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Lee KT, Liao HS, Hsieh MH. Glutamine Metabolism, Sensing and Signaling in Plants. PLANT & CELL PHYSIOLOGY 2023; 64:1466-1481. [PMID: 37243703 DOI: 10.1093/pcp/pcad054] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2023] [Revised: 04/23/2023] [Accepted: 05/24/2023] [Indexed: 05/29/2023]
Abstract
Glutamine (Gln) is the first amino acid synthesized in nitrogen (N) assimilation in plants. Gln synthetase (GS), converting glutamate (Glu) and NH4+ into Gln at the expense of ATP, is one of the oldest enzymes in all life domains. Plants have multiple GS isoenzymes that work individually or cooperatively to ensure that the Gln supply is sufficient for plant growth and development under various conditions. Gln is a building block for protein synthesis and an N-donor for the biosynthesis of amino acids, nucleic acids, amino sugars and vitamin B coenzymes. Most reactions using Gln as an N-donor are catalyzed by Gln amidotransferase (GAT) that hydrolyzes Gln to Glu and transfers the amido group of Gln to an acceptor substrate. Several GAT domain-containing proteins of unknown function in the reference plant Arabidopsis thaliana suggest that some metabolic fates of Gln have yet to be identified in plants. In addition to metabolism, Gln signaling has emerged in recent years. The N regulatory protein PII senses Gln to regulate arginine biosynthesis in plants. Gln promotes somatic embryogenesis and shoot organogenesis with unknown mechanisms. Exogenous Gln has been implicated in activating stress and defense responses in plants. Likely, Gln signaling is responsible for some of the new Gln functions in plants.
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Affiliation(s)
- Kim-Teng Lee
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei 11529, Taiwan
- Molecular and Biological Agricultural Sciences, The Taiwan International Graduate Program, Academia Sinica, Taipei 11529, Taiwan
- Biotechnology Center, National Chung-Hsing University, Taichung 40227, Taiwan
| | - Hong-Sheng Liao
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei 11529, Taiwan
| | - Ming-Hsiun Hsieh
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei 11529, Taiwan
- Molecular and Biological Agricultural Sciences, The Taiwan International Graduate Program, Academia Sinica, Taipei 11529, Taiwan
- Biotechnology Center, National Chung-Hsing University, Taichung 40227, Taiwan
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Comparing the Effects of N and P Deficiency on Physiology and Growth for Fast- and Slow-Growing Provenances of Fraxinus mandshurica. FORESTS 2021. [DOI: 10.3390/f12121760] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
With the continuous increase in atmospheric carbon dioxide emissions, nitrogen (N) and phosphorus (P) as mineral elements increasingly restrict plant growth. To explore the effect of deficiency of P and N on growth and physiology, Fraxinus mandshurica (hereafter “F. mandshurica”) Rupr. annual seedlings of Wuchang (WC) provenance with fast growth and Dailing (DL) provenance with slow growth were treated with complete nutrition or starvation of N (N-), P (P-) or both elements (NP-). Although P- and N- increased the use efficiency of P (PUE) and N (NUE), respectively, they reduced the leaf area, chlorophyll content and activities of N assimilation enzymes (NR, GS, GOGAT), which decreased the dry weight and P or N amount. The free amino acid content and activities of Phosphoenolpyruvate carboxylase (PEPC) and acid phosphatase enzymes were reduced by N-. The transcript levels of NRT2.1, NRT2.4, NRT2.5, NRT2.7, AVT1, AAP3, NIA2, PHT1-3, PHT1-4 and PHT2-1 in roots were increased, but those of NRT2.1, NRT2.4, NRT2.5, PHT1-3, PHT1-4, PHT2-1 and AAP3 in leaves were reduced by P-. WC was significantly greater than DL under P- in dry weight, C amount, N amount, leaf area, PUE, NUE, which related to greater chlorophyll content, PEPC enzyme activity, N assimilation enzyme activities, and transcript levels of N and P transporter genes in roots and foliage, indicating a greater ability of WC to absorb, transport and utilize N and P under P-. WC was also greater than DL under N- in terms of the above indicators except the transcript levels of N and P assimilation genes, but most of the indicators did not reach a significant level, indicating that WC might be more tolerant to N- than DL, which requires further verification. In summary, WC was identified as a P-efficient provenance, as the growth rate was greater for the genetic type with high than low tolerance to P-.
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Transcriptome Analysis for Fraxinus mandshurica Rupr. Seedlings from Different Carbon Sequestration Provenances in Response to Nitrogen Deficiency. FORESTS 2021. [DOI: 10.3390/f12020257] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
To explore the molecular regulatory mechanism of high-carbon (C) sequestration Fraxinus mandshurica Rupr. (F. mandshurica) provenance and the expression profile of F. mandshurica during nitrogen (N) starvation, the foliage and roots of the annual Wuchang (WC) seedlings with greater C amount and Hailin (HL) seedlings with smaller C amount, which were grown in N-deficient nutrition and complete N, were used for RNA-seq and physiological determination, respectively. One thousand and fifty-seven differentially expressed genes (DEGs) between WC and HL and 8173 DEGs related to N deficiency were identified, respectively. The root of F. mandshurica responded to N deficiency more strongly than foliar. The target genes that responded to N deficiency in roots were mainly regulatory genes (transcription factors, hormones and protein kinases), and their response patterns were upregulated. The growth and N concentration in both WC and HL were reduced by the N deficiency, which might result from the decrease of the leaf Nitrate reductase (NR) and glutamine synthetase (GS) enzyme activity and ABA content, although the root-to-shoot ratio; lateral root number; lignin content; endogenous hormones content (GA, IAA and ZR); root GS and glutamate synthetase activity and transcriptional level of most of the regulatory genes were increased. The C sequestration capacity in WC was greater than that in HL, which related to the higher GS enzymes activity and transcriptional levels of regulatory genes and metabolic genes (terpenes, carbohydrates, and lipid energy). However, the C sequestration advantage of WC was significantly reduced by the N deficiency, which was due to the smaller response to N deficiency compared to HL.
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Abstract
Nitrogen (N) is a macro-nutrient that is essential for growth development and resistance against biotic and abiotic stresses of plants. Nitrogen is a constituent of amino acids, proteins, nucleic acids, chlorophyll, and various primary and secondary metabolites. The atmosphere contains huge amounts of nitrogen but it cannot be taken up directly by plants. Plants can take up nitrogen in the form of nitrate, ammonium, urea, nitrite, or a combination of all these forms. In addition, in various leguminous rhizobia, bacteria can convert atmospheric nitrogen to ammonia and supply it to the plants. The form of nitrogen nutrition is also important in plant growth and resistance against pathogens. Nitrogen content has an important function in crop yield. Nitrogen deficiency can cause reduced root growth, change in root architecture, reduced plant biomass, and reduced photosynthesis. Hence, understanding the function and regulation of N metabolism is important. Several enzymes and intermediates are involved in nitrogen assimilation. Here we provide an overview of the important enzymes such as nitrate reductase, nitrite reductase, glutamine synthase, GOGAT, glutamate dehydrogenase, and alanine aminotransferase that are involved in nitrogen metabolism.
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Németh E, Nagy Z, Pécsváradi A. Chloroplast Glutamine Synthetase, the Key Regulator of Nitrogen Metabolism in Wheat, Performs Its Role by Fine Regulation of Enzyme Activity via Negative Cooperativity of Its Subunits. FRONTIERS IN PLANT SCIENCE 2018; 9:191. [PMID: 29520285 PMCID: PMC5827528 DOI: 10.3389/fpls.2018.00191] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2017] [Accepted: 02/01/2018] [Indexed: 05/24/2023]
Abstract
Glutamine synthetase (GS) is of central interest as the main route of ammonia assimilation in plants, and as a connection point between the organic and inorganic worlds. Even though GS activity is critical for producing high yields of crop plants, the autoregulation of substrate consumption of wheat GS remained unknown until now. Here we show kinetic evidence, that the chloroplast localized GS isoform (GS2) of wheat (Triticum aestivum L. cv. Jubilejnaja-50) takes place at the carbon-nitrogen metabolic branch point, where it is a mediator, and its enzymatic activity is regulated in a negatively cooperative allosteric manner. We have discovered that GS2 activity is described by a tetraphasic kinetic curve in response to increasing levels of glutamate supply. We constructed a model that explains the kinetic properties of glutamate consumption and this unique allosteric behavior. We also studied the subunit composition of both wheat leaf GS isoenzymes by a combination of two dimensional gel electrophoresis and protein blotting. Both leaf isozymes have homogeneous subunit composition. Glutamate is both a substrate, and an allosteric regulator of the biosynthetic reaction. We have concluded on the basis of our results and previous reports, that wheat GS2 is probably a homooctamer, and that it processes its substrate in a well-regulated, concentration dependent way, as a result of its negatively cooperative, allosteric activity. Thus, GS2 has a central role as a regulator between the nitrogen and the carbon cycles via maintaining glutamine-glutamate pool in the chloroplast on the level of substrates, in addition to its function in ammonia assimilation.
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Affiliation(s)
- Edit Németh
- Department of Plant Biology, University of Szeged, Szeged, Hungary
- Doctoral School in Biology, Faculty of Science and Informatics, University of Szeged, Szeged, Hungary
- Centre for Agricultural Research, Hungarian Academy of Sciences, Martonvásár, Hungary
| | - Zoltán Nagy
- Cereal Research Non-profit Ltd., Szeged, Hungary
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Yang X, Nian J, Xie Q, Feng J, Zhang F, Jing H, Zhang J, Dong G, Liang Y, Peng J, Wang G, Qian Q, Zuo J. Rice Ferredoxin-Dependent Glutamate Synthase Regulates Nitrogen-Carbon Metabolomes and Is Genetically Differentiated between japonica and indica Subspecies. MOLECULAR PLANT 2016; 9:1520-1534. [PMID: 27677460 DOI: 10.1016/j.molp.2016.09.004] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2016] [Revised: 09/11/2016] [Accepted: 09/18/2016] [Indexed: 05/03/2023]
Abstract
Plants assimilate inorganic nitrogen absorbed from soil into organic forms as Gln and Glu through the glutamine synthetase/glutamine:2-oxoglutarate amidotransferase (GS/GOGAT) cycle. Whereas GS catalyzes the formation of Gln from Glu and ammonia, GOGAT catalyzes the transfer of an amide group from Gln to 2-oxoglutarate to produce two molecules of Glu. However, the regulatory role of the GS/GOGAT cycle in the carbon-nitrogen balance is not well understood. Here, we report the functional characterization of rice ABNORMAL CYTOKININ RESPONSE 1 (ABC1) gene that encodes a ferredoxin-dependent (Fd)-GOGAT. The weak mutant allele abc1-1 mutant shows a typical nitrogen-deficient syndrome, whereas the T-DNA insertional mutant abc1-2 is seedling lethal. Metabolomics analysis revealed the accumulation of an excessive amount of amino acids with high N/C ratio (Gln and Asn) and several intermediates in the tricarboxylic acid cycle in abc1-1, suggesting that ABC1 plays a critical role in nitrogen assimilation and carbon-nitrogen balance. Five non-synonymous single-nucleotide polymorphisms were identified in the ABC1 coding region and characterized as three distinct haplotypes, which have been highly and specifically differentiated between japonica and indica subspecies. Collectively, these results suggest that ABC1/OsFd-GOGAT is essential for plant growth and development by modulating nitrogen assimilation and the carbon-nitrogen balance.
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Affiliation(s)
- Xiaolu Yang
- State Key Laboratory of Plant Genomics, National Plant Gene Research Center (Beijing), CAS Center for Excellence in Molecular Plant Sciences, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China; The University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jinqiang Nian
- State Key Laboratory of Plant Genomics, National Plant Gene Research Center (Beijing), CAS Center for Excellence in Molecular Plant Sciences, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Qingjun Xie
- State Key Laboratory of Plant Genomics, National Plant Gene Research Center (Beijing), CAS Center for Excellence in Molecular Plant Sciences, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China; The University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jian Feng
- State Key Laboratory of Plant Genomics, National Plant Gene Research Center (Beijing), CAS Center for Excellence in Molecular Plant Sciences, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China; The University of Chinese Academy of Sciences, Beijing 100049, China
| | - Fengxia Zhang
- State Key Laboratory of Plant Genomics, National Plant Gene Research Center (Beijing), CAS Center for Excellence in Molecular Plant Sciences, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Hongwei Jing
- State Key Laboratory of Plant Genomics, National Plant Gene Research Center (Beijing), CAS Center for Excellence in Molecular Plant Sciences, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China; The University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jian Zhang
- State Key Laboratory of Plant Genomics, National Plant Gene Research Center (Beijing), CAS Center for Excellence in Molecular Plant Sciences, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Guojun Dong
- State Key Laboratory of Rice Biology, China National Rice Research Institute, Chinese Academy of Agricultural Sciences, Hangzhou 310006, China
| | - Yan Liang
- State Key Laboratory of Plant Genomics, National Plant Gene Research Center (Beijing), CAS Center for Excellence in Molecular Plant Sciences, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Juli Peng
- State Key Laboratory of Plant Genomics, National Plant Gene Research Center (Beijing), CAS Center for Excellence in Molecular Plant Sciences, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Guodong Wang
- State Key Laboratory of Plant Genomics, National Plant Gene Research Center (Beijing), CAS Center for Excellence in Molecular Plant Sciences, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Qian Qian
- State Key Laboratory of Rice Biology, China National Rice Research Institute, Chinese Academy of Agricultural Sciences, Hangzhou 310006, China
| | - Jianru Zuo
- State Key Laboratory of Plant Genomics, National Plant Gene Research Center (Beijing), CAS Center for Excellence in Molecular Plant Sciences, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China.
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Grossman A, Takahashi H. MACRONUTRIENT UTILIZATION BY PHOTOSYNTHETIC EUKARYOTES AND THE FABRIC OF INTERACTIONS. ANNUAL REVIEW OF PLANT PHYSIOLOGY AND PLANT MOLECULAR BIOLOGY 2001; 52:163-210. [PMID: 11337396 DOI: 10.1146/annurev.arplant.52.1.163] [Citation(s) in RCA: 82] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Organisms acclimate to a continually fluctuating nutrient environment. Acclimation involves responses specific for the limiting nutrient as well as responses that are more general and occur when an organism experiences different stress conditions. Specific responses enable organisms to efficiently scavenge the limiting nutrient and may involve the induction of high-affinity transport systems and the synthesis of hydrolytic enzymes that facilitate the release of the nutrient from extracellular organic molecules or from internal reserves. General responses include changes in cell division rates and global alterations in metabolic activities. In photosynthetic organisms there must be precise regulation of photosynthetic activity since when severe nutrient limitation prevents continued cell growth, excitation of photosynthetic pigments could result in the formation of reactive oxygen species, which can severely damage structural and functional features of the cell. This review focuses on ways that photosynthetic eukaryotes assimilate the macronutrients nitrogen, sulfur, and phosphorus, and the mechanisms that govern assimilatory activities. Also discussed are molecular responses to macronutrient limitation and the elicitation of those responses through integration of environmental and cellular cues.
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Affiliation(s)
- Arthur Grossman
- Department of Plant Biology, The Carnegie Institution of Washington 260 Panama Street, Stanford, California 94305; e-mail: , RIKEN Plant Science Center, 2-l Hirosawa, Wako, Saitama, 351-0198, Japan; e-mail:
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8
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Control of Metabolism and Development in Higher Plant Plastids. INTERNATIONAL REVIEW OF CYTOLOGY VOLUME 145 1993. [DOI: 10.1016/s0074-7696(08)60427-1] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
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10
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Höpfner M, Ochs G, Wild A. Glutamine synthetases of green and etiolated leaves ofSinapis alba : Evidence of the identity of the respective enzyme proteins. PLANTA 1990; 181:155-161. [PMID: 24196731 DOI: 10.1007/bf02411532] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/1989] [Accepted: 12/07/1989] [Indexed: 06/02/2023]
Abstract
Studies on the glutamine synthetases (GS, EC 6.3.1.2) of green (GS2) and etiolated leaves (GSet) ofSinapis alba L. (cv. Steinacher) revealed striking similarities between the respective enzyme proteins. The enzymes showed corresponding chromatographic properties, both on dimethylaminoethyl-Sephacel and on hydroxylapatite columns. The purified GS proteins were also identical with regard to the molecular weight of their subunits. Isoelectrofocusing of pure GSet yielded two distinct polypeptide bands in the pH 5.6 region of the gels. This pattern corresponded to the two strong bands of GS2. Two charge variants of GS polypeptides could be detected by Western-blot analysis of the soluble protein of green leaves using antibodies against mustard GS2. In immunoprecipitation experiments, the holoenzymes of GS2 and GSet were recognized with identical affinities by this antiserum. We conclude that strong similarities exist between the proteins of the GS enzymes in green and etiolated leaves of mustard. Most probably only one GS form, namely the plastidic enzyme, can be found in the epigeal organs ofSinapis. The polypeptides of the GS2 subunits showed no differences in the hydrophobicity of the polypeptide chains. Neither glucosyl nor mannosyl residues could be detected.
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Affiliation(s)
- M Höpfner
- Institut für Allgemeine Botanik der Johannes Gutenberg-Universität, Saarstrasse 21, D-6500, Mainz, Germany
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11
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LEA PETERJ, BLACKWELL RAYD, CHEN FENGLING, HECHT URSULA. Enzymes of Ammonia Assimilation. METHODS IN PLANT BIOCHEMISTRY 1990. [DOI: 10.1016/b978-0-12-461013-2.50022-8] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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12
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Rees TAV, Shah N, Stewart GR. Glutamine synthetase isoforms in the green hydra symbiosis. THE NEW PHYTOLOGIST 1989; 111:621-623. [PMID: 33874060 DOI: 10.1111/j.1469-8137.1989.tb02355.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
The occurrence of glutamine synthetase isoforms in the green hydra symbiosis has been investigated using ion-exchange chromatography. There were three isoforms which were designated algal cytosolic, chloroplastic and host isoenzymes. Comparison of the proportions of algal isoforms from the intact association with those from nitrogen-replete and nitrogen-starved cultures of a Chlorella strain originally isolated from green hydra, suggests that symbionts in the intact association may be nitrogen-deficient.
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Affiliation(s)
- T A V Rees
- Department of Plant Sciences, University of Oxford, Parks Road, Oxford OX1 3PF, UK
| | - N Shah
- Department of Botany, Birkbeck College, University of London, Malet Street, London WC1E 7HX, UK
| | - G R Stewart
- Department of Botany, Birkbeck College, University of London, Malet Street, London WC1E 7HX, UK
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Schmidt S, Mohr H. Regulation of the appearance of glutamine synthetase in mustard (Sinapis alba L.) cotyledons by light, nitrate and ammonium. PLANTA 1989; 177:526-534. [PMID: 24212495 DOI: 10.1007/bf00392621] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/27/1988] [Accepted: 11/14/1988] [Indexed: 06/02/2023]
Abstract
During transformation of mustard seedlings cotyledons from storage organs to photosynthetically competent leaves, a process which occurs during the first 4 d after sowing, total glutamine-synthetase (GS, EC 6.3.1.2) activity increases from zero to the high level usually observed in green leaves. In the present study we have used ion-exchange chromatography to separate possible isoforms of GS during the development of the cotyledons. The approach failed since we could only detect a single form of GS, presumably plastidic GS, under all circumstances tested. The technique of selective photooxidative destruction of plastids in situ was applied to solve the problem of GS localization. It was inferred from the data that the GS as detected by ion-exchange chromatography is plastidic GS.The regulatory role, if any, of light, nitrate and ammonium in the process of the appearance of GS in the developing cotyledons was investigated. The results show that nitrate and ammonium play only minor roles. Light, operating via phytochrome, is the major regulatory factor.
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Affiliation(s)
- S Schmidt
- Biologisches Institut II der Universität, Schänzlestrasse 1, D-7800, Freiburg i. Br., Federal Republic of Germany
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Tobin AK, Ridley SM, Stewart GR. Changes in the activities of chloroplast and cytosolic isoenzymes of glutamine synthetase during normal leaf growth and plastid development in wheat. PLANTA 1985; 163:544-548. [PMID: 24249453 DOI: 10.1007/bf00392711] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/1984] [Accepted: 10/11/1984] [Indexed: 06/02/2023]
Abstract
Soluble protein extracts and chloroplasts from a serial sequence of transverse sections of a 7-d-old wheat leaf (Triticum aestivum cv. Maris Huntsman) were used to study changes in the activity of glutamine synthetase (GS; EC 6.3.1.2) during cell and chloroplast development. Glutamine synthetase activity increased more than 50-fold per cell from the base to the tip of the wheat leaf. Two isoenzymes of GS were separated using fast protein liquid chromatography (FPLC). Glutamine synthetase localized in the cytoplasm (GS1) eluted at about 0.21 M NaCl, and the isoenzyme localized in the chloroplast (GS2) eluted at about 0.33 M NaCl. The increase in GS activity during leaf development was found to be caused primarily by an increase in the activity of the chloroplast GS2. The activity of the cytoplasmic GS1 remained constant as the cells were displaced from the base to the tip of the leaf, whereas GS2 activity increased within the chloroplast throughout development. At the base of the leaf, 26% of total GS activity was cytoplasmic; the remaining 74% was in the chloroplast. At 10 cm from the base, only 4% of the activity was cytoplasmic, and 96% was in the chloroplast. The results indicate that the chloroplast GS2 is probably responsible for most of the ammonia assimilation in the mature wheat leaf, whereas cytoplasmic GS1 may serve a role in immature developing leaf cells.
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Affiliation(s)
- A K Tobin
- Department of Biology, University of York, Y01 5DD, York, UK
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Cánovas F, Valpuesta V, De Castro IN. Characterization of tomato leaf glutamine synthetase. ACTA ACUST UNITED AC 1984. [DOI: 10.1016/0304-4211(84)90207-4] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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16
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Hirel B, Nato A, Martin F. Glutamine synthetase in ribulose 1,5-bisphosphate carboxylase/oxygenase deficient tobacco mutants in cell suspension culture. PLANT CELL REPORTS 1984; 3:106-108. [PMID: 24253436 DOI: 10.1007/bf02441011] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/1984] [Revised: 05/02/1984] [Indexed: 06/02/2023]
Abstract
In two tobacco mutants lacking ribulose, 1,5-bisphosphate carboxylase/oxygenase the amount of glutamine synthetase and its activity were determined and compared with the wild type green cells. It was shown that in these two mutants glutamine synthetase protein content was six times lower than in the wild type. This situation was comparable to that found in etiolated cells where ribulose 1,5-bisphosphate carboxylase/oxygenase was absent. These observations suggest that a common regulatory mechanism might control the dual light dependent biosynthesis of both enzymes. The results have also implications concerning the efficiency of the reassimilation of ammonia by chloroplastic glutamine synthetase during the photorespiratory process.
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Affiliation(s)
- B Hirel
- Physiologie Végétale Métabolique E. R. A. CNRS, Université de Paris-Sud, no 799 Bâtiment 430, 91405, Orsay Cedex, France
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Hirel B, McNally SF, Gadal P, Sumar N, Stewart GR. Cytosolic glutamine synthetase in higher plants. A comparative immunological study. EUROPEAN JOURNAL OF BIOCHEMISTRY 1984; 138:63-6. [PMID: 6141048 DOI: 10.1111/j.1432-1033.1984.tb07881.x] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Cytosolic glutamine synthetase (GS1) was purified to homogeneity from etiolated barley leaves by DEAE-Sephacel and hydroxyapatite chromatography, gel filtration and polyacrylamide gel electrophoresis. Specific antibodies against the purified protein were raised by the immunization of rabbits. Immunoprecipitation experiments demonstrated that cytosolic glutamine synthetases isolated from the leaves of different plant species were very similar proteins. Good recognition of other cytosolic glutamine synthetases from roots, root nodular tissue and seeds by barley GS1 antibodies was obtained, suggesting that they too are all quite similar proteins. In contrast, chloroplast glutamine synthetase (GS2) was considered to be a different protein in view of its low level of recognition by barley GS1 antibodies.
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Dyviniak SD, Dunham VL. Four isoforms of glutamine synthetase in light-grown soybeans. Biochem Biophys Res Commun 1983; 114:604-11. [PMID: 6136278 DOI: 10.1016/0006-291x(83)90823-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Glutamine synthetase (GS) activity recovered from linear sucrose gradients was associated with the cytosol of cells isolated from etiolated soybean hypocotyls whereas light-grown tissue contained increased GS activity localized in both the cytosol and chloroplasts. DEAE-cellulose chromatography indicated two GS isoforms in etiolated hypocotyls whereas light-grown hypocotyls and primary leaves contained four isoforms. Only one GS isoform was recovered from both etiolated and light-grown cotyledons.
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Cullimore JV, Lara M, Lea PJ, Miflin BJ. Purification and properties of two forms of glutamine synthetase from the plant fraction of Phaseolus root nodules. PLANTA 1983; 157:245-253. [PMID: 24264154 DOI: 10.1007/bf00405189] [Citation(s) in RCA: 36] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/1982] [Accepted: 09/21/1982] [Indexed: 06/02/2023]
Abstract
Two forms of glutamine synthetase (GS) have been purified to apparent homogeneity from the plant fraction of Phaseolus vulgaris root nodules. One of these forms appears identical to the form of the enzyme found in roots but the other is probably specifically associated with the nodule. Free-living Rhizobium phaseoli also contain two forms of GS both of which have different molecular weights from the plant enzymes. Bacteroids contain solely the higher-molecular-weight form of rhizobial GS. There are only minor differences between the plant enzymes in Km or S0.5 values for the synthetase-reaction substrates and both forms have identical molecular weights of the holoenzyme (380,000 daltons) and its sub-units (41,000 daltons). They can be separated by ion-exchange chromatography on diethylaminoethyl-Sephacel and by native polyacrylamide-gel electrophoresis. The only other distinguishing feature observed is that the ratio of transferase: synthetase activity of the root form is threefold greater than that of the nodule-specific GS.
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Affiliation(s)
- J V Cullimore
- Biochemistry Department, Rothamsted Experimental Station, AL5 2JQ, Harpenden, Herts, UK
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Nagy A, Csanádi J, Turtóczky I, Gyurján I. Method for Simultaneous Determination of Glutamine Synthetase and Adenosine Triphosphatase Activities on Polyacrylamide Gel. ACTA ACUST UNITED AC 1983. [DOI: 10.1016/s0015-3796(83)80038-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Martin F, Suzuki A, Hirel B. A new high-performance liquid chromatography assay for glutamine synthetase and glutamate synthase in plant tissues. Anal Biochem 1982; 125:24-9. [PMID: 6128944 DOI: 10.1016/0003-2697(82)90378-5] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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Hirel B, Vidal J, Gadal P. Evidence for a cytosolic-dependent light induction of chloroplastic glutamine synthetase during greening of etiolated rice leaves. PLANTA 1982; 155:17-23. [PMID: 24271621 DOI: 10.1007/bf00402926] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/1981] [Accepted: 03/04/1982] [Indexed: 06/02/2023]
Abstract
During the greening of etiolated rice leaves, total glutamine synthetase activity increases about twofold, and after 48 h the level of activity usually observed in green leaves is obtained. A density-labeling experiment with deuterium demonstrates that the increase in enzyme activity is due to a synthesis of the enzyme. The enhanced activity obtained upon greening is the result of two different phenomena: there is a fivefold increase of chloroplastic glutamine synthetase content accompanied by a concommitant decrease (twofold) of the cytosolic glutamine synthetase. The increase of chloroplastic glutamine synthetase (GS2) is only inhibited by cycloheximide and not by lincomycin. This result indicates a cytosolic synthesis of GS2. The synthesis of GS2 was confirmed by a quantification of the protein by an immunochemical method. It was demonstrated that GS2 protein content in green leaves is fivefold higher than in etiolated leaves.
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Affiliation(s)
- B Hirel
- Laboratoire de Physiologie Végétale Métabolique, ERA CNRS no 799, Bâtiment 430, Université de Paris Sud, Centre d'Orsay, F-91405, Orsay-Cedex, France
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Pushkin A, Tsuprum V, Dzhokharidze T, Evstigneeva Z, Kretovich W. Glutamine synthetase from the pumpkin leaf cytosol. ACTA ACUST UNITED AC 1981. [DOI: 10.1016/0005-2744(81)90237-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Wedler FC, Shreve DS, Fisher KE, Merkler DJ. Complementarity of regulation for the two glutamine synthetases from Bacillus caldolyticus, an extreme thermophile. Arch Biochem Biophys 1981; 211:276-87. [PMID: 6118092 DOI: 10.1016/0003-9861(81)90455-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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Iyer RK, Tuli R, Thomas J. Glutamine synthetases from rice: purification and preliminary characterization of two forms in leaves and one form in roots. Arch Biochem Biophys 1981; 209:628-36. [PMID: 6117254 DOI: 10.1016/0003-9861(81)90322-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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Suzuki A, Gadal P, Oaks A. Intracellular distribution of enzymes associated with nitrogen assimilation in roots. PLANTA 1981; 151:457-461. [PMID: 24302111 DOI: 10.1007/bf00386539] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/04/1980] [Accepted: 11/28/1980] [Indexed: 06/02/2023]
Abstract
The cellular distribution of enzymes involved in nitrogen assimilation: nitrate reductase (EC 1.6.6.2), nitrite reductase (EC 1.6.6.4), glutamine synthetase (EC 6.3.1.2), glutamate synthase (EC 2.6.1.53), and glutamate dehydrogenase (EC 1.4.1.3) has been studied in the roots of five plants: maize (Zea mays L. hybrid W 64A x W 182E), rice (Oryza sativa L. cv. Delta), bean (Phaseolus vulgaris L. cv. Contender), pea (Pisum sativum L. cv. Demi-nain), and barley (Hordeum vulgare L.). Initially, cell organelles were separated from soluble proteins by differential centrifugation. Cell organelles were also subjected to sucrose density gradients. The results obtained by these two methods indicate that nitrite reductase and glutamate synthase are localized in plastids, nitrate reductase and glutamine synthetase are present in the cytosol, and glutamate dehydrogenase is a mitochondrial enzyme.
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Affiliation(s)
- A Suzuki
- Laboratoire de Biologie Végétale, ERA au CNRS No 799, Faculté des Sciences, Université de Nancy I, Case Officielle no 140, F-54037, Nancy Cedex, France
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Miflin BJ, Wallsgrove RM, Lea PJ. Glutamine metabolism in higher plants. CURRENT TOPICS IN CELLULAR REGULATION 1981; 20:1-43. [PMID: 6120060 DOI: 10.1016/b978-0-12-152820-1.50005-5] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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Identification of multiple forms of glutamine synthetase in field bean (Vicia faba L.). ACTA ACUST UNITED AC 1981. [DOI: 10.1016/0304-4211(81)90271-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Mann AF, Fentem PA, Stewart GR. Tissue localization of barley (Hordeum vulgare) glutamine synthetase isoenzymes. FEBS Lett 1980; 110:265-7. [PMID: 6102927 DOI: 10.1016/0014-5793(80)80088-3] [Citation(s) in RCA: 70] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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