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Gil-Cardeza ML, Calonne-Salmon M, Gómez E, Declerck S. Short-term chromium (VI) exposure increases phosphorus uptake by the extraradical mycelium of the arbuscular mycorrhizal fungus Rhizophagus irregularis MUCL 41833. CHEMOSPHERE 2017; 187:27-34. [PMID: 28829949 DOI: 10.1016/j.chemosphere.2017.08.079] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2017] [Revised: 08/01/2017] [Accepted: 08/16/2017] [Indexed: 06/07/2023]
Abstract
Hexavalent chromium is a potent carcinogen, while phosphorus is an essential nutrient. The role of arbuscular mycorrhizal fungi (AMF) in the uptake of P is well known and was also reported, at low levels, for Cr. However, it is unclear whether the uptake of Cr can impact the short-term uptake dynamics of P since both elements have a similar chemical structure and may thus potentially compete with each other during the uptake process. This study investigated the impact of Cr(VI) on short-term P uptake by the AMF Rhizophagus irregularis MUCL 41833 in Medicago truncatula. Bi-compartmented Petri plates were used to spatially separate a root compartment (RC) from a hyphal compartment (HC) using a whole plant in vitro culture system. The HC was supplemented with Cr(VI). Chromium(VI) as well as total Cr and P were monitored during 16 h within the HC and their concentrations determined by the end of the experiment within roots and shoots. Our results indicated that the uptake and translocation of Cr from hyphae to roots was a fast process: roots in which the extraradical mycelium (ERM) was exposed to Cr(VI) accumulated more Cr than roots of which the ERM was not exposed to Cr(VI) or was dead. Our results further confirmed that dead ERM immobilized more Cr than alive ERM. Finally our results demonstrated that the short exposure to Cr(VI) was sufficient to stimulate P uptake by the ERM and that the stimulation process began within the first 4 h of exposure.
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Affiliation(s)
- María Lourdes Gil-Cardeza
- Laboratorio de Biodiversidad Vegetal y Microbiana, IICAR (CONICET-UNR), Facultad de Cs Agrarias, Universidad Nacional de Rosario, Campo Exp. Villarino, Zavalla (2123), Argentina.
| | - Maryline Calonne-Salmon
- Université Catholique de Louvain, Earth and Life Institute, Mycology, Croix du Sud, 2 box L7.05.06, B-1348 Louvain-la-Neuve, Belgium
| | - Elena Gómez
- Laboratorio de Biodiversidad Vegetal y Microbiana, IICAR (CONICET-UNR), Facultad de Cs Agrarias, Universidad Nacional de Rosario, Campo Exp. Villarino, Zavalla (2123), Argentina
| | - Stéphane Declerck
- Université Catholique de Louvain, Earth and Life Institute, Mycology, Croix du Sud, 2 box L7.05.06, B-1348 Louvain-la-Neuve, Belgium
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De Jager A, Posno M. A COMPARISON OF THE REACTION TO A LOCALIZED SUPPLY OF PHOSPHATE IN PLANTAGO MAJOR, PLANTAGO LANCEOLATA AND PLANTAGO MEDIA*. ACTA ACUST UNITED AC 2015. [DOI: 10.1111/j.1438-8677.1979.tb01172.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- A. De Jager
- Botanisch Laboratorium; Lange Nieuwstraat 106 3512 PN Utrecht
| | - M. Posno
- Botanisch Laboratorium; Lange Nieuwstraat 106 3512 PN Utrecht
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Alexova R, Nelson CJ, Jacoby RP, Millar AH. Exposure of barley plants to low Pi leads to rapid changes in root respiration that correlate with specific alterations in amino acid substrates. THE NEW PHYTOLOGIST 2015; 206:696-708. [PMID: 25557489 DOI: 10.1111/nph.13245] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/16/2014] [Accepted: 11/18/2014] [Indexed: 05/28/2023]
Abstract
The majority of inorganic phosphate (Pi ) stress studies in plants have focused on the response after growth has been retarded. Evidence from transcript analysis, however, shows that a Pi -stress specific response is initiated within minutes of transfer to low Pi and in crop plants precedes the expression of Pi transporters and depletion of vacuolar Pi reserves by days. In order to investigate the physiological and metabolic events during early exposure to low Pi in grain crops, we monitored the response of whole barley plants during the first hours following Pi withdrawal. Lowering the concentration of Pi led to rapid changes in root respiration and leaf gas exchange throughout the early phase of the light course. Combining amino and organic acid analysis with (15) N labelling we show a root-specific effect on nitrogen metabolism linked to specific substrates of respiration as soon as 1 h following Pi withdrawal; this explains the respiratory responses observed and was confirmed by stimulation of respiration by exogenous addition of these respiratory substrates to roots. The rapid adjustment of substrates for respiration in roots during short-term Pi -stress is highlighted and this could help guide roots towards Pi -rich soil patches without compromising biomass accumulation of the plant.
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Affiliation(s)
- Ralitza Alexova
- ARC Centre of Excellence in Plant Energy Biology, University of Western Australia, 35 Stirling Highway, Crawley, WA, 6009, Australia; Centre for Comparative Analysis of Biomolecular Networks, University of Western Australia, 35 Stirling Highway, Crawley, WA, 6009, Australia
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Preuss CP, Huang CY, Tyerman SD. Proton-coupled high-affinity phosphate transport revealed from heterologous characterization in Xenopus of barley-root plasma membrane transporter, HvPHT1;1. PLANT, CELL & ENVIRONMENT 2011; 34:681-9. [PMID: 21309796 DOI: 10.1111/j.1365-3040.2010.02272.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
High-affinity phosphate transporters mediate uptake of inorganic phosphate (P(i) ) from soil solution under low P(i) conditions. The electrophysiological properties of any plant high-affinity P(i) transporter have not been described yet. Here, we report the detailed characterization of electrophysiological properties of the barley P(i) transporter, HvPHT1;1 in Xenopus laevis oocytes. A very low K(m) value (1.9 µm) for phosphate transport was observed in HvPHT1;1, which falls within the concentration range observed for barley roots. Inward currents at negative membrane potentials were identified as nH+ :P(i)⁻ (n > 1) co-transport based on simultaneous P(i) radiotracer uptake, oocyte voltage clamping and pH dependence. HvPHT1;1 showed preferential selectivity for P(i) and arsenate, but no transport of the other oxyanions SO₄²⁻ and NO₃⁻. In addition, HvPHT1;1 locates to the plasma membrane when expressed in onion (Allium cepa L.) epidermal cells, and is highly expressed in root segments with dense hairs. The electrophysiological properties, plasma membrane localization and cell-specific expression pattern of HvPHT1;1 support its role in the uptake of P(i) under low P(i) conditions.
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Affiliation(s)
- Christian P Preuss
- School of Agriculture, Food and Wine, The University of Adelaide, South Australia, Australia
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Gordon-Weeks R, Tong Y, Davies TGE, Leggewie G. Restricted spatial expression of a high-affinity phosphate transporter in potato roots. J Cell Sci 2003; 116:3135-44. [PMID: 12799416 DOI: 10.1242/jcs.00615] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Phosphorus deficiency limits plant growth, and high-affinity phosphate transporters, of the Pht1 family, facilitate phosphate uptake and translocation. The family is subdivided into root specific, phosphate deprivation induced members and those also expressed in leaves. An antibody to StPT2, a potato root specific transporter, detected two bands (52 kDa and 30 kDa) on western blots of root plasma membrane extracts that were most intense in whole extracts from the root tip and slightly increased throughout the root in response to phosphate depletion. RT-PCR, using StPT2 specific primers, confirmed these findings. Low power confocal immunofluorescent images showed StPT2 expression mainly in the elongation zone at the root tip. By contrast, a vacuolar pyrophosphatase and a plasma membrane ATPase antibody labelled the whole root. High power images showed, by comparison with alpha-tubulin, cell wall and plasma membrane ATPase labelling, that StPT2 was in the epidermal plasma membrane and restricted to the apical surface. This is the first evidence of polar plasma membrane localisation of a plant nutrient transporter and is consistent with a role for StPT2 in phosphate capture and uptake.
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Jolicoeur M, Bouchard-Marchand E, Bécard G, Perrier M. Regulation of mycorrhizal symbiosis: development of a structured nutritional dual model. Ecol Modell 2003. [DOI: 10.1016/s0304-3800(03)00024-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Jolicoeur M, Bouchard-Marchand E, Bécard G, Perrier M. Regulation of mycorrhizal symbiosis: development of a structured nutritional dual model. Ecol Modell 2002. [DOI: 10.1016/s0304-3800(02)00168-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Karthikeyan AS, Varadarajan DK, Mukatira UT, D'Urzo MP, Damsz B, Raghothama KG. Regulated expression of Arabidopsis phosphate transporters. PLANT PHYSIOLOGY 2002; 130:221-33. [PMID: 12226502 PMCID: PMC166555 DOI: 10.1104/pp.020007] [Citation(s) in RCA: 181] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
Phosphorus deficiency is one of the major abiotic stresses affecting plant growth. Plants respond to the persistent deficiency of phosphate (Pi) by coordinating the expression of genes involved in alleviation of the stress. The high-affinity Pi transporters are among the major molecular determinants that are activated during Pi stress. In this study, using three reporter genes (green fluorescent protein, luciferase, and beta-glucuronidase) regulated by two Pi transporter promoters, we have carried out an extensive analysis of transcriptional and spatial regulation of gene expression. Activation of the genes was rapid, repressible, and specific in response to changes in Pi availability. The phytohormones auxin and cytokinin suppressed the expression of the reporter gene driven by the AtPT1 promoter, and that of the native gene, suggesting that hormones may be involved in regulation of some component(s) of Pi starvation response pathway. These studies also provide molecular evidence for a potential role of high-affinity Pi transporters in mobilizing Pi into reproductive organs. The results suggest that members of the Pi transporter family may have similar but nonredundant functions in plants.
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Abstract
Phosphorus is one of the major plant nutrients that is least available in the soil. Consequently, plants have developed numerous morphological, physiological, biochemical, and molecular adaptations to acquire phosphate (Pi). Enhanced ability to acquire Pi and altered gene expression are the hallmarks of plant adaptation to Pi deficiency. The intricate mechanisms involved in maintaining Pi homeostasis reflect the complexity of Pi acquisition and translocation in plants. Recent discoveries of multiple Pi transporters have opened up opportunities to study the molecular basis of Pi acquisition by plants. An increasing number of genes are now known to be activated under Pi starvation. Some of these genes may be involved in Pi acquisition, transfer, and signal transduction during Pi stress. This review provides an overview of plant adaptations leading to enhanced Pi acquisition, with special emphasis on recent developments in the molecular biology of Pi acquisition.
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Affiliation(s)
- K. G. Raghothama
- Department of Horticulture, Purdue University, West Lafayette, Indiana 47907; e-mail:
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Muchhal US, Raghothama KG. Transcriptional regulation of plant phosphate transporters. Proc Natl Acad Sci U S A 1999; 96:5868-72. [PMID: 10318976 PMCID: PMC21952 DOI: 10.1073/pnas.96.10.5868] [Citation(s) in RCA: 134] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Phosphorus is acquired by plant roots primarily via the high-affinity inorganic phosphate (Pi) transporters. The transcripts for Pi transporters are highly inducible upon Pi starvation, which also results in enhanced Pi uptake when Pi is resupplied. Using antibodies specific to one of the tomato Pi transporters (encoded by LePT1), we show that an increase in the LePT1 transcript under Pi starvation leads to a concurrent increase in the transporter protein, suggesting a transcriptional regulation for Pi acquisition. LePT1 protein accumulates rapidly in tomato roots in response to Pi starvation. The level of transporter protein accumulation depends on the Pi concentration in the medium, and it is reversible upon resupply of Pi. LePT1 protein accumulates all along the roots under Pi starvation and is localized primarily in the plasma membranes. These results clearly demonstrate that plants increase their capacity for Pi uptake during Pi starvation by synthesis of additional transporter molecules.
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Affiliation(s)
- U S Muchhal
- Department of Horticulture and Landscape Architecture, Center for Plant Environmental Stress Physiology, Purdue University, West Lafayette, IN 47907, USA
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Mimura T. Regulation of Phosphate Transport and Homeostasis in Plant Cells. INTERNATIONAL REVIEW OF CYTOLOGY 1999. [DOI: 10.1016/s0074-7696(08)60159-x] [Citation(s) in RCA: 117] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
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Naylor J, Macnair MR, Williams END, Poulton PR. A polymorphism for phosphate uptake/arsenate tolerance in Holcus lanatus L.: is there a correlation with edaphic or environmental factors? Heredity (Edinb) 1996. [DOI: 10.1038/hdy.1996.178] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
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Genetic correlation between arsenate tolerance and the rate of influx of arsenate and phosphate in Holcus lanatus L. Heredity (Edinb) 1992. [DOI: 10.1038/hdy.1992.133] [Citation(s) in RCA: 58] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
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Meharg AA, Macnair MR. The mechanisms of arsenate tolerance in Deschampsia cespitosa (L.) Beauv. and Agrostis capillaris L.: Adaptation of the arsenate uptake system. THE NEW PHYTOLOGIST 1991; 119:291-297. [PMID: 33874130 DOI: 10.1111/j.1469-8137.1991.tb01033.x] [Citation(s) in RCA: 52] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Arsenate influx isotherms in Deschampsia cespitosa (L.) Beauv. and Agrostis capillaris L. showed that tolerance to arsenate in these grasses is achieved at least in part by adaptation of the arsenate uptake system, which leads to reduced influx of arsenate in arsenate-tolerant plants. In D. cespitosa, this reduction in arsenate ioflux was by suppression of the Vmax of the high-affinity uptake system and by an increase in the Km of the low-affinity uptake system. In A. capillaris the reduction in arsenate uptake in arsenate-tolerant plants was by a decrease in the Vmax of both uptake systems and by an increase in the Km of the high-affinity uptake system. The differences in the rates of arsenate influx between tolerant and non-tolerant plants was much greater for D. cespitosa than for A. capillaris. The mechanism of arsenate tolerance in D. cespitosa and A. capillaris was the same mechanism of tolerance that had been demonstrated in arsenate-tolerant Holcus lanatus L. Reduced arsenate influx by adaptation of the arsenate uptake mechanism is a mechanism of tolerance that has evolved in three separate species.
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Affiliation(s)
- Andrew A Meharg
- Department of Biological Sciences, Hatherly Laboratories, Prince of Wales Road, Exeter EX4 4PS, UK
| | - Mark R Macnair
- Department of Biological Sciences, Hatherly Laboratories, Prince of Wales Road, Exeter EX4 4PS, UK
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Effect of Mineral Nutrition on the Growth and Multiplication of in vitro Cultured Plants. PROGRESS IN PLANT CELLULAR AND MOLECULAR BIOLOGY 1990. [DOI: 10.1007/978-94-009-2103-0_15] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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Ernst M, Römheld V, Marschner H. Estimation of phosphorus uptake capacity by different zones of the primary root of soil-grown maize (Zea mays L.). ACTA ACUST UNITED AC 1989. [DOI: 10.1002/jpln.19891520105] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Drew MC, Saker LR. Uptake and long-distance transport of phosphate, potassium and chloride in relation to internal ion concentrations in barley: evidence of non-allosteric regulation. PLANTA 1984; 160:500-507. [PMID: 24258776 DOI: 10.1007/bf00411136] [Citation(s) in RCA: 33] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/1983] [Accepted: 09/20/1983] [Indexed: 05/28/2023]
Abstract
The extent to which uptake and transport of either phosphate, potassium or chloride are controlled by the concentration of these ions within the root, perhaps through an allosteric mechanism, was investigated with young barley plants in nutrient solution culture. Plants were grown with their roots divided between two containers, such that a single seminal root was continuously supplied with all the required nutrient ions, while the remaining four or five seminal roots were either supplied with the same solution (controls) or, temporarily, a solution lacking a particular nutrient ion (nutrient-deficient treatment). Compared with controls, there was a marked stimulation of uptake and transport of labelled ions by the single root following 24 h or more of nutrient dificiency to the remainder of the root system. This stimulation, which comprised an increased transport to the shoot and, for all ions except Cl(-), increased transport to the remainder of the root system, took place without appreciable change in the concentration of particular ions within the single root. However, nutrient deficiency quickly caused a lower concentration of ions in the shoot and the remaining roots. The results are discussed in relation to various mechanisms, proposed in the literature, by which the coordination of ion uptake and transport may be maintained within the plant. We suggest that under our conditions any putative allosteric control of uptake and transport by root cortical cells was masked by an alternative mechanism, in which ion influx appears to be regulated by ion efflux to the xylem, perhaps controlled by the concentration of particular ions recycled in the phloem to the root from the shoot.
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Affiliation(s)
- M C Drew
- Agricultural Research Council Letcombe Laboratory, OX12, 9JT, Wantage, UK
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