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Chattha MS, Ali Q, Haroon M, Afzal MJ, Javed T, Hussain S, Mahmood T, Solanki MK, Umar A, Abbas W, Nasar S, Schwartz-Lazaro LM, Zhou L. Enhancement of nitrogen use efficiency through agronomic and molecular based approaches in cotton. FRONTIERS IN PLANT SCIENCE 2022; 13:994306. [PMID: 36237509 PMCID: PMC9552886 DOI: 10.3389/fpls.2022.994306] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2022] [Accepted: 08/22/2022] [Indexed: 05/22/2023]
Abstract
Cotton is a major fiber crop grown worldwide. Nitrogen (N) is an essential nutrient for cotton production and supports efficient crop production. It is a crucial nutrient that is required more than any other. Nitrogen management is a daunting task for plants; thus, various strategies, individually and collectively, have been adopted to improve its efficacy. The negative environmental impacts of excessive N application on cotton production have become harmful to consumers and growers. The 4R's of nutrient stewardship (right product, right rate, right time, and right place) is a newly developed agronomic practice that provides a solid foundation for achieving nitrogen use efficiency (NUE) in cotton production. Cropping systems are equally crucial for increasing production, profitability, environmental growth protection, and sustainability. This concept incorporates the right fertilizer source at the right rate, time, and place. In addition to agronomic practices, molecular approaches are equally important for improving cotton NUE. This could be achieved by increasing the efficacy of metabolic pathways at the cellular, organ, and structural levels and NUE-regulating enzymes and genes. This is a potential method to improve the role of N transporters in plants, resulting in better utilization and remobilization of N in cotton plants. Therefore, we suggest effective methods for accelerating NUE in cotton. This review aims to provide a detailed overview of agronomic and molecular approaches for improving NUE in cotton production, which benefits both the environment and growers.
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Affiliation(s)
- Muhammad Sohaib Chattha
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-Products, Institute of Agro-Product Safety and Nutrition, Zhejiang Academy of Agricultural Sciences, Hangzhou, China
- School of Plant, Environmental and Soil Sciences, Louisiana State University Agricultural Center, Baton Rouge, LA, United States
| | - Qurban Ali
- Laboratory of Integrated Management of Crop Diseases and Pests, Department of Plant Pathology, College of Plant Protection, Ministry of Education, Nanjing Agricultural University, Nanjing, China
| | - Muhammad Haroon
- National Key Laboratory of Crop Genetic Improvement and National Centre of Plant Gene Research (Wuhan), Huazhong Agricultural University, Wuhan, China
| | | | - Talha Javed
- College of Agriculture, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Sadam Hussain
- Department of Agronomy, University of Agriculture Faisalabad, Faisalabad, Pakistan
| | - Tahir Mahmood
- Department of Plant Breeding & Genetics, Pir Mehr Ali Shah Arid Agriculture University, Rawalpindi, Pakistan
| | - Manoj K. Solanki
- Institute of Biology, Biotechnology and Environmental Protection, Faculty of Natural Sciences, University of Silesia in Katowice, Katowice, Poland
| | - Aisha Umar
- Institute of Botany, University of the Punjab, Lahore, Pakistan
| | - Waseem Abbas
- National Key Laboratory of Crop Genetic Improvement and National Centre of Plant Gene Research (Wuhan), Huazhong Agricultural University, Wuhan, China
| | - Shanza Nasar
- Department of Botany, University of Gujrat Hafiz Hayat Campus, Gujrat, Pakistan
| | - Lauren M. Schwartz-Lazaro
- School of Plant, Environmental and Soil Sciences, Louisiana State University Agricultural Center, Baton Rouge, LA, United States
| | - Lei Zhou
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-Products, Institute of Agro-Product Safety and Nutrition, Zhejiang Academy of Agricultural Sciences, Hangzhou, China
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Liao HS, Chung YH, Hsieh MH. Glutamate: A multifunctional amino acid in plants. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2022; 318:111238. [PMID: 35351313 DOI: 10.1016/j.plantsci.2022.111238] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Revised: 02/15/2022] [Accepted: 02/21/2022] [Indexed: 06/14/2023]
Abstract
Glutamate (Glu) is a versatile metabolite and a signaling molecule in plants. Glu biosynthesis is associated with the primary nitrogen assimilation pathway. The conversion between Glu and 2-oxoglutarate connects Glu metabolism to the tricarboxylic acid cycle, carbon metabolism, and energy production. Glu is the predominant amino donor for transamination reactions in the cell. In addition to protein synthesis, Glu is a building block for tetrapyrroles, glutathione, and folate. Glu is the precursor of γ-aminobutyric acid that plays an important role in balancing carbon/nitrogen metabolism and various cellular processes. Glu can conjugate to the major auxin indole 3-acetic acid (IAA), and IAA-Glu is destined for oxidative degradation. Glu also conjugates with isochorismate for the production of salicylic acid. Accumulating evidence indicates that Glu functions as a signaling molecule to regulate plant growth, development, and defense responses. The ligand-gated Glu receptor-like proteins (GLRs) mediate some of these responses. However, many of the Glu signaling events are GLR-independent. The receptor perceiving extracellular Glu as a danger signal is still unknown. In addition to GLRs, Glu may act on receptor-like kinases or receptor-like proteins to trigger immune responses. Glu metabolism and Glu signaling may entwine to regulate growth, development, and defense responses in plants.
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Affiliation(s)
- Hong-Sheng Liao
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei 11529, Taiwan
| | - Yi-Hsin Chung
- 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; Department of Life Sciences, National Central University, Taoyuan 32001, Taiwan.
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Tang D, Jiao Z, Zhang Q, Liu MY, Ruan J. Glutamate dehydrogenase isogenes CsGDHs cooperate with glutamine synthetase isogenes CsGSs to assimilate ammonium in tea plant (Camellia sinensis L.). PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2021; 312:111031. [PMID: 34620435 DOI: 10.1016/j.plantsci.2021.111031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2021] [Revised: 08/20/2021] [Accepted: 08/22/2021] [Indexed: 06/13/2023]
Abstract
Glutamate dehydrogenase (GDH) is a central enzyme in nitrogen metabolism, assimilating ammonia into glutamine or deaminating glutamate into α-oxoglutarate. Tea (Camellia sinensis L.) plants assimilate ammonium efficiently, but the role of CsGDH in ammonium assimilation remains unclear. We confirmed that tea has three GDH isogenes: CsGDH1-3. Bioinformatic analysis showed that CsGDH1 encodes the β-GDH subunit, CsGDH2/3 encode the α-GDH subunit, and their proteins all feature an NADH-specific motif. CsGDH1 is mainly expressed in mature leaves and roots, CsGDH3 is mainly expressed in new shoots and roots, and CsGDH2 has the highest expression level in flowers compared to the other five tissues. Expression patterns of CsGDHs and glutamine synthetase isogenes (CsGSs) under different ammonium concentrations suggested that CsGDHs cooperate with CsGSs to assimilate ammonium, especially under high ammonium conditions. Inhibition of GS and its isogenes resulted in significant induction of CsGDH3 in roots and CsGDH2 in leaves, indicating their potential roles in ammonium assimilation. Moreover, CsGDHs transcripts were highly abundant in chlorotic tea leaves, in constrast to those of CsGSs, suggesting that CsGDHs play a vital role in ammonium assimilation in chlorotic tea mutant. Altogether, our circumstantial evidence that CsGDHs cooperate with CsGSs in ammonium assimilation provides a basis for unveiling their functions in tea plants.
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Affiliation(s)
- Dandan Tang
- Tea Research Institute, Chinese Academy of Agricultural Sciences, Hangzhou, 310008, China; Key Laboratory of Tea Plant Biology and Resources Utilization (Ministry of Agriculture and Rural Affairs), Hangzhou, 310008, China; Graduate School, Chinese Academy of Agricultural Sciences, Beijing, 100081, China.
| | - Zixin Jiao
- Tea Research Institute, Chinese Academy of Agricultural Sciences, Hangzhou, 310008, China; Key Laboratory of Tea Plant Biology and Resources Utilization (Ministry of Agriculture and Rural Affairs), Hangzhou, 310008, China; Graduate School, Chinese Academy of Agricultural Sciences, Beijing, 100081, China.
| | - Qunfeng Zhang
- Tea Research Institute, Chinese Academy of Agricultural Sciences, Hangzhou, 310008, China; Key Laboratory of Tea Plant Biology and Resources Utilization (Ministry of Agriculture and Rural Affairs), Hangzhou, 310008, China.
| | - Mei-Ya Liu
- Tea Research Institute, Chinese Academy of Agricultural Sciences, Hangzhou, 310008, China; Key Laboratory of Tea Plant Biology and Resources Utilization (Ministry of Agriculture and Rural Affairs), Hangzhou, 310008, China.
| | - Jianyun Ruan
- Tea Research Institute, Chinese Academy of Agricultural Sciences, Hangzhou, 310008, China; Key Laboratory of Tea Plant Biology and Resources Utilization (Ministry of Agriculture and Rural Affairs), Hangzhou, 310008, China.
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Meng X, Wang X, Zhang Z, Xiong S, Wei Y, Guo J, Zhang J, Wang L, Ma X, Tegeder M. Transcriptomic, proteomic, and physiological studies reveal key players in wheat nitrogen use efficiency under both high and low nitrogen supply. JOURNAL OF EXPERIMENTAL BOTANY 2021; 72:4435-4456. [PMID: 33829261 DOI: 10.1093/jxb/erab153] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2021] [Accepted: 04/02/2021] [Indexed: 06/12/2023]
Abstract
The effective use of available nitrogen (N) to improve crop grain yields provides an important strategy to reduce environmental N pollution and promote sustainable agriculture. However, little is known about the common genetic basis of N use efficiency (NUE) at varying N availability. Two wheat (Triticum aestivum L.) cultivars were grown in the field with high, moderate, and low N supply. Cultivar Zhoumai 27 outperformed Aikang 58 independent of the N supply and showed improved growth, canopy leaf area index, flag leaf surface area, grain number, and yield, and enhanced NUE due to both higher N uptake and utilization efficiency. Further, transcriptome and proteome analyses were performed using flag leaves that provide assimilates for grain growth. The results showed that many genes or proteins that are up- or down-regulated under all N regimes are associated with N and carbon metabolism and transport. This was reinforced by cultivar differences in photosynthesis, assimilate phloem transport, and grain protein/starch yield. Overall, our study establishes that improving NUE at both high and low N supply requires distinct adjustments in leaf metabolism and assimilate partitioning. Identified key genes/proteins may individually or concurrently regulate NUE and are promising targets for maximizing crop NUE irrespective of the N supply.
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Affiliation(s)
- Xiaodan Meng
- Collaborative Innovation Center of Henan Grain Crops, Henan Agricultural University, ZhengzhouChina
- College of Agronomy, Henan Agricultural University, ZhengzhouChina
- School of Biological Sciences, Washington State University, Pullman, WAUSA
| | - Xiaochun Wang
- Collaborative Innovation Center of Henan Grain Crops, Henan Agricultural University, ZhengzhouChina
| | - Zhiyong Zhang
- Collaborative Innovation Center of Henan Grain Crops, Henan Agricultural University, ZhengzhouChina
- College of Agronomy, Henan Agricultural University, ZhengzhouChina
| | - Shuping Xiong
- Collaborative Innovation Center of Henan Grain Crops, Henan Agricultural University, ZhengzhouChina
- College of Agronomy, Henan Agricultural University, ZhengzhouChina
| | - Yihao Wei
- Collaborative Innovation Center of Henan Grain Crops, Henan Agricultural University, ZhengzhouChina
- College of Agronomy, Henan Agricultural University, ZhengzhouChina
| | - Jianbiao Guo
- College of Agronomy, Henan Agricultural University, ZhengzhouChina
| | - Jie Zhang
- College of Agronomy, Henan Agricultural University, ZhengzhouChina
| | - Lulu Wang
- College of Agronomy, Henan Agricultural University, ZhengzhouChina
| | - Xinming Ma
- Collaborative Innovation Center of Henan Grain Crops, Henan Agricultural University, ZhengzhouChina
- College of Agronomy, Henan Agricultural University, ZhengzhouChina
| | - Mechthild Tegeder
- School of Biological Sciences, Washington State University, Pullman, WAUSA
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The SV, Snyder R, Tegeder M. Targeting Nitrogen Metabolism and Transport Processes to Improve Plant Nitrogen Use Efficiency. FRONTIERS IN PLANT SCIENCE 2021; 11:628366. [PMID: 33732269 PMCID: PMC7957077 DOI: 10.3389/fpls.2020.628366] [Citation(s) in RCA: 47] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Accepted: 12/31/2020] [Indexed: 05/22/2023]
Abstract
In agricultural cropping systems, relatively large amounts of nitrogen (N) are applied for plant growth and development, and to achieve high yields. However, with increasing N application, plant N use efficiency generally decreases, which results in losses of N into the environment and subsequently detrimental consequences for both ecosystems and human health. A strategy for reducing N input and environmental losses while maintaining or increasing plant performance is the development of crops that effectively obtain, distribute, and utilize the available N. Generally, N is acquired from the soil in the inorganic forms of nitrate or ammonium and assimilated in roots or leaves as amino acids. The amino acids may be used within the source organs, but they are also the principal N compounds transported from source to sink in support of metabolism and growth. N uptake, synthesis of amino acids, and their partitioning within sources and toward sinks, as well as N utilization within sinks represent potential bottlenecks in the effective use of N for vegetative and reproductive growth. This review addresses recent discoveries in N metabolism and transport and their relevance for improving N use efficiency under high and low N conditions.
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Affiliation(s)
| | | | - Mechthild Tegeder
- School of Biological Sciences, Washington State University, Pullman, WA, United States
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Dellero Y. Manipulating Amino Acid Metabolism to Improve Crop Nitrogen Use Efficiency for a Sustainable Agriculture. FRONTIERS IN PLANT SCIENCE 2020; 11:602548. [PMID: 33329673 PMCID: PMC7733991 DOI: 10.3389/fpls.2020.602548] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/03/2020] [Accepted: 11/03/2020] [Indexed: 05/06/2023]
Abstract
In a context of a growing worldwide food demand coupled to the need to develop a sustainable agriculture, it is crucial to improve crop nitrogen use efficiency (NUE) while reducing field N inputs. Classical genetic approaches based on natural allelic variations existing within crops have led to the discovery of quantitative trait loci controlling NUE under low nitrogen conditions; however, the identification of candidate genes from mapping studies is still challenging. Amino acid metabolism is the cornerstone of plant N management, which involves N uptake, assimilation, and remobilization efficiencies, and it is finely regulated during acclimation to low N conditions and other abiotic stresses. Over the last two decades, biotechnological engineering of amino acid metabolism has led to promising results for the improvement of crop NUE, and more recently under low N conditions. This review summarizes current work carried out in crops and provides perspectives on the identification of new candidate genes and future strategies for crop improvement.
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Magadlela A, Morcillo RJL, Kleinert A, Venter M, Steenkamp E, Valentine A. Glutamate dehydrogenase is essential in the acclimation of Virgilia divaricata, a legume indigenous to the nutrient-poor Mediterranean-type ecosystems of the Cape Fynbos. JOURNAL OF PLANT PHYSIOLOGY 2019; 243:153053. [PMID: 31644998 DOI: 10.1016/j.jplph.2019.153053] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2019] [Revised: 09/13/2019] [Accepted: 09/17/2019] [Indexed: 06/10/2023]
Abstract
Glutamate dehydrogenase (NAD(H)- GDH, EC 1.4.1.2) is an important enzyme in nitrogen (N) metabolism. It serves as a link between C and N metabolism, in its role of assimilating ammonia into glutamine or deaminating glutamate into 2-oxoglutarate and ammonia. GDH may also have a key in the N assimilation of legumes growing in P-poor soils. Virgilia divaricata is such a legume, growing in the nutrient limited soils of the mediterranean-type Cape fynbos ecosystem. In order to understand the role of GDH in the nitrogen nutrition of V. divaricata, the aim of this study was to identify the GDH gene transcripts, their relative expressions and enzyme activity in P-stressed roots and nodules during N metabolism. During P deficiency there was a reduction in total plant biomass as well as total plant P concentration. The analysis of the GDH cDNA sequences in V. divaricata revealed the presence of GHD1 and GHD2 subunits, these corresponding to the GDH1, GDH-B and GDH3 genes of legumes and non-legume plants. The relative expression of GDH1 and GDH2 genes in the roots and nodules, indicates that two the subunits were differently regulated depending on the organ type, rather than P supply. Although both transcripts appeared to be ubiquitously expressed in the roots and nodules, the GDH2 transcript evidently predominated over those of GDH1. Furthermore, the higher expression of both GDH transcripts in the roots than nodules, suggests that roots are more reliant on on GDH in P-poor soils, than nodules. With regards to GHD activity, both aminating and deaminating GDH activities were differently affected by P deficiency in roots and nodules. This may function to assimilate N and regulate internal C and N in the roots and nodules. The variation in GDH1 and GDH2 transcript expression and GDH enzyme activities, indicate that the enzyme may be regulated by post-translational modification, instead of by gene expression during P deficiency in V. divaricata.
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Affiliation(s)
- Anathi Magadlela
- School of Life Sciences, University of KwaZulu-Natal, Private Bag X 01, Scottsville 3209, South Africa
| | - Rafael Jorge Leon Morcillo
- Shanghai Center for Plant Stress Biology, Chinese Academy of Sciences, No. 3888 Chenhua Road, Shanghai 201602, People's Republic of China
| | - Aleysia Kleinert
- Botany and Zoology Department, University of Stellenbosch, Private Bag X1, Matieland 7602, South Africa
| | - Mauritz Venter
- AzarGen Biotechnologies, Launchlab, Hammandshand Road, Stellenbosch 7600, South Africa
| | - Emma Steenkamp
- Department of Microbiology and Plant Pathology, Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria 0002, South Africa
| | - Alex Valentine
- Botany and Zoology Department, University of Stellenbosch, Private Bag X1, Matieland 7602, South Africa.
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Vita F, Giuntoli B, Arena S, Quaranta F, Bertolini E, Lucarotti V, Guglielminetti L, Alessio M, Scaloni A, Alpi A. Effects of different nitrogen fertilizers on two wheat cultivars: An integrated approach. PLANT DIRECT 2018; 2:e00089. [PMID: 31245689 PMCID: PMC6508776 DOI: 10.1002/pld3.89] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/13/2018] [Revised: 09/06/2018] [Accepted: 10/01/2018] [Indexed: 06/09/2023]
Abstract
Investigation of cultivated plant physiology grown under low energy input plays an important role to indicate their fitness to the new environmental conditions. The durum-wheat cultivars Creso and Dylan were tested to evaluate the growth, production, and proteomic and transcriptomic profiles of the crop under different synthetic and organic nitrogen fertilization regimes. In this work, a two-dimensional gel electrophoresis (2-DE) approach combined with liquid chromatography-mass spectrometry (LC-MS) was used to investigate the protein changes induced by the use of different nitrogen sources (hydrolysate of proteins 1 and 2, rhizovit, synthesis, leather) on wheat plants. Proteomic studies were integrated with qPCR analysis of genes related to glutamine synthetase/glutamine-2-oxoglutarate aminotransferase (GS-GOGAT) and tricarboxylic acid (TCA) metabolic pathways because most relevant for nitrogen-dependent plants growth. The proteomic analysis lead to the isolation of 23 spots that were able to distinguish the analyzed samples. These spots yielded the identification of 60 proteins involved in photosynthesis, glycolysis, and nitrogen metabolism. As an example, the quinone oxidoreductase-like protein and probable glutathione S-transferase GSTU proteins were identified in two spots that represents the most statistically significant ones in Dylan samples. Transcript analysis indicated that related genes exhibited different expression trends; the heat map also revealed the different behaviors of the hydrolysates of the proteins 1 and 2 nitrogen sources. The effects of nitrogenous fertilizers at the proteomic and agronomic levels revealed that plants fertilized with synthesis or rhizovit gave the best results concerning yield, whereas rhizovit and protein hydrolysates were most effective for proteins content in the grain (% of dry weight). Therefore, all parameters measured in this study indicated that different kinds of nitrogen fertilization used have a relevant impact on plant growth and production.
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Affiliation(s)
- Federico Vita
- LINV-Department of Plant Soil and Environmental Science University of Florence Florence Italy
- A.R.E.A. Foundation Pisa Italy
| | - Beatrice Giuntoli
- Biology Department University of Pisa Pisa Italy
- Institute of Life Sciences Scuola Superiore Sant'Anna Pisa Italy
| | - Simona Arena
- Proteomics and Mass Spectrometry Laboratory I.S.P.A.A.M. National Research Council Napoli Italy
| | - Fabrizio Quaranta
- Council for Agricultural Research and Agricultural Economics Analysis Unità di ricerca per la valorizzazione qualitativa dei cereali (CREA-QCE) Rome Italy
| | - Edoardo Bertolini
- Institute of Life Sciences Scuola Superiore Sant'Anna Pisa Italy
- Present address: Donald Danforth Plant Science Center Saint Louis Missouri
| | - Valentina Lucarotti
- Department of Agriculture, Food and Environment (DiSAAA) University of Pisa Pisa Italy
| | | | - Massimo Alessio
- Proteome Biochemistry Unit IRCCS-San Raffaele Scientific Institute Milan Italy
| | - Andrea Scaloni
- Proteomics and Mass Spectrometry Laboratory I.S.P.A.A.M. National Research Council Napoli Italy
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Gaufichon L, Rothstein SJ, Suzuki A. Asparagine Metabolic Pathways in Arabidopsis. PLANT & CELL PHYSIOLOGY 2016; 57:675-89. [PMID: 26628609 DOI: 10.1093/pcp/pcv184] [Citation(s) in RCA: 71] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2015] [Accepted: 11/18/2015] [Indexed: 05/03/2023]
Abstract
Inorganic nitrogen in the form of ammonium is assimilated into asparagine via multiple steps involving glutamine synthetase (GS), glutamate synthase (GOGAT), aspartate aminotransferase (AspAT) and asparagine synthetase (AS) in Arabidopsis. The asparagine amide group is liberated by the reaction catalyzed by asparaginase (ASPG) and also the amino group of asparagine is released by asparagine aminotransferase (AsnAT) for use in the biosynthesis of amino acids. Asparagine plays a primary role in nitrogen recycling, storage and transport in developing and germinating seeds, as well as in vegetative and senescence organs. A small multigene family encodes isoenzymes of each step of asparagine metabolism in Arabidopsis, except for asparagine aminotransferase encoded by a single gene. The aim of this study is to highlight the structure of the genes and encoded enzyme proteins involved in asparagine metabolic pathways; the regulation and role of different isogenes; and kinetic and physiological properties of encoded enzymes in different tissues and developmental stages.
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Affiliation(s)
- Laure Gaufichon
- INRA, IJPB, UMR1318, ERL CNRS 3559, Saclay Plant Sciences, RD10, F-78026 Versailles, France
| | - Steven J Rothstein
- University of Guelph, Department of Molecular and Cellular Biology, Guelph, Ontario, Canada N1G 2W1
| | - Akira Suzuki
- INRA, IJPB, UMR1318, ERL CNRS 3559, Saclay Plant Sciences, RD10, F-78026 Versailles, France
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10
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Tercé-Laforgue T, Clément G, Marchi L, Restivo FM, Lea PJ, Hirel B. Resolving the Role of Plant NAD-Glutamate Dehydrogenase: III. Overexpressing Individually or Simultaneously the Two Enzyme Subunits Under Salt Stress Induces Changes in the Leaf Metabolic Profile and Increases Plant Biomass Production. PLANT & CELL PHYSIOLOGY 2015; 56:1918-29. [PMID: 26251210 DOI: 10.1093/pcp/pcv114] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2015] [Accepted: 07/31/2015] [Indexed: 05/03/2023]
Abstract
NAD-dependent glutamate dehydrogenase (NAD-GDH) of higher plants has a central position at the interface between carbon and nitrogen metabolism due to its ability to carry out the deamination of glutamate. In order to obtain a better understanding of the physiological function of NAD-GDH under salt stress conditions, transgenic tobacco (Nicotiana tabacum L.) plants that overexpress two genes from Nicotiana plumbaginifolia individually (GDHA and GDHB) or simultaneously (GDHA/B) were grown in the presence of 50 mM NaCl. In the different GDH overexpressors, the NaCl treatment induced an additional increase in GDH enzyme activity, indicating that a post-transcriptional mechanism regulates the final enzyme activity under salt stress conditions. A greater shoot and root biomass production was observed in the three types of GDH overexpressors following growth in 50 mM NaCl, when compared with the untransformed plants subjected to the same salinity stress. Changes in metabolites representative of the plant carbon and nitrogen status were also observed. They were mainly characterized by an increased amount of starch present in the leaves of the GDH overexpressors as compared with the wild type when plants were grown in 50 mM NaCl. Metabolomic analysis revealed that overexpressing the two genes GDHA and GDHB, individually or simultaneously, induced a differential accumulation of several carbon- and nitrogen-containing molecules involved in a variety of metabolic, developmental and stress-responsive processes. An accumulation of digalactosylglycerol, erythronate and porphyrin was found in the GDHA, GDHB and GDHA/B overexpressors, suggesting that these molecules could contribute to the improved performance of the transgenic plants under salinity stress conditions.
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Affiliation(s)
- Thérèse Tercé-Laforgue
- Adaptation des Plantes à leur Environnement, Unité Mixte de Recherche 1318, Institut Jean-Pierre Bourgin, Saclay Plant Sciences, Institut National de la Recherche Agronomique (INRA), Centre de Versailles-Grignon, RD 10, 78026 Versailles cedex, France
| | - Gilles Clément
- Adaptation des Plantes à leur Environnement, Unité Mixte de Recherche 1318, Institut Jean-Pierre Bourgin, Saclay Plant Sciences, Institut National de la Recherche Agronomique (INRA), Centre de Versailles-Grignon, RD 10, 78026 Versailles cedex, France
| | - Laura Marchi
- Dipartimento di Bioscienze, Università di Parma, Parco Area delle Scienze 11/A, 43100 Parma, Italy
| | - Francesco M Restivo
- Dipartimento di Bioscienze, Università di Parma, Parco Area delle Scienze 11/A, 43100 Parma, Italy
| | - Peter J Lea
- Lancaster Environment Centre, Lancaster University, Lancaster LA1 4YQ, UK
| | - Bertrand Hirel
- Adaptation des Plantes à leur Environnement, Unité Mixte de Recherche 1318, Institut Jean-Pierre Bourgin, Saclay Plant Sciences, Institut National de la Recherche Agronomique (INRA), Centre de Versailles-Grignon, RD 10, 78026 Versailles cedex, France
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11
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Sarasketa A, González-Moro MB, González-Murua C, Marino D. Exploring ammonium tolerance in a large panel of Arabidopsis thaliana natural accessions. JOURNAL OF EXPERIMENTAL BOTANY 2014; 65:6023-33. [PMID: 25205573 PMCID: PMC4203136 DOI: 10.1093/jxb/eru342] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
Plants are dependent on exogenous nitrogen (N) supply. Ammonium (NH₄(+)), together with nitrate (NO₃(-)), is one of the main nitrogenous compounds available in the soil. Paradoxically, although NH4 (+) assimilation requires less energy than that of NO₃(-), many plants display toxicity symptoms when grown with NH₄(+) as the sole N source. However, in addition to species-specific ammonium toxicity, intraspecific variability has also been shown. Thus, the aim of this work was to study the intraspecific ammonium tolerance in a large panel of Arabidopsis thaliana natural accessions. Plants were grown with either 1mM NO₃(-) or NH₄(+) as the N source, and several parameters related to ammonium tolerance and assimilation were determined. Overall, high variability was observed in A. thaliana shoot growth under both forms of N nutrition. From the parameters determined, tissue ammonium content was the one with the highest impact on shoot biomass, and interestingly this was also the case when N was supplied as NO₃(-). Enzymes of nitrogen assimilation did not have an impact on A. thaliana biomass variation, but the N source affected their activity. Glutamate dehydrogenase (GDH) aminating activity was, in general, higher in NH4 (+)-fed plants. In contrast, GDH deaminating activity was higher in NO₃(-)-fed plants, suggesting a differential role for this enzyme as a function of the N form supplied. Overall, NH4 (+) accumulation seems to be an important player in Arabidopsis natural variability in ammonium tolerance rather than the cell NH₄(+) assimilation capacity.
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Affiliation(s)
- Asier Sarasketa
- Department of Plant Biology and Ecology, University of the Basque Country (UPV/EHU), Apdo. 644, E-48080 Bilbao, Spain
| | - María Begoña González-Moro
- Department of Plant Biology and Ecology, University of the Basque Country (UPV/EHU), Apdo. 644, E-48080 Bilbao, Spain
| | - Carmen González-Murua
- Department of Plant Biology and Ecology, University of the Basque Country (UPV/EHU), Apdo. 644, E-48080 Bilbao, Spain
| | - Daniel Marino
- Department of Plant Biology and Ecology, University of the Basque Country (UPV/EHU), Apdo. 644, E-48080 Bilbao, Spain Ikerbasque, Basque Foundation for Science, E-48011 Bilbao, Spain
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12
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Du C, Lin J, Yang Y, Liu H, Li C, Zhou Y, Li Y, Tang D, Zhao X, Zhu Y, Liu X. Molecular cloning, characterization and function analysis of a GDH gene from Sclerotinia sclerotiorum in rice. Mol Biol Rep 2014; 41:3683-93. [DOI: 10.1007/s11033-014-3233-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2013] [Accepted: 02/04/2014] [Indexed: 11/29/2022]
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13
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Tercé-Laforgue T, Bedu M, Dargel-Grafin C, Dubois F, Gibon Y, Restivo FM, Hirel B. Resolving the role of plant glutamate dehydrogenase: II. Physiological characterization of plants overexpressing the two enzyme subunits individually or simultaneously. PLANT & CELL PHYSIOLOGY 2013; 54:1635-47. [PMID: 23893023 DOI: 10.1093/pcp/pct108] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Glutamate dehydrogenase (GDH; EC 1.4.1.2) is able to carry out the deamination of glutamate in higher plants. In order to obtain a better understanding of the physiological function of GDH in leaves, transgenic tobacco (Nicotiana tabacum L.) plants were constructed that overexpress two genes from Nicotiana plumbaginifolia (GDHA and GDHB under the control of the Cauliflower mosiac virus 35S promoter), which encode the α- and β-subunits of GDH individually or simultaneously. In the transgenic plants, the GDH protein accumulated in the mitochondria of mesophyll cells and in the mitochondria of the phloem companion cells (CCs), where the native enzyme is normally expressed. Such a shift in the cellular location of the GDH enzyme induced major changes in carbon and nitrogen metabolite accumulation and a reduction in growth. These changes were mainly characterized by a decrease in the amount of sucrose, starch and glutamine in the leaves, which was accompanied by an increase in the amount of nitrate and Chl. In addition, there was an increase in the content of asparagine and a decrease in proline. Such changes may explain the lower plant biomass determined in the GDH-overexpressing lines. Overexpressing the two genes GDHA and GDHB individually or simultaneously induced a differential accumulation of glutamate and glutamine and a modification of the glutamate to glutamine ratio. The impact of the metabolic changes occurring in the different types of GDH-overexpressing plants is discussed in relation to the possible physiological function of each subunit when present in the form of homohexamers or heterohexamers.
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Affiliation(s)
- Thérèse Tercé-Laforgue
- Adaptation des Plantes à leur Environnement, Unité Mixte de Recherche 1318, Institut Jean-Pierre Bourgin, Institut National de la Recherche Agronomique (INRA), Centre de Versailles-Grignon, RD 10, 78026 Versailles cedex, France
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14
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Setién I, Fuertes-Mendizabal T, González A, Aparicio-Tejo PM, González-Murua C, González-Moro MB, Estavillo JM. High irradiance improves ammonium tolerance in wheat plants by increasing N assimilation. JOURNAL OF PLANT PHYSIOLOGY 2013; 170:758-71. [PMID: 23485260 DOI: 10.1016/j.jplph.2012.12.015] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2012] [Revised: 12/27/2012] [Accepted: 12/29/2012] [Indexed: 05/09/2023]
Abstract
Ammonium is a paradoxical nutrient ion. Despite being a common intermediate in plant metabolism whose oxidation state eliminates the need for its reduction in the plant cell, as occurs with nitrate, it can also result in toxicity symptoms. Several authors have reported that carbon enrichment in the root zone enhances the synthesis of carbon skeletons and, accordingly, increases the capacity for ammonium assimilation. In this work, we examined the hypothesis that increasing the photosynthetic photon flux density is a way to increase plant ammonium tolerance. Wheat plants were grown in a hydroponic system with two different N sources (10mM nitrate or 10mM ammonium) and with two different light intensity conditions (300 μmol photon m(-2)s(-1) and 700 μmol photon m(-2)s(-1)). The results show that, with respect to biomass yield, photosynthetic rate, shoot:root ratio and the root N isotopic signature, wheat behaves as a sensitive species to ammonium nutrition at the low light intensity, while at the high intensity, its tolerance is improved. This improvement is a consequence of a higher ammonium assimilation rate, as reflected by the higher amounts of amino acids and protein accumulated mainly in the roots, which was supported by higher tricarboxylic acid cycle activity. Glutamate dehydrogenase was a key root enzyme involved in the tolerance to ammonium, while glutamine synthetase activity was low and might not be enough for its assimilation.
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Affiliation(s)
- Igor Setién
- Departmento de Biología Vegetal y Ecología, Universidad del País Vasco UPV/EHU, Apdo. 644, 48080 Bilbao, Spain.
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15
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Yang Y, Lu X, Yan B, Li B, Sun J, Guo S, Tezuka T. Bottle gourd rootstock-grafting affects nitrogen metabolism in NaCl-stressed watermelon leaves and enhances short-term salt tolerance. JOURNAL OF PLANT PHYSIOLOGY 2013; 170:653-61. [PMID: 23399406 DOI: 10.1016/j.jplph.2012.12.013] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/25/2012] [Revised: 12/06/2012] [Accepted: 12/11/2012] [Indexed: 05/07/2023]
Abstract
The plant growth, nitrogen absorption, and assimilation in watermelon (Citrullus lanatus [Thunb.] Mansf.) were investigated in self-grafted and grafted seedlings using the salt-tolerant bottle gourd rootstock Chaofeng Kangshengwang (Lagenaria siceraria Standl.) exposed to 100mM NaCl for 3d. The biomass and NO3(-) uptake rate were significantly increased by rootstock while these values were remarkably decreased by salt stress. However, compared with self-grafted plants, rootstock-grafted plants showed higher salt tolerance with higher biomass and NO3(-) uptake rate under salt stress. Salinity induced strong accumulation of nitrate, ammonium and protein contents and a significant decrease of nitrogen content and the activities of nitrate reductase (NR), nitrite reductase (NiR), glutamine synthetase (GS), and glutamate synthase (GOGAT) in leaves of self-grafted seedlings. In contrast, salt stress caused a remarkable decrease in nitrate content and the activities of GS and GOGAT, and a significant increase of ammonium, protein, and nitrogen contents and NR activity, in leaves of rootstock-grafted seedlings. Compared with that of self-grafted seedlings, the ammonium content in leaves of rootstock-grafted seedlings was much lower under salt stress. Glutamate dehydrogenase (GDH) activity was notably enhanced in leaves of rootstock-grafted seedlings, whereas it was significantly inhibited in leaves of self-grafted seedlings, under salinity stress. Three GDH isozymes were isolated by native gel electrophoresis and their expressions were greatly enhanced in leaves of rootstock-grafted seedlings than those of self-grafted seedlings under both normal and salt-stress conditions. These results indicated that the salt tolerance of rootstock-grafted seedlings might (be enhanced) owing to the higher nitrogen absorption and the higher activities of enzymes for nitrogen assimilation induced by the rootstock. Furthermore, the detoxification of ammonium by GDH when the GS/GOGAT pathway was inhibited under salt stress might play an important role in the release of salt stress in rootstock-grafted seedlings.
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Affiliation(s)
- Yanjuan Yang
- Key Laboratory of Southern Vegetable Crop Genetic Improvement in Ministry of Agriculture, College of Horticulture, Nanjing Agricultural University, Nanjing 210095, PR China
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16
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Fontaine JX, Tercé-Laforgue T, Bouton S, Pageau K, Lea PJ, Dubois F, Hirel B. Further insights into the isoenzyme composition and activity of glutamate dehydrogenase in Arabidopsis thaliana. PLANT SIGNALING & BEHAVIOR 2013; 8:e23329. [PMID: 23299333 PMCID: PMC3676500 DOI: 10.4161/psb.23329] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Following the discovery that in Arabidopsis, a third isoenzyme of NADH-dependent glutamate dehydrogenase (GDH) is expressed in the mitochondria of the root companion cells, we have re-examined the GDH isoenzyme composition. By analyzing the NADH-GDH isoenzyme composition of single, double and triple mutants deficient in the expression of the three genes encoding the enzyme, we have found that the α, β and γ polypeptides that comprise the enzyme can be assembled into a complex combination of heterohexamers in roots. Moreover, we observed that when one or two of the three root isoenzymes were missing from the mutants, the remaining isoenzymes compensated for this deficiency. The significance of such complexity is discussed in relation to the metabolic and signaling function of the NADH-GDH enzyme. Although it has been shown that a fourth gene encoding a NADPH-dependent enzyme is present in Arabidopsis, we were not able to detect corresponding enzyme activity, even in the triple mutant totally lacking NADH-GDH activity.
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Affiliation(s)
- Jean-Xavier Fontaine
- Equipe d’Accueil 3900; Biologie des Plantes et Innovation (BIOPI); Faculté de Pharmacie; Picardie, France
| | - Thérèse Tercé-Laforgue
- Adaptation des Plantes à leur Environnement; Unité Mixte de Recherche 1318; Institut Jean-Pierre Bourgin; Institut National de la Recherche Agronomique (INRA); Centre de Versailles-Grignon; Versailles, France
| | - Sophie Bouton
- Equipe d’Accueil 3900; Biologie des Plantes et Innovation (BIOPI); Faculté de Pharmacie; Picardie, France
| | - Karine Pageau
- Equipe d’Accueil 3900; Biologie des Plantes et Innovation (BIOPI); Faculté de Pharmacie; Picardie, France
| | - Peter J. Lea
- Lancaster Environment Centre; Lancaster University; Lancaster, UK
| | - Frédéric Dubois
- Equipe d’Accueil Ecologie et Dynamique des Systèmes Antropisés (EDYSAN); Agroécologie, Ecophysiologie et Biologie intégrative (AEB); Faculté des Sciences; Amiens, France
| | - Bertrand Hirel
- Adaptation des Plantes à leur Environnement; Unité Mixte de Recherche 1318; Institut Jean-Pierre Bourgin; Institut National de la Recherche Agronomique (INRA); Centre de Versailles-Grignon; Versailles, France
- Correspondence to: Bertrand Hirel,
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17
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Ferraro G, Bortolotti S, Mortera P, Schlereth A, Stitt M, Carrari F, Kamenetzky L, Valle EM. Novel glutamate dehydrogenase genes show increased transcript and protein abundances in mature tomato fruits. JOURNAL OF PLANT PHYSIOLOGY 2012; 169:899-907. [PMID: 22459323 DOI: 10.1016/j.jplph.2012.02.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2011] [Revised: 02/13/2012] [Accepted: 02/14/2012] [Indexed: 05/13/2023]
Abstract
NAD(P)H-glutamate dehydrogenase (GDH, EC 1.4.1.3) contributes to the control of glutamate homeostasis in all living organisms. In bacteria and animals, GDH is a homohexamer allosterically regulated, whereas in plants NADH-GDH (EC 1.4.1.2) is also found as heterohexamer of α- and β-subunits, but its regulation remains undefined. In tomato (Solanum lycopersicum), GDH activity increases during the fruit ripening along with the content of free glutamate, the most abundant amino acid of ripe fruit involved in conferring the genuine tomato flavour. In this work, novel Slgdh-NAD genes were identified in the recently deciphered tomato genome: three encoding the α-subunit (Slgdh-NAD;A1-3) and one additional gene encoding the β-subunit of GDH (Slgdh-NAD;B1) isolated from a genomic library. These genes are located in different chromosomes. Slgdh-NAD;A1-3 show conserved structures, whereas Slgdh-NAD;B1 includes a novel 5'-untranslated exon. Slgdh-NAD;A1-3 transcripts were detected in all tomato tissues examined, showing the highest levels in mature green fruits, contrasting with Slgdh-NAD;B1 transcripts which were detected mainly in roots or in mature fruits when treated with glutamate, NaCl or salicylic acid. Analyses of GDH activity and protein distribution in different tissues of the Micro-Tom cultivar showed that only the active homohexamer of GDH β-subunits was detected in roots while heterohexamers of GDH α- and β-subunits were found in fruits. These results indicate that GDH β-subunit could modulate the heteromeric isoforms of GDH in response to the environment and physiology of the tomato fruit. This information is relevant to manipulate glutamate contents in tomato fruits genetically.
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Affiliation(s)
- Gisela Ferraro
- Instituto de Biología Molecular y Celular de Rosario (IBR-CONICET), Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Suipacha, 531, S2002LRK Rosario, Argentina
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18
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Xia Z, Sun K, Wang M, Wu K, Zhang H, Wu J. Overexpression of a maize sulfite oxidase gene in tobacco enhances tolerance to sulfite stress via sulfite oxidation and CAT-mediated H2O2 scavenging. PLoS One 2012; 7:e37383. [PMID: 22693572 PMCID: PMC3365070 DOI: 10.1371/journal.pone.0037383] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2012] [Accepted: 04/18/2012] [Indexed: 01/24/2023] Open
Abstract
Sulfite oxidase (SO) plays an important role in sulfite metabolism. To date, the molecular mechanisms of sulfite metabolism in plants are largely unknown. Previously, a full-length cDNA of the putative sulfite oxidase gene from maize (ZmSO) was cloned, and its response to SO(2)/sulfite stress at the transcriptional level was characterized. In this study, the recombinant ZmSO protein was purified from E. coli. It exhibited sulfite-dependent activity and had strong affinity for the substrate sulfite. Over-expression (OE) of ZmSO in tobacco plants enhanced their tolerance to sulfite stress. The plants showed much less damage, less sulfite accumulation, but greater amounts of sulfate. This suggests that tolerance of transgenic plants to sulfite was enhanced by increasing SO expression levels. Interestingly, H(2)O(2) accumulation levels by histochemical detection and quantitative determination in the OE plants were much less than those in the wild-type upon sulfite stress. Furthermore, reductions of catalase levels detected in the OE lines were considerably less than in the wild-type plants. This indicates that SO may play an important role in protecting CAT from inhibition by excess sulfite. Collectively, these data demonstrate that transgenic tobacco plants over-expressing ZmSO enhance tolerance to excess sulfite through sulfite oxidation and catalase-mediated hydrogen peroxide scavenging. This is the first SO gene from monocots to be functionally characterized.
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Affiliation(s)
- Zongliang Xia
- College of Life Science, Henan Agricultural University, Zhengzhou, People’s Republic of China
- Key Laboratory of Physiology, Ecology and Genetic Improvement of Food Crops in Henan Province, Zhengzhou, People’s Republic of China
| | - Kaile Sun
- College of Life Science, Henan Agricultural University, Zhengzhou, People’s Republic of China
| | - Meiping Wang
- College of Life Science, Henan Agricultural University, Zhengzhou, People’s Republic of China
| | - Ke Wu
- College of Life Science, Henan Agricultural University, Zhengzhou, People’s Republic of China
| | - Hua Zhang
- College of Life Science, Henan Agricultural University, Zhengzhou, People’s Republic of China
| | - Jianyu Wu
- College of Life Science, Henan Agricultural University, Zhengzhou, People’s Republic of China
- Key Laboratory of Physiology, Ecology and Genetic Improvement of Food Crops in Henan Province, Zhengzhou, People’s Republic of China
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Araújo WL, Tohge T, Nunes-Nesi A, Daloso DM, Nimick M, Krahnert I, Bunik VI, Moorhead GBG, Fernie AR. Phosphonate analogs of 2-oxoglutarate perturb metabolism and gene expression in illuminated Arabidopsis leaves. FRONTIERS IN PLANT SCIENCE 2012; 3:114. [PMID: 22876250 PMCID: PMC3410613 DOI: 10.3389/fpls.2012.00114] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/04/2012] [Accepted: 05/14/2012] [Indexed: 05/19/2023]
Abstract
Although the role of the 2-oxoglutarate dehydrogenase complex (2-OGDHC) has previously been demonstrated in plant heterotrophic tissues its role in photosynthetically active tissues remains poorly understood. By using a combination of metabolite and transcript profiles we here investigated the function of 2-OGDHC in leaves of Arabidopsis thaliana via use of specific phosphonate inhibitors of the enzyme. Incubation of leaf disks with the inhibitors revealed that they produced the anticipated effects on the in situ enzyme activity. In vitro experiments revealed that succinyl phosphonate (SP) and a carboxy ethyl ester of SP are slow-binding inhibitors of the 2-OGDHC. Our results indicate that the reduced respiration rates are associated with changes in the regulation of metabolic and signaling pathways leading to an imbalance in carbon-nitrogen metabolism and cell homeostasis. The inducible alteration of primary metabolism was associated with altered expression of genes belonging to networks of amino acids, plant respiration, and sugar metabolism. In addition, by using isothermal titration calorimetry we excluded the possibility that the changes in gene expression resulted from an effect on 2-oxoglutarate (2OG) binding to the carbon/ATP sensing protein PII. We also demonstrated that the 2OG degradation by the 2-oxoglutarate dehydrogenase strongly influences the distribution of intermediates of the tricarboxylic acid (TCA) cycle and the GABA shunt. Our results indicate that the TCA cycle activity is clearly working in a non-cyclic manner upon 2-OGDHC inhibition during the light period.
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Affiliation(s)
- Wagner L. Araújo
- Max-Planck-Institut für Molekulare PflanzenphysiologiePotsdam-Golm, Germany
- Departamento de Biologia Vegetal, Universidade Federal de ViçosaViçosa, Minas Gerais, Brazil
| | - Takayuki Tohge
- Max-Planck-Institut für Molekulare PflanzenphysiologiePotsdam-Golm, Germany
| | - Adriano Nunes-Nesi
- Max-Planck Partner Group, Departamento de Biologia Vegetal, Universidade Federal de ViçosaViçosa, Minas Gerais, Brazil
| | - Danilo M. Daloso
- Max-Planck-Institut für Molekulare PflanzenphysiologiePotsdam-Golm, Germany
- Departamento de Biologia Vegetal, Universidade Federal de ViçosaViçosa, Minas Gerais, Brazil
| | - Mhairi Nimick
- Department of Biological Sciences, University of CalgaryCalgary, AB, Canada
| | - Ina Krahnert
- Max-Planck-Institut für Molekulare PflanzenphysiologiePotsdam-Golm, Germany
| | - Victoria I. Bunik
- A.N. Belozersly Institute of Physico-Chemical Biology, Moscow State UniversityMoscow, Russia
| | | | - Alisdair R. Fernie
- Max-Planck-Institut für Molekulare PflanzenphysiologiePotsdam-Golm, Germany
- *Correspondence: Alisdair R. Fernie, Max-Planck-Institut für Molekulare Pflanzenphysiologie, Am Mühlenberg 1, 14476 Potsdam-Golm, Germany. e-mail:
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20
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Beato VM, Teresa Navarro-Gochicoa M, Rexach J, Begoña Herrera-Rodríguez M, Camacho-Cristóbal JJ, Kempa S, Weckwerth W, González-Fontes A. Expression of root glutamate dehydrogenase genes in tobacco plants subjected to boron deprivation. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2011; 49:1350-4. [PMID: 21705226 DOI: 10.1016/j.plaphy.2011.06.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2011] [Accepted: 06/02/2011] [Indexed: 05/02/2023]
Abstract
Recently it has been reported that boron (B) deficiency increases the expression of Nicotiana tabacum asparagine synthetase (AS) gene in roots, and that AS might play a main role as a detoxifying mechanism to convert ammonium into asparagine. Interestingly, glutamate dehydrogenase (GDH) genes, Ntgdh-NAD;A1 and Ntgdh-NAD;B2, were up-regulated when tobacco roots were subjected to B deprivation for 8 and 24 h. In addition, aminating and deaminating GDH (EC 1.4.1.2) activities were higher in B-deficient than in B-sufficient plants after 24 h of B deficiency. Ammonium concentrations were kept sufficiently low and with similar values in B-deficient roots when compared to control. Glucose and fructose contents decreased after 24 h of B deprivation. This drop in hexoses, which was corroborated by metabolomic analysis, correlated with higher GDH gene expression. Furthermore, metabolomic profiling showed that concentrations of several organic acids, phenolics, and amino acids increased after 24 h of B deficiency. Our results suggest that GDH enzyme plays an important role in metabolic acclimation of tobacco roots to B deprivation. A putative model to explain these results is proposed and discussed.
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Affiliation(s)
- Víctor M Beato
- Departamento de Fisiología, Anatomía y Biología Celular, Universidad Pablo de Olavide, E-41013 Sevilla, Spain.
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21
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Lehmann T, Dabert M, Nowak W. Organ-specific expression of glutamate dehydrogenase (GDH) subunits in yellow lupine. JOURNAL OF PLANT PHYSIOLOGY 2011; 168:1060-1066. [PMID: 21333382 DOI: 10.1016/j.jplph.2010.12.016] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2010] [Revised: 12/03/2010] [Accepted: 12/18/2010] [Indexed: 05/30/2023]
Abstract
Glutamate dehydrogenase (GDH, EC 1.4.2-4) is present in yellow lupine (Lupinus luteus cv. Juno) in many isoforms. The number and banding pattern of isoenzymes varies with respect to plant organ and developmental stage. To better understand the complex nature of GDH regulation in plants, the levels of GDH transcripts, enzyme activity and isoenzyme patterns in germinating seeds and roots of yellow lupine were examined. The analysis of GDH cDNA sequences in lupine revealed three mRNA types, of which two encoded the β-GDH subunit and one encoded the α-GDH subunit (corresponding to the GDH1(GDH3) and GDH2 genes, respectively). The relative expression of GDH1 and GDH2 genes was analyzed in various lupine organs by using quantitative real-time PCR. Our results indicate that different mRNA types were differently regulated depending on organ type. Although both genes appeared to be ubiquitously expressed in all lupine tissues, the GDH1 transcripts evidently predominated over those of GDH2. Immunochemical analyses confirmed that, during embryo development, varied expression of two GDH subunits takes place. The α-GDH subunit (43kDa) predominated in the early stages of germinating seeds, while the β-GDH subunit (44kDa) was the only GDH polypeptide present in lupine roots. These results firmly support the hypothesis that isoenzyme variability of GDH in yellow lupine is associated with the varied expression of α and β subunits into the complexes of hexameric GDH forms. The presence of several isogenes of GDH in yellow lupine may explain the high number (over 20) of its molecular forms in germinating lupine.
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Affiliation(s)
- Teresa Lehmann
- Department of Plant Physiology, Faculty of Biology, Adam Mickiewicz University, Umultowska 89, 61-614 Poznań, Poland.
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22
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Abiko T, Wakayama M, Kawakami A, Obara M, Kisaka H, Miwa T, Aoki N, Ohsugi R. Changes in nitrogen assimilation, metabolism, and growth in transgenic rice plants expressing a fungal NADP(H)-dependent glutamate dehydrogenase (gdhA). PLANTA 2010; 232:299-311. [PMID: 20443025 DOI: 10.1007/s00425-010-1172-3] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2010] [Accepted: 04/11/2010] [Indexed: 05/23/2023]
Abstract
In plants, glutamine synthetase (GS) is the enzyme that is mainly responsible for the assimilation of ammonium. Conversely, in microorganisms such as bacteria and Ascomycota, NADP(H)-dependent glutamate dehydrogenase (GDH) and GS both have important roles in ammonium assimilation. Here, we report the changes in nitrogen assimilation, metabolism, growth, and grain yield of rice plants caused by an ectopic expression of NADP(H)-GDH (gdhA) from the fungus Aspergillus niger in the cytoplasm. An investigation of the kinetic properties of purified recombinant protein showed that the fungal gdhA had 5.4-10.2 times higher V(max) value and 15.9-43.1 times higher K(m) value for NH(4)(+), compared with corresponding values for rice cytosolic GS as reported in the literature. These results suggested that the introduction of fungal GDH into rice could modify its ammonium assimilation pathway. We therefore expressed gdhA in the cytoplasm of rice plants. NADP(H)-GDH activities in the gdhA-transgenic lines were markedly higher than those in a control line. Tracer experiments by feeding with (15)NH(4)(+) showed that the introduced gdhA, together with the endogenous GS, directly assimilated NH(4)(+) absorbed from the roots. Furthermore, in comparison with the control line, the transgenic lines showed an increase in dry weight and nitrogen content when sufficient nitrogen was present, but did not do so under low-nitrogen conditions. Under field condition, the transgenic line examined showed a significant increase in grain yield in comparison with the control line. These results suggest that the introduction of fungal gdhA into rice plants could lead to better growth and higher grain yield by enhancing the assimilation of ammonium.
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Affiliation(s)
- Tomomi Abiko
- Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan
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23
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Lehmann T, Skrok A, Dabert M. Stress-induced changes in glutamate dehydrogenase activity imply its role in adaptation to C and N metabolism in lupine embryos. PHYSIOLOGIA PLANTARUM 2010; 138:35-47. [PMID: 19843240 DOI: 10.1111/j.1399-3054.2009.01294.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
The modifying effect of sucrose on glutamate dehydrogenase (GDH) activity and isoenzyme pattern was investigated in isolated embryos of lupine (Lupinus luteus L.), cultured in vitro in a medium with sucrose (+S) or without sucrose (-S) and exposed to cadmium (Cd) and lead (Pb) stress. Sucrose starvation of lupine embryos led to a rapid increase in the specific activity of GDH, immunoreactive beta-polypeptide and it was accompanied by appearance of new cathodal isoforms of enzyme. This suggests that isoenzymes induced in lupine embryos by sucrose starvation combine into GDH hexamers with the predominance of beta-GDH subunits synthetized under GDH1 gene control. The addition of sucrose to the medium caused an opposite effect. Along with upregulation of catabolic activity of GDH by sucrose starvation, activity of proteolytic enzymes was also induced. These data can point to regulatory mechanism implying a sucrose dependent repression of the GDH1 gene according to the mechanism of catabolic repression. Treatment of embryos with Cd(2+) or Pb(2+) resulted in ammonium accumulation in the tissues, accompanied by an increase in anabolic activity of GDH and activity of anodal isoenzymes, in both (+S) and (-S) embryos without new de novo synthesis of alpha subunit proteins. Thus, GDH isoenzyme profiles may reflect the physiological function of GDH, which appears to be an important link of metabolic adaptation in cells, aimed at using carbon sources other than sugar during carbohydrate starvation (catabolic activity of GDH) and protecting plant tissues against ammonium accumulated because of heavy metal stress (anabolic activity of GDH).
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Affiliation(s)
- Teresa Lehmann
- Department of Plant Physiology, Institute of Experimental Biology, Adam Mickiewicz University, Poznań, Poland.
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Labboun S, Tercé-Laforgue T, Roscher A, Bedu M, Restivo FM, Velanis CN, Skopelitis DS, Moshou PN, Roubelakis-Angelakis KA, Suzuki A, Hirel B. Resolving the role of plant glutamate dehydrogenase. I. In vivo real time nuclear magnetic resonance spectroscopy experiments. PLANT & CELL PHYSIOLOGY 2009; 50:1761-73. [PMID: 19690000 PMCID: PMC2759343 DOI: 10.1093/pcp/pcp118] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2009] [Accepted: 08/11/2009] [Indexed: 05/18/2023]
Abstract
In higher plants the glutamate dehydrogenase (GDH) enzyme catalyzes the reversible amination of 2-oxoglutarate to form glutamate, using ammonium as a substrate. For a better understanding of the physiological function of GDH either in ammonium assimilation or in the supply of 2-oxoglutarate, we used transgenic tobacco (Nicotiana tabacum L.) plants overexpressing the two genes encoding the enzyme. An in vivo real time (15)N-nuclear magnetic resonance (NMR) spectroscopy approach allowed the demonstration that, when the two GDH genes were overexpressed individually or simultaneously, the transgenic plant leaves did not synthesize glutamate in the presence of ammonium when glutamine synthetase (GS) was inhibited. In contrast we confirmed that the primary function of GDH is to deaminate Glu. When the two GDH unlabeled substrates ammonium and Glu were provided simultaneously with either [(15)N]Glu or (15)NH(4)(+) respectively, we found that the ammonium released from the deamination of Glu was reassimilated by the enzyme GS, suggesting the occurrence of a futile cycle recycling both ammonium and Glu. Taken together, these results strongly suggest that the GDH enzyme, in conjunction with NADH-GOGAT, contributes to the control of leaf Glu homeostasis, an amino acid that plays a central signaling and metabolic role at the interface of the carbon and nitrogen assimilatory pathways. Thus, in vivo NMR spectroscopy appears to be an attractive technique to follow the flux of metabolites in both normal and genetically modified plants.
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Affiliation(s)
- Soraya Labboun
- Génie Enzymatique et Cellulaire, UMR CNRS 6022, UFR des Sciences, Université de Picardie Jules Verne, 33, Rue Saint-Leu, 80039 Amiens cedex, France
| | - Thérèse Tercé-Laforgue
- Unité de Nutrition Azotée des Plantes, Unité de Recherche 511, Institut National de la Recherche Agronomique, Centre de Versailles-Grignon, Institut Jean-Pierre Bourgin, 78026 Versailles cedex, France
| | - Albrecht Roscher
- Génie Enzymatique et Cellulaire, UMR CNRS 6022, UFR des Sciences, Université de Picardie Jules Verne, 33, Rue Saint-Leu, 80039 Amiens cedex, France
| | - Magali Bedu
- Unité de Nutrition Azotée des Plantes, Unité de Recherche 511, Institut National de la Recherche Agronomique, Centre de Versailles-Grignon, Institut Jean-Pierre Bourgin, 78026 Versailles cedex, France
| | - Francesco M. Restivo
- Department of Genetics, Biology of Microorganisms, Anthropology and Evolution, University of Parma, Parco Area delle Scienze 11/A, 43100 Parma, Italy
| | | | | | | | | | - Akira Suzuki
- Unité de Nutrition Azotée des Plantes, Unité de Recherche 511, Institut National de la Recherche Agronomique, Centre de Versailles-Grignon, Institut Jean-Pierre Bourgin, 78026 Versailles cedex, France
| | - Bertrand Hirel
- Unité de Nutrition Azotée des Plantes, Unité de Recherche 511, Institut National de la Recherche Agronomique, Centre de Versailles-Grignon, Institut Jean-Pierre Bourgin, 78026 Versailles cedex, France
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25
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Liu YJ, Nunes-Nesi A, Wallström SV, Lager I, Michalecka AM, Norberg FEB, Widell S, Fredlund KM, Fernie AR, Rasmusson AG. A redox-mediated modulation of stem bolting in transgenic Nicotiana sylvestris differentially expressing the external mitochondrial NADPH dehydrogenase. PLANT PHYSIOLOGY 2009; 150:1248-59. [PMID: 19429607 PMCID: PMC2705030 DOI: 10.1104/pp.109.136242] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2009] [Accepted: 05/04/2009] [Indexed: 05/08/2023]
Abstract
Cytosolic NADPH can be directly oxidized by a calcium-dependent NADPH dehydrogenase, NDB1, present in the plant mitochondrial electron transport chain. However, little is known regarding the impact of modified cytosolic NADPH reduction levels on growth and metabolism. Nicotiana sylvestris plants overexpressing potato (Solanum tuberosum) NDB1 displayed early bolting, whereas sense suppression of the same gene led to delayed bolting, with consequential changes in flowering time. The phenotype was dependent on light irradiance but not linked to any change in biomass accumulation. Whereas the leaf NADPH/NADP(+) ratio was unaffected, the stem NADPH/NADP(+) ratio was altered following the genetic modification and strongly correlated with the bolting phenotype. Metabolic profiling of the stem showed that the NADP(H) change affected relatively few, albeit central, metabolites, including 2-oxoglutarate, glutamate, ascorbate, sugars, and hexose-phosphates. Consistent with the phenotype, the modified NDB1 level also affected the expression of putative floral meristem identity genes of the SQUAMOSA and LEAFY types. Further evidence for involvement of the NADPH redox in stem development was seen in the distinct decrease in the stem apex NADPH/NADP(+) ratio during bolting. Additionally, the potato NDB1 protein was specifically detected in mitochondria, and a survey of its abundance in major organs revealed that the highest levels are found in green stems. These results thus strongly suggest that NDB1 in the mitochondrial electron transport chain can, by modifying cell redox levels, specifically affect developmental processes.
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Affiliation(s)
- Yun-Jun Liu
- Department of Cell and Organism Biology, Lund University, SE-22362 Lund, Sweden
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26
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Qiu X, Xie W, Lian X, Zhang Q. Molecular analyses of the rice glutamate dehydrogenase gene family and their response to nitrogen and phosphorous deprivation. PLANT CELL REPORTS 2009; 28:1115-26. [PMID: 19430792 DOI: 10.1007/s00299-009-0709-z] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/02/2008] [Revised: 04/01/2009] [Accepted: 04/20/2009] [Indexed: 05/20/2023]
Abstract
Glutamate dehydrogenases (GDH, EC 1.4.1.2 approximately 4) are ubiquitous enzymes encoded by GDH genes. So far, at least two GDH members have been characterized in plants, but most members of this family in rice remains to be characterized. Here, we show that four putative GDH genes (OsGDH1-4) are present in the rice genome. The GDH sequences from rice and other species can be classified into two types (I and II). OsGDH1-3 belonged to type II genes, whereas OsGDH4 belonged to type I like gene. Our data implied that the expansion rate of type I genes was much slower than that of type II genes and species-specific expansion contributed to the evolution of type II genes in plants. The expression levels of the different members of GDH family in rice were evaluated using quantitative real-time PCR and microarray analysis. Gene expression patterns revealed that OsGDH1, OsGDH2, and OsGDH4 are expressed ubiquitously in various tissues, whereas OsGDH3 expression is glumes and stamens specific. The expression of the OsGDH family members responded differentially to nitrogen and phosphorus-deprivation, indicating their roles under such stress conditions. Implications of the expression patterns with respect to the functions of these genes were discussed.
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Affiliation(s)
- Xuhua Qiu
- National Key Laboratory of Crop Genetic Improvement, National Center of Plant Gene Research (Wuhan), Huazhong Agricultural University, 430070, Wuhan, China
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27
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Armengaud P, Sulpice R, Miller AJ, Stitt M, Amtmann A, Gibon Y. Multilevel analysis of primary metabolism provides new insights into the role of potassium nutrition for glycolysis and nitrogen assimilation in Arabidopsis roots. PLANT PHYSIOLOGY 2009; 150:772-85. [PMID: 19346439 PMCID: PMC2689955 DOI: 10.1104/pp.108.133629] [Citation(s) in RCA: 157] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/2008] [Accepted: 03/23/2009] [Indexed: 05/18/2023]
Abstract
Potassium (K) is required in large quantities by growing crops, but faced with high fertilizer prices, farmers often neglect K application in favor of nitrogen and phosphorus. As a result, large areas of farmland are now depleted of K. K deficiency affects the metabolite content of crops with negative consequences for nutritional quality, mechanical stability, and pathogen/pest resistance. Known functions of K in solute transport, protein synthesis, and enzyme activation point to a close relationship between K and metabolism, but it is unclear which of these are the most critical ones and should be targeted in biotechnological efforts to improve K usage efficiency. To identify metabolic targets and signaling components of K stress, we adopted a multilevel approach combining transcript profiles with enzyme activities and metabolite profiles of Arabidopsis (Arabidopsis thaliana) plants subjected to low K and K resupply. Roots and shoots were analyzed separately. Our results show that regulation of enzymes at the level of transcripts and proteins is likely to play an important role in plant adaptation to K deficiency by (1) maintaining carbon flux into amino acids and proteins, (2) decreasing negative metabolic charge, and (3) increasing the nitrogen-carbon ratio in amino acids. However, changes in transcripts and enzyme activities do not explain the strong and reversible depletion of pyruvate and accumulation of sugars observed in the roots of low-K plants. We propose that the primary cause of metabolic disorders in low-K plants resides in the direct inhibition of pyruvate kinase activity by low cytoplasmic K in root cells.
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Affiliation(s)
- Patrick Armengaud
- Plant Science Group, Faculty of Biomedical and Life Sciences, University of Glasgow, G128QQ Glasgow, United Kingdom
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28
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Araújo WL, Nunes-Nesi A, Trenkamp S, Bunik VI, Fernie AR. Inhibition of 2-oxoglutarate dehydrogenase in potato tuber suggests the enzyme is limiting for respiration and confirms its importance in nitrogen assimilation,. PLANT PHYSIOLOGY 2008; 148:1782-96. [PMID: 18842826 PMCID: PMC2593666 DOI: 10.1104/pp.108.126219] [Citation(s) in RCA: 98] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/11/2008] [Accepted: 10/01/2008] [Indexed: 05/19/2023]
Abstract
The 2-oxoglutarate dehydrogenase complex constitutes a mitochondrially localized tricarboxylic acid cycle multienzyme system responsible for the conversion of 2-oxoglutarate to succinyl-coenzyme A concomitant with NAD(+) reduction. Although regulatory mechanisms of plant enzyme complexes have been characterized in vitro, little is known concerning their role in plant metabolism in situ. This issue has recently been addressed at the cellular level in nonplant systems via the use of specific phosphonate inhibitors of the enzyme. Here, we describe the application of these inhibitors for the functional analysis of the potato (Solanum tuberosum) tuber 2-oxoglutarate dehydrogenase complex. In vitro experiments revealed that succinyl phosphonate (SP) and a carboxy ethyl ester of SP are slow-binding inhibitors of the 2-oxoglutarate dehydrogenase complex, displaying greater inhibitory effects than a diethyl ester of SP, a phosphono ethyl ester of SP, or a triethyl ester of SP. Incubation of potato tuber slices with the inhibitors revealed that they were adequately taken up by the tissue and produced the anticipated effects on the in situ enzyme activity. In order to assess the metabolic consequences of the 2-oxoglutarate dehydrogenase complex inhibition, we evaluated the levels of a broad range of primary metabolites using an established gas chromatography-mass spectrometry method. We additionally analyzed the rate of respiration in both tuber discs and isolated mitochondria. Finally, we evaluated the metabolic fate of radiolabeled acetate, 2-oxoglutarate or glucose, and (13)C-labeled pyruvate and glutamate following incubation of tuber discs in the presence or absence of either SP or the carboxy ethyl ester of SP. The data obtained are discussed in the context of the roles of the 2-oxoglutarate dehydrogenase complex in respiration and carbon-nitrogen interactions.
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Affiliation(s)
- Wagner L Araújo
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, 14476 Potsdam-Golm, Germany
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29
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Hansen M, Friis C, Bowra S, Holm PB, Vincze E. A pathway-specific microarray analysis highlights the complex and co-ordinated transcriptional networks of the developing grain of field-grown barley. JOURNAL OF EXPERIMENTAL BOTANY 2008; 60:153-167. [PMID: 19015218 PMCID: PMC3298879 DOI: 10.1093/jxb/ern270] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/30/2008] [Revised: 10/08/2008] [Accepted: 10/09/2008] [Indexed: 05/27/2023]
Abstract
The aim of the study was to describe the molecular and biochemical interactions associated with amino acid biosynthesis and storage protein accumulation in the developing grains of field-grown barley. Our strategy was to analyse the transcription of genes associated with the biosynthesis of storage products during the development of field-grown barley grains using a grain-specific microarray assembled in our laboratory. To identify co-regulated genes, a distance matrix was constructed which enabled the identification of three clusters corresponding to early, middle, and late grain development. The gene expression pattern associated with the clusters was investigated using pathway-specific analysis with specific reference to the temporal expression levels of a range of genes involved mainly in the photosynthesis process, amino acid and storage protein metabolism. It is concluded that the grain-specific microarray is a reliable and cost-effective tool for monitoring temporal changes in the transcriptome of the major metabolic pathways in the barley grain. Moreover, it was sensitive enough to monitor differences in the gene expression profiles of different homologues from the storage protein families. The study described here should provide a strong complement to existing knowledge assisting further understanding of grain development and thereby provide a foundation for plant breeding towards storage proteins with improved nutritional quality.
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Affiliation(s)
- Michael Hansen
- Department of Genetics and Biotechnology, Faculty of Agricultural Sciences, University of Aarhus, Research Centre Flakkebjerg, DK-4200 Slagelse, Denmark
| | - Carsten Friis
- Center for Biological Sequence Analysis, BioCentrum, Technical University of Denmark, Building 208, DK-2800, Lyngby, Denmark
| | - Steve Bowra
- Verzyme (UK) Ltd., Plas Gogerddan, Aberystwyth, Wales SY23 3EB, UK
| | - Preben Bach Holm
- Department of Genetics and Biotechnology, Faculty of Agricultural Sciences, University of Aarhus, Research Centre Flakkebjerg, DK-4200 Slagelse, Denmark
| | - Eva Vincze
- Department of Genetics and Biotechnology, Faculty of Agricultural Sciences, University of Aarhus, Research Centre Flakkebjerg, DK-4200 Slagelse, Denmark
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30
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Miyashita Y, Good AG. Glutamate deamination by glutamate dehydrogenase plays a central role in amino acid catabolism in plants. PLANT SIGNALING & BEHAVIOR 2008; 3:842-3. [PMID: 19704517 PMCID: PMC2634392 DOI: 10.4161/psb.3.10.5936] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2008] [Accepted: 03/19/2008] [Indexed: 05/08/2023]
Abstract
Glutamate is of central importance in plant N metabolism since the biosynthesis of all other amino acids requires this compound. Glutamate dehydrogenase (GDH; EC 1.4.1.2), which catalyzes in vitro reversible reductive amination of 2-oxoglutatre to form glutamate, is a key player in the metabolism of glutamate. While most previous studies have indicated that the oxidative deamination is the in vivo direction of the GDH reaction, its physiological role has remained ambiguous for decades. We have recently isolated mutants for the two known Arabidopsis GDH genes and created a gdh double mutant. Our recent work revealed an increased susceptibility of the gdh double mutant to dark-induced C starvation, the first phenotype associated with the loss of GDH activity in plants. Monitoring the amino acid breakdown during the dark treatment also suggested that the deamination of glutamate catalyzed by GDH is central to the catabolism of many other amino acids.
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Affiliation(s)
- Yo Miyashita
- Department of Biological Sciences; University of Alberta; Edmonton, Alberta Canada
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31
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Moschou PN, Paschalidis KA, Delis ID, Andriopoulou AH, Lagiotis GD, Yakoumakis DI, Roubelakis-Angelakis KA. Spermidine exodus and oxidation in the apoplast induced by abiotic stress is responsible for H2O2 signatures that direct tolerance responses in tobacco. THE PLANT CELL 2008; 20:1708-24. [PMID: 18577660 PMCID: PMC2483379 DOI: 10.1105/tpc.108.059733] [Citation(s) in RCA: 106] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2008] [Revised: 05/07/2008] [Accepted: 06/02/2008] [Indexed: 05/18/2023]
Abstract
Polyamines (PAs) exert a protective effect against stress challenges, but their molecular role in this remains speculative. In order to detect the signaling role of apoplastic PA-derived hydrogen peroxide (H2O2) under abiotic stress, we developed a series of tobacco (Nicotiana tabacum cv Xanthi) transgenic plants overexpressing or downregulating apoplastic polyamine oxidase (PAO; S-pao and A-pao plants, respectively) or downregulating S-adenosyl-l-methionine decarboxylase (samdc plants). Upon salt stress, plants secreted spermidine (Spd) into the apoplast, where it was oxidized by the apoplastic PAO, generating H2O2. A-pao plants accumulated less H2O2 and exhibited less programmed cell death (PCD) than did wild-type plants, in contrast with S-pao and samdc downregulating plants. Induction of either stress-responsive genes or PCD was dependent on the level of Spd-derived apoplastic H2O2. Thus, in wild-type and A-pao plants, stress-responsive genes were efficiently induced, although in the latter at a lower rate, while S-pao plants, with higher H2O2 levels, failed to accumulate stress-responsive mRNAs, inducing PCD instead. Furthermore, decreasing intracellular PAs, while keeping normal apoplastic Spd oxidation, as in samdc downregulating transgenic plants, caused enhanced salinity-induced PCD. These results reveal that salinity induces the exodus of Spd into the apoplast, where it is catabolized by PAO, producing H2O2. The accumulated H2O2 results in the induction of either tolerance responses or PCD, depending also on the levels of intracellular PAs.
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MESH Headings
- Adaptation, Physiological/drug effects
- Adaptation, Physiological/genetics
- Adaptation, Physiological/physiology
- Adenosylmethionine Decarboxylase/genetics
- Adenosylmethionine Decarboxylase/metabolism
- Apoptosis/drug effects
- Dose-Response Relationship, Drug
- Gene Expression Regulation, Plant/drug effects
- Germination/drug effects
- Germination/genetics
- Germination/physiology
- Hydrogen Peroxide/metabolism
- Microscopy, Electron, Transmission
- Oxidation-Reduction/drug effects
- Oxidoreductases Acting on CH-NH Group Donors/genetics
- Oxidoreductases Acting on CH-NH Group Donors/metabolism
- Plants, Genetically Modified/genetics
- Plants, Genetically Modified/metabolism
- Plants, Genetically Modified/ultrastructure
- Reactive Oxygen Species/metabolism
- Reverse Transcriptase Polymerase Chain Reaction
- Seeds/genetics
- Seeds/metabolism
- Seeds/ultrastructure
- Sodium Chloride/pharmacology
- Spermidine/metabolism
- Spermidine/pharmacology
- Nicotiana/genetics
- Nicotiana/metabolism
- Nicotiana/ultrastructure
- Polyamine Oxidase
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32
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Lehmann T, Ratajczak L. The pivotal role of glutamate dehydrogenase (GDH) in the mobilization of N and C from storage material to asparagine in germinating seeds of yellow lupine. JOURNAL OF PLANT PHYSIOLOGY 2008; 165:149-58. [PMID: 17566603 DOI: 10.1016/j.jplph.2006.12.010] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2006] [Accepted: 12/18/2006] [Indexed: 05/15/2023]
Abstract
In germinating seeds of legumes, amino acids liberated during mobilization of storage proteins are partially used for synthesis of storage proteins of the developing axis, but some of them are respired. The amino acids are catabolized by both glutamate dehydrogenase (GDH) and transaminases. Ammonium is reassimilated by glutamine synthetase (GS) and, through the action of asparagine synthetase (AS), is stored in asparagine (Asn). This review presents the ways in which amino acids are converted into Asn and their regulation, mostly in germinating seeds of yellow lupine, where Asn can make up to 30% of dry matter. The energy balance of the synthesis of Asn from glutamate, the most common amino acid in lupine storage proteins, also shows an adaptation of lupine for oxidation of amino acids in early stages of germination. Regulation of the pathway of Asn synthesis is described with regard to the role of GDH and AS, as well as compartmentation of particular metabolites. The regulatory effect of sugar on major links of the pathway (mobilization of storage proteins, induction of genes and activity of GDH and AS) is discussed with respect to recent genetic and molecular studies. Moreover, the effect of glutamate and phytohormones is presented at various stages of Asn biosynthesis.
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Affiliation(s)
- Teresa Lehmann
- Department of Plant Physiology, A. Mickiewicz University, Umultowska 89, 61-614 Poznań, Poland.
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33
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Miyashita Y, Good AG. NAD(H)-dependent glutamate dehydrogenase is essential for the survival of Arabidopsis thaliana during dark-induced carbon starvation. JOURNAL OF EXPERIMENTAL BOTANY 2008; 59:667-80. [PMID: 18296429 DOI: 10.1093/jxb/erm340] [Citation(s) in RCA: 95] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Interconversion between glutamate and 2-oxoglutarate, which can be catalysed by glutamate dehydrogenase (GDH), is a key reaction in plant carbon (C) and nitrogen (N) metabolism. However, the physiological role of plant GDH has been a controversial issue for several decades. To elucidate the function of GDH, the expression of GDH in various tissues of Arabidopsis thaliana was studied. Results suggested that the expression of two Arabidopsis GDH genes was differently regulated depending on the organ/tissue types and cellular C availability. Moreover, Arabidopsis mutants defective in GDH genes were identified and characterized. The two isolated mutants, gdh1-2 and gdh2-1, were crossed to make a double knockout mutant, gdh1-2/gdh2-1, which contained negligible levels of NAD(H)-dependent GDH activity. Phenotypic analysis on these mutants revealed an increased susceptibility of gdh1-2/gdh2-1 plants to C-deficient conditions. This conditional phenotype of the double knockout mutant supports the catabolic role of GDH and its role in fuelling the TCA cycle during C starvation. The reduced rate of glutamate catabolism in the gdh2-1 and gdh1-2/gdh2-1 plants was also evident by the growth retardation of these mutants when glutamate was supplied as the alternative N source. Furthermore, amino acid profiles during prolonged dark conditions were significantly different between WT and the gdh mutant plants. For instance, glutamate levels increased in WT plants but decreased in gdh1-2/gdh2-1 plants, and aberrant accumulation of several amino acids was detected in the gdh1-2/gdh2-1 plants. These results suggest that GDH plays a central role in amino acid breakdown under C-deficient conditions.
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Affiliation(s)
- Yo Miyashita
- Department of Biological Sciences, University of Alberta, Edmonton, AB T6G 2E9, Canada.
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34
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Studart-Guimarães C, Fait A, Nunes-Nesi A, Carrari F, Usadel B, Fernie AR. Reduced expression of succinyl-coenzyme A ligase can be compensated for by up-regulation of the gamma-aminobutyrate shunt in illuminated tomato leaves. PLANT PHYSIOLOGY 2007; 145:626-39. [PMID: 17885090 PMCID: PMC2048777 DOI: 10.1104/pp.107.103101] [Citation(s) in RCA: 124] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2007] [Accepted: 09/11/2007] [Indexed: 05/17/2023]
Abstract
Increasing experimental evidence suggests that the tricarboxylic acid cycle in plants is of greater importance in illuminated photosynthetic tissues than previously thought. In this study, transgenic tomato (Solanum lycopersicum) plants expressing a fragment of the beta-subunit of succinyl-coenzyme A ligase in either the antisense orientation or using the RNA interference approach, however, revealed little alteration in either photosynthesis or plant growth despite exhibiting dramatic reductions in activity. Moreover, the rate of respiration was only moderately affected in the transformants, suggesting that this enzyme does not catalyze a crucial step in mitochondrial respiration. However, metabolite and transcript profiling of these lines alongside enzyme and label redistribution experiments revealed that, whereas considerable activity of this enzyme appears to be dispensable, the reason for such a mild phenotype in extremely inhibited lines was an up-regulation of an alternative pathway for succinate production-that offered by the gamma-aminobutyric acid shunt. When taken together, these data highlight the importance both of succinate production for mitochondrial metabolism and the interplay between various routes of its production. The results are discussed in the context of current models of plant respiration in mitochondrial and cellular metabolism of the illuminated leaf.
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35
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Fairbairn DJ, Cavallaro AS, Bernard M, Mahalinga-Iyer J, Graham MW, Botella JR. Host-delivered RNAi: an effective strategy to silence genes in plant parasitic nematodes. PLANTA 2007; 226:1525-33. [PMID: 17653759 DOI: 10.1007/s00425-007-0588-x] [Citation(s) in RCA: 83] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2007] [Accepted: 07/02/2007] [Indexed: 05/16/2023]
Abstract
Root-knot nematodes (Meloidogyne spp.) are obligate, sedentary endoparasites that infect many plant species causing large economic losses worldwide. Available nematicides are being banned due to their toxicity or ozone-depleting properties and alternative control strategies are urgently required. We have produced transgenic tobacco (Nicotiana tabacum) plants expressing different dsRNA hairpin structures targeting a root-knot nematode (Meloidogyne javanica) putative transcription factor, MjTis11. We provide evidence that MjTis11 was consistently silenced in nematodes feeding on the roots of transgenic plants. The observed silencing was specific for MjTis11, with other sequence-unrelated genes being unaffected in the nematodes. Those transgenic plants able to induce silencing of MjTis11, also showed the presence of small interfering RNAs. Even though down-regulation of MjTis11 did not result in a lethal phenotype, this study demonstrates the feasibility of silencing root-knot nematode genes by expressing dsRNA in the host plant. Host-delivered RNA interference-triggered (HD-RNAi) silencing of parasite genes provides a novel disease resistance strategy with wide biotechnological applications. The potential of HD-RNAi is not restricted to parasitic nematodes but could be adapted to control other plant-feeding pests.
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Affiliation(s)
- David J Fairbairn
- Department of Botany, School of Integrative Biology, University of Queensland, Brisbane, QLD 4072, Australia
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36
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Petrasovits LA, Purnell MP, Nielsen LK, Brumbley SM. Production of polyhydroxybutyrate in sugarcane. PLANT BIOTECHNOLOGY JOURNAL 2007; 5:162-72. [PMID: 17207265 DOI: 10.1111/j.1467-7652.2006.00229.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
We report here the production of the bacterial polyester, polyhydroxybutyrate (PHB), in the crop species sugarcane (Saccharum spp. hybrids). The PHB biosynthesis enzymes of Ralstonia eutropha [beta-ketothiolase (PHAA), acetoacetyl-reductase (PHAB) and PHB synthase (PHAC)] were expressed in the cytosol or targeted to mitochondria or plastids. PHB accumulated in cytosolic lines at trace amounts, but was not detected in mitochondrial lines. In plastidic lines, PHB accumulated in leaves to a maximum of 1.88% of dry weight without obvious deleterious effects. Epifluorescence and electron microscopy of leaf sections from these lines revealed that PHB granules were visible in plastids of most cell types, except mesophyll cells. The concentration of PHB in culm internodes of plastidic lines was substantially lower than in leaves. Western blot analysis of these lines indicated that expression of the PHB biosynthesis proteins was not limiting in culm internodes. Epifluorescence microscopy of culm internode sections from plastidic lines showed that PHB granules were visible in most cell types, except photosynthetic cortical cells in the rind, and that the lower PHB concentration in culm internodes was probably a result of dilution of PHB-containing cells by the large number of cells with little or no PHB. We discuss strategies for producing PHB in mitochondria and mesophyll cell plastids, and for increasing PHB yields in culms.
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37
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Skopelitis DS, Paranychianakis NV, Paschalidis KA, Pliakonis ED, Delis ID, Yakoumakis DI, Kouvarakis A, Papadakis AK, Stephanou EG, Roubelakis-Angelakis KA. Abiotic stress generates ROS that signal expression of anionic glutamate dehydrogenases to form glutamate for proline synthesis in tobacco and grapevine. THE PLANT CELL 2006; 18:2767-81. [PMID: 17041150 PMCID: PMC1626620 DOI: 10.1105/tpc.105.038323] [Citation(s) in RCA: 245] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Glutamate dehydrogenase (GDH) may be a stress-responsive enzyme, as GDH exhibits considerable thermal stability, and de novo synthesis of the alpha-GDH subunit is induced by exogenous ammonium and senescence. NaCl treatment induces reactive oxygen species (ROS), intracellular ammonia, expression of tobacco (Nicotiana tabacum cv Xanthi) gdh-NAD;A1 encoding the alpha-subunit of GDH, increase in immunoreactive alpha-polypeptide, assembly of the anionic isoenzymes, and in vitro GDH aminating activity in tissues from hypergeous plant organs. In vivo aminating GDH activity was confirmed by gas chromatorgraphy-mass spectrometry monitoring of (15)N-Glu, (15)N-Gln, and (15)N-Pro in the presence of methionine sulfoximine and amino oxyacetic acid, inhibitors of Gln synthetase and transaminases, respectively. Along with upregulation of alpha-GDH by NaCl, isocitrate dehydrogenase genes, which provide 2-oxoglutarate, are also induced. Treatment with menadione also elicits a severalfold increase in ROS and immunoreactive alpha-polypeptide and GDH activity. This suggests that ROS participate in the signaling pathway for GDH expression and protease activation, which contribute to intracellular hyperammonia. Ammonium ions also mimic the effects of salinity in induction of gdh-NAD;A1 expression. These results, confirmed in tobacco and grape (Vitis vinifera cv Sultanina) tissues, support the hypothesis that the salinity-generated ROS signal induces alpha-GDH subunit expression, and the anionic iso-GDHs assimilate ammonia, acting as antistress enzymes in ammonia detoxification and production of Glu for Pro synthesis.
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Fontaine JX, Saladino F, Agrimonti C, Bedu M, Tercé-Laforgue T, Tétu T, Hirel B, Restivo FM, Dubois F. Control of the synthesis and subcellular targeting of the two GDH genes products in leaves and stems of Nicotiana plumbaginifolia and Arabidopsis thaliana. PLANT & CELL PHYSIOLOGY 2006; 47:410-8. [PMID: 16418233 DOI: 10.1093/pcp/pcj008] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Although the physiological role of the enzyme glutamate dehydrogenase which catalyses in vitro the reversible amination of 2-oxoglutarate to glutamate remains to be elucidated, it is now well established that in higher plants the enzyme preferentially occurs in the mitochondria of phloem companion cells. The Nicotiana plumbaginifolia and Arabidopis thaliana enzyme is encoded by two distinct genes encoding either an alpha- or a beta-subunit. Using antisense plants and mutants impaired in the expression of either of the two genes, we showed that in leaves and stems both the alpha- and beta-subunits are targeted to the mitochondria of the companion cells. In addition, we found in both species that there is a compensatory mechanism up-regulating the expression of the alpha-subunit in the stems when the expression of the beta-subunit is impaired in the leaves, and of the beta-subunit in the leaves when the expression of the alpha-subunit is impaired in the stems. When one of the two genes encoding glutamate dehydrogenase is ectopically expressed, the corresponding protein is targeted to the mitochondria of both leaf and stem parenchyma cells and its production is increased in the companion cells. These results are discussed in relation to the possible signalling and/or physiological function of the enzyme which appears to be coordinated in leaves and stems.
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Affiliation(s)
- Jean-Xavier Fontaine
- Laboratoire d'Androgénèse et Biotechnologie Végétale, Université de Picardie Jules Verne, Amiens, France
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