mitochondrial membrane potential (Δψm) level. The results expose that there is a loss in membrane integrity with ROS formation that leads to alteration in the Δψm, which ends up with severe mitochondrial injury in copper oxide nanoparticles treated cells. Hence, green way synthesized copper oxide nanoparticles may be a useful selective biological agent for the control of M. aeruginosa.
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Affiliation(s)
- Renu Sankar
- Department of Biochemistry, School of Life Sciences, Bharathidasan University, Tiruchirappalli, 620 024, Tamil Nadu, India
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17
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Cheng TS, Hung MJ, Cheng YI, Cheng LJ. Calcium-induced proline accumulation contributes to amelioration of NaCl injury and expression of glutamine synthetase in greater duckweed (Spirodela polyrhiza L.). AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2013; 144-145:265-274. [PMID: 24200992 DOI: 10.1016/j.aquatox.2013.10.015] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2013] [Revised: 10/07/2013] [Accepted: 10/12/2013] [Indexed: 06/02/2023]
Abstract
The calcium-mediated proline accumulation is a critical response under NaCl stress and the function of the induced proline as a glutamine synthetase (GS) protectant in greater duckweed was investigated. The plants were treated with solutions containing 100mM NaCl, 200 mM NaCl, 200 mM NaCl plus 10mM CaCl2, or 10mM CaCl2 alone for 4 days. At the end of the experiment, the fronds of inoculum treated with 200 mM NaCl showed the chlorotic effect, higher glutamate dehydrogenase (NADH-GDH) activity and lower GS activity. At the lower salinity, the activities of GS and NADH-GDH were not altered markedly. A significant accumulation of proline was not found under either low or high salinity. The activity of Δ(1)-pyrroline-5-carboxylate reductase (P5CR) was enhanced only at 200 mM NaCl but remained unchanged at 100mM NaCl. The activity of Δ(1)-pyrroline-5-carboxylate synthetase (P5CS) did not change under salinity-stressed. Addition of CaCl2 to the salt stressed plants not only lowered NaCl injury but also showed an elevated level of proline contents in response to the salinity treatment. In addition, both GS activity and corresponding polypeptides were expressed close to the level of control. Exogenous proline protects GS2 and the 32 kDa protein in photosystem II reaction center (D1) from H2O2-induced redox degradation in the chloroplast lysates of duckweed. The results suggest that calcium-induced proline accumulation may play an important role as a GS protectant under NaCl exposure in S. polyrhiza.
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Affiliation(s)
- Tai-Sheng Cheng
- Department of Biological Sciences and Technology, National University of Tainan, Tainan 70005, Taiwan, ROC
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18
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Guiboileau A, Avila-Ospina L, Yoshimoto K, Soulay F, Azzopardi M, Marmagne A, Lothier J, Masclaux-Daubresse C. Physiological and metabolic consequences of autophagy deficiency for the management of nitrogen and protein resources in Arabidopsis leaves depending on nitrate availability. THE NEW PHYTOLOGIST 2013; 199:683-94. [PMID: 23647084 DOI: 10.1111/nph.12307] [Citation(s) in RCA: 100] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2013] [Accepted: 04/03/2013] [Indexed: 05/18/2023]
Abstract
Autophagy is present at a basal level in all plant tissues and is induced during leaf ageing and in response to nitrogen (N) starvation. Nitrogen remobilization from the rosette to the seeds is impaired in autophagy mutants. This report focuses on the role of autophagy in leaf N management and proteolysis during plant ageing. Metabolites, enzyme activities and protein contents were monitored in several autophagy-defective (atg) Arabidopsis mutants grown under low and high nitrate conditions. Results showed that carbon (C) and N statuses were affected in atg mutants before any senescence symptoms appeared. atg mutants accumulated larger amounts of ammonium, amino acids and proteins than wild type, and were depleted in sugars. Over-accumulation of proteins in atg mutants was selective and occurred despite higher endopeptidase and carboxypeptidase activities. Specific over-accumulation of the ribosomal proteins S6 and L13 subunits, and of catalase and glutamate dehydrogenase proteins was observed. atg mutants also accumulated peptides putatively identified as degradation products of the Rubisco large subunit and glutamine synthetase 2 (GS2). Incomplete chloroplast protein degradation resulting from autophagy defects could explain the higher N concentrations measured in atg rosettes and defects in N remobilization. It is concluded that autophagy controls C : N status and protein content in leaves of Arabidopsis.
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Affiliation(s)
- Anne Guiboileau
- UMR1318, INRA, Institut Jean-Pierre Bourgin, RD10, 78026, Versailles Cedex, France
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19
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Murshed R, Lopez-Lauri F, Sallanon H. Effect of water stress on antioxidant systems and oxidative parameters in fruits of tomato (Solanum lycopersicon L, cv. Micro-tom). PHYSIOLOGY AND MOLECULAR BIOLOGY OF PLANTS : AN INTERNATIONAL JOURNAL OF FUNCTIONAL PLANT BIOLOGY 2013; 19:363-78. [PMID: 24431505 PMCID: PMC3715648 DOI: 10.1007/s12298-013-0173-7] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
The effects of different levels of water stress on oxidative parameters (H2O2 and MDA), the total pool sizes of ascorbate, the activities of antioxidant enzymes superoxide dismutase (SOD) and catalase (CAT), as well as the activities and relative transcript levels of the enzymes of ascorbate-glutathione cycle ascorbate peroxidase (APX), monodehydroascorbate reductase (MDHAR), dehydroascorbate reductase (DHAR) and glutathione reductase (GR) were studied in the fruit of tomato (Solanum lycopersicum L. cv. Micro-Tom). Plants were subjected to three levels of water stress (S50, S25 and S0) and fruits at different development stages were harvested after 3, 6 and 10 days of stress. Changes in H2O2 and MDA contents indicated that water stress induced oxidative stress in fruits. The concentrations of ascorbate (AsA) and dehydroascorbate (DHA) generally modified with water stress treatments. Moreover, changes in SOD and CAT activities and DHAR, MDHAR, APX and GR activities and relative transcript levels were dependent on the fruit development stage and the intensity and the duration of water stress. These results suggest that the response of antioxidant systems of tomato fruits to oxidative stress induced by water stress treatments was different depending on the fruit development stage.
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Affiliation(s)
- Ramzi Murshed
- />Department of Horticultural Sciences, Faculty of Agriculture, University of Damascus, Damascus, P. O. Box: 30621, Syria
| | - Félicie Lopez-Lauri
- />Laboratoire de Physiologie des Fruits et Légumes, Campus agrosciences, 84916 Avignon Cedex 9, France
| | - Huguette Sallanon
- />Laboratoire de Physiologie des Fruits et Légumes, Campus agrosciences, 84916 Avignon Cedex 9, France
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20
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Cheng TS. The toxic effects of diethyl phthalate on the activity of glutamine synthetase in greater duckweed (Spirodela polyrhiza L.). AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2012; 124-125:171-178. [PMID: 22975440 DOI: 10.1016/j.aquatox.2012.08.014] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2012] [Revised: 08/14/2012] [Accepted: 08/17/2012] [Indexed: 06/01/2023]
Abstract
The toxic effects of diethyl phthalate (DEP), a potent allelochemical, on the enzyme activity and polypeptide accumulation of glutamine synthetase (GS) in greater duckweed were investigated. In our previous studies, DEP induced oxidative responses at concentrations from 0.5 to 2 mM in greater duckweed and the antioxidant enzymes played important roles in the defense strategy against DEP stress. In this study, DAB-H(2)O(2) and NBT stain for superoxide radicals (O(2)(·-)), lipid peroxidation, HSP70, and ammonia accumulation in DEP-treated duckweed tissues revealed adverse effect of DEP in plant growth. Biochemical analysis and physiological methods were combined to investigate GS activity and polypeptide accumulation under DEP-induced stress. The results showed that GS activity was reduced with the increasing concentration of DEP, indicative of enhanced toxic effect. Immunoblot analysis with chloroplast soluble fractions indicated that the chloroplastic GS (GS2) polypeptide from greater duckweed was degraded under DEP stress conditions. The response of GS2 to the DEP stress may be modulated by means of redox change in plant tissues, chloroplasts, and chloroplast lysates. The results suggest that DEP is toxic to the greater duckweed by inhibition of the GS isoenzymes in nitrogen assimilation and the GS2 plays important roles in the adaptation strategy against DEP toxicity.
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Affiliation(s)
- Tai-Sheng Cheng
- Department of Biological Sciences and Technology, National University of Tainan, Tainan, Taiwan, ROC.
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21
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Guiboileau A, Masclaux-Daubresse C. L’autophagie chez les plantes : mécanismes, régulations et fonctions. C R Biol 2012; 335:375-88. [DOI: 10.1016/j.crvi.2012.04.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2012] [Revised: 04/13/2012] [Accepted: 04/14/2012] [Indexed: 12/20/2022]
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22
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Sharmin SA, Alam I, Kim KH, Kim YG, Kim PJ, Bahk JD, Lee BH. Chromium-induced physiological and proteomic alterations in roots of Miscanthus sinensis. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2012; 187:113-26. [PMID: 22404839 DOI: 10.1016/j.plantsci.2012.02.002] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2011] [Revised: 01/31/2012] [Accepted: 02/02/2012] [Indexed: 05/23/2023]
Abstract
Despite the widespread occurrence of chromium toxicity, its molecular mechanism is poorly documented in plants compared to other heavy metals. To investigate the molecular mechanisms that regulate the response of Miscanthus sinensis roots to elevated level of chromium, seedlings were grown for 4 weeks and exposed to potassium dichromate for 3 days. Physiological, biochemical and proteomic changes in roots were investigated. Lipid peroxidation and H₂O₂ content in roots were significantly increased. Protein profiles analyzed by two-dimensional gel electrophoresis revealed that 36 protein spots were differentially expressed in chromium-treated root samples. Of these, 13 protein spots were up-regulated, 21 protein spots were down-regulated and 2 spots were newly induced. These differentially displayed proteins were identified by MALDI-TOF and MALDI-TOF/TOF mass spectrometry. The identified proteins included known heavy metal-inducible proteins such as carbohydrate and nitrogen metabolism, molecular chaperone proteins and novel proteins such as inositol monophosphatase, nitrate reductase, adenine phosphoribosyl transferase, formate dehydrogenase and a putative dihydrolipoamide dehydrogenase that were not known previously as chromium-responsive. Taken together, these results suggest that Cr toxicity is linked to heavy metal tolerance and senescence pathways, and associated with altered vacuole sequestration, nitrogen metabolism and lipid peroxidation in Miscanthus roots.
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Affiliation(s)
- Shamima Akhtar Sharmin
- Division of Applied Life Science (BK21 program), IALS, PMBBRC, Gyeongsang National University, Jinju 660-701, Republic of Korea
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23
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Qian H, Pan X, Chen J, Zhou D, Chen Z, Zhang L, Fu Z. Analyses of gene expression and physiological changes in Microcystis aeruginosa reveal the phytotoxicities of three environmental pollutants. ECOTOXICOLOGY (LONDON, ENGLAND) 2012; 21:847-859. [PMID: 22218976 DOI: 10.1007/s10646-011-0845-4] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 12/16/2011] [Indexed: 05/31/2023]
Abstract
When the concentrations of ampicillin (Amp), atrazine (Atr) and cadmium chloride (Cd) reach excessive quantities, they become toxic to aquatic organisms. Due to the acceleration of the industrialization and the intensification of human activities, the incidence and concentrations of these types of pollutants in aquatic systems are increasing. The primary purpose of this study was to evaluate the short-term effects of Amp, Atr and Cd on the physiological indices and gene expression levels in Microcystis aeruginosa. These three pollutants significantly induced antioxidant activity but continuously accelerated the cellular oxidative damage in microalgae, which suggests an imbalance between the oxidant and the antioxidant systems. Amp, Atr and Cd also decreased the transcription of psaB, psbD1 and rbcL; the lowest transcription of these genes was only 38.1, 23.7 and 7% of the control, respectively. These three pollutants affected nitrogen (N) and phosphorous (P) uptake by inhibiting the transcription of N or P absorbing and transporting related genes, and they down regulated the transcription of microcystin-related genes, which caused a decrease of microcystin levels; and the lowest level of microcystin was only 42.4% of the control. Our results suggest that these pollutants may cause pleiotropic effects on algal growth and physiological and biochemical reactions, and they may even affect secondary metabolic processes.
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Affiliation(s)
- Haifeng Qian
- College of Biological and Environmental Engineering, Zhejiang University of Technology, Hangzhou, 310032 Zhejiang, China
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24
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Chu CC, Li HM. The amino-terminal domain of chloroplast Hsp93 is important for its membrane association and functions in vivo. PLANT PHYSIOLOGY 2012; 158:1656-65. [PMID: 22353577 PMCID: PMC3320176 DOI: 10.1104/pp.112.193300] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/05/2012] [Accepted: 02/16/2012] [Indexed: 05/08/2023]
Abstract
Chloroplast 93-kD heat shock protein (Hsp93/ClpC), an Hsp100 family member, is suggested to have various functions in chloroplasts, including serving as the regulatory chaperone for the ClpP protease in the stroma and acting as a motor component of the protein translocon at the envelope. Indeed, although Hsp93 is a soluble stromal protein, a portion of it is associated with the inner envelope membrane. The mechanism and functional significance of this Hsp93 membrane association have not been determined. Here, we mapped the region important for Hsp93 membrane association by creating various deletion constructs and found that only the construct with the amino-terminal domain deleted, Hsp93-ΔN, had reduced membrane association. When transformed into Arabidopsis (Arabidopsis thaliana), most atHsp93V-ΔN proteins did not associate with membranes and atHsp93V-ΔΝ failed to complement the pale-green and protein import-defective phenotypes of an hsp93V knockout mutant. The residual atHsp93V-ΔN at the membranes had further reduced association with the central protein translocon component Tic110. However, the degradation of chloroplast glutamine synthetase, a potential substrate for the ClpP protease, was not affected in the hsp93V mutant or in the atHSP93V-ΔN transgenic plants. Hsp93-ΔN also had the same ATPase activity as that of full-length Hsp93. These data suggest that the association of Hsp93 with the inner envelope membrane through its amino-terminal domain is important for the functions of Hsp93 in vivo.
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Affiliation(s)
- Chiung-Chih Chu
- Institute of Molecular Biology, Academia Sinica, Nankang, Taipei 11529, Taiwan
| | - Hsou-min Li
- Institute of Molecular Biology, Academia Sinica, Nankang, Taipei 11529, Taiwan
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25
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Melo PM, Silva LS, Ribeiro I, Seabra AR, Carvalho HG. Glutamine synthetase is a molecular target of nitric oxide in root nodules of Medicago truncatula and is regulated by tyrosine nitration. PLANT PHYSIOLOGY 2011; 157:1505-17. [PMID: 21914816 PMCID: PMC3252174 DOI: 10.1104/pp.111.186056] [Citation(s) in RCA: 98] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2011] [Accepted: 09/12/2011] [Indexed: 05/20/2023]
Abstract
Nitric oxide (NO) is emerging as an important regulatory player in the Rhizobium-legume symbiosis, but its biological role in nodule functioning is still far from being understood. To unravel the signal transduction cascade and ultimately NO function, it is necessary to identify its molecular targets. This study provides evidence that glutamine synthetase (GS), a key enzyme for root nodule metabolism, is a molecular target of NO in root nodules of Medicago truncatula, being regulated by tyrosine (Tyr) nitration in relation to active nitrogen fixation. In vitro studies, using purified recombinant enzymes produced in Escherichia coli, demonstrated that the M. truncatula nodule GS isoenzyme (MtGS1a) is subjected to NO-mediated inactivation through Tyr nitration and identified Tyr-167 as the regulatory nitration site crucial for enzyme inactivation. Using a sandwich enzyme-linked immunosorbent assay, it is shown that GS is nitrated in planta and that its nitration status changes in relation to active nitrogen fixation. In ineffective nodules and in nodules fed with nitrate, two conditions in which nitrogen fixation is impaired and GS activity is reduced, a significant increase in nodule GS nitration levels was observed. Furthermore, treatment of root nodules with the NO donor sodium nitroprusside resulted in increased in vivo GS nitration accompanied by a reduction in GS activity. Our results support a role of NO in the regulation of nitrogen metabolism in root nodules and places GS as an important player in the process. We propose that the NO-mediated GS posttranslational inactivation is related to metabolite channeling to boost the nodule antioxidant defenses in response to NO.
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Jiang H, Chen Y, Li M, Xu X, Wu G. Overexpression of SGR results in oxidative stress and lesion-mimic cell death in rice seedlings. JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2011; 53:375-87. [PMID: 21375689 DOI: 10.1111/j.1744-7909.2011.01037.x] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
It is thought that the Stay Green Rice (SGR) gene is involved in the disaggregation of the light harvesting complex and in the subsequent breakdown of chlorophyll and apo-protein during senescence. In this study, we found that overexpression of SGR (Ov-SGR) resulted in the generation of singlet oxygen and other reactive oxygen species and produced a chlorophyll-dependent regional cell death phenotype on leaves of rice seedlings. Transcriptome analyses using Affymetrix Rice GeneChips revealed that Ov-SGR rice seedlings exhibited a number of signs of singlet oxygen response. The genes and their associated biochemical pathways identified provide an insight into how rice plants respond to singlet oxygen at the molecular and physiologic level.
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Affiliation(s)
- Huawu Jiang
- Key Laboratory of Plant Resources Conservation and Sustainable Utilization, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, China
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Vannini C, Domingo G, Marsoni M, De Mattia F, Labra M, Castiglioni S, Bracale M. Effects of a complex mixture of therapeutic drugs on unicellular algae Pseudokirchneriella subcapitata. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2011; 101:459-465. [PMID: 21112099 DOI: 10.1016/j.aquatox.2010.10.011] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2010] [Revised: 09/20/2010] [Accepted: 10/31/2010] [Indexed: 05/30/2023]
Abstract
Pharmaceutically-active compounds are regularly and widely released into the aquatic environment in an unaltered form or as metabolites. So far, little is known about their potential detrimental effects on algae populations which can ultimately impact nutrient cycling and oxygen balance. For our analysis, the common microalga Pseudokirchneriella subcapitata (P. subcapitata) was exposed to a mixture of 13 drugs found in Italian wastewaters and rivers. Traces of pharmaceuticals investigated were detected in treated algal cells, except for cyclophosphamide and ranitidine, indicating that these algae are able to absorb pharmaceutical pollutants from the environment. The effects of the treatment were investigated by Amplified Fragment Length Polymorphism (AFLP) assessment of DNA damage and 2-DE proteomic analysis. While no genotoxic effect was detected, proteomic analysis showed that algae are sensitive to the presence of drugs and that, in particular, the chloroplast is affected.
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Affiliation(s)
- Candida Vannini
- Department of Environment-Health-Safety, University of Insubria, Via G.B. Vico 46, I-21100 Varese, Italy
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Liu G, Ji Y, Bhuiyan NH, Pilot G, Selvaraj G, Zou J, Wei Y. Amino acid homeostasis modulates salicylic acid-associated redox status and defense responses in Arabidopsis. THE PLANT CELL 2010; 22:3845-63. [PMID: 21097712 PMCID: PMC3015111 DOI: 10.1105/tpc.110.079392] [Citation(s) in RCA: 161] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/13/2010] [Revised: 09/13/2010] [Accepted: 10/28/2010] [Indexed: 05/17/2023]
Abstract
The tight association between nitrogen status and pathogenesis has been broadly documented in plant-pathogen interactions. However, the interface between primary metabolism and disease responses remains largely unclear. Here, we show that knockout of a single amino acid transporter, LYSINE HISTIDINE TRANSPORTER1 (LHT1), is sufficient for Arabidopsis thaliana plants to confer a broad spectrum of disease resistance in a salicylic acid-dependent manner. We found that redox fine-tuning in photosynthetic cells was causally linked to the lht1 mutant-associated phenotypes. Furthermore, the enhanced resistance in lht1 could be attributed to a specific deficiency of its main physiological substrate, Gln, and not to a general nitrogen deficiency. Thus, by enabling nitrogen metabolism to moderate the cellular redox status, a plant primary metabolite, Gln, plays a crucial role in plant disease resistance.
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Affiliation(s)
- Guosheng Liu
- Department of Biology, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E2, Canada
| | - Yuanyuan Ji
- Department of Biology, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E2, Canada
| | - Nazmul H. Bhuiyan
- Department of Biology, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E2, Canada
| | - Guillaume Pilot
- Department of Plant Biology, Carnegie Institution for Science, Stanford, California 94305
| | - Gopalan Selvaraj
- Plant Biotechnology Institute, National Research Council of Canada, Saskatoon, Saskatchewan S7N 0W9, Canada
| | - Jitao Zou
- Plant Biotechnology Institute, National Research Council of Canada, Saskatoon, Saskatchewan S7N 0W9, Canada
| | - Yangdou Wei
- Department of Biology, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E2, Canada
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Lin YL, Chao YY, Kao CH. Exposure of rice seedlings to heat shock protects against subsequent Cd-induced decrease in glutamine synthetase activity and increase in specific protease activity in leaves. JOURNAL OF PLANT PHYSIOLOGY 2010; 167:1061-1065. [PMID: 20399533 DOI: 10.1016/j.jplph.2010.03.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2010] [Revised: 03/09/2010] [Accepted: 03/10/2010] [Indexed: 05/29/2023]
Abstract
In the present study, we investigated the effect of heat shock (HS) on the subsequent Cd-induced decrease in the activity of glutamine synthetase (GS) and increase in the specific activity of protease in rice leaves. HS exposure of rice seedlings for 3h in the dark was effective in reducing subsequent Cd-induced decrease in the activity of glutamine synthetase and increase in the specific activity of protease. The effect of HS can be mimicked by pretreatment of rice seedlings with exogenous H(2)O(2) or reduced glutathione (GSH) under non-HS conditions. We also found that HS protected against subsequent Cd-induced decrease in the activity of GS and increase in the specific activity of protease can be counteracted by imidazole, a NADPH oxidase inhibitor. Pretreatment with buthione sulfoximine (a GSH synthesis inhibitor) under HS conditions enhanced subsequent Cd effects on the activity of GS and the specific activity of protease. Moreover, the effect of BSO can be reversed by the addition of GSH. The mechanisms of the protective effect of HS effect against subsequent Cd effects are discussed.
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Affiliation(s)
- Ya-Lin Lin
- Department of Agronomy, National Taiwan University, Taipei, Taiwan, ROC
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Masclaux-Daubresse C, Daniel-Vedele F, Dechorgnat J, Chardon F, Gaufichon L, Suzuki A. Nitrogen uptake, assimilation and remobilization in plants: challenges for sustainable and productive agriculture. ANNALS OF BOTANY 2010; 105:1141-57. [PMID: 20299346 PMCID: PMC2887065 DOI: 10.1093/aob/mcq028] [Citation(s) in RCA: 675] [Impact Index Per Article: 48.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2009] [Revised: 11/13/2009] [Accepted: 12/17/2009] [Indexed: 05/18/2023]
Abstract
BACKGROUND Productive agriculture needs a large amount of expensive nitrogenous fertilizers. Improving nitrogen use efficiency (NUE) of crop plants is thus of key importance. NUE definitions differ depending on whether plants are cultivated to produce biomass or grain yields. However, for most plant species, NUE mainly depends on how plants extract inorganic nitrogen from the soil, assimilate nitrate and ammonium, and recycle organic nitrogen. Efforts have been made to study the genetic basis as well as the biochemical and enzymatic mechanisms involved in nitrogen uptake, assimilation, and remobilization in crops and model plants. The detection of the limiting factors that could be manipulated to increase NUE is the major goal of such research. SCOPE An overall examination of the physiological, metabolic, and genetic aspects of nitrogen uptake, assimilation and remobilization is presented in this review. The enzymes and regulatory processes manipulated to improve NUE components are presented. Results obtained from natural variation and quantitative trait loci studies are also discussed. CONCLUSIONS This review presents the complexity of NUE and supports the idea that the integration of the numerous data coming from transcriptome studies, functional genomics, quantitative genetics, ecophysiology and soil science into explanatory models of whole-plant behaviour will be promising.
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Zurbriggen MD, Carrillo N, Tognetti VB, Melzer M, Peisker M, Hause B, Hajirezaei MR. Chloroplast-generated reactive oxygen species play a major role in localized cell death during the non-host interaction between tobacco and Xanthomonas campestris pv. vesicatoria. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2009; 60:962-73. [PMID: 19719480 DOI: 10.1111/j.1365-313x.2009.04010.x] [Citation(s) in RCA: 89] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Attempted infection of plants by pathogens elicits a complex defensive response. In many non-host and incompatible host interactions it includes the induction of defence-associated genes and a form of localized cell death (LCD), purportedly designed to restrict pathogen advance, collectively known as the hypersensitive response (HR). It is preceded by an oxidative burst, generating reactive oxygen species (ROS) that are proposed to cue subsequent deployment of the HR, although neither the origin nor the precise role played by ROS in the execution of this response are completely understood. We used tobacco plants expressing cyanobacterial flavodoxin to address these questions. Flavodoxin is an electron shuttle present in prokaryotes and algae that, when expressed in chloroplasts, specifically prevents ROS formation in plastids during abiotic stress episodes. Infiltration of tobacco wild-type leaves with high titres of Xanthomonas campestris pv. vesicatoria (Xcv), a non-host pathogen, resulted in ROS accumulation in chloroplasts, followed by the appearance of localized lesions typical of the HR. In contrast, chloroplast ROS build-up and LCD were significantly reduced in Xcv-inoculated plants expressing plastid-targeted flavodoxin. Metabolic routes normally inhibited by pathogens were protected in the transformants, whereas other aspects of the HR, including the induction of defence-associated genes and synthesis of salicylic and jasmonic acid, proceeded as in inoculated wild-type plants. Therefore, ROS generated in chloroplasts during this non-host interaction are essential for the progress of LCD, but do not contribute to the induction of pathogenesis-related genes or other signalling components of the response.
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Affiliation(s)
- Matias D Zurbriggen
- Instituto de Biología Molecular y Celular de Rosario (IBR, UNR/CONICET), División Biología Molecular, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Suipacha 531, S2002LRK Rosario, Argentina
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Teixeira J, Fidalgo F. Salt stress affects glutamine synthetase activity and mRNA accumulation on potato plants in an organ-dependent manner. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2009; 47:807-13. [PMID: 19481951 DOI: 10.1016/j.plaphy.2009.05.002] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2008] [Revised: 05/01/2009] [Accepted: 05/12/2009] [Indexed: 05/12/2023]
Abstract
Ammonium assimilation into glutamine and glutamate is vital for plant growth as these are precursors for almost all nitrogenous compounds. Ammonium can be assimilated onto nitrogenous organic compounds by the concerted action of two enzymes that compose the glutamine synthetase (GS, EC 6.3.1.2) - glutamate synthase (Fd-GOGAT, EC 1.4.7.1; NADH-GOGAT, EC 1.4.1.14) cycle. Ammonium may also be directly incorporated into glutamate by the glutamate dehydrogenase (GDH, EC 1.4.1.2) aminating reaction. However, as GDH reversibly deaminates glutamate, its physiological role in vivo remains controversial. Potato has been classified as moderately tolerant to salinity. Potato GS is encoded by a small multigene family which is differentially regulated in an organ and age-dependent way. In this study, the effect of increasing concentrations of salinity in the soil in GS activity and gene-specific mRNA accumulation levels were studied on potato leaves and roots, as well as the biochemical parameters protein, chlorophyll, lipid peroxidation and proline levels, in order to evaluate the severity of the imposed stress. The data obtained suggests that when potato plants are subjected to salt stress, increased ammonium assimilation occurs in roots, due to an increased GS accumulation, along with a decreased assimilation in leaves. Regarding GS gene-specific mRNA accumulation, an organ-dependent response was also observed that contributes for the detected alteration in the ammonium assimilatory metabolism. This response may be a key feature for future genetic manipulations in order to increase crop productivity in salty soils. The possible contribution of GDH for ammonia assimilation was also investigated.
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Affiliation(s)
- Jorge Teixeira
- Faculty of Sciences of the University of Porto, Botany Department, Porto, Portugal.
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Fahnenstich H, Flügge UI, Maurino VG. Arabidopsis thaliana overexpressing glycolate oxidase in chloroplasts: H(2)O(2)-induced changes in primary metabolic pathways. PLANT SIGNALING & BEHAVIOR 2008; 3:1122-5. [PMID: 19704454 PMCID: PMC2634475 DOI: 10.4161/psb.3.12.7040] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/10/2008] [Accepted: 09/17/2008] [Indexed: 05/08/2023]
Abstract
Reactive oxygen species (ROS) represent both toxic by-products of aerobic metabolism as well as signaling molecules in processes like growth regulation and defense pathways. The study of signaling and oxidative-damage effects can be separated in plants expressing glycolate oxidase in the plastids (GO plants), where the production of H(2)O(2) in the chloroplasts is inducible and sustained perturbations can reproducibly be provoked by exposing the plants to different ambient conditions. Thus, GO plants represent an ideal non-invasive model to study events related to the perception and responses to H(2)O(2) accumulation. Metabolic profiling of GO plants indicated that under high light a sustained production of H(2)O(2) imposes coordinate changes on central metabolic pathways. The overall metabolic scenario is consistent with decreased carbon assimilation, which results in lower abundance of glycolytic and tricarboxylic acid cycle intermediates, while simultaneously amino acid metabolism routes are specifically modulated. The GO plants, although retarded in growth and flowering, can complete their life cycle indicating that the reconfiguration of the central metabolic pathways is part of a response to survive and thus, to adapt to stress conditions imposed by the accumulation of H(2)O(2) during the light period.
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Dietzel L, Pfannschmidt T. Photosynthetic acclimation to light gradients in plant stands comes out of shade. PLANT SIGNALING & BEHAVIOR 2008; 3:1116-8. [PMID: 19704452 PMCID: PMC2634473 DOI: 10.4161/psb.3.12.7038] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/10/2008] [Accepted: 09/17/2008] [Indexed: 05/19/2023]
Abstract
Dense plant populations or canopies exhibit a strong enrichment in far-red wavelengths which leads to unequal excitation of the two photosystems. In the long-term plants acclimate to changes in light quality by adjusting photosystem stoichiometry and antenna structure, a mechanism called here long-term response (LTR). Using an artificial light system it is possible to mimic such naturally occurring gradients in light quality under controlled laboratory conditions. By this means we recently demonstrated that the LTR is crucial for plant fitness and survival of Arabidopsis. We could also demonstrate that the chlorophyll fluorescence parameter Fs/Fm is a genuine non-invasive functional indicator for acclimatory changes during the LTR. Here we give supportive data that the Fs/Fm can be also used to monitor the LTR in field experiments in which Arabidopsis plants were grown either under canopies or wavelength-neutral shade. Furthermore our data support the notion that acclimation responses to light quality and light quantity are separate mechanisms. Thus, the long-term response to light quality represents an important and distinct acclimation strategy for improving plant survival under changing light quality conditions.
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Affiliation(s)
- Lars Dietzel
- Institute for General Botany and Plant Physiology; Friedrich-Schiller University Jena; Jena, Thuringia Germany
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Fahnenstich H, Scarpeci TE, Valle EM, Flügge UI, Maurino VG. Generation of hydrogen peroxide in chloroplasts of Arabidopsis overexpressing glycolate oxidase as an inducible system to study oxidative stress. PLANT PHYSIOLOGY 2008; 148:719-29. [PMID: 18685041 PMCID: PMC2556821 DOI: 10.1104/pp.108.126789] [Citation(s) in RCA: 111] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2008] [Accepted: 08/04/2008] [Indexed: 05/18/2023]
Abstract
Arabidopsis (Arabidopsis thaliana) overexpressing glycolate oxidase (GO) in chloroplasts accumulates both hydrogen peroxide (H(2)O(2)) and glyoxylate. GO-overexpressing lines (GO plants) grown at 75 micromol quanta m(-2) s(-1) show retarded development, yellowish rosettes, and impaired photosynthetic performance, while at 30 micromol quanta m(-2) s(-1), this phenotype virtually disappears. The GO plants develop oxidative stress lesions under photorespiratory conditions but grow like wild-type plants under nonphotorespiratory conditions. GO plants coexpressing enzymes that further metabolize glyoxylate but still accumulate H(2)O(2) show all features of the GO phenotype, indicating that H(2)O(2) is responsible for the GO phenotype. The GO plants can complete their life cycle, showing that they are able to adapt to the stress conditions imposed by the accumulation of H(2)O(2) during the light period. Moreover, the data demonstrate that a response to oxidative stress is installed, with increased expression and/or activity of known oxidative stress-responsive components. Hence, the GO plants are an ideal noninvasive model system in which to study the effects of H(2)O(2) directly in the chloroplasts, because H(2)O(2) accumulation is inducible and sustained perturbations can reproducibly be provoked by exposing the plants to different ambient conditions.
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Scarpeci TE, Zanor MI, Carrillo N, Mueller-Roeber B, Valle EM. Generation of superoxide anion in chloroplasts of Arabidopsis thaliana during active photosynthesis: a focus on rapidly induced genes. PLANT MOLECULAR BIOLOGY 2008; 66:361-78. [PMID: 18158584 PMCID: PMC2758387 DOI: 10.1007/s11103-007-9274-4] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2007] [Accepted: 12/12/2007] [Indexed: 05/18/2023]
Abstract
The antioxidant defense system involves complex functional coordination of multiple components in different organelles within the plant cell. Here, we have studied the Arabidopsis thaliana early response to the generation of superoxide anion in chloroplasts during active photosynthesis. We exposed plants to methyl viologen (MV), a superoxide anion propagator in the light, and performed biochemical and expression profiling experiments using Affymetrix ATH1 GeneChip microarrays under conditions in which photosynthesis and antioxidant enzymes were active. Data analysis identified superoxide-responsive genes that were compared with available microarray results. Examples include genes encoding proteins with unknown function, transcription factors and signal transduction components. A common GAAAAGTCAAAC motif containing the W-box consensus sequence of WRKY transcription factors, was found in the promoters of genes highly up-regulated by superoxide. Band shift assays showed that oxidative treatments enhanced the specific binding of leaf protein extracts to this motif. In addition, GUS reporter gene fused to WRKY30 promoter, which contains this binding motif, was induced by MV and H(2)O(2). Overall, our study suggests that genes involved in signalling pathways and with unknown functions are rapidly activated by superoxide anion generated in photosynthetically active chloroplasts, as part of the early antioxidant response of Arabidopsis leaves.
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Affiliation(s)
- Telma E. Scarpeci
- Facultad de Ciencias Bioquímicas y Farmacéuticas, Instituto de Biología Molecular y Celular de Rosario (IBR-CONICET), Universidad Nacional de Rosario, Suipacha 531, S2002LRK Rosario, Argentina
| | - María I. Zanor
- Max-Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476 Golm, Germany
| | - Néstor Carrillo
- Facultad de Ciencias Bioquímicas y Farmacéuticas, Instituto de Biología Molecular y Celular de Rosario (IBR-CONICET), Universidad Nacional de Rosario, Suipacha 531, S2002LRK Rosario, Argentina
| | - Bernd Mueller-Roeber
- Max-Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476 Golm, Germany
- Institut für Biochemie und Biologie, Universität Potsdam, Karl-Liebknecht-Str. 25, 14476 Golm, Germany
| | - Estela M. Valle
- Facultad de Ciencias Bioquímicas y Farmacéuticas, Instituto de Biología Molecular y Celular de Rosario (IBR-CONICET), Universidad Nacional de Rosario, Suipacha 531, S2002LRK Rosario, Argentina
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Prins A, van Heerden PDR, Olmos E, Kunert KJ, Foyer CH. Cysteine proteinases regulate chloroplast protein content and composition in tobacco leaves: a model for dynamic interactions with ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) vesicular bodies. JOURNAL OF EXPERIMENTAL BOTANY 2008; 59:1935-50. [PMID: 18503045 DOI: 10.1093/jxb/ern086] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
The roles of cysteine proteinases (CP) in leaf protein accumulation and composition were investigated in transgenic tobacco (Nicotiana tabacum L.) plants expressing the rice cystatin, OC-1. The OC-1 protein was present in the cytosol, chloroplasts, and vacuole of the leaves of OC-1 expressing (OCE) plants. Changes in leaf protein composition and turnover caused by OC-1-dependent inhibition of CP activity were assessed in 8-week-old plants using proteomic analysis. Seven hundred and sixty-five soluble proteins were detected in the controls compared to 860 proteins in the OCE leaves. A cyclophilin, a histone, a peptidyl-prolyl cis-trans isomerase, and two ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) activase isoforms were markedly altered in abundance in the OCE leaves. The senescence-related decline in photosynthesis and Rubisco activity was delayed in the OCE leaves. Similarly, OCE leaves maintained higher leaf Rubisco activities and protein than controls following dark chilling. Immunogold labelling studies with specific antibodies showed that Rubisco was present in Rubisco vesicular bodies (RVB) as well as in the chloroplasts of leaves from 8-week-old control and OCE plants. Western blot analysis of plants at 14 weeks after both genotypes had flowered revealed large increases in the amount of Rubisco protein in the OCE leaves compared to controls. These results demonstrate that CPs are involved in Rubisco turnover in leaves under optimal and stress conditions and that extra-plastidic RVB bodies are present even in young source leaves. Furthermore, these data form the basis for a new model of Rubisco protein turnover involving CPs and RVBs.
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Affiliation(s)
- Anneke Prins
- School of Agriculture, Food and Rural Development, Agriculture Building, Newcastle University, Newcastle upon Tyne NE1 7RU, UK
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Hung KT, Kao CH. The participation of hydrogen peroxide in methyl jasmonate-induced NH(4)(+) accumulation in rice leaves. JOURNAL OF PLANT PHYSIOLOGY 2007; 164:1469-79. [PMID: 17215059 DOI: 10.1016/j.jplph.2006.10.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2006] [Revised: 10/14/2006] [Accepted: 10/17/2006] [Indexed: 05/13/2023]
Abstract
Ammonium is a central intermediate in the nitrogen metabolism of plants. We have previously shown that methyl jasmonate (MJ) not only increases the content of H(2)O(2), but also causes NH(4)(+) accumulation in rice leaves. More recently, H(2)O(2) is thought to constitute a general signal molecule participating in the recognition of and the response to stress factors. In this study, we examined the role of H(2)O(2) as a link between MJ and subsequent NH(4)(+) accumulation in detached rice leaves. MJ treatment resulted in an accumulation of NH(4)(+) in detached rice leaves, which was preceded by a decrease in the activity of glutamine synthetase (GS) and an increase in the specific activities of protease and phenylalanine ammonia-lyase (PAL). GS, PAL, and protease appear to be the enzymes responsible for the accumulation of NH(4)(+) in MJ-treated detached rice leaves. Dimethylthiourea (DMTU), a chemical trap for H(2)O(2), was observed to be effective in inhibiting MJ-induced NH(4)(+) accumulation in detached rice leaves. Scavengers of free radicals (sodium benzoate, SB, and glutathione, GSH), nitric oxide donor (N-tert-butyl-alpha-phenylnitrone, PBN), the inhibitors of NADPH oxidase (diphenyleneiodonium chloride, DPI, and imidazole, IMD), and inhibitors of phosphatidylinositol 3-kinase (wortmannin, WM, and LY 294002, LY), which have previously been shown to prevent MJ-induced H(2)O(2) production in detached rice leaves, inhibited MJ-induced NH(4)(+) accumulation. Similarly, changes in enzymes responsible for NH(4)(+) accumulation induced by MJ were observed to be inhibited by DMTU, SB, GSH, PBN DPI, IMD, WM, or LY. Seedlings of rice cultivar Taichung Native 1 (TN1) are jasmonic acid (JA)-sensitive and those of cultivar Tainung 67 (TNG67) are JA-insensitive. On treatment with JA, H(2)O(2) accumulated in the leaves of TN1 seedlings but not in the leaves of TNG67. Ethylene action inhibitor, silver thiosulfate, was observed to inhibit MJ- and abscisic acid-induced accumulation of NH(4)(+) and changes in enzymes responsible for NH(4)(+) accumulation in detached rice leaves, suggesting that the action of MJ and ABA is ethylene dependent.
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Affiliation(s)
- Kuo Tung Hung
- Department of Agronomy, National Taiwan University, Taipei, Taiwan, Republic of China
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39
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Rodriguez RE, Lodeyro A, Poli HO, Zurbriggen M, Peisker M, Palatnik JF, Tognetti VB, Tschiersch H, Hajirezaei MR, Valle EM, Carrillo N. Transgenic tobacco plants overexpressing chloroplastic ferredoxin-NADP(H) reductase display normal rates of photosynthesis and increased tolerance to oxidative stress. PLANT PHYSIOLOGY 2007; 143:639-49. [PMID: 17189326 PMCID: PMC1803747 DOI: 10.1104/pp.106.090449] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2006] [Accepted: 12/13/2006] [Indexed: 05/13/2023]
Abstract
Ferredoxin-NADP(H) reductase (FNR) catalyzes the last step of photosynthetic electron transport in chloroplasts, driving electrons from reduced ferredoxin to NADP+. This reaction is rate limiting for photosynthesis under a wide range of illumination conditions, as revealed by analysis of plants transformed with an antisense version of the FNR gene. To investigate whether accumulation of this flavoprotein over wild-type levels could improve photosynthetic efficiency and growth, we generated transgenic tobacco (Nicotiana tabacum) plants expressing a pea (Pisum sativum) FNR targeted to chloroplasts. The alien product distributed between the thylakoid membranes and the chloroplast stroma. Transformants grown at 150 or 700 micromol quanta m(-2) s(-1) displayed wild-type phenotypes regardless of FNR content. Thylakoids isolated from plants with a 5-fold FNR increase over the wild type displayed only moderate stimulation (approximately 20%) in the rates of electron transport from water to NADP+. In contrast, when donors of photosystem I were used to drive NADP+ photoreduction, the activity was 3- to 4-fold higher than the wild-type controls. Plants expressing various levels of FNR (from 1- to 3.6-fold over the wild type) failed to show significant differences in CO2 assimilation rates when assayed over a range of light intensities and CO2 concentrations. Transgenic lines exhibited enhanced tolerance to photooxidative damage and redox-cycling herbicides that propagate reactive oxygen species. The results suggest that photosynthetic electron transport has several rate-limiting steps, with FNR catalyzing just one of them.
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Affiliation(s)
- Ramiro E Rodriguez
- Instituto de Biología Molecular y Celular de Rosario, División Biología Molecular, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, S2002LRK Rosario, Argentina
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40
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Effect of chilling and acclimation on the activity of glutamine synthetase isoforms in maize seedlings. ARCH BIOL SCI 2007. [DOI: 10.2298/abs0703177s] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
Effects of chilling and acclimation on the activity of cytosolic (GS1) and plastidic (GS2) isoforms of glutamine synthetase (E.C. 6.3.1.2) were studied in chilling-sensitive and acclimation-responsive maize inbred G50. Glutamine synthetase activity in mesocotyls and roots of chilled (7 d/4?C) and rewarmed (1 d/27?C) etiolated plants was "1/3 that of controls. In coleoptiles+leaves of light-grown plants, GS1 was reduced to 75%, and GS2 to 50%. Acclimation (3 d/14?C) increased GS activity and alleviated the effects of chilling. Exposure to H2O2 or menadione also reduced GS activity. Since chilling causes oxidative stress in maize, acclimation probably preserves GS activity by protecting GS from oxidative inactivation. .
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41
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Betti M, Arcondéguy T, Márquez AJ. Molecular analysis of two mutants from Lotus japonicus deficient in plastidic glutamine synthetase: functional properties of purified GLN2 enzymes. PLANTA 2006; 224:1068-79. [PMID: 16685525 DOI: 10.1007/s00425-006-0279-z] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2005] [Accepted: 03/29/2006] [Indexed: 05/09/2023]
Abstract
Two photorespiratory mutants from Lotus japonicus, namely Ljgln2-1 and Ljgln2-2, deficient in plastidic glutamine synthetase (GLN2), were analysed at the molecular level. Both mutants showed normal levels of Gln2 mRNA, indicating that they were affected post-transcriptionally. Complete sequencing of full-length Gln2 cDNAs revealed the presence of a single point mutation on each mutant, leading to G85R and L278H amino acid replacements, respectively. Different types of experimental approaches, including heterologous expression and complementation tests in Escherichia coli, showed that both GLN2 mutant proteins completely lacked of biosynthetic and transferase enzyme activities. Moreover, it was also shown that while GLN2-1 mutant protein was assembled into a less stable inactive octamer, GLN2-2 mutant protein was unable to acquire a proper quaternary structure and was rapidly degraded. Therefore, the mutations analysed are the first of their type affecting the stability and/or the quaternary structure of the GLN2 enzyme. The kinetic parameters of purified recombinant GLN2 were determined. The enzyme showed positive cooperativity towards ammonium and Mg(2+). Thiol compounds stimulated by twofold the biosynthetic activity but not the transferase activity of recombinant GLN2 and were able to alter the kinetics towards glutamate of the enzyme. Moreover, the biosynthetic activity of recombinant GLN2 was stimulated by more than tenfold by the presence of free Mg(2+).
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Affiliation(s)
- Marco Betti
- Departamento de Bioquímica Vegetal y Biología Molecular, Facultad de Química, Universidad de Sevilla, Apartado 553, 41080 Sevilla, Spain
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42
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Wirth S, Segretin ME, Mentaberry A, Bravo-Almonacid F. Accumulation of hEGF and hEGF-fusion proteins in chloroplast-transformed tobacco plants is higher in the dark than in the light. J Biotechnol 2006; 125:159-72. [PMID: 16584796 DOI: 10.1016/j.jbiotec.2006.02.012] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2005] [Revised: 01/27/2006] [Accepted: 02/17/2006] [Indexed: 10/24/2022]
Abstract
Chloroplast transformation has many potential advantages for the production of recombinant proteins in plants. However, it has been reported that heterologous protein accumulation in chloroplasts could be hindered by post-transcriptional mechanisms not yet characterized. Here, we describe the development and characterization of transplastomic tobacco plants transformed with four different transformation vectors for the expression of human epidermal growth factor (hEGF). We showed that, although the corresponding transcript was present in all of the analyzed plants, hEGF could only be detected when fused to the first 186 amino acids of bacterial beta-glucuronidase (GUS). In addition, we observed that the expression levels of recombinant protein increased when plants were placed in the dark or when leaves were incubated in the presence of electron transport inhibitors, such as methyl viologen (MV) and 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU). These results suggest that the mechanism responsible for hEGF instability in chloroplasts is regulated by light.
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Affiliation(s)
- Sonia Wirth
- Instituto de Investigaciones en Ingeniería Genética y Biología Molecular, INGEBI-CONICET, and FCEN-UBA, Vuelta de Obligado 2490, Buenos Aires, Argentina
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43
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Lima L, Seabra A, Melo P, Cullimore J, Carvalho H. Phosphorylation and subsequent interaction with 14-3-3 proteins regulate plastid glutamine synthetase in Medicago truncatula. PLANTA 2006; 223:558-67. [PMID: 16136328 DOI: 10.1007/s00425-005-0097-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2005] [Accepted: 07/13/2005] [Indexed: 05/04/2023]
Abstract
In this report we demonstrate that plastid glutamine synthetase of Medicago truncatula (MtGS2) is regulated by phosphorylation and 14-3-3 interaction. To investigate regulatory aspects of GS2 phosphorylation, we have produced non-phosphorylated GS2 proteins by expressing the plant cDNA in E. coli and performed in vitro phosphorylation assays. The recombinant isoenzyme was phosphorylated by calcium dependent kinase(s) present in leaves, roots and nodules. Using an (His)6-tagged 14-3-3 protein column affinity purification method, we demonstrate that phosphorylated GS2 interacts with 14-3-3 proteins and that this interaction leads to selective proteolysis of the plastid located isoform, resulting in inactivation of the isoenzyme. By site directed mutagenesis we were able to identify a GS2 phosphorylation site (Ser97) crucial for the interaction with 14-3-3s. Phosphorylation of this target residue can be functionally mimicked by replacing Ser97 by Asp, indicating that the introduction of a negative charge contributes to the interaction with 14-3-3 proteins and subsequent specific proteolysis. Furthermore, we document that plant extracts contain protease activity that cleaves the GS2 protein only when it is bound to 14-3-3 proteins following either phosphorylation or mimicking of phosphorylation by Ser97Asp.
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Affiliation(s)
- Lígia Lima
- Instituto de Biologia Molecular e Celular Rua do Campo Alegre, 823, 4150-180 Porto, Portugal
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44
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Yu CC, Hung KT, Kao CH. Nitric oxide reduces Cu toxicity and Cu-induced NH4+ accumulation in rice leaves. JOURNAL OF PLANT PHYSIOLOGY 2005; 162:1319-30. [PMID: 16425450 DOI: 10.1016/j.jplph.2005.02.003] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Nitric oxide (NO) is a highly reactive, membrane-permeable free radical, which has recently emerged as an important antioxidant. Here we investigated the protective effect of NO against the toxicity and NH4+ accumulation in rice leaves caused by excess CuSO4 (10mmol L(-1)). It was found that free radical scavengers (sodium benzoate, thiourea, and reduced glutathione) reduced the toxicity and NH4+ accumulation in rice leaves caused by excess CuSO4. NO donor sodium nitroprusside (SNP) was also effective in reducing CuSO4-induced toxicity and NH4+ accumulation in rice leaves. The protective effect of SNP on the toxicity and NH4+ accumulation can be reversed by 2-(4-carboxy-2-phenyl)-4,4,5,5-tetramethyl- imidazoline-1-oxyl-3-oxide, a NO scavenger, suggesting that the protective effect of SNP is attributable to NO released. Results obtained in the present study suggest that reduction of CuSO4-induced toxicity and NH4+ accumulation by SNP is most likely mediated through its ability to scavenge active oxygen species.
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Affiliation(s)
- Chia Chi Yu
- Department of Agronomy, National Taiwan University, Taipei, Taiwan, China
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45
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Hung KT, Kao CH. Hydrogen peroxide is required for abscisic acid-induced NH4+ accumulation in rice leaves. JOURNAL OF PLANT PHYSIOLOGY 2005; 162:1022-9. [PMID: 16173463 DOI: 10.1016/j.jplph.2004.11.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
The role of H2O2 in abscisic acid (ABA)-induced NH4+ accumulation in rice leaves was investigated. ABA treatment resulted in an accumulation of NH4+ in rice leaves, which was preceded by a decrease in the activity of glutamine synthetase (GS) and an increase in the specific activities of protease and phenylalanine ammonia-lyase (PAL). GS, PAL, and protease seem to be the enzymes responsible for the accumulation of NH4+ in ABA-treated rice leaves. Dimethylthiourea (DMTU), a chemical trap for H2O2, was observed to be effective in inhibiting ABA-induced accumulation of NH4+ in rice Leaves. Inhibitors of NADPH oxidase, diphenyleneiodonium chloride (DPI) and imidazole (IMD), and nitric oxide donor (N-tert-butyl-alpha-phenylnitrone, PBN), which have previously been shown to prevent ABA-induced increase in H2O2 contents in rice leaves, inhibited ABA-induced increase in the content of NH4+. Similarly, the changes of enzymes responsible for NH4+ accumulation induced by ABA were observed to be inhibited by DMTU, DPI, IMD, and PBN. Exogenous application of H2O2 was found to increase NH4+ content, decrease GS activity, and increase protease and PAL-specific activities in rice leaves. Our results suggest that H2O2 is involved in ABA-induced NH4+ accumulation in rice leaves.
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Affiliation(s)
- Kuo Tung Hung
- Department of Agronomy, National Taiwan University, Taipei, Taiwan, Republic of China
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46
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Kichey T, Le Gouis J, Sangwan B, Hirel B, Dubois F. Changes in the Cellular and Subcellular Localization of Glutamine Synthetase and Glutamate Dehydrogenase During Flag Leaf Senescence in Wheat (Triticum aestivum L.). ACTA ACUST UNITED AC 2005; 46:964-74. [PMID: 15840646 DOI: 10.1093/pcp/pci105] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
In order to improve our understanding of the regulation of nitrogen assimilation and recycling in wheat (Triticum aestivum L.), we studied the localization of plastidic (GS2) and cytosolic (GS1) glutamine synthetase isoenzymes and of glutamate dehydrogenase (GDH) during natural senescence of the flag leaf and in the stem. In mature flag leaves, large amounts of GS1 were detected in the connections between the mestome sheath cells and the vascular cells, suggesting an active transfer of nitrogen organic molecules within the vascular system in the mature flag leaf. Parallel to leaf senescence, an increase of a GS1 polypeptide (GS1b) was detected in the mesophyll cytosol of senescing leaves, while the GS protein content represented by another polypetide (GS1a) in the phloem companion cells remained practically constant in both leaves and stems. Both GDH aminating activity and protein content were strongly induced in senescing flag leaves. The induction occurred both in the mitochondria and in the cytosol of phloem companion cells, suggesting that the shift in GDH cellular compartmentation is important during leaf nitrogen remobilization although the metabolic or sensing role of the enzyme remains to be elucidated. Taken together, our results suggest that in wheat, nitrogen assimilation and recycling are compartmentalized between the mesophyll and the vasculature, and are shifted in different cellular compartments within these two tissues during the transition of sink leaves to source leaves.
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Affiliation(s)
- Thomas Kichey
- Laboratoire d'Androgenèse et Biotechnologie Végétale, Université de Picardie Jules Verne, 33, Rue saint-Leu, 80039 Amiens Cedex, France
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47
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García-Fernández JM, de Marsac NT, Diez J. Streamlined regulation and gene loss as adaptive mechanisms in Prochlorococcus for optimized nitrogen utilization in oligotrophic environments. Microbiol Mol Biol Rev 2005; 68:630-8. [PMID: 15590777 PMCID: PMC539009 DOI: 10.1128/mmbr.68.4.630-638.2004] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Prochlorococcus is one of the dominant cyanobacteria and a key primary producer in oligotrophic intertropical oceans. Here we present an overview of the pathways of nitrogen assimilation in Prochlorococcus, which have been significantly modified in these microorganisms for adaptation to the natural limitations of their habitats, leading to the appearance of different ecotypes lacking key enzymes, such as nitrate reductase, nitrite reductase, or urease, and to the simplification of the metabolic regulation systems. The only nitrogen source utilizable by all studied isolates is ammonia, which is incorporated into glutamate by glutamine synthetase. However, this enzyme shows unusual regulatory features, although its structural and kinetic features are unchanged. Similarly, urease activities remain fairly constant under different conditions. The signal transduction protein P(II) is apparently not phosphorylated in Prochlorococcus, despite its conserved amino acid sequence. The genes amt1 and ntcA (coding for an ammonium transporter and a global nitrogen regulator, respectively) show noncorrelated expression in Prochlorococcus under nitrogen stress; furthermore, high rates of organic nitrogen uptake have been observed. All of these unusual features could provide a physiological basis for the predominance of Prochlorococcus over Synechococcus in oligotrophic oceans.
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Affiliation(s)
- Jose Manuel García-Fernández
- Departamento de Bioquímica y Biología Molecular, Universidad de Córdoba, Edificio Severo Ochoa, Planta 1, Campus de Rabanales, 14071-Córdoba, Spain.
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48
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Cuevas JC, Sánchez DH, Marina M, Ruiz OA. Do polyamines modulate the Lotus glaber NADPH oxidation activity induced by the herbicide methyl viologen? FUNCTIONAL PLANT BIOLOGY : FPB 2004; 31:921-928. [PMID: 32688960 DOI: 10.1071/fp04007] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2004] [Accepted: 06/07/2004] [Indexed: 06/11/2023]
Abstract
In recent years, there has been a growing interest in NADPH-oxidases which are involved in the active generation of reactive oxygen species (ROS), owing to their role in oxidative burst, signalling and oxidative damage derived from biotic and abiotic stresses. NADPH oxidase activity is enhanced by some environmental cues, such as zinc deficiency and chilling stress, where zinc and polyamines have been suggested to be involved in the modulation of ROS generation. In order to further characterise NADPH oxidation activity during oxidative stress we exposed Lotus glaber Mill. (narrow-leaf trefoil; syn. L. tenuis Waldst. et Kit. ex Wild var. Miller) plants to the herbicide methyl viologen (MV) and evaluated zinc and polyamines as oxidative stress regulatory compounds. For this purpose we conducted in vitro and in vivo experiments, observing that zinc and the higher polyamines spermidine and spermine inhibited the NADPH oxidation activity in vitro while preventing methyl viologen-induced superoxide production in vivo. It is suggested that these substances act through a direct effect on flavin oxidases. However, it was not possible to correlate free polyamine content of L. glaber with their hypothetical inhibitory role during oxidative stress, probably owing to the plant's natural tolerance to the herbicide tested. Therefore, tobacco, a more sensitive species, was tested for methyl viologen toxicity. High concentrations of methyl viologen induced free polyamine levels in crude extracts and intercellular fluids. However, only free polyamine content in the intercellular fluids was increased in plants treated with low methyl viologen concentrations. These results support the notion that polyamine metabolism in the apoplast is involved in the physiological response to oxidative stress.
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Affiliation(s)
- Juan C Cuevas
- Unidad de Biotecnología 1, Instituto Tecnológico de Chascomús / Universidad Nacional de General San Martín-Consejo Nacional de Investigaciones Científicas y Técnicas (IIB-INTECH / UNSAM-CONICET), Camino circunvalación laguna, Km. 6 CC164 (B7130IWA) Chascomús, Pcia. de Buenos Aires, Argentina
| | - Diego H Sánchez
- Unidad de Biotecnología 1, Instituto Tecnológico de Chascomús / Universidad Nacional de General San Martín-Consejo Nacional de Investigaciones Científicas y Técnicas (IIB-INTECH / UNSAM-CONICET), Camino circunvalación laguna, Km. 6 CC164 (B7130IWA) Chascomús, Pcia. de Buenos Aires, Argentina
| | - María Marina
- Unidad de Biotecnología 1, Instituto Tecnológico de Chascomús / Universidad Nacional de General San Martín-Consejo Nacional de Investigaciones Científicas y Técnicas (IIB-INTECH / UNSAM-CONICET), Camino circunvalación laguna, Km. 6 CC164 (B7130IWA) Chascomús, Pcia. de Buenos Aires, Argentina
| | - Oscar A Ruiz
- Unidad de Biotecnología 1, Instituto Tecnológico de Chascomús / Universidad Nacional de General San Martín-Consejo Nacional de Investigaciones Científicas y Técnicas (IIB-INTECH / UNSAM-CONICET), Camino circunvalación laguna, Km. 6 CC164 (B7130IWA) Chascomús, Pcia. de Buenos Aires, Argentina. Corresponding author;
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49
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Palatnik JF, Tognetti VB, Poli HO, Rodríguez RE, Blanco N, Gattuso M, Hajirezaei MR, Sonnewald U, Valle EM, Carrillo N. Transgenic tobacco plants expressing antisense ferredoxin-NADP(H) reductase transcripts display increased susceptibility to photo-oxidative damage. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2003; 35:332-41. [PMID: 12887584 DOI: 10.1046/j.1365-313x.2003.01809.x] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Ferredoxin-NADP(H) reductase (FNR) catalyses the final step of the photosynthetic electron transport in chloroplasts. Using an antisense RNA strategy to reduce expression of this flavoenzyme in transgenic tobacco plants, it has been demonstrated that FNR mediates a rate-limiting step of photosynthesis under both limiting and saturating light conditions. Here, we show that these FNR-deficient plants are abnormally prone to photo-oxidative injury. When grown under autotrophic conditions for 3 weeks, specimens with 20-40% extant reductase undergo leaf bleaching, lipid peroxidation and membrane damage. The magnitude of the effect was proportional to the light intensity and to the extent of FNR depletion, and was accompanied by morphological changes involving accumulation of aberrant plastids with defective thylakoid stacking. Damage was initially confined to chloroplast membranes, whereas Rubisco and other stromal proteins began to decline only after several weeks of autotrophic growth, paralleled by partial recovery of NADPH levels. Exposure of the transgenic plants to moderately high irradiation resulted in rapid loss of photosynthetic capacity and accumulation of singlet oxygen in leaves. The collected results suggest that the extensive photo-oxidative damage sustained by plants impaired in FNR expression was caused by singlet oxygen building up to toxic levels in these tissues, as a direct consequence of the over-reduction of the electron transport chain in FNR-deficient chloroplasts.
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Affiliation(s)
- Javier F Palatnik
- Instituto de Biología Molecular y Celular de Rosario (IBR), Universidad Nacional de Rosario, Suipacha 531, S2002-LRK Rosario, Argentina
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50
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Gómez-Baena G, Diez J, García-Fernández JM, El Alaoui S, Humanes L. Regulation of glutamine synthetase by metal-catalyzed oxidative modification in the marine oxyphotobacterium Prochlorococcus. BIOCHIMICA ET BIOPHYSICA ACTA 2001; 1568:237-44. [PMID: 11786230 DOI: 10.1016/s0304-4165(01)00226-4] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The inactivation of glutamine synthetase (GS; EC 6.3.1.2) by metal-catalyzed oxidation (MCO) systems was studied in several Prochlorococcus strains, including the axenic PCC 9511. GS was inactivated in the presence of various oxidative systems, either enzymatic (as NAD(P)H+NAD(P)H-oxidase+Fe(3+)+O(2)) or non-enzymatic (as ascorbate+Fe(3+)+O(2)). This process required the presence of oxygen and a metal cation, and is prevented under anaerobic conditions. Catalase and peroxidase, but not superoxide dismutase, effectively protected the enzyme against inactivation, suggesting that hydrogen peroxide mediates this mechanism, although it is not directly responsible for the reaction. Addition of azide (an inhibitor of both catalase and peroxidase) to the MCO systems enhanced the inactivation. Different thiols induced the inactivation of the enzyme, even in the absence of added metals. However, this inactivation could not be reverted by addition of strong oxidants, as hydrogen peroxide or oxidized glutathione. After studying the effect of addition of the physiological substrates and products of GS on the inactivation mechanism, we could detect a protective effect in the case of inorganic phosphate and glutamine. Immunochemical determinations showed that the concentration of GS protein significantly decreased by effect of the MCO systems, indicating that inactivation precedes the degradation of the enzyme.
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Affiliation(s)
- G Gómez-Baena
- Departamento de Bioquímica y Biología Molecular, Edificio Severo Ochoa, 1a planta, Campus de Rabanales, Universidad de Córdoba, E-14071 Córdoba, Spain
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