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Li S, Yan L, Zhang W, Yi C, Haider S, Wang C, Liu Y, Shi L, Xu F, Ding G. Nitrate alleviates ammonium toxicity in Brassica napus by coordinating rhizosphere and cell pH and ammonium assimilation. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2024; 117:786-804. [PMID: 37955989 DOI: 10.1111/tpj.16529] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Revised: 10/19/2023] [Accepted: 10/25/2023] [Indexed: 11/15/2023]
Abstract
In natural and agricultural situations, ammonium (NH 4 + ) is a preferred nitrogen (N) source for plants, but excessive amounts can be hazardous to them, known asNH 4 + toxicity. Nitrate (NO 3 - ) has long been recognized to reduceNH 4 + toxicity. However, little is known about Brassica napus, a major oil crop that is sensitive to highNH 4 + . Here, we found thatNO 3 - can mitigateNH 4 + toxicity by balancing rhizosphere and intracellular pH and accelerating ammonium assimilation in B. napus.NO 3 - increased the uptake ofNO 3 - andNH 4 + under highNH 4 + circumstances by triggering the expression ofNO 3 - andNH 4 + transporters, whileNO 3 - and H+ efflux from the cytoplasm to the apoplast was enhanced by promoting the expression ofNO 3 - efflux transporters and genes encoding plasma membrane H+ -ATPase. In addition,NO 3 - increased pH in the cytosol, vacuole, and rhizosphere, and down-regulated genes induced by acid stress. Root glutamine synthetase (GS) activity was elevated byNO 3 - under highNH 4 + conditions to enhance the assimilation ofNH 4 + into amino acids, thereby reducingNH 4 + accumulation and translocation to shoot in rapeseed. In addition, root GS activity was highly dependent on the environmental pH.NO 3 - might induce metabolites involved in amino acid biosynthesis and malate metabolism in the tricarboxylic acid cycle, and inhibit phenylpropanoid metabolism to mitigateNH 4 + toxicity. Collectively, our results indicate thatNO 3 - balances both rhizosphere and intracellular pH via effectiveNO 3 - transmembrane cycling, acceleratesNH 4 + assimilation, and up-regulates malate metabolism to mitigateNH 4 + toxicity in oilseed rape.
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Affiliation(s)
- Shuang Li
- Microelement Research Center/Key Laboratory of Arable Land Conservation (Middle and Lower Reaches of Yangtze River), Ministry of Agriculture and Rural Affairs/National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, 430070, China
| | - Lei Yan
- Institute of Biomedical Engineering, College of Life Science, Qingdao University, Qingdao, 266071, China
| | - Wen Zhang
- Microelement Research Center/Key Laboratory of Arable Land Conservation (Middle and Lower Reaches of Yangtze River), Ministry of Agriculture and Rural Affairs/National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, 430070, China
| | - Ceng Yi
- Microelement Research Center/Key Laboratory of Arable Land Conservation (Middle and Lower Reaches of Yangtze River), Ministry of Agriculture and Rural Affairs/National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, 430070, China
| | - Sharjeel Haider
- Microelement Research Center/Key Laboratory of Arable Land Conservation (Middle and Lower Reaches of Yangtze River), Ministry of Agriculture and Rural Affairs/National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, 430070, China
| | - Chuang Wang
- Microelement Research Center/Key Laboratory of Arable Land Conservation (Middle and Lower Reaches of Yangtze River), Ministry of Agriculture and Rural Affairs/National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, 430070, China
| | - Yu Liu
- College of Life Sciences, Zhejiang University, Hangzhou, 310058, China
| | - Lei Shi
- Microelement Research Center/Key Laboratory of Arable Land Conservation (Middle and Lower Reaches of Yangtze River), Ministry of Agriculture and Rural Affairs/National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, 430070, China
| | - Fangsen Xu
- Microelement Research Center/Key Laboratory of Arable Land Conservation (Middle and Lower Reaches of Yangtze River), Ministry of Agriculture and Rural Affairs/National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, 430070, China
| | - Guangda Ding
- Microelement Research Center/Key Laboratory of Arable Land Conservation (Middle and Lower Reaches of Yangtze River), Ministry of Agriculture and Rural Affairs/National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, 430070, China
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Poucet T, Beauvoit B, González‐Moro MB, Cabasson C, Pétriacq P, Flandin A, Gibon Y, Marino D, Dieuaide‐Noubhani M. Impaired cell growth under ammonium stress explained by modeling the energy cost of vacuole expansion in tomato leaves. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2022; 112:1014-1028. [PMID: 36198049 PMCID: PMC9828129 DOI: 10.1111/tpj.15991] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/17/2022] [Revised: 09/20/2022] [Accepted: 09/23/2022] [Indexed: 06/16/2023]
Abstract
Ammonium (NH4 + )-based fertilization efficiently mitigates the adverse effects of nitrogen fertilization on the environment. However, high concentrations of soil NH4 + provoke growth inhibition, partly caused by the reduction of cell enlargement and associated with modifications of cell composition, such as an increase of sugars and a decrease in organic acids. Cell expansion depends largely on the osmotic-driven enlargement of the vacuole. However, the involvement of subcellular compartmentation in the adaptation of plants to ammonium nutrition has received little attention, until now. To investigate this, tomato (Solanum lycopersicum) plants were cultivated under nitrate and ammonium nutrition and the fourth leaf was harvested at seven developmental stages. The vacuolar expansion was monitored and metabolites and inorganic ion contents, together with intracellular pH, were determined. A data-constrained model was constructed to estimate subcellular concentrations of major metabolites and ions. It was first validated at the three latter developmental stages by comparison with subcellular concentrations obtained experimentally using non-aqueous fractionation. Then, the model was used to estimate the subcellular concentrations at the seven developmental stages and the net vacuolar uptake of solutes along the developmental series. Our results showed ammonium nutrition provokes an acidification of the vacuole and a reduction in the flux of solutes into the vacuoles. Overall, analysis of the subcellular compartmentation reveals a mechanism behind leaf growth inhibition under ammonium stress linked to the higher energy cost of vacuole expansion, as a result of alterations in pH, the inhibition of glycolysis routes and the depletion of organic acids.
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Affiliation(s)
- Théo Poucet
- Department of Plant Biology and EcologyUniversity of the Basque Country (UPV/EHU)E‐48940LeioaSpain
- Université de Bordeaux, INRAE, UMR Biologie du Fruit et PathologieVillenave d'Ornon33140France
| | - Bertrand Beauvoit
- Université de Bordeaux, INRAE, UMR Biologie du Fruit et PathologieVillenave d'Ornon33140France
| | | | - Cécile Cabasson
- Université de Bordeaux, INRAE, UMR Biologie du Fruit et PathologieVillenave d'Ornon33140France
- Bordeaux Metabolome, MetaboHUBPHENOME‐EMPHASISVillenave d'Ornon33140France
| | - Pierre Pétriacq
- Université de Bordeaux, INRAE, UMR Biologie du Fruit et PathologieVillenave d'Ornon33140France
- Bordeaux Metabolome, MetaboHUBPHENOME‐EMPHASISVillenave d'Ornon33140France
| | - Amélie Flandin
- Université de Bordeaux, INRAE, UMR Biologie du Fruit et PathologieVillenave d'Ornon33140France
- Bordeaux Metabolome, MetaboHUBPHENOME‐EMPHASISVillenave d'Ornon33140France
| | - Yves Gibon
- Université de Bordeaux, INRAE, UMR Biologie du Fruit et PathologieVillenave d'Ornon33140France
- Bordeaux Metabolome, MetaboHUBPHENOME‐EMPHASISVillenave d'Ornon33140France
| | - Daniel Marino
- Department of Plant Biology and EcologyUniversity of the Basque Country (UPV/EHU)E‐48940LeioaSpain
- Ikerbasque, Basque Foundation for ScienceE‐48011BilbaoSpain
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Feng H, Fan X, Miller AJ, Xu G. Plant nitrogen uptake and assimilation: regulation of cellular pH homeostasis. JOURNAL OF EXPERIMENTAL BOTANY 2020; 71:4380-4392. [PMID: 32206788 PMCID: PMC7382382 DOI: 10.1093/jxb/eraa150] [Citation(s) in RCA: 68] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/22/2019] [Accepted: 03/19/2020] [Indexed: 05/10/2023]
Abstract
The enzymatic controlled metabolic processes in cells occur at their optimized pH ranges, therefore cellular pH homeostasis is fundamental for life. In plants, the nitrogen (N) source for uptake and assimilation, mainly in the forms of nitrate (NO3-) and ammonium (NH4+) quantitatively dominates the anion and cation equilibrium and the pH balance in cells. Here we review ionic and pH homeostasis in plant cells and regulation by N source from the rhizosphere to extra- and intracellular pH regulation for short- and long-distance N distribution and during N assimilation. In the process of N transport across membranes for uptake and compartmentation, both proton pumps and proton-coupled N transporters are essential, and their proton-binding sites may sense changes of apoplastic or intracellular pH. In addition, during N assimilation, carbon skeletons are required to synthesize amino acids, thus the combination of NO3- or NH4+ transport and assimilation results in different net charge and numbers of protons in plant cells. Efficient maintenance of N-controlled cellular pH homeostasis may improve N uptake and use efficiency, as well as enhance the resistance to abiotic stresses.
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Affiliation(s)
- Huimin Feng
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing, China
- MOA Key Laboratory of Plant Nutrition and Fertilization in Lower-Middle Reaches of the Yangtze River, Nanjing Agricultural University, Nanjing, China
| | - Xiaorong Fan
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing, China
- MOA Key Laboratory of Plant Nutrition and Fertilization in Lower-Middle Reaches of the Yangtze River, Nanjing Agricultural University, Nanjing, China
| | - Anthony J Miller
- Metabolic Biology, John Innes Centre, Norwich Research Park, Norwich, UK
| | - Guohua Xu
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing, China
- MOA Key Laboratory of Plant Nutrition and Fertilization in Lower-Middle Reaches of the Yangtze River, Nanjing Agricultural University, Nanjing, China
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Vega-Mas I, Pérez-Delgado CM, Marino D, Fuertes-Mendizábal T, González-Murua C, Márquez AJ, Betti M, Estavillo JM, González-Moro MB. Elevated CO2 Induces Root Defensive Mechanisms in Tomato Plants When Dealing with Ammonium Toxicity. PLANT & CELL PHYSIOLOGY 2017; 58:2112-2125. [PMID: 29059445 DOI: 10.1093/pcp/pcx146] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2017] [Accepted: 09/20/2017] [Indexed: 05/23/2023]
Abstract
An adequate carbon supply is fundamental for plants to thrive under ammonium stress. In this work, we studied the mechanisms involved in tomato (Solanum lycopersicum L.) response to ammonium toxicity when grown under ambient or elevated CO2 conditions (400 or 800 p.p.m. CO2). Tomato roots were observed to be the primary organ dealing with ammonium nutrition. We therefore analyzed nitrogen (N) and carbon (C) metabolism in the roots, integrating the physiological response with transcriptomic regulation. Elevated levels of CO2 preferentially stimulated root growth despite the high ammonium content. The induction of anaplerotic enzymes from the tricarboxylic acid (TCA) cycle led to enhanced amino acid synthesis under ammonium nutrition. Furthermore, the root transcriptional response to ammonium toxicity was improved by CO2-enriched conditions, leading to higher expression of stress-related genes, as well as enhanced modulation of genes related to signaling, transcription, transport and hormone metabolism. Tomato roots exposed to ammonium stress also showed a defense-like transcriptional response according to the modulation of genes related to detoxification and secondary metabolism, involving principally terpenoid and phenolic compounds. These results indicate that increasing C supply allowed the co-ordinated regulation of root defense mechanisms when dealing with ammonium toxicity.
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Affiliation(s)
- Izargi Vega-Mas
- Department of Plant Biology and Ecology, University of the Basque Country (UPV/EHU), Apdo. 644, E-48080 Bilbao, Spain
| | - Carmen M Pérez-Delgado
- Departamento de Bioquímica Vegetal y Biología Molecular, Facultad de Química, Universidad de Sevilla, Calle Profesor García González, 1, Sevilla, 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, Bilbao, Spain
| | - Teresa Fuertes-Mendizábal
- 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
| | - Antonio J Márquez
- Departamento de Bioquímica Vegetal y Biología Molecular, Facultad de Química, Universidad de Sevilla, Calle Profesor García González, 1, Sevilla, Spain
| | - Marco Betti
- Departamento de Bioquímica Vegetal y Biología Molecular, Facultad de Química, Universidad de Sevilla, Calle Profesor García González, 1, Sevilla, Spain
| | - José María Estavillo
- 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
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5
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Geilfus CM. The pH of the Apoplast: Dynamic Factor with Functional Impact Under Stress. MOLECULAR PLANT 2017; 10:1371-1386. [PMID: 28987886 DOI: 10.1016/j.molp.2017.09.018] [Citation(s) in RCA: 99] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2017] [Revised: 09/22/2017] [Accepted: 09/30/2017] [Indexed: 05/23/2023]
Abstract
The apoplast is an interconnected compartment with a thin water-film that alkalinizes under stress. This systemic pH increase may be a secondary effect without functional implications, arising from ion movements or proton-pump regulations. On the other hand, there are increasing indications that it is part of a mechanism to withstand stress. Regardless of this controversy, alkalinization of the apoplast has received little attention. The apoplastic pH (pHapo) increases not only during plant-pathogen interactions but also in response to salinity or drought. Not much is known about the mechanisms that cause the leaf apoplast to alkalinize, nor whether, and if so, how functional impact is conveyed. Controversial explanations have been given, and the unusual complexity of pHapo regulation is considered as the primary reason behind this lack of knowledge. A gathering of scattered information revealed that changes in pHapo convey functionality by regulating stomatal aperture via the effects exerted on abscisic acid. Moreover, apoplastic alkalinization may regulate growth under stress, whereas this needs to be verified. In this review, a comprehensive survey about several physiological mechanisms that alkalize the apoplast under stress is given, and the suitability of apoplastic alkalinization as transducing element for the transmission of sensory information is discussed.
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Affiliation(s)
- Christoph-Martin Geilfus
- Division of Controlled Environment Horticulture, Faculty of Life Sciences, Albrecht Daniel Thaer-Institute of Agricultural and Horticultural Sciences, Humboldt-University of Berlin, Albrecht-Thaer-Weg 1, 14195 Berlin, Germany.
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6
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Liu Y, von Wirén N. Ammonium as a signal for physiological and morphological responses in plants. JOURNAL OF EXPERIMENTAL BOTANY 2017; 68:2581-2592. [PMID: 28369490 DOI: 10.1093/jxb/erx086] [Citation(s) in RCA: 177] [Impact Index Per Article: 25.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Ammonium is a major inorganic nitrogen source for plants. At low external supplies, ammonium promotes plant growth, while at high external supplies it causes toxicity. Ammonium triggers rapid changes in cytosolic pH, in gene expression, and in post-translational modifications of proteins, leading to apoplastic acidification, co-ordinated ammonium uptake, enhanced ammonium assimilation, altered oxidative and phytohormonal status, and reshaped root system architecture. Some of these responses are dependent on AMT-type ammonium transporters and are not linked to a nutritional effect, indicating that ammonium is perceived as a signaling molecule by plant cells. This review summarizes current knowledge of ammonium-triggered physiological and morphological responses and highlights existing and putative mechanisms mediating ammonium signaling and sensing events in plants. We put forward the hypothesis that sensing of ammonium takes place at multiple steps along its transport, storage, and assimilation pathways.
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Affiliation(s)
- Ying Liu
- Molecular Plant Nutrition, Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), Corrensstrasse 3, 06466 Stadt Seeland, OT Gatersleben, Germany
| | - Nicolaus von Wirén
- Molecular Plant Nutrition, Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), Corrensstrasse 3, 06466 Stadt Seeland, OT Gatersleben, Germany
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7
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Sarasketa A, González-Moro MB, González-Murua C, Marino D. Nitrogen Source and External Medium pH Interaction Differentially Affects Root and Shoot Metabolism in Arabidopsis. FRONTIERS IN PLANT SCIENCE 2016; 7:29. [PMID: 26870054 PMCID: PMC4734181 DOI: 10.3389/fpls.2016.00029] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2015] [Accepted: 01/10/2016] [Indexed: 05/09/2023]
Abstract
Ammonium nutrition often represents an important growth-limiting stress in plants. Some of the symptoms that plants present under ammonium nutrition have been associated with pH deregulation, in fact external medium pH control is known to improve plants ammonium tolerance. However, the way plant cell metabolism adjusts to these changes is not completely understood. Thus, in this work we focused on how Arabidopsis thaliana shoot and root respond to different nutritional regimes by varying the nitrogen source ([Formula: see text] and [Formula: see text]), concentration (2 and 10 mM) and pH of the external medium (5.7 and 6.7) to gain a deeper understanding of cell metabolic adaptation upon altering these environmental factors. The results obtained evidence changes in the response of ammonium assimilation machinery and of the anaplerotic enzymes associated to Tricarboxylic Acids (TCA) cycle in function of the plant organ, the nitrogen source and the degree of ammonium stress. A greater stress severity at pH 5.7 was related to [Formula: see text] accumulation; this could not be circumvented in spite of the stimulation of glutamine synthetase, glutamate dehydrogenase, and TCA cycle anaplerotic enzymes. Moreover, this study suggests specific functions for different gln and gdh isoforms based on the nutritional regime. Overall, [Formula: see text] accumulation triggering ammonium stress appears to bear no relation to nitrogen assimilation impairment.
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Affiliation(s)
- Asier Sarasketa
- Department of Plant Biology and Ecology, University of the Basque Country (UPV/EHU)Bilbao, Spain
| | - M. Begoña González-Moro
- Department of Plant Biology and Ecology, University of the Basque Country (UPV/EHU)Bilbao, Spain
| | - Carmen González-Murua
- Department of Plant Biology and Ecology, University of the Basque Country (UPV/EHU)Bilbao, Spain
| | - Daniel Marino
- Department of Plant Biology and Ecology, University of the Basque Country (UPV/EHU)Bilbao, Spain
- Ikerbasque, Basque Foundation for ScienceBilbao, Spain
- *Correspondence: Daniel Marino
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Ge X, d'Avignon DA, Ackerman JJH, Sammons RD. In vivo ³¹P-nuclear magnetic resonance studies of glyphosate uptake, vacuolar sequestration, and tonoplast pump activity in glyphosate-resistant horseweed. PLANT PHYSIOLOGY 2014; 166:1255-68. [PMID: 25185124 PMCID: PMC4226384 DOI: 10.1104/pp.114.247197] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2014] [Accepted: 08/25/2014] [Indexed: 05/20/2023]
Abstract
Horseweed (Conyza canadensis) is considered a significant glyphosate-resistant (GR) weed in agriculture, spreading to 21 states in the United States and now found globally on five continents. This laboratory previously reported rapid vacuolar sequestration of glyphosate as the mechanism of resistance in GR horseweed. The observation of vacuole sequestration is consistent with the existence of a tonoplast-bound transporter. (31)P-Nuclear magnetic resonance experiments performed in vivo with GR horseweed leaf tissue show that glyphosate entry into the plant cell (cytosolic compartment) is (1) first order in extracellular glyphosate concentration, independent of pH and dependent upon ATP; (2) competitively inhibited by alternative substrates (aminomethyl phosphonate [AMPA] and N-methyl glyphosate [NMG]), which themselves enter the plant cell; and (3) blocked by vanadate, a known inhibitor/blocker of ATP-dependent transporters. Vacuole sequestration of glyphosate is (1) first order in cytosolic glyphosate concentration and dependent upon ATP; (2) competitively inhibited by alternative substrates (AMPA and NMG), which themselves enter the plant vacuole; and (3) saturable. (31)P-Nuclear magnetic resonance findings with GR horseweed are consistent with the active transport of glyphosate and alternative substrates (AMPA and NMG) across the plasma membrane and tonoplast in a manner characteristic of ATP-binding cassette transporters, similar to those that have been identified in mammalian cells.
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Affiliation(s)
- Xia Ge
- Departments of Chemistry (X.G., D.A.d'A., J.J.H.A.), Radiology (J.J.H.A.), and Internal Medicine (J.J.H.A.), Washington University, St. Louis, Missouri 63130; andMonsanto Company, St. Louis, Missouri 63167 (R.D.S.)
| | - D André d'Avignon
- Departments of Chemistry (X.G., D.A.d'A., J.J.H.A.), Radiology (J.J.H.A.), and Internal Medicine (J.J.H.A.), Washington University, St. Louis, Missouri 63130; andMonsanto Company, St. Louis, Missouri 63167 (R.D.S.)
| | - Joseph J H Ackerman
- Departments of Chemistry (X.G., D.A.d'A., J.J.H.A.), Radiology (J.J.H.A.), and Internal Medicine (J.J.H.A.), Washington University, St. Louis, Missouri 63130; andMonsanto Company, St. Louis, Missouri 63167 (R.D.S.)
| | - R Douglas Sammons
- Departments of Chemistry (X.G., D.A.d'A., J.J.H.A.), Radiology (J.J.H.A.), and Internal Medicine (J.J.H.A.), Washington University, St. Louis, Missouri 63130; andMonsanto Company, St. Louis, Missouri 63167 (R.D.S.)
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Geilfus CM, Mühling KH, Kaiser H, Plieth C. Bacterially produced Pt-GFP as ratiometric dual-excitation sensor for in planta mapping of leaf apoplastic pH in intact Avena sativa and Vicia faba. PLANT METHODS 2014; 10:31. [PMID: 25313311 PMCID: PMC4194361 DOI: 10.1186/1746-4811-10-31] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2014] [Accepted: 09/20/2014] [Indexed: 05/24/2023]
Abstract
BACKGROUND Ratiometric analysis with H(+)-sensitive fluorescent sensors is a suitable approach for monitoring apoplastic pH dynamics. For the acidic range, the acidotropic dual-excitation dye Oregon Green 488 is an excellent pH sensor. Long lasting (hours) recordings of apoplastic pH in the near neutral range, however, are more problematic because suitable pH indicators that combine a good pH responsiveness at a near neutral pH with a high photostability are lacking. The fluorescent pH reporter protein from Ptilosarcus gurneyi (Pt-GFP) comprises both properties. But, as a genetically encoded indicator and expressed by the plant itself, it can be used almost exclusively in readily transformed plants. In this study we present a novel approach and use purified recombinant indicators for measuring ion concentrations in the apoplast of crop plants such as Vicia faba L. and Avena sativa L. RESULTS Pt-GFP was purified using a bacterial expression system and subsequently loaded through stomata into the leaf apoplast of intact plants. Imaging verified the apoplastic localization of Pt-GFP and excluded its presence in the symplast. The pH-dependent emission signal stood out clearly from the background. PtGFP is highly photostable, allowing ratiometric measurements over hours. By using this approach, a chloride-induced alkalinizations of the apoplast was demonstrated for the first in oat. CONCLUSIONS Pt-GFP appears to be an excellent sensor for the quantification of leaf apoplastic pH in the neutral range. The presented approach encourages to also use other genetically encoded biosensors for spatiotemporal mapping of apoplastic ion dynamics.
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Affiliation(s)
- Christoph-Martin Geilfus
- />Institute of Plant Nutrition and Soil Science, Christian-Albrechts-Universität zu Kiel, Hermann-Rodewald-Str. 2, 24118 Kiel, Germany
| | - Karl H Mühling
- />Institute of Plant Nutrition and Soil Science, Christian-Albrechts-Universität zu Kiel, Hermann-Rodewald-Str. 2, 24118 Kiel, Germany
| | - Hartmut Kaiser
- />Botanisches Institut, Christian-Albrechts-Universität zu Kiel, Am Botanischen Garten 3-9, 24118 Kiel, Germany
| | - Christoph Plieth
- />Zentrum für Biochemie und Molekularbiologie, Christian-Albrechts-Universität zu Kiel, Am Botanischen Garten 3-9, 24118 Kiel, Germany
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10
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Geilfus CM, Mühling KH. Microscopic and macroscopic monitoring of adaxial-abaxial pH gradients in the leaf apoplast of Vicia faba L. as primed by NaCl stress at the roots. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2014; 223:109-115. [PMID: 24767120 DOI: 10.1016/j.plantsci.2014.03.012] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/07/2014] [Revised: 03/12/2014] [Accepted: 03/16/2014] [Indexed: 06/03/2023]
Abstract
The pH is a basic chemical requirement in cellular and apoplastic compartments that influences various physiological processes in plants. Apoplastic pH shifts can modulate the apoplastic and symplastic distribution of plant hormones or influence proton motive force-driven uptake processes over the plasma-membrane. Changing environments are known to effect on the apoplastic H(+)-concentration in leaves and roots. The onset of NaCl-stress at the roots for instance primes a chloride-specific systemic alkalinization of the leaf apoplast. By means of microscopy- and macroscopy-based in planta ratio-imaging we surprisingly found that large adaxial-abaxial pH gradients were established throughout the leaf apoplast during the formation of the NaCl-induced alkalinization. Moreover, the root system is necessary to ensure the transient nature of the leaf apoplastic alkalinization.
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Affiliation(s)
- Christoph-Martin Geilfus
- Institute of Plant Nutrition and Soil Science, Kiel University, Hermann-Rodewald-Str. 2, 24118 Kiel, Germany.
| | - Karl-Hermann Mühling
- Institute of Plant Nutrition and Soil Science, Kiel University, Hermann-Rodewald-Str. 2, 24118 Kiel, Germany.
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11
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Stevens CJ, Manning P, van den Berg LJL, de Graaf MCC, Wamelink GWW, Boxman AW, Bleeker A, Vergeer P, Arroniz-Crespo M, Limpens J, Lamers LPM, Bobbink R, Dorland E. Ecosystem responses to reduced and oxidised nitrogen inputs in European terrestrial habitats. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2011; 159:665-76. [PMID: 21215502 DOI: 10.1016/j.envpol.2010.12.008] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2010] [Revised: 11/29/2010] [Accepted: 12/09/2010] [Indexed: 05/06/2023]
Abstract
While it is well established that ecosystems display strong responses to elevated nitrogen deposition, the importance of the ratio between the dominant forms of deposited nitrogen (NH(x) and NO(y)) in determining ecosystem response is poorly understood. As large changes in the ratio of oxidised and reduced nitrogen inputs are occurring, this oversight requires attention. One reason for this knowledge gap is that plants experience a different NH(x):NO(y) ratio in soil to that seen in atmospheric deposits because atmospheric inputs are modified by soil transformations, mediated by soil pH. Consequently species of neutral and alkaline habitats are less likely to encounter high NH(4)(+) concentrations than species from acid soils. We suggest that the response of vascular plant species to changing ratios of NH(x):NO(y) deposits will be driven primarily by a combination of soil pH and nitrification rates. Testing this hypothesis requires a combination of experimental and survey work in a range of systems.
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Affiliation(s)
- Carly J Stevens
- Department of Life Sciences, The Open University, Walton Hall, Milton Keynes MK7 6AA, UK.
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Horchani F, R`bia O, Hajri R, Aschi-Smit S. Retracted: Nitrogen Nutrition and Ammonium Toxicity in Higher Plants. ACTA ACUST UNITED AC 2010. [DOI: 10.3923/ijb.2011.1.16] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Hachiya T, Watanabe CK, Boom C, Tholen D, Takahara K, Kawai-Yamada M, Uchimiya H, Uesono Y, Terashima I, Noguchi K. Ammonium-dependent respiratory increase is dependent on the cytochrome pathway in Arabidopsis thaliana shoots. PLANT, CELL & ENVIRONMENT 2010; 33:1888-97. [PMID: 20545883 DOI: 10.1111/j.1365-3040.2010.02189.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Oxygen uptake rates are increased when concentrated ammonium instead of nitrate is used as sole N source. Several explanations for this increased respiration have been suggested, but the underlying mechanisms are still unclear. To investigate possible factors responsible for this respiratory increase, we measured the O₂ uptake rate, activity and transcript level of respiratory components, and concentration of adenylates using Arabidopsis thaliana shoots grown in media containing various N sources. The O₂ uptake rate was correlated with concentrations of ammonium and ATP in shoots, but not related to the ammonium assimilation. The capacity of the ATP-coupling cytochrome pathway (CP) and its related genes were up-regulated when concentrated ammonium was sole N source, whereas the ATP-uncoupling alternative oxidase did not influence the extent of the respiratory increase. Our results suggest that the ammonium-dependent increase of the O₂ uptake rate can be explained by the up-regulation of the CP, which may be related to the ATP consumption by the plasma-membrane H+ -ATPase.
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Affiliation(s)
- Takushi Hachiya
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
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YANG J, LU CY. Possible Mechanism Associated with Herbicidal Activity of Soybean Meal Hydrolysate (SMH). ACTA ACUST UNITED AC 2010. [DOI: 10.1016/s1671-2927(09)60164-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Ruan J, Gerendás J, Härdter R, Sattelmacher B. Effect of nitrogen form and root-zone pH on growth and nitrogen uptake of tea (Camellia sinensis) plants. ANNALS OF BOTANY 2007; 99:301-10. [PMID: 17204540 PMCID: PMC2802997 DOI: 10.1093/aob/mcl258] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
BACKGROUND AND AIMS Tea (Camellia sinensis) is considered to be acid tolerant and prefers ammonium nutrition, but the interaction between root zone acidity and N form is not properly understood. The present study was performed to characterize their interaction with respect to growth and mineral nutrition. METHODS Tea plants were hydroponically cultured with NH4+, NO3- and NH(4+) + NO3-, at pH 4.0, 5.0 and 6.0, which were maintained by pH stat systems. KEY RESULTS Plants supplied with NO3- showed yellowish leaves resembling nitrogen deficiency and grew much slower than those receiving NH4+ or NH(4+) + NO3- irrespective of root-zone pH. Absorption of NH4+ was 2- to 3.4-fold faster than NO3- when supplied separately, and 6- to 16-fold faster when supplied simultaneously. Nitrate-grown plants had significantly reduced glutamine synthetase activity, and lower concentrations of total N, free amino acids and glucose in the roots, but higher concentrations of cations and carboxylates (mainly oxalate) than those grown with NH4+ or NH(4+) + NO3-. Biomass production was largest at pH 5.0 regardless of N form, and was drastically reduced by a combination of high root-zone pH and NO3-. Low root-zone pH reduced root growth only in NO(3-)-fed plants. Absorption of N followed a similar pattern as root-zone pH changed, showing highest uptake rates at pH 5.0. The concentrations of total N, free amino acids, sugars and the activity of GS were generally not influenced by pH, whereas the concentrations of cations and carboxylates were generally increased with increasing root-zone pH. CONCLUSIONS Tea plants are well-adapted to NH(4+)-rich environments by exhibiting a high capacity for NH4+ assimilation in their roots, reflected in strongly increased key enzyme activities and improved carbohydrate status. The poor plant growth with NO3- was largely associated with inefficient absorption of this N source. Decreased growth caused by inappropriate external pH corresponded well with the declining absorption of nitrogen.
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Affiliation(s)
- Jianyun Ruan
- Institute for Plant Nutrition and Soil Science, Kiel University, Kiel, D-24098, Germany.
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Prusky D, Lichter A. Activation of quiescent infections by postharvest pathogens during transition from the biotrophic to the necrotrophic stage. FEMS Microbiol Lett 2007; 268:1-8. [PMID: 17227463 DOI: 10.1111/j.1574-6968.2006.00603.x] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Insidious fungal infections of postharvest pathogens remain quiescent, as biotrophs, during fruit growth and harvest, but activate their development and transform to necrotrophs, which elicit decay symptoms, during ripening and senescence. Exposure of unripe hosts to pathogens quickly initiates defensive signal-transduction cascades that limit fungal growth and development, but exposure to the same pathogens during ripening and storage activates a substantially different signaling cascade that facilitates fungal colonization. The first step in the activation of quiescent infections may involve the fungal capability to cope with plant defense responses by detoxification and efflux transport of antifungals, or by overcoming the suppression of pathogenicity factors. The second step toward the activation of quiescent infections is actively modulated by the pathogen in response to a host signal(s), and includes alkalization or ammonification of the host tissue, which sensitizes the host and activates the transcription and secretion of fungal-degradative enzymes that promote maceration of the host tissue. Feedback signals involving, for example, nitrogen and sugar further enhance pH changes, synthesis of hydrolytic enzymes and saprophytic development in the macerated tissue. This review describes the coordinated series of mechanisms that regulate the activation of quiescent infections in various fruit/vegetable-pathogen interactions.
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Affiliation(s)
- Dov Prusky
- Department of Postharvest Science of Fresh Produce, Agricultural Research Organization, Bet Dagan, Israel.
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Mesnard F, Ratcliffe RG. NMR analysis of plant nitrogen metabolism. PHOTOSYNTHESIS RESEARCH 2005; 83:163-80. [PMID: 16143850 DOI: 10.1007/s11120-004-2081-8] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2004] [Accepted: 07/17/2004] [Indexed: 05/04/2023]
Abstract
The analysis of primary and secondary nitrogen metabolism in plants by nuclear magnetic resonance (NMR) spectroscopy is comprehensively reviewed. NMR is a versatile analytical tool, and the combined use of (1)H, (2)H, (13)C, (14)N and (15)N NMR allows detailed investigation of the acquisition, assimilation and metabolism of nitrogen. The analysis of tissue extracts can be complemented by the in vivo NMR analysis of functioning tissues and cell suspensions, and by the application of solid state NMR techniques. Moreover stable isotope labelling with (2)H-, (13)C- and (15)N-labelled precursors provides direct insight into specific pathways, with the option of both time-course and steady state analysis increasing the potential value of the approach. The scope of the NMR method, and its contribution to studies of plant nitrogen metabolism, are illustrated with a wide range of examples. These include studies of the GS/GOGAT pathway of ammonium assimilation, investigations of the metabolism of glutamate, glycine and other amino acids, and applications to tropane alkaloid metabolism. The continuing development of the NMR technique, together with potential applications in the emerging fields of metabolomics and metabolic flux analysis, leads to the conclusion that NMR will play an increasingly valuable role in the analysis of plant nitrogen metabolism.
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Affiliation(s)
- F Mesnard
- EA 2084, Faculté de Pharmacie, Laboratoire de Phytotechnologie, 1 rue des Louvels, F-80037 Amiens Cedex 1, France
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Hartung W, Schraut D, Jiang F. Physiology of abscisic acid (ABA) in roots under stress—a review of the relationship between root ABA and radial water and ABA flows. ACTA ACUST UNITED AC 2005. [DOI: 10.1071/ar05065] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Abscisic acid (ABA), the universal plant stress hormone, is accumulated in roots subjected to a range of external stresses, including drought, salinity, and nutrient deficiencies. This accumulation is regulated by ABA-metabolism (biosynthesis and degradation), -recirculation, and -exudation. Stress ABA serves as a long-distance signal regulating the water relations of shoots (stomata, meristems) and roots (hydraulic conductivity, root development, desiccation tolerance). Endogenous ABA, radial water flows (JV), and radial ABA flows (JABA) are closely coupled. Here we described the relations between these processes that are crucial factors for the role of ABA as a stress hormone and a long-distance stress signal. Crop varieties with high ABA concentrations exhibit an intensified long distance ABA signalling that reduces water consumption and, in the case of grapevine, improves the quality of the berries.
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Britto DT, Kronzucker HJ. NH4+ toxicity in higher plants: a critical review. JOURNAL OF PLANT PHYSIOLOGY 2002. [PMID: 0 DOI: 10.1078/0176-1617-0774] [Citation(s) in RCA: 671] [Impact Index Per Article: 30.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
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Ratcliffe RG, Shachar-Hill Y. PROBING PLANT METABOLISM WITH NMR. ANNUAL REVIEW OF PLANT PHYSIOLOGY AND PLANT MOLECULAR BIOLOGY 2001; 52:499-526. [PMID: 11337407 DOI: 10.1146/annurev.arplant.52.1.499] [Citation(s) in RCA: 88] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Analytical methods for probing plant metabolism are taking on new significance in the era of functional genomics and metabolic engineering. Among the available methods, nuclear magnetic resonance (NMR) spectroscopy is a technique that can provide insights into the integration and regulation of plant metabolism through a combination of in vivo and in vitro measurements. Thus NMR can be used to identify, quantify, and localize metabolites, to define the intracellular environment, and to explore pathways and their operation. We review these applications and their significance from a metabolic perspective. Topics of current interest include applications of NMR to metabolic flux analysis, metabolite profiling, and metabolite imaging. These and other areas are discussed in relation to NMR investigations of intermediary carbon and nitrogen metabolism. We conclude that metabolic NMR has a continuing role to play in the development of a quantitative understanding of plant metabolism and in the characterization of metabolic phenotypes.
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Affiliation(s)
- R George Ratcliffe
- Department of Plant Sciences, University of Oxford, South Parks Road, Oxford, OX1 3RB, United Kingdom; e-mail: , Department of Chemistry and Biochemistry, New Mexico State University, Las Cruces, New Mexico 88003; e-mail:
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Walker RP, Chen ZH, Johnson KE, Famiani F, Tecsi L, Leegood RC. Using immunohistochemistry to study plant metabolism: the examples of its use in the localization of amino acids in plant tissues, and of phosphoenolpyruvate carboxykinase and its possible role in pH regulation. JOURNAL OF EXPERIMENTAL BOTANY 2001; 52:565-576. [PMID: 11373305 DOI: 10.1093/jexbot/52.356.565] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
To understand many aspects of the metabolism of complex plant structures such as leaves, fruit and roots it is important to understand how metabolic processes are compartmentalized between tissues. The aim of this article is to show how immunohistochemistry, in conjunction with biochemical and physiological studies, is useful in understanding both the function of an enzyme in a tissue and metabolic processes occurring in plant tissues. This is illustrated by two examples. Firstly, the use of immunohistochemisty in the localization of amino acids in plant tissues is described. Secondly, the use of immunohistochemistry in understanding the function of an enzyme in a tissue and the metabolic processes occurring within the tissue is described. To illustrate this the example of phosophoenolpyruvate carboxykinase (PEPCK), an enzyme which is present in many plant tissues in which its function is unknown, is used. Evidence is provided that PEPCK may play a role in pH regulation in tissues active in the metabolism of nitrogen.
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Affiliation(s)
- R P Walker
- Department of Animal and Plant Sciences, University of Sheffield, Sheffield S10 2TN, UK. Istituto di Coltivazioni Arboree, Universita degli Studi di Perugia, via BorgoXX Guigno, 74-06121 Perugia, Italy.
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