251
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Bao AK, Wang YW, Xi JJ, Liu C, Zhang JL, Wang SM. Co-expression of xerophyte Zygophyllum xanthoxylum ZxNHX and ZxVP1-1 enhances salt and drought tolerance in transgenic Lotus corniculatus by increasing cations accumulation. FUNCTIONAL PLANT BIOLOGY : FPB 2014; 41:203-214. [PMID: 32480979 DOI: 10.1071/fp13106] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2013] [Accepted: 08/15/2013] [Indexed: 05/20/2023]
Abstract
Lotus corniculatus L. is an important legume for forage, but is sensitive to salinity and drought. To develop salt- and drought-resistant L. corniculatus, ZxNHX and ZxVP1-1 genes encoding tonoplast Na+/H+ antiporter and H+-pyrophosphatase (H+-PPase) from a succulent xerophyte Zygophyllum xanthoxylum L., which is well adapted to arid environments through accumulating Na+ in its leaves, were transferred into this forage. We obtained the transgenic lines co-expressing ZxNHX and ZxVP1-1 genes (VX) as well as expressing ZxVP1-1 gene alone (VP). Compared with wild-type, both VX and VP transgenic lines grew better at 200mM NaCl, and also exhibited higher tolerance and faster recovery from water-deficit stress: these performances were associated with more Na+, K+ and Ca2+ accumulation in their leaves and roots, which caused lower leaf solute potential and thus retained more water. Moreover, the transgenic lines maintained lower relative membrane permeability and higher net photosynthesis rate under salt or water-deficit stress. These results indicate that expression of tonoplast Na+/H+ antiporter and H+-PPase genes from xerophyte enhanced salt and drought tolerance of L. corniculatus. Furthermore, compared with VP, VX showed higher shoot biomass, more cations accumulation, higher water retention, lesser cell membrane damage and higher photosynthesis capacity under salt or water-deficit condition, suggesting that co-expression of ZxVP1-1 and ZxNHX confers even greater performance to transgenic L. corniculatus than expression of the single ZxVP1-1.
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Affiliation(s)
- Ai-Ke Bao
- State Key Laboratory of Grassland Agro-ecosystems, College of Pastoral Agriculture Science and Technology, Lanzhou University, Lanzhou 730020, PR China
| | - Yan-Wen Wang
- State Key Laboratory of Grassland Agro-ecosystems, College of Pastoral Agriculture Science and Technology, Lanzhou University, Lanzhou 730020, PR China
| | - Jie-Jun Xi
- State Key Laboratory of Grassland Agro-ecosystems, College of Pastoral Agriculture Science and Technology, Lanzhou University, Lanzhou 730020, PR China
| | - Chen Liu
- State Key Laboratory of Grassland Agro-ecosystems, College of Pastoral Agriculture Science and Technology, Lanzhou University, Lanzhou 730020, PR China
| | - Jin-Lin Zhang
- State Key Laboratory of Grassland Agro-ecosystems, College of Pastoral Agriculture Science and Technology, Lanzhou University, Lanzhou 730020, PR China
| | - Suo-Min Wang
- State Key Laboratory of Grassland Agro-ecosystems, College of Pastoral Agriculture Science and Technology, Lanzhou University, Lanzhou 730020, PR China
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252
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Cloning and characterization of Na+/H+ antiporter (LfNHX1) gene from a halophyte grass Leptochloa fusca for drought and salt tolerance. Mol Biol Rep 2014; 41:1669-82. [PMID: 24420850 DOI: 10.1007/s11033-013-3015-3] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2013] [Accepted: 12/30/2013] [Indexed: 10/25/2022]
Abstract
Abiotic stresses such as salinity and drought have adverse effects on plants. In the present study, a Na(+)/H(+) antiporter gene homologue (LfNHX1) has been cloned from a local halophyte grass (Leptochloa fusca). The LfNHX1 cDNA contains an open reading frame of 1,623 bp that encodes a polypeptide chain of 540 amino acid residues. LfNHX1 protein sequence showed high similarity with NHX1 homologs reported from other halophyte plants. Amino acid and nucleotide sequence similarity, protein topology modeling and the presence of conserved functional domains in the LfNHX1 protein sequence classified it as a vacuolar NHX1 homolog. The overexpression of LfNHX1 gene under CaMV35S promoter conferred salt and drought tolerance in tobacco plants. Under drought stress, transgenic plants showed higher relative water contents, photosynthetic rate, stomatal conductance and membrane stability index as compared to wild type plants. More negative value of leaf osmotic potential was also observed in transgenic plants when compared with wild type control plants. Transgenic plants showed better germination and root growth at 2 mg L(-1) Basta herbicide and three levels (100, 200 and 250 mM) of sodium chloride. These results showed that LfNHX1 is a potential candidate gene for enhancing drought and salt tolerance in crops.
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253
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Faraco M, Spelt C, Bliek M, Verweij W, Hoshino A, Espen L, Prinsi B, Jaarsma R, Tarhan E, de Boer AH, Di Sansebastiano GP, Koes R, Quattrocchio FM. Hyperacidification of vacuoles by the combined action of two different P-ATPases in the tonoplast determines flower color. Cell Rep 2014; 6:32-43. [PMID: 24388746 DOI: 10.1016/j.celrep.2013.12.009] [Citation(s) in RCA: 89] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2013] [Revised: 10/14/2013] [Accepted: 12/04/2013] [Indexed: 10/25/2022] Open
Abstract
The acidification of endomembrane compartments is essential for enzyme activities, sorting, trafficking, and trans-membrane transport of various compounds. Vacuoles are mildly acidic in most plant cells because of the action of V-ATPase and/or pyrophosphatase proton pumps but are hyperacidified in specific cells by mechanisms that remained unclear. Here, we show that the blue petal color of petunia ph mutants is due to a failure to hyperacidify vacuoles. We report that PH1 encodes a P3B-ATPase, hitherto known as Mg2(+) transporters in bacteria only, that resides in the vacuolar membrane (tonoplast). In vivo nuclear magnetic resonance and genetic data show that PH1 is required and, together with the tonoplast H(+) P3A-ATPase PH5, sufficient to hyperacidify vacuoles. PH1 has no H(+) transport activity on its own but can physically interact with PH5 and boost PH5 H(+) transport activity. Hence, the hyperacidification of vacuoles in petals, and possibly other tissues, relies on a heteromeric P-ATPase pump.
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Affiliation(s)
- Marianna Faraco
- Department of Molecular Cell Biology, Graduate School of Experimental Plant Sciences, VU University, De Boelelaan 1085, 1081HV Amsterdam, the Netherlands
| | - Cornelis Spelt
- Department of Molecular Cell Biology, Graduate School of Experimental Plant Sciences, VU University, De Boelelaan 1085, 1081HV Amsterdam, the Netherlands
| | - Mattijs Bliek
- Department of Molecular Cell Biology, Graduate School of Experimental Plant Sciences, VU University, De Boelelaan 1085, 1081HV Amsterdam, the Netherlands
| | - Walter Verweij
- Department of Molecular Cell Biology, Graduate School of Experimental Plant Sciences, VU University, De Boelelaan 1085, 1081HV Amsterdam, the Netherlands
| | - Atsushi Hoshino
- Department of Molecular Cell Biology, Graduate School of Experimental Plant Sciences, VU University, De Boelelaan 1085, 1081HV Amsterdam, the Netherlands; National Institute for Basic Biology, Nishigonaka 38, Myodaiji, Okazaki, 444-8585 Aichi, Japan; Department of Basic Biology, The Graduate University for Advanced Studies (Sokendai), 444-8585 Okazaki, Japan
| | - Luca Espen
- Dipartimento Scienze Agrarie e Ambientali, Produzione, Territorio, Agroenergia, Università degli Studi di Milano, Via G. Celoria 2, 20133 Milano, Italy
| | - Bhakti Prinsi
- Dipartimento Scienze Agrarie e Ambientali, Produzione, Territorio, Agroenergia, Università degli Studi di Milano, Via G. Celoria 2, 20133 Milano, Italy
| | - Rinse Jaarsma
- Department of Molecular Cell Biology, Graduate School of Experimental Plant Sciences, VU University, De Boelelaan 1085, 1081HV Amsterdam, the Netherlands
| | - Eray Tarhan
- Department of Molecular Cell Biology, Graduate School of Experimental Plant Sciences, VU University, De Boelelaan 1085, 1081HV Amsterdam, the Netherlands
| | - Albertus H de Boer
- Department of Molecular Cell Biology, Graduate School of Experimental Plant Sciences, VU University, De Boelelaan 1085, 1081HV Amsterdam, the Netherlands
| | | | - Ronald Koes
- Department of Molecular Cell Biology, Graduate School of Experimental Plant Sciences, VU University, De Boelelaan 1085, 1081HV Amsterdam, the Netherlands.
| | - Francesca M Quattrocchio
- Department of Molecular Cell Biology, Graduate School of Experimental Plant Sciences, VU University, De Boelelaan 1085, 1081HV Amsterdam, the Netherlands.
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254
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Huertas R, Rubio L, Cagnac O, García-Sánchez MJ, Alché JDD, Venema K, Fernández JA, Rodríguez-Rosales MP. The K+/H+ antiporter LeNHX2 increases salt tolerance by improving K+ homeostasis in transgenic tomato. PLANT, CELL & ENVIRONMENT 2013; 36:2135-49. [PMID: 23550888 DOI: 10.1111/pce.12109] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2012] [Revised: 03/22/2013] [Accepted: 03/25/2013] [Indexed: 05/18/2023]
Abstract
The endosomal LeNHX2 ion transporter exchanges H(+) with K(+) and, to lesser extent, Na(+) . Here, we investigated the response to NaCl supply and K(+) deprivation in transgenic tomato (Solanum lycopersicum L.) overexpressing LeNHX2 and show that transformed tomato plants grew better in saline conditions than untransformed controls, whereas in the absence of K(+) the opposite was found. Analysis of mineral composition showed a higher K(+) content in roots, shoots and xylem sap of transgenic plants and no differences in Na(+) content between transgenic and untransformed plants grown either in the presence or the absence of 120 mm NaCl. Transgenic plants showed higher Na(+)/H(+) and, above all, K(+)/H(+) transport activity in root intracellular membrane vesicles. Under K(+) limiting conditions, transgenic plants enhanced root expression of the high-affinity K(+) uptake system HAK5 compared to untransformed controls. Furthermore, tomato overexpressing LeNHX2 showed twofold higher K(+) depletion rates and half cytosolic K(+) activity than untransformed controls. Under NaCl stress, transgenic plants showed higher uptake velocity for K(+) and lower cytosolic K(+) activity than untransformed plants. These results indicate the fundamental role of K(+) homeostasis in the better performance of LeNHX2 overexpressing tomato under NaCl stress.
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Affiliation(s)
- Raúl Huertas
- Departamento de Bioquímica, Biología Celular y Molecular de Plantas, Estación Experimental del Zaidín, CSIC, Calle Profesor Albareda, 1, 18008, Granada, Spain
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255
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Zheng S, Pan T, Fan L, Qiu QS. A novel AtKEA gene family, homolog of bacterial K+/H+ antiporters, plays potential roles in K+ homeostasis and osmotic adjustment in Arabidopsis. PLoS One 2013; 8:e81463. [PMID: 24278440 PMCID: PMC3835744 DOI: 10.1371/journal.pone.0081463] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2013] [Accepted: 10/13/2013] [Indexed: 12/28/2022] Open
Abstract
AtKEAs, homologs of bacterial KefB/KefC, are predicted to encode K+/H+ antiporters in Arabidopsis. The AtKEA family contains six genes forming two subgroups in the cladogram: AtKEA1-3 and AtKEA4-6. AtKEA1 and AtKEA2 have a long N-terminal domain; the full-length AtKEA1 was inactive in yeast. The transport activity was analyzed by expressing the AtKEA genes in yeast mutants lacking multiple ion carriers. AtKEAs conferred resistance to high K+ and hygromycin B but not to salt and Li+ stress. AtKEAs expressed in both the shoot and root of Arabidopsis. The expression of AtKEA1, -3 and -4 was enhanced under low K+ stress, whereas AtKEA2 and AtKEA5 were induced by sorbitol and ABA treatments. However, osmotic induction of AtKEA2 and AtKEA5 was not observed in aba2-3 mutants, suggesting an ABA regulated mechanism for their osmotic response. AtKEAs’ expression may not be regulated by the SOS pathway since their expression was not affected in sos mutants. The GFP tagging analysis showed that AtKEAs distributed diversely in yeast. The Golgi localization of AtKEA3 was demonstrated by both the stably transformed seedlings and the transient expression in protoplasts. Overall, AtKEAs expressed and localized diversely, and may play roles in K+ homeostasis and osmotic adjustment in Arabidopsis.
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Affiliation(s)
- Sheng Zheng
- MOE Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, Gansu, China
| | - Ting Pan
- MOE Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, Gansu, China
| | - Ligang Fan
- MOE Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, Gansu, China
| | - Quan-Sheng Qiu
- MOE Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, Gansu, China
- *
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256
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Xu Y, Zhou Y, Hong S, Xia Z, Cui D, Guo J, Xu H, Jiang X. Functional characterization of a wheat NHX antiporter gene TaNHX2 that encodes a K(+)/H(+) exchanger. PLoS One 2013; 8:e78098. [PMID: 24223765 PMCID: PMC3815223 DOI: 10.1371/journal.pone.0078098] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2013] [Accepted: 09/09/2013] [Indexed: 12/22/2022] Open
Abstract
The subcellular localization of a wheat NHX antiporter, TaNHX2, was studied in Arabidopsis protoplasts, and its function was evaluated using Saccharomyces cerevisiae as a heterologous expression system. Fluorescence patterns of TaNHX2-GFP fusion protein in Arabidopsis cells indicated that TaNHX2 localized at endomembranes. TaNHX2 has significant sequence homology to NHX sodium exchangers from Arabidopsis, is abundant in roots and leaves and is induced by salt or dehydration treatments. Western blot analysis showed that TaNHX2 could be expressed in transgenic yeast cells. Expressed TaNHX2 protein suppressed the salt sensitivity of a yeast mutant strain by increasing its K+ content when exposed to salt stress. TaNHX2 also increased the tolerance of the strain to potassium stress. However, the expression of TaNHX2 did not affect the sodium concentration in transgenic cells. Western blot analysis for tonoplast proteins indicated that the TaNHX2 protein localized at the tonoplast of transgenic yeast cells. The tonoplast vesicles from transgenic yeast cells displayed enhanced K+/H+ exchange activity but very little Na+/H+ exchange compared with controls transformed with the empty vector; Na+/H+ exchange was not detected with concentrations of less than 37.5 mM Na+ in the reaction medium. Our data suggest that TaNHX2 is a endomembrane-bound protein and may primarily function as a K+/H+ antiporter, which is involved in cellular pH regulation and potassium nutrition under normal conditions. Under saline conditions, the protein mediates resistance to salt stress through the intracellular compartmentalization of potassium to regulate cellular pH and K+ homeostasis.
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Affiliation(s)
- Yuanyuan Xu
- College of Agronomy/Key laboratory of Physiological Ecology and Genetic Improvement of Food Crops in Henan Province, Henan Agricultural University, Zhengzhou, China
| | - Yang Zhou
- Hainan Key Laboratory for Sustainable Utilization of Tropical Bioresources/College of Agriculture, Hainan University, Haikou, China
- Institute of Tropical Bioscience and Biotechnology, Chinese Academy of Tropical Agricultural Sciences, Haikou, China
| | - Sha Hong
- Hainan Key Laboratory for Sustainable Utilization of Tropical Bioresources/College of Agriculture, Hainan University, Haikou, China
| | - Zhihui Xia
- Hainan Key Laboratory for Sustainable Utilization of Tropical Bioresources/College of Agriculture, Hainan University, Haikou, China
| | - Dangqun Cui
- College of Agronomy/Key laboratory of Physiological Ecology and Genetic Improvement of Food Crops in Henan Province, Henan Agricultural University, Zhengzhou, China
| | - Jianchun Guo
- Institute of Tropical Bioscience and Biotechnology, Chinese Academy of Tropical Agricultural Sciences, Haikou, China
| | - Haixia Xu
- College of Agronomy/Key laboratory of Physiological Ecology and Genetic Improvement of Food Crops in Henan Province, Henan Agricultural University, Zhengzhou, China
- * E-mail: (HX); (XJ)
| | - Xingyu Jiang
- Hainan Key Laboratory for Sustainable Utilization of Tropical Bioresources/College of Agriculture, Hainan University, Haikou, China
- * E-mail: (HX); (XJ)
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257
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Wang L, Zhang J, Wang D, Zhang J, Cui Y, Liu Y, Yang H, Binyu. Assessment of Salt Tolerance in Transgenic Potato Carrying AtNHX1
Gene. CROP SCIENCE 2013. [PMID: 0 DOI: 10.2135/cropsci2013.03.0179] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Affiliation(s)
- Li Wang
- Gansu Key Laboratory of Crop Genetic and Germplasm Enhancement; Gansu Agricultural Univ.; Lanzhou 730070 China
- Gansu Provincial Key Laboratory of Aridland Crop Science; Gansu Agricultural Univ.; Lanzhou 730070 China
- College of Life Science and Technology; Gansu Agricultural Univ.; Lanzhou 730070 China
| | - Junlian Zhang
- Gansu Key Laboratory of Crop Genetic and Germplasm Enhancement; Gansu Agricultural Univ.; Lanzhou 730070 China
- Gansu Provincial Key Laboratory of Aridland Crop Science; Gansu Agricultural Univ.; Lanzhou 730070 China
- College of Agronomy; Gansu Agricultural Univ.; Lanzhou 730070 China
| | - Di Wang
- Gansu Key Laboratory of Crop Genetic and Germplasm Enhancement; Gansu Agricultural Univ.; Lanzhou 730070 China
- Gansu Provincial Key Laboratory of Aridland Crop Science; Gansu Agricultural Univ.; Lanzhou 730070 China
- College of Agronomy; Gansu Agricultural Univ.; Lanzhou 730070 China
| | - Jinwen Zhang
- Gansu Key Laboratory of Crop Genetic and Germplasm Enhancement; Gansu Agricultural Univ.; Lanzhou 730070 China
- Gansu Provincial Key Laboratory of Aridland Crop Science; Gansu Agricultural Univ.; Lanzhou 730070 China
- College of Agronomy; Gansu Agricultural Univ.; Lanzhou 730070 China
| | - Yansen Cui
- Forestry Dep. of Shanxi Provincial Lu'an Group; Changzhi 046000 China
| | - Yuhui Liu
- Gansu Key Laboratory of Crop Genetic and Germplasm Enhancement; Gansu Agricultural Univ.; Lanzhou 730070 China
- Gansu Provincial Key Laboratory of Aridland Crop Science; Gansu Agricultural Univ.; Lanzhou 730070 China
- College of Agronomy; Gansu Agricultural Univ.; Lanzhou 730070 China
| | - Hongyu Yang
- Gansu Key Laboratory of Crop Genetic and Germplasm Enhancement; Gansu Agricultural Univ.; Lanzhou 730070 China
- Gansu Provincial Key Laboratory of Aridland Crop Science; Gansu Agricultural Univ.; Lanzhou 730070 China
- College of Agronomy; Gansu Agricultural Univ.; Lanzhou 730070 China
| | - Binyu
- Gansu Key Laboratory of Crop Genetic and Germplasm Enhancement; Gansu Agricultural Univ.; Lanzhou 730070 China
- Gansu Provincial Key Laboratory of Aridland Crop Science; Gansu Agricultural Univ.; Lanzhou 730070 China
- College of Agronomy; Gansu Agricultural Univ.; Lanzhou 730070 China
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258
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Yamaguchi T, Hamamoto S, Uozumi N. Sodium transport system in plant cells. FRONTIERS IN PLANT SCIENCE 2013; 4:410. [PMID: 24146669 PMCID: PMC3797977 DOI: 10.3389/fpls.2013.00410] [Citation(s) in RCA: 94] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2013] [Accepted: 09/27/2013] [Indexed: 05/18/2023]
Abstract
Since sodium, Na, is a non-essential element for the plant growth, the molecular mechanism of Na(+) transport system in plants has remained elusive for the last two decades. The accumulation of Na(+) in soil through irrigation for sustainable agricultural crop production, particularly in arid land, and by changes in environmental and climate conditions leads to the buildup of toxic level of salts in the soil. Since the latter half of the twentieth century, extensive molecular research has identified several classes of Na(+) transporters that play major roles in the alleviation of ionic stress by excluding toxic Na(+) from the cytosol or preventing Na(+) transport to the photosynthetic organs, and also in osmotic stress by modulating intra/extracellular osmotic balance. In this review, we summarize the current knowledge of three major Na(+) transporters, namely NHX, SOS1, and HKT transporters, including recently revealed characteristics of these transporters.
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Affiliation(s)
- Toshio Yamaguchi
- Department of Microbiology, Faculty of Pharmacy, Niigata University of Pharmacy and Applied Life SciencesNiigata, Japan
| | - Shin Hamamoto
- Department of Biomolecular Engineering, Graduate School of Engineering, Tohoku UniversitySendai, Japan
| | - Nobuyuki Uozumi
- Department of Biomolecular Engineering, Graduate School of Engineering, Tohoku UniversitySendai, Japan
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259
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Martinière A, Bassil E, Jublanc E, Alcon C, Reguera M, Sentenac H, Blumwald E, Paris N. In vivo intracellular pH measurements in tobacco and Arabidopsis reveal an unexpected pH gradient in the endomembrane system. THE PLANT CELL 2013; 25:4028-43. [PMID: 24104564 PMCID: PMC3877828 DOI: 10.1105/tpc.113.116897] [Citation(s) in RCA: 134] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2013] [Revised: 07/30/2013] [Accepted: 09/18/2013] [Indexed: 05/18/2023]
Abstract
The pH homeostasis of endomembranes is essential for cellular functions. In order to provide direct pH measurements in the endomembrane system lumen, we targeted genetically encoded ratiometric pH sensors to the cytosol, the endoplasmic reticulum, and the trans-Golgi, or the compartments labeled by the vacuolar sorting receptor (VSR), which includes the trans-Golgi network and prevacuoles. Using noninvasive live-cell imaging to measure pH, we show that a gradual acidification from the endoplasmic reticulum to the lytic vacuole exists, in both tobacco (Nicotiana tabacum) epidermal (ΔpH -1.5) and Arabidopsis thaliana root cells (ΔpH -2.1). The average pH in VSR compartments was intermediate between that of the trans-Golgi and the vacuole. Combining pH measurements with in vivo colocalization experiments, we found that the trans-Golgi network had an acidic pH of 6.1, while the prevacuole and late prevacuole were both more alkaline, with pH of 6.6 and 7.1, respectively. We also showed that endosomal pH, and subsequently vacuolar trafficking of soluble proteins, requires both vacuolar-type H(+) ATPase-dependent acidification as well as proton efflux mediated at least by the activity of endosomal sodium/proton NHX-type antiporters.
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Affiliation(s)
- Alexandre Martinière
- Biochemistry and Plant Molecular Biology Lab, Unité Mixte de Recherche 5004, 34060 Montpellier, France
| | - Elias Bassil
- Department of Plant Sciences, University of California, Davis, California 95616
| | - Elodie Jublanc
- Institut National de la Recherche Agronomique, Unité Mixte de Recherche 866, Dynamique Musculaire et Métabolisme, 34060 Montpellier, France
| | - Carine Alcon
- Biochemistry and Plant Molecular Biology Lab, Unité Mixte de Recherche 5004, 34060 Montpellier, France
| | - Maria Reguera
- Department of Plant Sciences, University of California, Davis, California 95616
| | - Hervé Sentenac
- Biochemistry and Plant Molecular Biology Lab, Unité Mixte de Recherche 5004, 34060 Montpellier, France
| | - Eduardo Blumwald
- Department of Plant Sciences, University of California, Davis, California 95616
| | - Nadine Paris
- Biochemistry and Plant Molecular Biology Lab, Unité Mixte de Recherche 5004, 34060 Montpellier, France
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260
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Joshi M, Jha A, Mishra A, Jha B. Developing transgenic Jatropha using the SbNHX1 gene from an extreme halophyte for cultivation in saline wasteland. PLoS One 2013; 8:e71136. [PMID: 23940703 PMCID: PMC3733712 DOI: 10.1371/journal.pone.0071136] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2013] [Accepted: 07/02/2013] [Indexed: 12/21/2022] Open
Abstract
Jatropha is an important second-generation biofuel plant. Salinity is a major factor adversely impacting the growth and yield of several plants including Jatropha. SbNHX1 is a vacuolar Na+/H+ antiporter gene that compartmentalises excess Na+ ions into the vacuole and maintains ion homeostasis. We have previously cloned and characterised the SbNHX1 gene from an extreme halophyte, Salicornia brachiata. Transgenic plants of Jatropha curcas with the SbNHX1 gene were developed using microprojectile bombardment mediated transformation. Integration of the transgene was confirmed by PCR and Rt-PCR and the copy number was determined by real time qPCR. The present study of engineering salt tolerance in Jatropha is the first report to date. Salt tolerance of the transgenic lines JL2, JL8 and JL19 was confirmed by leaf senescence assay, chlorophyll estimation, plant growth, ion content, electrolyte leakage and malondialdehyde (MDA) content analysis. Transgenic lines showed better salt tolerance than WT up to 200 mM NaCl. Imparting salt tolerance to Jatropha using the SbNHX1 gene may open up the possibility of cultivating it in marginal salty land, releasing arable land presently under Jatropha cultivation for agriculture purposes. Apart from this, transgenic Jatropha can be cultivated with brackish water, opening up the possibility of sustainable cultivation of this biofuel plant in salty coastal areas.
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Affiliation(s)
| | - Anupama Jha
- Discipline of Marine Biotechnology and Ecology, CSIR-Central Salt and Marine Chemicals Research Institute, Bhavnagar, Gujarat, India.
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261
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Wang Y, Jin S, Wang M, Zhu L, Zhang X. Isolation and characterization of a conserved domain in the eremophyte H+-PPase family. PLoS One 2013; 8:e70099. [PMID: 23922918 PMCID: PMC3726567 DOI: 10.1371/journal.pone.0070099] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2013] [Accepted: 06/14/2013] [Indexed: 11/24/2022] Open
Abstract
H+-translocating inorganic pyrophosphatases (H+-PPase) were recognized as the original energy donors in the development of plants. A large number of researchers have shown that H+-PPase could be an early-originated protein that participated in many important biochemical and physiological processes. In this study we cloned 14 novel sequences from 7 eremophytes: Sophora alopecuroid (Sa), Glycyrrhiza uralensis (Gu), Glycyrrhiza inflata (Gi), Suaeda salsa (Ss), Suaeda rigida (Sr), Halostachys caspica (Hc), and Karelinia caspia (Kc). These novel sequences included 6 ORFs and 8 fragments, and they were identified as H+-PPases based on the typical conserved domains. Besides the identified domains, sequence alignment showed that there still were two novel conserved motifs. A phylogenetic tree was constructed, including the 14 novel H+-PPase amino acid sequences and the other 34 identified H+-PPase protein sequences representing plants, algae, protozoans and bacteria. It was shown that these 48 H+-PPases were classified into two groups: type I and type II H+-PPase. The novel 14 eremophyte H+-PPases were classified into the type I H+-PPase. The 3D structures of these H+-PPase proteins were predicted, which suggested that all type I H+-PPases from higher plants and algae were homodimers, while other type I H+-PPases from bacteria and protozoans and all type II H+-PPases were monomers. The 3D structures of these novel H+-PPases were homodimers except for SaVP3, which was a monomer. This regular structure could provide important evidence for the evolutionary origin and study of the relationship between the structure and function among members of the H+-PPase family.
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Affiliation(s)
- Yanqin Wang
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, Hubei, China
- College of Life Science, Tarim University, Alaer, Xinjiang, China
| | - Shuangxia Jin
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, Hubei, China
| | - Maojun Wang
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, Hubei, China
| | - Longfu Zhu
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, Hubei, China
- * E-mail:
| | - Xianlong Zhang
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, Hubei, China
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RNAi-directed downregulation of vacuolar H(+) -ATPase subunit a results in enhanced stomatal aperture and density in rice. PLoS One 2013; 8:e69046. [PMID: 23894405 PMCID: PMC3718813 DOI: 10.1371/journal.pone.0069046] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2013] [Accepted: 06/05/2013] [Indexed: 11/19/2022] Open
Abstract
Stomatal movement plays a key role in plant development and response to drought and salt stress by regulating gas exchange and water loss. A number of genes have been demonstrated to be involved in the regulation of this process. Using inverse genetics approach, we characterized the function of a rice (Oryza sativa L.) vacuolar H(+)-ATPase subunit A (OsVHA-A) gene in stomatal conductance regulation and physiological response to salt and osmotic stress. OsVHA-A was constitutively expressed in different rice tissues, and the fusion protein of GFP-OsVHA-A was exclusively targeted to tonoplast when transiently expressed in the onion epidermal cells. Heterologous expression of OsVHA-A was able to rescue the yeast mutant vma1Δ (lacking subunit A activity) phenotype, suggesting that it partially restores the activity of V-ATPase. Meanwhile, RNAi-directed knockdown of OsVHA-A led to a reduction of vacuolar H(+)-ATPase activity and an enhancement of plasma membrane H(+)-ATPase activity, thereby increasing the concentrations of extracellular H(+) and intracellular K(+) and Na(+) under stress conditions. Knockdown of OsVHA-A also resulted in the upregulation of PAM3 (plasma membrane H(+)-ATPase 3) and downregulation of CAM1 (calmodulin 1), CAM3 (calmodulin 3) and YDA1 (YODA, a MAPKK gene). Altered level of the ion concentration and the gene expression by knockdown of OsVHA-A probably resulted in expanded aperture of stomatal pores and increased stomatal density. In addition, OsVHA-A RNAi plants displayed significant growth inhibition under salt and osmotic stress conditions. Taken together, our results suggest that OsVHA-A takes part in regulating stomatal density and opening via interfering with pH value and ionic equilibrium in guard cells and thereby affects the growth of rice plants.
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263
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Pires IS, Negrão S, Pentony MM, Abreu IA, Oliveira MM, Purugganan MD. Different evolutionary histories of two cation/proton exchanger gene families in plants. BMC PLANT BIOLOGY 2013; 13:97. [PMID: 23822194 PMCID: PMC3726471 DOI: 10.1186/1471-2229-13-97] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2013] [Accepted: 06/27/2013] [Indexed: 05/22/2023]
Abstract
BACKGROUND Gene duplication events have been proposed to be involved in the adaptation of plants to stress conditions; precisely how is unclear. To address this question, we studied the evolution of two families of antiporters. Cation/proton exchangers are important for normal cell function and in plants, Na+,K+/H+ antiporters have also been implicated in salt tolerance. Two well-known plant cation/proton antiporters are NHX1 and SOS1, which perform Na+ and K+ compartmentalization into the vacuole and Na+ efflux from the cell, respectively. However, our knowledge about the evolution of NHX and SOS1 stress responsive gene families is still limited. RESULTS In this study we performed a comprehensive molecular evolutionary analysis of the NHX and SOS1 families. Using available sequences from a total of 33 plant species, we estimated gene family phylogenies and gene duplication histories, as well as examined heterogeneous selection pressure on amino acid sites. Our results show that, while the NHX family expanded and specialized, the SOS1 family remained a low copy gene family that appears to have undergone neofunctionalization during its evolutionary history. Additionally, we found that both families are under purifying selection although SOS1 is less constrained. CONCLUSIONS We propose that the different evolution histories are related with the proteins' function and localization, and that the NHX and SOS1 families are examples of two different evolutionary paths through which duplication events may result in adaptive evolution of stress tolerance.
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Affiliation(s)
- Inês S Pires
- Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Av. da República, 2780-157 Oeiras, Portugal and iBET, Apartado 12 2781-901, Oeiras, Portugal
- Department of Biology and Center for Genomics and Systems Biology, New York University, New York, US
| | - Sónia Negrão
- Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Av. da República, 2780-157 Oeiras, Portugal and iBET, Apartado 12 2781-901, Oeiras, Portugal
| | - Melissa M Pentony
- Department of Biology and Center for Genomics and Systems Biology, New York University, New York, US
| | - Isabel A Abreu
- Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Av. da República, 2780-157 Oeiras, Portugal and iBET, Apartado 12 2781-901, Oeiras, Portugal
| | - Margarida M Oliveira
- Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Av. da República, 2780-157 Oeiras, Portugal and iBET, Apartado 12 2781-901, Oeiras, Portugal
| | - Michael D Purugganan
- Department of Biology and Center for Genomics and Systems Biology, New York University, New York, US
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Bonales-Alatorre E, Shabala S, Chen ZH, Pottosin I. Reduced tonoplast fast-activating and slow-activating channel activity is essential for conferring salinity tolerance in a facultative halophyte, quinoa. PLANT PHYSIOLOGY 2013; 162:940-52. [PMID: 23624857 PMCID: PMC3668082 DOI: 10.1104/pp.113.216572] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/18/2013] [Accepted: 04/25/2013] [Indexed: 05/18/2023]
Abstract
Halophyte species implement a "salt-including" strategy, sequestering significant amounts of Na(+) to cell vacuoles. This requires a reduction of passive Na(+) leak from the vacuole. In this work, we used quinoa (Chenopodium quinoa) to investigate the ability of halophytes to regulate Na(+)-permeable slow-activating (SV) and fast-activating (FV) tonoplast channels, linking it with Na(+) accumulation in mesophyll cells and salt bladders as well as leaf photosynthetic efficiency under salt stress. Our data indicate that young leaves rely on Na(+) exclusion to salt bladders, whereas old ones, possessing far fewer salt bladders, depend almost exclusively on Na(+) sequestration to mesophyll vacuoles. Moreover, although old leaves accumulate more Na(+), this does not compromise their leaf photochemistry. FV and SV channels are slightly more permeable for K(+) than for Na(+), and vacuoles in young leaves express less FV current and with a density unchanged in plants subjected to high (400 mm NaCl) salinity. In old leaves, with an intrinsically lower density of the FV current, FV channel density decreases about 2-fold in plants grown under high salinity. In contrast, intrinsic activity of SV channels in vacuoles from young leaves is unchanged under salt stress. In vacuoles of old leaves, however, it is 2- and 7-fold lower in older compared with young leaves in control- and salt-grown plants, respectively. We conclude that the negative control of SV and FV tonoplast channel activity in old leaves reduces Na(+) leak, thus enabling efficient sequestration of Na(+) to their vacuoles. This enables optimal photosynthetic performance, conferring salinity tolerance in quinoa species.
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Affiliation(s)
- Edgar Bonales-Alatorre
- School of Agricultural Science, University of Tasmania, Hobart, Tas 7001, Australia (E.B.-A., S.S., I.P.)
- School of Science and Health, University of Western Sydney, Richmond, NSW 2753, Australia (Z.-H.C.); and
- Centro Universitario de Investigaciones Biomédicas, Universidad de Colima, 28045 Colima, Mexico (I.P.)
| | | | - Zhong-Hua Chen
- School of Agricultural Science, University of Tasmania, Hobart, Tas 7001, Australia (E.B.-A., S.S., I.P.)
- School of Science and Health, University of Western Sydney, Richmond, NSW 2753, Australia (Z.-H.C.); and
- Centro Universitario de Investigaciones Biomédicas, Universidad de Colima, 28045 Colima, Mexico (I.P.)
| | - Igor Pottosin
- School of Agricultural Science, University of Tasmania, Hobart, Tas 7001, Australia (E.B.-A., S.S., I.P.)
- School of Science and Health, University of Western Sydney, Richmond, NSW 2753, Australia (Z.-H.C.); and
- Centro Universitario de Investigaciones Biomédicas, Universidad de Colima, 28045 Colima, Mexico (I.P.)
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265
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Zhou LZ, Li S, Feng QN, Zhang YL, Zhao X, Zeng YL, Wang H, Jiang L, Zhang Y. Protein S-ACYL Transferase10 is critical for development and salt tolerance in Arabidopsis. THE PLANT CELL 2013; 25:1093-107. [PMID: 23482856 PMCID: PMC3634679 DOI: 10.1105/tpc.112.108829] [Citation(s) in RCA: 99] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2012] [Revised: 02/11/2013] [Accepted: 02/17/2013] [Indexed: 05/18/2023]
Abstract
Protein S-acylation, commonly known as palmitoylation, is a reversible posttranslational modification that catalyzes the addition of a saturated lipid group, often palmitate, to the sulfhydryl group of a Cys. Palmitoylation regulates enzyme activity, protein stability, subcellular localization, and intracellular sorting. Many plant proteins are palmitoylated. However, little is known about protein S-acyl transferases (PATs), which catalyze palmitoylation. Here, we report that the tonoplast-localized PAT10 is critical for development and salt tolerance in Arabidopsis thaliana. PAT10 loss of function resulted in pleiotropic growth defects, including smaller leaves, dwarfism, and sterility. In addition, pat10 mutants are hypersensitive to salt stresses. We further show that PAT10 regulates the tonoplast localization of several calcineurin B-like proteins (CBLs), including CBL2, CBL3, and CBL6, whose membrane association also depends on palmitoylation. Introducing a C192S mutation within the highly conserved catalytic motif of PAT10 failed to complement pat10 mutants, indicating that PAT10 functions through protein palmitoylation. We propose that PAT10-mediated palmitoylation is critical for vacuolar function by regulating membrane association or the activities of tonoplast proteins.
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Affiliation(s)
- Liang-Zi Zhou
- State Key Laboratory of Crop Biology, Shandong Agricultural University, Tai'an 271018, Shandong, China
| | - Sha Li
- State Key Laboratory of Crop Biology, Shandong Agricultural University, Tai'an 271018, Shandong, China
| | - Qiang-Nan Feng
- State Key Laboratory of Crop Biology, Shandong Agricultural University, Tai'an 271018, Shandong, China
| | - Yu-Ling Zhang
- State Key Laboratory of Crop Biology, Shandong Agricultural University, Tai'an 271018, Shandong, China
| | - Xinying Zhao
- State Key Laboratory of Crop Biology, Shandong Agricultural University, Tai'an 271018, Shandong, China
| | - Yong-lun Zeng
- School of Life Sciences, Centre for Cell and Developmental Biology, The Chinese University of Hong Kong, Hong Kong 999077, China
| | - Hao Wang
- School of Life Sciences, Centre for Cell and Developmental Biology, The Chinese University of Hong Kong, Hong Kong 999077, China
| | - Liwen Jiang
- School of Life Sciences, Centre for Cell and Developmental Biology, The Chinese University of Hong Kong, Hong Kong 999077, China
| | - Yan Zhang
- State Key Laboratory of Crop Biology, Shandong Agricultural University, Tai'an 271018, Shandong, China
- Address correspondence to
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266
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Osakabe Y, Arinaga N, Umezawa T, Katsura S, Nagamachi K, Tanaka H, Ohiraki H, Yamada K, Seo SU, Abo M, Yoshimura E, Shinozaki K, Yamaguchi-Shinozaki K. Osmotic stress responses and plant growth controlled by potassium transporters in Arabidopsis. THE PLANT CELL 2013; 25:609-624. [PMID: 23396830 DOI: 10.2307/41812291] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Osmotic adjustment plays a fundamental role in water stress responses and growth in plants; however, the molecular mechanisms governing this process are not fully understood. Here, we demonstrated that the KUP potassium transporter family plays important roles in this process, under the control of abscisic acid (ABA) and auxin. We generated Arabidopsis thaliana multiple mutants for K(+) uptake transporter 6 (KUP6), KUP8, KUP2/SHORT HYPOCOTYL3, and an ABA-responsive potassium efflux channel, guard cell outward rectifying K(+) channel (GORK). The triple mutants, kup268 and kup68 gork, exhibited enhanced cell expansion, suggesting that these KUPs negatively regulate turgor-dependent growth. Potassium uptake experiments using (86)radioactive rubidium ion ((86)Rb(+)) in the mutants indicated that these KUPs might be involved in potassium efflux in Arabidopsis roots. The mutants showed increased auxin responses and decreased sensitivity to an auxin inhibitor (1-N-naphthylphthalamic acid) and ABA in lateral root growth. During water deficit stress, kup68 gork impaired ABA-mediated stomatal closing, and kup268 and kup68 gork decreased survival of drought stress. The protein kinase SNF1-related protein kinases 2E (SRK2E), a key component of ABA signaling, interacted with and phosphorylated KUP6, suggesting that KUP functions are regulated directly via an ABA signaling complex. We propose that the KUP6 subfamily transporters act as key factors in osmotic adjustment by balancing potassium homeostasis in cell growth and drought stress responses.
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Affiliation(s)
- Yuriko Osakabe
- Laboratory of Plant Molecular Physiology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo-ku, Tokyo 113-8657, Japan
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267
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Osakabe Y, Arinaga N, Umezawa T, Katsura S, Nagamachi K, Tanaka H, Ohiraki H, Yamada K, Seo SU, Abo M, Yoshimura E, Shinozaki K, Yamaguchi-Shinozaki K. Osmotic stress responses and plant growth controlled by potassium transporters in Arabidopsis. THE PLANT CELL 2013; 25:609-24. [PMID: 23396830 PMCID: PMC3608781 DOI: 10.1105/tpc.112.105700] [Citation(s) in RCA: 207] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
Osmotic adjustment plays a fundamental role in water stress responses and growth in plants; however, the molecular mechanisms governing this process are not fully understood. Here, we demonstrated that the KUP potassium transporter family plays important roles in this process, under the control of abscisic acid (ABA) and auxin. We generated Arabidopsis thaliana multiple mutants for K(+) uptake transporter 6 (KUP6), KUP8, KUP2/SHORT HYPOCOTYL3, and an ABA-responsive potassium efflux channel, guard cell outward rectifying K(+) channel (GORK). The triple mutants, kup268 and kup68 gork, exhibited enhanced cell expansion, suggesting that these KUPs negatively regulate turgor-dependent growth. Potassium uptake experiments using (86)radioactive rubidium ion ((86)Rb(+)) in the mutants indicated that these KUPs might be involved in potassium efflux in Arabidopsis roots. The mutants showed increased auxin responses and decreased sensitivity to an auxin inhibitor (1-N-naphthylphthalamic acid) and ABA in lateral root growth. During water deficit stress, kup68 gork impaired ABA-mediated stomatal closing, and kup268 and kup68 gork decreased survival of drought stress. The protein kinase SNF1-related protein kinases 2E (SRK2E), a key component of ABA signaling, interacted with and phosphorylated KUP6, suggesting that KUP functions are regulated directly via an ABA signaling complex. We propose that the KUP6 subfamily transporters act as key factors in osmotic adjustment by balancing potassium homeostasis in cell growth and drought stress responses.
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Affiliation(s)
- Yuriko Osakabe
- Laboratory of Plant Molecular Physiology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo-ku, Tokyo 113-8657, Japan
- Gene Discovery Research Group, RIKEN Plant Science Center, Tsukuba, Ibaraki 305-0074, Japan
| | - Naoko Arinaga
- Laboratory of Plant Molecular Physiology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Taishi Umezawa
- Gene Discovery Research Group, RIKEN Plant Science Center, Tsukuba, Ibaraki 305-0074, Japan
| | - Shogo Katsura
- Laboratory of Plant Molecular Physiology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Keita Nagamachi
- Laboratory of Plant Molecular Physiology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Hidenori Tanaka
- Laboratory of Plant Molecular Physiology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Haruka Ohiraki
- Laboratory of Plant Molecular Physiology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Kohji Yamada
- Laboratory of Plant Molecular Physiology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo-ku, Tokyo 113-8657, Japan
| | - So-Uk Seo
- Laboratory of Plant Molecular Physiology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Mitsuru Abo
- Laboratory of Analytical Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Etsuro Yoshimura
- Laboratory of Analytical Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Kazuo Shinozaki
- Gene Discovery Research Group, RIKEN Plant Science Center, Tsukuba, Ibaraki 305-0074, Japan
| | - Kazuko Yamaguchi-Shinozaki
- Laboratory of Plant Molecular Physiology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo-ku, Tokyo 113-8657, Japan
- Biological Resources and Post-harvest Division, Japan International Research Center for Agricultural Sciences, Tsukuba, Ibaraki 305-8686, Japan
- Address correspondence to
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268
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Dang ZH, Zheng LL, Wang J, Gao Z, Wu SB, Qi Z, Wang YC. Transcriptomic profiling of the salt-stress response in the wild recretohalophyte Reaumuria trigyna. BMC Genomics 2013; 14:29. [PMID: 23324106 PMCID: PMC3562145 DOI: 10.1186/1471-2164-14-29] [Citation(s) in RCA: 121] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2012] [Accepted: 01/09/2013] [Indexed: 11/20/2022] Open
Abstract
Background Reaumuria trigyna is an endangered small shrub endemic to desert regions in Inner Mongolia. This dicotyledonous recretohalophyte has unique morphological characteristics that allow it to tolerate the stress imposed by semi-desert saline soil. However, it is impossible to explore the mechanisms underlying this tolerance without detailed genomic information. Fortunately, newly developed high-throughput sequencing technologies are powerful tools for de novo sequencing to gain such information for this species. Results Two sequencing libraries prepared from control (C21) and NaCl-treated samples (T43) were sequenced using short reads sequencing technology (Illumina) to investigate changes in the R. trigyna transcriptome in response to salt stress. Among 65340 unigenes, 35495 (52.27%) were annotated with gene descriptions, conserved domains, gene ontology terms, and metabolic pathways with a cut-off E-value of 10-5. These included 44 Gene Ontology (GO) terms, 119 Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways, and 25 Clusters of Orthologous Groups families. By comparing the transcriptomes from control and NaCl-treated plants, 5032 genes showed significantly differences in transcript abundance under salt stress (false discovery rate ≤ 0.001 and |log2Ratio| ≥ 1). These genes were significantly enriched in 29 KEGG pathways and 26 GO terms. The transcription profiles indicated that genes related to ion transport and the reactive oxygen species scavenging system were relevant to the morphological and physiological characteristics of this species. The expression patterns of 30 randomly selected genes resulted from quantitative real-time PCR were basically consistent with their transcript abundance changes identified by RNA-seq. Conclusions The present study identified potential genes involved in salt tolerance of R. trigyna. The globally sequenced genes covered a considerable proportion of the R. trigyna transcriptome. These data represent a genetic resource for the discovery of genes related to salt tolerance in this species, and may be a useful source of reference sequences for closely related taxa. These results can also further our understanding of salt tolerance in other halophytes surviving under sodic stress.
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Affiliation(s)
- Zhen-hua Dang
- Key Laboratory of Herbage & Endemic Crop Biotechnology, and College of Life Sciences, Inner Mongolia University, Hohhot, 010020, PR China
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269
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Shitan N, Yazaki K. New insights into the transport mechanisms in plant vacuoles. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2013; 305:383-433. [PMID: 23890387 DOI: 10.1016/b978-0-12-407695-2.00009-3] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The vacuole is the largest compartment in plant cells, often occupying more than 80% of the total cell volume. This organelle accumulates a large variety of endogenous ions, metabolites, and xenobiotics. The compartmentation of divergent substances is relevant for a wide range of biological processes, such as the regulation of stomata movement, defense mechanisms against herbivores, flower coloration, etc. Progress in molecular and cellular biology has revealed that a large number of transporters and channels exist at the tonoplast. In recent years, various biochemical and physiological functions of these proteins have been characterized in detail. Some are involved in maintaining the homeostasis of ions and metabolites, whereas others are related to defense mechanisms against biotic and abiotic stresses. In this review, we provide an updated inventory of vacuolar transport mechanisms and a comprehensive summary of their physiological functions.
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Affiliation(s)
- Nobukazu Shitan
- Laboratory of Natural Medicinal Chemistry, Kobe Pharmaceutical University, Kobe, Japan.
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270
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Trentmann O, Haferkamp I. Current progress in tonoplast proteomics reveals insights into the function of the large central vacuole. FRONTIERS IN PLANT SCIENCE 2013; 4:34. [PMID: 23459586 PMCID: PMC3584717 DOI: 10.3389/fpls.2013.00034] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2012] [Accepted: 02/11/2013] [Indexed: 05/20/2023]
Abstract
Vacuoles of plants fulfill various biologically important functions, like turgor generation and maintenance, detoxification, solute sequestration, or protein storage. Different types of plant vacuoles (lytic versus protein storage) are characterized by different functional properties apparently caused by a different composition/abundance and regulation of transport proteins in the surrounding membrane, the tonoplast. Proteome analyses allow the identification of vacuolar proteins and provide an informative basis for assigning observed transport processes to specific carriers or channels. This review summarizes techniques required for vacuolar proteome analyses, like e.g., isolation of the large central vacuole or tonoplast membrane purification. Moreover, an overview about diverse published vacuolar proteome studies is provided. It becomes evident that qualitative proteomes from different plant species represent just the tip of the iceberg. During the past few years, mass spectrometry achieved immense improvement concerning its accuracy, sensitivity, and application. As a consequence, modern tonoplast proteome approaches are suited for detecting alterations in membrane protein abundance in response to changing environmental/physiological conditions and help to clarify the regulation of tonoplast transport processes.
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Affiliation(s)
- Oliver Trentmann
- Pflanzenphysiologie, Technische Universität KaiserslauternKaiserslautern, Germany
- *Correspondence: Oliver Trentmann, Pflanzenphysiologie, Technische Universität Kaiserslautern, Postfach 3049, D-67653 Kaiserslautern, Germany. e-mail:
| | - Ilka Haferkamp
- Pflanzenphysiologie, Technische Universität KaiserslauternKaiserslautern, Germany
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271
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Bassil E, Krebs M, Halperin* S, Schumacher K, Blumwald E. Fluorescent Dye Based Measurement of Vacuolar pH and K+. Bio Protoc 2013. [DOI: 10.21769/bioprotoc.810] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022] Open
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272
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Abstract
As one of the most important mineral nutrient elements, potassium (K(+)) participates in many plant physiological processes and determines the yield and quality of crop production. In this review, we summarize K(+) signaling processes and K(+) transport regulation in higher plants, especially in plant responses to K(+)-deficiency stress. Plants perceive external K(+) fluctuations and generate the initial K(+) signal in root cells. This signal is transduced into the cytoplasm and encoded as Ca(2+) and reactive oxygen species signaling. K(+)-deficiency-induced signals are subsequently decoded by cytoplasmic sensors, which regulate the downstream transcriptional and posttranslational responses. Eventually, plants produce a series of adaptive events in both physiological and morphological alterations that help them survive K(+) deficiency.
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Affiliation(s)
- Yi Wang
- State Key Laboratory of Plant Physiology and Biochemistry, National Center of Plant Gene Research (Beijing), College of Biological Sciences, China Agricultural University, Beijing 100193, China
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273
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Baltierra F, Castillo M, Gamboa MC, Rothhammer M, Krauskopf E. Molecular characterization of a novel Na⁺/H⁺ antiporter cDNA from Eucalyptus globulus. Biochem Biophys Res Commun 2012; 430:535-40. [PMID: 23232113 DOI: 10.1016/j.bbrc.2012.11.118] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2012] [Accepted: 11/30/2012] [Indexed: 02/04/2023]
Abstract
Environmental stress factors such as salt, drought and heat are known to affect plant productivity. However, high salinity is spreading throughout the world, currently affecting more than 45 millionha. One of the mechanisms that allow plants to withstand salt stress consists on vacuolar sequestration of Na(+), through a Na(+)/H(+) antiporter. We isolated a new vacuolar Na(+)/H(+) antiporter from Eucalyptus globulus from a cDNA library. The cDNA had a 1626 bp open reading frame encoding a predicted protein of 542 amino acids with a deduced molecular weight of 59.1 KDa. Phylogenetic and bioinformatic analyses indicated that EgNHX1 localized in the vacuole. To assess its role in Na(+) exchange, we performed complementation studies using the Na(+) sensitive yeast mutant strain Δnhx1. The results showed that EgNHX1 partially restored the salt sensitive phenotype of the yeast Δnhx1 strain. However, its overexpression in transgenic Arabidopsis confers tolerance in the presence of increasing NaCl concentrations while the wild type plants exhibited growth retardation. Expression profiles of Eucalyptus seedlings subjected to salt, drought, heat and ABA treatment were established. The results revealed that Egnhx1 was induced significantly only by drought. Together, these results suggest that the product of Egnhx1 from E. globulus is a functional vacuolar Na(+)/H(+) antiporter.
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274
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Tang RJ, Liu H, Yang Y, Yang L, Gao XS, Garcia VJ, Luan S, Zhang HX. Tonoplast calcium sensors CBL2 and CBL3 control plant growth and ion homeostasis through regulating V-ATPase activity in Arabidopsis. Cell Res 2012. [PMID: 23184060 DOI: 10.1038/cr.2012.161] [Citation(s) in RCA: 110] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Plant responses to developmental and environmental cues are often mediated by calcium (Ca(2+)) signals that are transmitted by diverse calcium sensors. The calcineurin B-like (CBL) protein family represents calcium sensors that decode calcium signals through specific interactions with a group of CBL-interacting protein kinases. We report functional analysis of Arabidopsis CBL2 and CBL3, two closely related CBL members that are localized to the vacuolar membrane through the N-terminal tonoplast-targeting sequence. While cbl2 or cbl3 single mutant did not show any phenotypic difference from the wild type, the cbl2 cbl3 double mutant was stunted with leaf tip necrosis, underdeveloped roots, shorter siliques and fewer seeds. These defects were reminiscent of those in the vha-a2 vha-a3 double mutant deficient in vacuolar H(+)-ATPase (V-ATPase). Indeed, the V-ATPase activity was reduced in the cbl2 cbl3 double mutant, connecting tonoplast CBL-type calcium sensors to the regulation of V-ATPase. Furthermore, cbl2 cbl3 double mutant was compromised in ionic tolerance and micronutrient accumulation, consistent with the defect in V-ATPase activity that has been shown to function in ion compartmentalization. Our results suggest that calcium sensors CBL2 and CBL3 serve as molecular links between calcium signaling and V-ATPase, a central regulator of intracellular ion homeostasis.
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Affiliation(s)
- Ren-Jie Tang
- National Key Laboratory of Plant Molecular Genetics, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, China
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Abstract
ATP-hydrolysis and proton pumping by the V-ATPase (vacuolar proton-translocating ATPase) are subject to redox regulation in mammals, yeast and plants. Oxidative inhibition of the V-ATPase is ascribed to disulfide-bond formation between conserved cysteine residues at the catalytic site of subunit A. Subunits containing amino acid substitutions of one of three conserved cysteine residues of VHA-A were expressed in a vha-A null mutant background in Arabidopsis. In vitro activity measurements revealed a complete absence of oxidative inhibition in the transgenic line expressing VHA-A C256S, confirming that Cys256 is necessary for redox regulation. In contrast, oxidative inhibition was unaffected in plants expressing VHA-A C279S and VHA-A C535S, indicating that disulfide bridges involving these cysteine residues are not essential for oxidative inhibition. In vivo data suggest that oxidative inhibition might not represent a general regulatory mechanism in plants.
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276
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Bassil E, Coku A, Blumwald E. Cellular ion homeostasis: emerging roles of intracellular NHX Na+/H+ antiporters in plant growth and development. JOURNAL OF EXPERIMENTAL BOTANY 2012; 63:5727-40. [PMID: 22991159 DOI: 10.1093/jxb/ers250] [Citation(s) in RCA: 156] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Recent evidence highlights novel roles for intracellular Na(+)/H(+) antiporters (NHXs) in plants. The availability of knockouts and overexpressors of specific NHX isoforms has provided compelling genetic evidence to support earlier physiological and biochemical data which suggested the involvement of NHX antiporters in ion and pH regulation. Most plants sequenced to date contain multiple NHX members and, based on their sequence identity and localization, can be grouped into three distinct functional classes: plasma membrane, vacuolar, and endosomal associated. Orthologues of each functional class are represented in all sequenced plant genomes, suggesting conserved and fundamental roles across taxa. In this review we seek to highlight recent findings which demonstrate that intracellular NHX antiporters (i.e. vacuolar and endosomal isoforms) play roles in growth and development, including cell expansion, cell volume regulation, ion homeostasis, osmotic adjustment, pH regulation, vesicular trafficking, protein processing, cellular stress responses, as well as flowering. A significant new discovery demonstrated that in addition to the better known vacuolar NHX isoforms, plants also contain endosomal NHX isoforms that regulate protein processing and trafficking of cellular cargo. We draw parallels from close orthologues in yeast and mammals and discuss distinctive NHX functions in plants.
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Affiliation(s)
- Elias Bassil
- Department of Plant Sciences, University of California, One Shields Ave, Davis, CA 95616, USA
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277
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Liu C, Li C, Liang D, Wei Z, Zhou S, Wang R, Ma F. Differential expression of ion transporters and aquaporins in leaves may contribute to different salt tolerance in Malus species. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2012; 58:159-65. [PMID: 22819861 DOI: 10.1016/j.plaphy.2012.06.019] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/10/2012] [Accepted: 06/14/2012] [Indexed: 05/03/2023]
Abstract
Maintaining ion and water homeostasis in plants is an important defense strategy against salinity stress. Divergence in ion homeostasis between the salt-tolerant Malus hupehensis Rehd. and salt-sensitive Malus prunifolia 'yingyehaitang' was studied to understand their mechanisms for tolerance. Compared with the control on Day 15, plants of those two genotypes under high-salinity treatment had less K(+) in the leaves, stems, and roots. Contents were higher in the roots but lower in the leaves of M. hupehensis while levels in the stems were similar to those from M. prunifolia. For both genotypes, the sodium content increased after salinity treatment in all tissue types. However, the leaves from M. hupehensis had less Na(+) and maintained a lower Na(+)/K(+) ratio. To understand the basis for these differences, we studied the ion transporters and regulation of aquaporin transcripts in the leaves. Transcript levels for both MdHKT1 and MdSOS1 were higher in M. hupehensis, implying that this species had better capacity to exclude sodium so that less Na(+) occurred in the leaves but more in the stems. M. hupehensis also had a greater amount of MdNHX1 transcripts, which could have assisted in sequestering excess Na(+) into the vacuoles and sustaining a better cellular environment. A relatively higher level of aquaporin transcript was also found in M. hupehensis, suggesting that those plants were more capable of maintaining a better leaf water status and diluting excess ions effectively under high-salinity conditions. Therefore, these tested transporters may play important roles in determining how salinity tolerance is conferred in Malus species.
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Affiliation(s)
- Changhai Liu
- State Key Laboratory of Crop Stress Biology in Arid Areas, College of Horticulture, Northwest A&F University, Yangling, Shaanxi 712100, China
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278
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Zhang YM, Liu ZH, Wen ZY, Zhang HM, Yang F, Guo XL. The vacuolar Na +-H + antiport gene TaNHX2 confers salt tolerance on transgenic alfalfa (Medicago sativa). FUNCTIONAL PLANT BIOLOGY : FPB 2012; 39:708-716. [PMID: 32480822 DOI: 10.1071/fp12095] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2011] [Accepted: 06/06/2012] [Indexed: 06/11/2023]
Abstract
TaNHX2, a vacuolar Na+-H+ antiport gene from wheat (Triticum aestivum L.), was transformed into alfalfa (Medicago sativa L.) via Agrobacterium-mediated transformation to evaluate the role of vacuolar energy providers in plant salt stress responses. PCR and Southern blotting analysis showed that the target gene was integrated into the Medicago genome. Reverse transcription-PCR indicated that gene TaNHX2 was expressed at the transcriptional level. The relative electrical conductivity in the T2 transgenic plants was lower and the osmotic potential was higher compared to the wild-type plants under salt stress conditions. The tonoplast H+-ATPase, H+-pyrophosphatase (PPase) hydrolysis activities and ATP-dependent proton pump activities in transgenic plants were all higher than those of wild-type plants, and the enzyme activities could be induced by salt stress. The PPi-dependent proton pump activities decreased when NaCl concentrations increased from 100mM to 200mM, especially in transgenic plants. The vacuolar Na+-H+ antiport activities of transgenic plants were 2-3 times higher than those of the wild -type plants under 0mM and 100mM NaCl stress. Na+-H+ antiport activity was not detectable for wild-type plants under 200mM NaCl, but for transgenic plants, it was further increased with an increment in salt stress intensity. These results demonstrated that expression of the foreign TaNHX2 gene enhanced salt tolerance in transgenic alfalfa.
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Affiliation(s)
- Yan-Min Zhang
- Institute of Genetics and Physiology, Hebei Academy of Agriculture and Forestry Sciences, Plant Genetic Engineering Center of Hebei Province, Shijiazhuang 050051, China
| | - Zi-Hui Liu
- Institute of Genetics and Physiology, Hebei Academy of Agriculture and Forestry Sciences, Plant Genetic Engineering Center of Hebei Province, Shijiazhuang 050051, China
| | - Zhi-Yu Wen
- Institute of Genetics and Physiology, Hebei Academy of Agriculture and Forestry Sciences, Plant Genetic Engineering Center of Hebei Province, Shijiazhuang 050051, China
| | - Hong-Mei Zhang
- Institute of Genetics and Physiology, Hebei Academy of Agriculture and Forestry Sciences, Plant Genetic Engineering Center of Hebei Province, Shijiazhuang 050051, China
| | - Fan Yang
- Institute of Genetics and Physiology, Hebei Academy of Agriculture and Forestry Sciences, Plant Genetic Engineering Center of Hebei Province, Shijiazhuang 050051, China
| | - Xiu-Lin Guo
- Institute of Genetics and Physiology, Hebei Academy of Agriculture and Forestry Sciences, Plant Genetic Engineering Center of Hebei Province, Shijiazhuang 050051, China
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279
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Zhong NQ, Han LB, Wu XM, Wang LL, Wang F, Ma YH, Xia GX. Ectopic expression of a bacterium NhaD-type Na+/H+ antiporter leads to increased tolerance to combined salt/alkali stresses. JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2012; 54:412-21. [PMID: 22583823 DOI: 10.1111/j.1744-7909.2012.01129.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
AaNhaD, a gene isolated from the soda lake alkaliphile Alkalimonas amylolytica, encodes a Na(+) /H(+) antiporter crucial for the bacterium's resistance to salt/alkali stresses. However, it remains unknown whether this type of bacterial gene may be able to increase the tolerance of flowering plants to salt/alkali stresses. To investigate the use of extremophile genetic resources in higher plants, transgenic tobacco BY-2 cells and plants harboring AaNhaD were generated and their stress tolerance was evaluated. Ectopic expression of AaNhaD enhanced the salt tolerance of the transgenic BY-2 cells in a pH-dependent manner. Compared to wild-type controls, the transgenic cells exhibited increased Na(+) concentrations and pH levels in the vacuoles. Subcellular localization analysis indicated that AaNhaD-GFP fusion proteins were primarily localized in the tonoplasts. Similar to the transgenic BY-2 cells, AaNhaD-overexpressing tobacco plants displayed enhanced stress tolerance when grown in saline-alkali soil. These results indicate that AaNhaD functions as a pH-dependent tonoplast Na(+) /H(+) antiporter in plant cells, thus presenting a new avenue for the genetic improvement of salinity/alkalinity tolerance.
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Affiliation(s)
- Nai-Qin Zhong
- Institute of Microbiology, Chinese Academy of Sciences, Beijing
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280
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Gouiaa S, Khoudi H, Leidi EO, Pardo JM, Masmoudi K. Expression of wheat Na(+)/H(+) antiporter TNHXS1 and H(+)- pyrophosphatase TVP1 genes in tobacco from a bicistronic transcriptional unit improves salt tolerance. PLANT MOLECULAR BIOLOGY 2012; 79:137-55. [PMID: 22415161 DOI: 10.1007/s11103-012-9901-6] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2011] [Accepted: 02/20/2012] [Indexed: 05/23/2023]
Abstract
Abiotic stress tolerance of plants is a very complex trait and involves multiple physiological and biochemical processes. Thus, the improvement of plant stress tolerance should involve pyramiding of multiple genes. In the present study, we report the construction and application of a bicistronic system, involving the internal ribosome entry site (IRES) sequence from the 5'UTR of the heat-shock protein of tobacco gene NtHSF-1, to the improvement of salt tolerance in transgenic tobacco plants. Two genes from wheat encoding two important vacuolar ion transporters, Na(+)/H(+) antiporter (TNHXS1) and H(+)-pyrophosphatase (TVP1), were linked via IRES to generate the bicistronic construct TNHXS1-IRES-TVP1. Molecular analysis of transgenic tobacco plants revealed the correct integration of the TNHXS1-IRES-TVP1construct into tobacco genome and the production of the full-length bicistronic mRNA from the 35S promoter. Ion transport analyses with tonoplast vesicles isolated from transgenic lines confirmed that single-transgenic lines TVP1cl19 and TNHXS1cl7 had greater H(+)-PPiase and Na(+)/H(+) antiport activity, respectively, than the WT. Interestingly, the co-expression of TVP1 and TNHXS1 increased both Na(+)/H(+) antiport and H(+)-PPiase activities and induced the H(+) pumping activity of the endogenous V-ATPase. Transgenic tobacco plants expressing TNHXS1-IRES-TVP1 showed a better performance than either of the single gene-transformed lines and the wild type plants when subjected to salt treatment. In addition, the TNHXS1-IRES-TVP1 transgenic plants accumulated less Na(+) and more K(+) in their leaf tissue than did the wild type and the single gene-transformed lines. These results demonstrate that IRES system, described herein, can co-ordinate the expression of two important abiotic stress-tolerance genes and that this expression system is a valuable tool for obtaining transgenic plants with improved salt tolerance.
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Affiliation(s)
- Sandra Gouiaa
- Laboratory of Plant Protection and Improvement, Center of Biotechnology of Sfax, University of Sfax, Route Sidi Mansour Km 6, B.P'1177', 3018 Sfax, Tunisia
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281
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Barragán V, Leidi EO, Andrés Z, Rubio L, De Luca A, Fernández JA, Cubero B, Pardo JM. Ion exchangers NHX1 and NHX2 mediate active potassium uptake into vacuoles to regulate cell turgor and stomatal function in Arabidopsis. THE PLANT CELL 2012; 24:1127-42. [PMID: 22438021 PMCID: PMC3336136 DOI: 10.1105/tpc.111.095273] [Citation(s) in RCA: 350] [Impact Index Per Article: 29.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/26/2011] [Revised: 02/20/2012] [Accepted: 03/05/2012] [Indexed: 05/18/2023]
Abstract
Intracellular NHX proteins are Na(+),K(+)/H(+) antiporters involved in K(+) homeostasis, endosomal pH regulation, and salt tolerance. Proteins NHX1 and NHX2 are the two major tonoplast-localized NHX isoforms. Here, we show that NHX1 and NHX2 have similar expression patterns and identical biochemical activity, and together they account for a significant amount of the Na(+),K(+)/H(+) antiport activity in tonoplast vesicles. Reverse genetics showed functional redundancy of NHX1 and NHX2 genes. Growth of the double mutant nhx1 nhx2 was severely impaired, and plants were extremely sensitive to external K(+). By contrast, nhx1 nhx2 mutants showed similar sensitivity to salinity stress and even greater rates of Na(+) sequestration than the wild type. Double mutants had reduced ability to create the vacuolar K(+) pool, which in turn provoked greater K(+) retention in the cytosol, impaired osmoregulation, and compromised turgor generation for cell expansion. Genes NHX1 and NHX2 were highly expressed in guard cells, and stomatal function was defective in mutant plants, further compromising their ability to regulate water relations. Together, these results show that tonoplast-localized NHX proteins are essential for active K(+) uptake at the tonoplast, for turgor regulation, and for stomatal function.
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Affiliation(s)
- Verónica Barragán
- Instituto de Recursos Naturales y Agrobiologia, Consejo Superior de Investigaciones Cientificas, Sevilla 41012, Spain
| | - Eduardo O. Leidi
- Instituto de Recursos Naturales y Agrobiologia, Consejo Superior de Investigaciones Cientificas, Sevilla 41012, Spain
| | - Zaida Andrés
- Instituto de Recursos Naturales y Agrobiologia, Consejo Superior de Investigaciones Cientificas, Sevilla 41012, Spain
| | - Lourdes Rubio
- Departamento de Biologia Vegetal, Facultad de Ciencias, Universidad de Malaga, Malaga 29071, Spain
| | - Anna De Luca
- Instituto de Recursos Naturales y Agrobiologia, Consejo Superior de Investigaciones Cientificas, Sevilla 41012, Spain
| | - José A. Fernández
- Departamento de Biologia Vegetal, Facultad de Ciencias, Universidad de Malaga, Malaga 29071, Spain
| | - Beatriz Cubero
- Instituto de Recursos Naturales y Agrobiologia, Consejo Superior de Investigaciones Cientificas, Sevilla 41012, Spain
| | - José M. Pardo
- Instituto de Recursos Naturales y Agrobiologia, Consejo Superior de Investigaciones Cientificas, Sevilla 41012, Spain
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282
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Chanroj S, Wang G, Venema K, Zhang MW, Delwiche CF, Sze H. Conserved and diversified gene families of monovalent cation/h(+) antiporters from algae to flowering plants. FRONTIERS IN PLANT SCIENCE 2012; 3:25. [PMID: 22639643 PMCID: PMC3355601 DOI: 10.3389/fpls.2012.00025] [Citation(s) in RCA: 143] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2011] [Accepted: 01/21/2012] [Indexed: 05/18/2023]
Abstract
All organisms have evolved strategies to regulate ion and pH homeostasis in response to developmental and environmental cues. One strategy is mediated by monovalent cation-proton antiporters (CPA) that are classified in two superfamilies. Many CPA1 genes from bacteria, fungi, metazoa, and plants have been functionally characterized; though roles of plant CPA2 genes encoding K(+)-efflux antiporter (KEA) and cation/H(+) exchanger (CHX) families are largely unknown. Phylogenetic analysis showed that three clades of the CPA1 Na(+)-H(+) exchanger (NHX) family have been conserved from single-celled algae to Arabidopsis. These are (i) plasma membrane-bound SOS1/AtNHX7 that share ancestry with prokaryote NhaP, (ii) endosomal AtNHX5/6 that is part of the eukaryote Intracellular-NHE clade, and (iii) a vacuolar NHX clade (AtNHX1-4) specific to plants. Early diversification of KEA genes possibly from an ancestral cyanobacterium gene is suggested by three types seen in all plants. Intriguingly, CHX genes diversified from three to four members in one subclade of early land plants to 28 genes in eight subclades of Arabidopsis. Homologs from Spirogyra or Physcomitrella share high similarity with AtCHX20, suggesting that guard cell-specific AtCHX20 and its closest relatives are founders of the family, and pollen-expressed CHX genes appeared later in monocots and early eudicots. AtCHX proteins mediate K(+) transport and pH homeostasis, and have been localized to intracellular and plasma membrane. Thus KEA genes are conserved from green algae to angiosperms, and their presence in red algae and secondary endosymbionts suggest a role in plastids. In contrast, AtNHX1-4 subtype evolved in plant cells to handle ion homeostasis of vacuoles. The great diversity of CHX genes in land plants compared to metazoa, fungi, or algae would imply a significant role of ion and pH homeostasis at dynamic endomembranes in the vegetative and reproductive success of flowering plants.
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Affiliation(s)
- Salil Chanroj
- Department of Cell Biology and Molecular Genetics, Maryland Agricultural Experiment Station, University of MarylandCollege Park, MD, USA
| | - Guoying Wang
- Department of Cell Biology and Molecular Genetics, Maryland Agricultural Experiment Station, University of MarylandCollege Park, MD, USA
| | - Kees Venema
- Departmento de Bioquímica, Biología Celular y Molecular de Plantas, Estación Experimental del Zaidín, Consejo Superior de Investigaciones CientíficasGranada, Spain
| | - Muren Warren Zhang
- Department of Cell Biology and Molecular Genetics, Maryland Agricultural Experiment Station, University of MarylandCollege Park, MD, USA
| | - Charles F. Delwiche
- Department of Cell Biology and Molecular Genetics, Maryland Agricultural Experiment Station, University of MarylandCollege Park, MD, USA
| | - Heven Sze
- Department of Cell Biology and Molecular Genetics, Maryland Agricultural Experiment Station, University of MarylandCollege Park, MD, USA
- *Correspondence: Heven Sze, Department of Cell Biology and Molecular Genetics, Maryland Agricultural Experiment Station, University of Maryland, Bioscience Research Building # 413, College Park, MD 20742, USA. e-mail:
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283
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Pittman JK. Multiple Transport Pathways for Mediating Intracellular pH Homeostasis: The Contribution of H(+)/ion Exchangers. FRONTIERS IN PLANT SCIENCE 2012; 3:11. [PMID: 22645567 PMCID: PMC3355781 DOI: 10.3389/fpls.2012.00011] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2011] [Accepted: 01/11/2012] [Indexed: 05/21/2023]
Abstract
Intracellular pH homeostasis is an essential process in all plant cells. The transport of H(+) into intracellular compartments is critical for providing pH regulation. The maintenance of correct luminal pH in the vacuole and in compartments of the secretory/endocytic pathway is important for a variety of cellular functions including protein modification, sorting, and trafficking. It is becoming increasingly evident that coordination between primary H(+) pumps, most notably the V-ATPase, and secondary ion/H(+) exchangers allows this endomembrane pH maintenance to occur. This article describes some of the recent insights from the studies of plant cation/H(+) exchangers and anion/H(+) exchangers that demonstrate the fundamental roles of these transporters in pH homeostasis within intracellular compartments.
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Affiliation(s)
- Jon K. Pittman
- Faculty of Life Sciences, University of ManchesterManchester, UK
- *Correspondence: Jon K. Pittman, Faculty of Life Sciences, University of Manchester, Michael Smith Building, Oxford Road, Manchester M13 9PT, UK. e-mail:
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284
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Eckardt NA, Berkowitz GA. Functional analysis of Arabidopsis NHX antiporters: the role of the vacuole in cellular turgor and growth. THE PLANT CELL 2011; 23:3087-8. [PMID: 21954465 PMCID: PMC3203418 DOI: 10.1105/tpc.111.230914] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
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