301
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Dayod M, Tyerman SD, Leigh RA, Gilliham M. Calcium storage in plants and the implications for calcium biofortification. PROTOPLASMA 2010. [PMID: 20658253 DOI: 10.1007/s00709-010-0182-180] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
Calcium (Ca) is an essential nutrient for plants and animals, with key structural and signalling roles, and its deficiency in plants can result in poor biotic and abiotic stress tolerance, reduced crop quality and yield. Likewise, low Ca intake in humans has been linked to various diseases (e.g. rickets, osteoporosis, hypertension and colorectal cancer) which can threaten quality of life and have major economic costs. Biofortification of various food crops with Ca has been suggested as a good method to enhance human intake of Ca and is advocated as an economically and environmentally advantageous strategy. Efforts to enhance Ca content of crops via transgenic means have had promising results. Overall Ca content of transgenic plants has been increased but in some cases adverse affects on plant function have been observed. This suggests that a better understanding of how Ca ions (Ca(2+)) are stored and transported through plants is required to maximise the effectiveness of future approaches.
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Affiliation(s)
- Maclin Dayod
- Waite Research Institute, School of Agriculture, Food and Wine, University of Adelaide, PMB1, Glen Osmond, SA 5064, Australia
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302
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Baxter I, Brazelton JN, Yu D, Huang YS, Lahner B, Yakubova E, Li Y, Bergelson J, Borevitz JO, Nordborg M, Vitek O, Salt DE. A coastal cline in sodium accumulation in Arabidopsis thaliana is driven by natural variation of the sodium transporter AtHKT1;1. PLoS Genet 2010; 6:e1001193. [PMID: 21085628 PMCID: PMC2978683 DOI: 10.1371/journal.pgen.1001193] [Citation(s) in RCA: 267] [Impact Index Per Article: 19.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2010] [Accepted: 10/01/2010] [Indexed: 01/26/2023] Open
Abstract
The genetic model plant Arabidopsis thaliana, like many plant species, experiences a range of edaphic conditions across its natural habitat. Such heterogeneity may drive local adaptation, though the molecular genetic basis remains elusive. Here, we describe a study in which we used genome-wide association mapping, genetic complementation, and gene expression studies to identify cis-regulatory expression level polymorphisms at the AtHKT1;1 locus, encoding a known sodium (Na(+)) transporter, as being a major factor controlling natural variation in leaf Na(+) accumulation capacity across the global A. thaliana population. A weak allele of AtHKT1;1 that drives elevated leaf Na(+) in this population has been previously linked to elevated salinity tolerance. Inspection of the geographical distribution of this allele revealed its significant enrichment in populations associated with the coast and saline soils in Europe. The fixation of this weak AtHKT1;1 allele in these populations is genetic evidence supporting local adaptation to these potentially saline impacted environments.
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Affiliation(s)
- Ivan Baxter
- United States Department of Agriculture–Agricultural Research Service, Plant Genetics Research Unit, Donald Danforth Plant Sciences Center, St. Louis, Missouri, United States of America
| | - Jessica N. Brazelton
- Department of Horticulture and Landscape Architecture, Purdue University, West Lafayette, Indiana, United States of America
| | - Danni Yu
- Department of Statistics, Purdue University, West Lafayette, Indiana, United States of America
| | - Yu S. Huang
- Molecular and Computational Biology, University of Southern California, Los Angeles, California, United States of America
| | - Brett Lahner
- Department of Horticulture and Landscape Architecture, Purdue University, West Lafayette, Indiana, United States of America
| | - Elena Yakubova
- Department of Horticulture and Landscape Architecture, Purdue University, West Lafayette, Indiana, United States of America
| | - Yan Li
- Department of Ecology and Evolution, University of Chicago, Chicago, Illinois, United States of America
| | - Joy Bergelson
- Department of Ecology and Evolution, University of Chicago, Chicago, Illinois, United States of America
| | - Justin O. Borevitz
- Department of Ecology and Evolution, University of Chicago, Chicago, Illinois, United States of America
| | - Magnus Nordborg
- Gregor Mendel Institute of Molecular Plant Biology, Austrian Academy of Sciences, Vienna, Austria
| | - Olga Vitek
- Department of Statistics, Purdue University, West Lafayette, Indiana, United States of America
| | - David E. Salt
- Department of Horticulture and Landscape Architecture, Purdue University, West Lafayette, Indiana, United States of America
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303
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Daldoul S, Guillaumie S, Reustle GM, Krczal G, Ghorbel A, Delrot S, Mliki A, Höfer MU. Isolation and expression analysis of salt induced genes from contrasting grapevine (Vitis vinifera L.) cultivars. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2010; 179:489-98. [PMID: 21802607 DOI: 10.1016/j.plantsci.2010.07.017] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2010] [Revised: 06/17/2010] [Accepted: 07/22/2010] [Indexed: 05/11/2023]
Abstract
Salt stress adversely affects the growth of grapevine plants. In order to understand the molecular basis of salt stress response in grapevine plants, suppression subtractive hybridization (SSH) and microarray based screening approaches were combined. Two leaf-specific subtractive cDNA libraries were constructed from grapevine plants subjected to a moderate, incremental salt stress treatment. SSH were performed 6h and 24h after NaCl peaked at 100mM using cDNAs prepared from leaves of a salt tolerant cultivar (Razegui) as testers and cDNAs from unstressed leaves as drivers. Then, a pre-screened subset of cDNA clones from these SSH libraries were used to construct a Vitis vinifera cDNA array, in order to verify the expression changes of the genes upon salt treatment. Expression profiles were compared between the salt tolerant and a susceptible cultivar (Syrah) under both control conditions and after salt stress treatment. Seven cDNA clones were identified which were up-regulated by salt stress in two independent growth experiments and confirmed by RNA blot analysis. The transcript expression patterns of the selected genes differed between the contrasting grapevine cultivars tested with respect to stress-regulation. The possible relationship of individual cDNAs with salinity tolerance mechanisms is discussed.
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Affiliation(s)
- Samia Daldoul
- Centre de Biotechnologie de Borj cédria, Laboratoire de Physiologie Moléculaire des Plantes, B.P.901, 2050 Hammam-Lif, Tunisia; RLP-Agroscience GmbH/Alplanta-Institute for Plant Research, Breitenweg 71, 67435 Neustadt and der Weinstraße, Germany.
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304
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Chen F, Chen L, Zhao H, Korpelainen H, Li C. Sex-specific responses and tolerances of Populus cathayana to salinity. PHYSIOLOGIA PLANTARUM 2010; 140:163-73. [PMID: 20561244 DOI: 10.1111/j.1399-3054.2010.01393.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Responses of males and females to salinity were studied in order to reveal sex-specific adaptation and evolution in Populus cathayana Rehd cuttings. This dioecious tree species plays an important role in maintaining ecological stability and providing commercial raw material in southwest China. Female and male cuttings of P. cathayana were treated for about 1 month with 0, 75 and 150 mM NaCl. Plant growth traits, gas exchange parameters, chlorophyll pigments, intrinsic water use efficiency (WUEi), membrane system injuries, ion transport and ultrastructural morphology were assessed and compared between sexes. Salt stress caused less negative effects on the dry matter accumulation, growth rate of height, growth rate of stem base diameter, total number of leaves and photosynthetic abilities in males than in females. Relative electrolyte leakage increased more in females than in males under salinity stress. Soil salinity reduced the amounts of leaf chlorophyll a, chlorophyll b and total chlorophyll, and the chlorophyll a/b ratio more in females than in males. WUEi decreased in both sexes under salinity. Regarding the ultrastructural morphology, thylakoid swelling in chloroplasts and degrading structures in mitochondria were more frequent in females than in males. Moreover, females exhibited significantly higher Na(+) and Cl(-) concentrations in leaves and stems, but lower concentrations in roots than did males under salinity. In all, female cuttings of P. cathayana are more sensitive to salinity stress than males, which could be partially due to males having a better ability to restrain Na(+) transport from roots to shoots than do females.
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Affiliation(s)
- Fugui Chen
- Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu, China
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305
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Plett D, Safwat G, Gilliham M, Skrumsager Møller I, Roy S, Shirley N, Jacobs A, Johnson A, Tester M. Improved salinity tolerance of rice through cell type-specific expression of AtHKT1;1. PLoS One 2010; 5:e12571. [PMID: 20838445 PMCID: PMC2933239 DOI: 10.1371/journal.pone.0012571] [Citation(s) in RCA: 89] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2010] [Accepted: 08/12/2010] [Indexed: 11/18/2022] Open
Abstract
Previously, cell type-specific expression of AtHKT1;1, a sodium transporter, improved sodium (Na(+)) exclusion and salinity tolerance in Arabidopsis. In the current work, AtHKT1;1, was expressed specifically in the root cortical and epidermal cells of an Arabidopsis GAL4-GFP enhancer trap line. These transgenic plants were found to have significantly improved Na(+) exclusion under conditions of salinity stress. The feasibility of a similar biotechnological approach in crop plants was explored using a GAL4-GFP enhancer trap rice line to drive expression of AtHKT1;1 specifically in the root cortex. Compared with the background GAL4-GFP line, the rice plants expressing AtHKT1;1 had a higher fresh weight under salinity stress, which was related to a lower concentration of Na(+) in the shoots. The root-to-shoot transport of (22)Na(+) was also decreased and was correlated with an upregulation of OsHKT1;5, the native transporter responsible for Na(+) retrieval from the transpiration stream. Interestingly, in the transgenic Arabidopsis plants overexpressing AtHKT1;1 in the cortex and epidermis, the native AtHKT1;1 gene responsible for Na(+) retrieval from the transpiration stream, was also upregulated. Extra Na(+) retrieved from the xylem was stored in the outer root cells and was correlated with a significant increase in expression of the vacuolar pyrophosphatases (in Arabidopsis and rice) the activity of which would be necessary to move the additional stored Na(+) into the vacuoles of these cells. This work presents an important step in the development of abiotic stress tolerance in crop plants via targeted changes in mineral transport.
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Affiliation(s)
- Darren Plett
- Australian Centre for Plant Functional Genomics, University of Adelaide, Glen Osmond, South Australia, Australia
- School of Agriculture, Food and Wine, Waite Research Institute, University of Adelaide, Glen Osmond, South Australia, Australia
| | - Gehan Safwat
- Australian Centre for Plant Functional Genomics, University of Adelaide, Glen Osmond, South Australia, Australia
- School of Agriculture, Food and Wine, Waite Research Institute, University of Adelaide, Glen Osmond, South Australia, Australia
| | - Matthew Gilliham
- School of Agriculture, Food and Wine, Waite Research Institute, University of Adelaide, Glen Osmond, South Australia, Australia
| | - Inge Skrumsager Møller
- Australian Centre for Plant Functional Genomics, University of Adelaide, Glen Osmond, South Australia, Australia
- School of Agriculture, Food and Wine, Waite Research Institute, University of Adelaide, Glen Osmond, South Australia, Australia
| | - Stuart Roy
- Australian Centre for Plant Functional Genomics, University of Adelaide, Glen Osmond, South Australia, Australia
- School of Agriculture, Food and Wine, Waite Research Institute, University of Adelaide, Glen Osmond, South Australia, Australia
| | - Neil Shirley
- Australian Centre for Plant Functional Genomics, University of Adelaide, Glen Osmond, South Australia, Australia
- School of Agriculture, Food and Wine, Waite Research Institute, University of Adelaide, Glen Osmond, South Australia, Australia
| | - Andrew Jacobs
- Australian Centre for Plant Functional Genomics, University of Adelaide, Glen Osmond, South Australia, Australia
- School of Agriculture, Food and Wine, Waite Research Institute, University of Adelaide, Glen Osmond, South Australia, Australia
| | - Alexander Johnson
- Australian Centre for Plant Functional Genomics, University of Adelaide, Glen Osmond, South Australia, Australia
- School of Agriculture, Food and Wine, Waite Research Institute, University of Adelaide, Glen Osmond, South Australia, Australia
| | - Mark Tester
- Australian Centre for Plant Functional Genomics, University of Adelaide, Glen Osmond, South Australia, Australia
- School of Agriculture, Food and Wine, Waite Research Institute, University of Adelaide, Glen Osmond, South Australia, Australia
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306
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Li Q, Li BH, Kronzucker HJ, Shi WM. Root growth inhibition by NH(4)(+) in Arabidopsis is mediated by the root tip and is linked to NH(4)(+) efflux and GMPase activity. PLANT, CELL & ENVIRONMENT 2010; 33:272-89. [PMID: 20444215 DOI: 10.1111/j.1365-3040.2009.02080.x] [Citation(s) in RCA: 85] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Root growth in higher plants is sensitive to excess ammonium (NH(4)(+)). Our study shows that contact of NH(4)(+) with the primary root tip is both necessary and sufficient to the development of arrested root growth under NH(4)(+) nutrition in Arabidopsis. We show that cell elongation and not cell division is the principal target in the NH(4)(+) inhibition of primary root growth. Mutant and expression analyses using DR5:GUS revealed that the growth inhibition is furthermore independent of auxin and ethylene signalling. NH(4)(+) fluxes along the primary root, measured using the Scanning Ion-selective Electrode Technique, revealed a significant stimulation of NH(4)(+) efflux at the elongation zone following treatment with elevated NH(4)(+), coincident with the inhibition of root elongation. Stimulation of NH(4)(+) efflux and inhibition of cell expansion were significantly more pronounced in the NH(4)(+)-hypersensitive mutant vtc1-1, deficient in the enzyme GDP-mannose pyrophosphorylase (GMPase). We conclude that both restricted transmembrane NH(4)(+) fluxes and proper functioning of GMPase in roots are critical to minimizing the severity of the NH(4)(+) toxicity response in Arabidopsis.
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Affiliation(s)
- Qing Li
- Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China
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307
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Conn S, Gilliham M. Comparative physiology of elemental distributions in plants. ANNALS OF BOTANY 2010; 105:1081-102. [PMID: 20410048 PMCID: PMC2887064 DOI: 10.1093/aob/mcq027] [Citation(s) in RCA: 182] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2009] [Revised: 11/16/2009] [Accepted: 12/16/2009] [Indexed: 05/18/2023]
Abstract
BACKGROUND Plants contain relatively few cell types, each contributing a specialized role in shaping plant function. With respect to plant nutrition, different cell types accumulate certain elements in varying amounts within their storage vacuole. The role and mechanisms underlying cell-specific distribution of elements in plants is poorly understood. SCOPE The phenomenon of cell-specific elemental accumulation has been briefly reviewed previously, but recent technological advances with the potential to probe mechanisms underlying elemental compartmentation have warranted an updated evaluation. We have taken this opportunity to catalogue many of the studies, and techniques used for, recording cell-specific compartmentation of particular elements. More importantly, we use three case-study elements (Ca, Cd and Na) to highlight the basis of such phenomena in terms of their physiological implications and underpinning mechanisms; we also link such distributions to the expression of known ion or solute transporters. CONCLUSIONS Element accumulation patterns are clearly defined by expression of key ion or solute transporters. Although the location of element accumulation is fairly robust, alterations in expression of certain solute transporters, through genetic modifications or by growth under stress, result in perturbations to these patterns. However, redundancy or induced pleiotropic expression effects may complicate attempts to characterize the pathways that lead to cell-specific elemental distribution. Accumulation of one element often has consequences on the accumulation of others, which seems to be driven largely to maintain vacuolar and cytoplasmic osmolarity and charge balance, and also serves as a detoxification mechanism. Altered cell-specific transcriptomics can be shown, in part, to explain some of this compensation.
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Affiliation(s)
- Simon Conn
- School of Agriculture, Food, and Wine, University of Adelaide, Waite Campus, Glen Osmond, South Australia 5064, Australia
| | - Matthew Gilliham
- School of Agriculture, Food, and Wine, University of Adelaide, Waite Campus, Glen Osmond, South Australia 5064, Australia
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308
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Wee CW, Dinneny JR. Tools for high-spatial and temporal-resolution analysis of environmental responses in plants. Biotechnol Lett 2010; 32:1361-71. [PMID: 20502944 DOI: 10.1007/s10529-010-0307-8] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2010] [Accepted: 05/10/2010] [Indexed: 01/09/2023]
Abstract
Understanding how plants cope with environmental change requires a spatiotemporal perspective. In this review, we highlight recent work which has led to the development and use of novel tools for the high spatial and temporal-resolution analysis of the plant-environment interaction. FACS-based transcriptome and immunoprecipitation-based translatome data sets have provided an important foundation for the analysis of the transcriptional and translational control of environmental responses in each tissue layer of the plant. Complementary approaches, based on a proteomic toolkit, have provided insight into the biological response of Arabidopsis to NaCl and the relationship between transcript and protein levels. The development and adaptation of biosensors and ion-specific dyes provides the capacity to visualize changes in the transport and accumulation of metabolites and small molecules such as sugars, Na(+) and Ca(2+) at the cellular level. Finally, live-imaging approaches coupled with automated image-analysis algorithms are revealing new levels of dynamism and plasticity in the response to light and gravity. Together, these tools will provide a more comprehensive understanding of environmental responses in plants, which will aide in the development of new crop varieties for sustainable agriculture.
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Affiliation(s)
- Choon W Wee
- Temasek Lifesciences Laboratory, National University of Singapore, 1 Research Link, Singapore, 117604, Republic of Singapore
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309
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Jha D, Shirley N, Tester M, Roy SJ. Variation in salinity tolerance and shoot sodium accumulation in Arabidopsis ecotypes linked to differences in the natural expression levels of transporters involved in sodium transport. PLANT, CELL & ENVIRONMENT 2010; 33:793-804. [PMID: 20040066 DOI: 10.1111/j.1365-3040.2009.02105.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
Salinity tolerance can be attributed to three different mechanisms: Na+ exclusion from the shoot, Na+ tissue tolerance and osmotic tolerance. Although several key ion channels and transporters involved in these processes are known, the variation in expression profiles and the effects of these proteins on Na+ transport in different accessions of the same species are unknown. Here, expression profiles of the genes AtHKT1;1, AtSOS1, AtNHX1 and AtAVP1 are determined in four ecotypes of Arabidopsis thaliana. Not only are these genes differentially regulated between ecotypes, the expression levels of the genes can be linked to the concentration of Na+ in the plant. An inverse relationship was found between AtSOS1 expression in the root and total plant Na+ accumulation, supporting a role for AtSOS1 in Na+ efflux from the plant. Similarly, ecotypes with high expression levels of AtHKT1;1 in the root had lower shoot Na+ concentrations, due to the hypothesized role of AtHKT1;1 in retrieval of Na+ from the transpiration stream. The inverse relationship between shoot Na+ concentration and salinity tolerance typical of most cereal crop plants was not demonstrated, but a positive relationship was found between salt tolerance and levels of AtAVP1 expression, which may be related to tissue tolerance.
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Affiliation(s)
- D Jha
- The Australian Centre for Plant Functional Genomics and the University of Adelaide, PMB1, Glen Osmond, SA 5064, Australia
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310
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Li JY, Fu YL, Pike SM, Bao J, Tian W, Zhang Y, Chen CZ, Zhang Y, Li HM, Huang J, Li LG, Schroeder JI, Gassmann W, Gong JM. The Arabidopsis nitrate transporter NRT1.8 functions in nitrate removal from the xylem sap and mediates cadmium tolerance. THE PLANT CELL 2010; 22:1633-46. [PMID: 20501909 PMCID: PMC2899866 DOI: 10.1105/tpc.110.075242] [Citation(s) in RCA: 274] [Impact Index Per Article: 19.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2010] [Revised: 04/26/2010] [Accepted: 05/10/2010] [Indexed: 05/18/2023]
Abstract
Long-distance transport of nitrate requires xylem loading and unloading, a successive process that determines nitrate distribution and subsequent assimilation efficiency. Here, we report the functional characterization of NRT1.8, a member of the nitrate transporter (NRT1) family in Arabidopsis thaliana. NRT1.8 is upregulated by nitrate. Histochemical analysis using promoter-beta-glucuronidase fusions, as well as in situ hybridization, showed that NRT1.8 is expressed predominantly in xylem parenchyma cells within the vasculature. Transient expression of the NRT1.8:enhanced green fluorescent protein fusion in onion epidermal cells and Arabidopsis protoplasts indicated that NRT1.8 is plasma membrane localized. Electrophysiological and nitrate uptake analyses using Xenopus laevis oocytes showed that NRT1.8 mediates low-affinity nitrate uptake. Functional disruption of NRT1.8 significantly increased the nitrate concentration in xylem sap. These data together suggest that NRT1.8 functions to remove nitrate from xylem vessels. Interestingly, NRT1.8 was the only nitrate assimilatory pathway gene that was strongly upregulated by cadmium (Cd(2+)) stress in roots, and the nrt1.8-1 mutant showed a nitrate-dependent Cd(2+)-sensitive phenotype. Further analyses showed that Cd(2+) stress increases the proportion of nitrate allocated to wild-type roots compared with the nrt1.8-1 mutant. These data suggest that NRT1.8-regulated nitrate distribution plays an important role in Cd(2+) tolerance.
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Affiliation(s)
- Jian-Yong Li
- National Key Laboratory of Plant Molecular Genetics, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, People's Republic of China
| | - Yan-Lei Fu
- National Key Laboratory of Plant Molecular Genetics, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, People's Republic of China
| | - Sharon M. Pike
- Division of Plant Sciences, C.S. Bond Life Sciences Center and Interdisciplinary Plant Group, University of Missouri, Columbia, Missouri 65211-7310
| | - Juan Bao
- National Key Laboratory of Plant Molecular Genetics, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, People's Republic of China
| | - Wang Tian
- College of Life Sciences, Capital Normal University, Beijing 100037, People's Republic of China
| | - Yu Zhang
- National Key Laboratory of Plant Molecular Genetics, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, People's Republic of China
| | - Chun-Zhu Chen
- National Key Laboratory of Plant Molecular Genetics, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, People's Republic of China
| | - Yi Zhang
- National Key Laboratory of Plant Molecular Genetics, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, People's Republic of China
| | - Hong-Mei Li
- National Key Laboratory of Plant Molecular Genetics, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, People's Republic of China
| | - Jing Huang
- National Key Laboratory of Plant Molecular Genetics, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, People's Republic of China
| | - Le-Gong Li
- College of Life Sciences, Capital Normal University, Beijing 100037, People's Republic of China
| | - Julian I. Schroeder
- Division of Biological Sciences and Center for Molecular Genetics, Cell and Developmental Biology Section, University of California, San Diego, California 92093-0116
| | - Walter Gassmann
- Division of Plant Sciences, C.S. Bond Life Sciences Center and Interdisciplinary Plant Group, University of Missouri, Columbia, Missouri 65211-7310
| | - Ji-Ming Gong
- National Key Laboratory of Plant Molecular Genetics, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, People's Republic of China
- Address correspondence to
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311
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Pardo JM. Biotechnology of water and salinity stress tolerance. Curr Opin Biotechnol 2010; 21:185-96. [DOI: 10.1016/j.copbio.2010.02.005] [Citation(s) in RCA: 103] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2010] [Revised: 02/02/2010] [Accepted: 02/02/2010] [Indexed: 12/20/2022]
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312
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Hauser F, Horie T. A conserved primary salt tolerance mechanism mediated by HKT transporters: a mechanism for sodium exclusion and maintenance of high K(+)/Na(+) ratio in leaves during salinity stress. PLANT, CELL & ENVIRONMENT 2010; 33:552-65. [PMID: 19895406 DOI: 10.1111/j.1365-3040.2009.02056.x] [Citation(s) in RCA: 263] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Increasing soil salinity is a serious threat to agricultural productions worldwide in the 21st century. Several essential Na(+) transporters such as AtNHX1 and AtSOS1 function in Na(+) tolerance under salinity stress in plants. Recently, evidence for a new primary salt tolerance mechanism has been reported, which is mediated by a class of HKT transporters both in dicots such as Arabidopsis and monocot crops such as rice and wheat. Here we present a review on vital physiological functions of HKT transporters including AtHKT1;1 and OsHKT1;5 in preventing shoot Na(+) over-accumulation by mediating Na(+) exclusion from xylem vessels in the presence of a large amount of Na(+) thereby protecting leaves from salinity stress. Findings of the HKT2 transporter sub-family are also updated in this review. Subjects regarding function and regulation of HKT transporters, which need to be elucidated in future research, are discussed.
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Affiliation(s)
- Felix Hauser
- Center for Molecular Genetics, University of California, San Diego, La Jolla, 92093-0116, USA
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313
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Tester M, Langridge P. Breeding technologies to increase crop production in a changing world. Science 2010; 327:818-22. [PMID: 20150489 DOI: 10.1126/science.1183700] [Citation(s) in RCA: 852] [Impact Index Per Article: 60.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
To feed the several billion people living on this planet, the production of high-quality food must increase with reduced inputs, but this accomplishment will be particularly challenging in the face of global environmental change. Plant breeders need to focus on traits with the greatest potential to increase yield. Hence, new technologies must be developed to accelerate breeding through improving genotyping and phenotyping methods and by increasing the available genetic diversity in breeding germplasm. The most gain will come from delivering these technologies in developing countries, but the technologies will have to be economically accessible and readily disseminated. Crop improvement through breeding brings immense value relative to investment and offers an effective approach to improving food security.
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Affiliation(s)
- Mark Tester
- Australian Centre for Plant Functional Genomics, University of Adelaide, South Australia SA 5064, Australia.
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314
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Katori T, Ikeda A, Iuchi S, Kobayashi M, Shinozaki K, Maehashi K, Sakata Y, Tanaka S, Taji T. Dissecting the genetic control of natural variation in salt tolerance of Arabidopsis thaliana accessions. JOURNAL OF EXPERIMENTAL BOTANY 2010; 61:1125-38. [PMID: 20080827 PMCID: PMC2826654 DOI: 10.1093/jxb/erp376] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Many accessions (ecotypes) of Arabidopsis have been collected. Although few differences exist among their nucleotide sequences, these subtle differences induce large genetic variation in phenotypic traits such as stress tolerance and flowering time. To understand the natural variability in salt tolerance, large-scale soil pot experiments were performed to evaluate salt tolerance among 350 Arabidopsis thaliana accessions. The evaluation revealed a wide variation in the salt tolerance among accessions. Several accessions, including Bu-5, Bur-0, Ll-1, Wl-0, and Zu-0, exhibited marked stress tolerance compared with a salt-sensitive experimental accession, Col-0. The salt-tolerant accessions were also evaluated by agar plate assays. The data obtained by the large-scale assay correlated well with the results of a salt acclimation (SA) assay, in which plants were transferred to high-salinity medium following placement on moderate-salinity medium for 7 d. Genetic analyses indicated that the salt tolerance without SA is a quantitative trait under polygenic control, whereas salt tolerance with SA is regulated by a single gene located on chromosome 5 that is common among the markedly salt-tolerant accessions. These results provide important information for understanding the mechanisms underlying natural variation of salt tolerance in Arabidopsis.
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Affiliation(s)
- Taku Katori
- Department of Bioscience, Tokyo University of Agriculture, 1-1-1 Sakuragaoka, Setagaya, Tokyo 156-8502, Japan
| | - Akiro Ikeda
- Department of Bioscience, Tokyo University of Agriculture, 1-1-1 Sakuragaoka, Setagaya, Tokyo 156-8502, Japan
| | - Satoshi Iuchi
- RIKEN Bioresource Center, 3-1-1 Koyadai, Tsukuba, Ibaraki 305-0074, Japan
| | - Masatomo Kobayashi
- RIKEN Bioresource Center, 3-1-1 Koyadai, Tsukuba, Ibaraki 305-0074, Japan
| | - Kazuo Shinozaki
- RIKEN Yokohama Institute, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama 230-0045, Japan
| | - Kenji Maehashi
- Department of Fermentation Science, Tokyo University of Agriculture, 1-1-1 Sakuragaoka, Setagaya, Tokyo 156-8502, Japan
| | - Yoichi Sakata
- Department of Bioscience, Tokyo University of Agriculture, 1-1-1 Sakuragaoka, Setagaya, Tokyo 156-8502, Japan
| | - Shigeo Tanaka
- Department of Bioscience, Tokyo University of Agriculture, 1-1-1 Sakuragaoka, Setagaya, Tokyo 156-8502, Japan
| | - Teruaki Taji
- Department of Bioscience, Tokyo University of Agriculture, 1-1-1 Sakuragaoka, Setagaya, Tokyo 156-8502, Japan
- To whom correspondence should be addressed. E-mail:
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315
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Abstract
There is an intrinsic link between the challenge we face to ensure food security through the twenty-first century and other global issues, most notably climate change, population growth and the need to sustainably manage the world's rapidly growing demand for energy and water. Our progress in reducing global poverty and achieving the Millennium Development Goals will be determined to a great extent by how coherently these long-term challenges are tackled. A key question is whether we can feed a future nine billion people equitably, healthily and sustainably. Science and technology can make a major contribution, by providing practical solutions. Securing this contribution requires that high priority be attached both to research and to facilitating the real world deployment of existing and emergent technologies. Put simply, we need a new, 'greener revolution'. Important areas for focus include: crop improvement; smarter use of water and fertilizers; new pesticides and their effective management to avoid resistance problems; introduction of novel non-chemical approaches to crop protection; reduction of post-harvest losses; and more sustainable livestock and marine production. Techniques and technologies from many disciplines, ranging from biotechnology and engineering to newer fields such as nanotechnology, will be needed.
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316
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Yao X, Horie T, Xue S, Leung HY, Katsuhara M, Brodsky DE, Wu Y, Schroeder JI. Differential sodium and potassium transport selectivities of the rice OsHKT2;1 and OsHKT2;2 transporters in plant cells. PLANT PHYSIOLOGY 2010; 152:341-55. [PMID: 19889878 PMCID: PMC2799368 DOI: 10.1104/pp.109.145722] [Citation(s) in RCA: 95] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2009] [Accepted: 10/26/2009] [Indexed: 05/18/2023]
Abstract
Na(+) and K(+) homeostasis are crucial for plant growth and development. Two HKT transporter/channel classes have been characterized that mediate either Na(+) transport or Na(+) and K(+) transport when expressed in Xenopus laevis oocytes and yeast. However, the Na(+)/K(+) selectivities of the K(+)-permeable HKT transporters have not yet been studied in plant cells. One study expressing 5' untranslated region-modified HKT constructs in yeast has questioned the relevance of cation selectivities found in heterologous systems for selectivity predictions in plant cells. Therefore, here we analyze two highly homologous rice (Oryza sativa) HKT transporters in plant cells, OsHKT2;1 and OsHKT2;2, that show differential K(+) permeabilities in heterologous systems. Upon stable expression in cultured tobacco (Nicotiana tabacum) Bright-Yellow 2 cells, OsHKT2;1 mediated Na(+) uptake, but little Rb(+) uptake, consistent with earlier studies and new findings presented here in oocytes. In contrast, OsHKT2;2 mediated Na(+)-K(+) cotransport in plant cells such that extracellular K(+) stimulated OsHKT2;2-mediated Na(+) influx and vice versa. Furthermore, at millimolar Na(+) concentrations, OsHKT2;2 mediated Na(+) influx into plant cells without adding extracellular K(+). This study shows that the Na(+)/K(+) selectivities of these HKT transporters in plant cells coincide closely with the selectivities in oocytes and yeast. In addition, the presence of external K(+) and Ca(2+) down-regulated OsHKT2;1-mediated Na(+) influx in two plant systems, Bright-Yellow 2 cells and intact rice roots, and also in Xenopus oocytes. Moreover, OsHKT transporter selectivities in plant cells are shown to depend on the imposed cationic conditions, supporting the model that HKT transporters are multi-ion pores.
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Affiliation(s)
| | | | | | | | | | | | | | - Julian I. Schroeder
- Division of Biological Sciences, Cell and Developmental Biology Section, and Center for Molecular Genetics, University of California, San Diego, La Jolla, California 92093–0116 (X.Y., T.H., S.X., H.-Y.L., D.E.B., J.I.S.); Key Laboratory of Ministry of Education for Plant Developmental Biology, College of Life Sciences, Wuhan University, Wuhan, Hubei 430072, China (X.Y., Y.W.); and Group of Molecular and Functional Plant Biology, Research Institute for Bioresources, Okayama University, Kurashiki, Okayama 710–0046, Japan (T.H., M.K.)
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317
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Horie T, Hauser F, Schroeder JI. HKT transporter-mediated salinity resistance mechanisms in Arabidopsis and monocot crop plants. TRENDS IN PLANT SCIENCE 2009; 14:660-8. [PMID: 19783197 PMCID: PMC2787891 DOI: 10.1016/j.tplants.2009.08.009] [Citation(s) in RCA: 273] [Impact Index Per Article: 18.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/30/2009] [Revised: 08/04/2009] [Accepted: 08/17/2009] [Indexed: 05/17/2023]
Abstract
The salinization of irrigated lands is increasingly detrimental to plant biomass production and agricultural productivity, as most plant species are sensitive to high concentrations of sodium (Na(+)), which causes combined Na(+) toxicity and osmotic stress. Plants have multiple Na(+)-transport systems to circumvent Na(+) toxicity. Essential physiological functions of major Na(+) transporters and their mechanisms mediating salinity resistance have been identified in Arabidopsis , including the AtSOS1, AtNHX and AtHKT1;1 transporters. As we discuss here, recent studies have demonstrated that a class of xylem-parenchyma-expressed Na(+)-permeable plant HKT transporters represent a primary mechanism mediating salt tolerance and Na(+) exclusion from leaves in Arabidopsis, and that major salt-tolerance quantitative trait loci in monocot crop plants are also based on this HKT-mediated mechanism.
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Affiliation(s)
- Tomoaki Horie
- Group of Molecular and Functional Plant Biology, Research Institute for Bioresources, Okayama University, Kurashiki, Okayama 710-0046, Japan.
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318
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Li B, Li N, Duan X, Wei A, Yang A, Zhang J. Generation of marker-free transgenic maize with improved salt tolerance using the FLP/FRT recombination system. J Biotechnol 2009; 145:206-13. [PMID: 19932138 DOI: 10.1016/j.jbiotec.2009.11.010] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2009] [Revised: 10/13/2009] [Accepted: 11/12/2009] [Indexed: 01/31/2023]
Abstract
The possible release of selectable marker genes from genetically modified transgenic plants, or of gut microbes, to the environment, has raised worldwide public concerns. In this study, we showed the generation of marker-free transgenic maize plants constitutively expressing AtNHX1, a Na(+)/H(+) antiporter gene from Arabidopsis that conferred salt tolerance on plants, using the FLP/FRT site-specific recombination system. Transgenic plant expressing a modified FLP recombinase gene was crossed with transgenic plant harboring AtNHX1 and mutant als, a selectable marker gene flanked by two directed FRT sites. The sexual crossing led to precise and complete excision of the FRT-surrounded als marker gene in the F1 progenies. Further salt tolerance examinations indicated that marker-free AtNHX1 transgenic plants accumulated more Na(+) and K(+), and produced greater biomass and yields than did the wild-type plants when grown in high saline fields. These results demonstrate the feasibility of using this FLP/FRT-based marker elimination system to generate marker-free transgenic important cereal crops with improved salt tolerance.
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Affiliation(s)
- Bei Li
- School of Life Science, Shandong University, 27 Shanda South Road, Jinan 250100, PR China
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319
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Farquharson KL. Targeted overexpression of a sodium transporter in the root stele increases salinity tolerance. THE PLANT CELL 2009; 21:1875. [PMID: 19602620 PMCID: PMC2729610 DOI: 10.1105/tpc.109.210710] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
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