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Boyer JC, Véry AA, Fristot E, Guyot V, Sentenac H, Peltier JB. Cell-free expressed uniporter and symporter systems from the plant HKT transporter family display channel-like gating and unitary conductances. THE NEW PHYTOLOGIST 2024; 243:1651-1657. [PMID: 38992953 DOI: 10.1111/nph.19958] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/22/2023] [Accepted: 06/24/2024] [Indexed: 07/13/2024]
Affiliation(s)
- Jean-Christophe Boyer
- IPSiM, Univ Montpellier, CNRS, INRAE, Institut Agro, CEDEX 2, Montpellier, 34060, France
| | - Anne-Aliénor Véry
- IPSiM, Univ Montpellier, CNRS, INRAE, Institut Agro, CEDEX 2, Montpellier, 34060, France
| | - Elsa Fristot
- IPSiM, Univ Montpellier, CNRS, INRAE, Institut Agro, CEDEX 2, Montpellier, 34060, France
| | - Valentin Guyot
- IPSiM, Univ Montpellier, CNRS, INRAE, Institut Agro, CEDEX 2, Montpellier, 34060, France
| | - Hervé Sentenac
- IPSiM, Univ Montpellier, CNRS, INRAE, Institut Agro, CEDEX 2, Montpellier, 34060, France
| | - Jean-Benoît Peltier
- IPSiM, Univ Montpellier, CNRS, INRAE, Institut Agro, CEDEX 2, Montpellier, 34060, France
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2
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Nampei M, Ogi H, Sreewongchai T, Nishida S, Ueda A. Potassium transporter OsHAK17 may contribute to saline-alkaline tolerant mechanisms in rice (Oryza sativa). JOURNAL OF PLANT RESEARCH 2024; 137:505-520. [PMID: 38427146 PMCID: PMC11082038 DOI: 10.1007/s10265-024-01529-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2023] [Accepted: 01/28/2024] [Indexed: 03/02/2024]
Abstract
Rice production is seriously affected by saline-alkaline stress worldwide. To elucidate the saline-alkaline tolerance mechanisms in a novel tolerant rice variety, Shwe Nang Gyi (SNG), we investigated ion accumulation in SNG and Koshihikari (KSH), which is a saline-alkaline sensitive rice variety, and the candidates for saline-alkaline inducible genes in SNG using RNA-seq. SNG had superior ion accumulation capacity, such as K and Zn, compared to KSH. In contrast, SNG accumulated the same level of Na content in its leaf blades as KSH despite the higher dry weight of the SNG leaf blades. We further found that the expression of numerous genes, including several K+ transporter/high-affinity K+ transporter/K+ uptake protein/K+ transporter (HAK/KUP/KT) family members, were upregulated in SNG, and that OsHAK17 and OsHAK21 expression levels in the roots were significantly higher in SNG than in KSH. Moreover, yeast complementation analysis revealed that OsHAK17 was involved in K+ uptake under high-Na conditions. These results suggested that SNG has an effective K+ acquisition system supported by OsHAK17 functioning in saline-alkaline environments.
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Affiliation(s)
- Mami Nampei
- Graduate School of Integrated Sciences for Life, Hiroshima University, 1-4-4 Kagamiyama, Higashi-Hiroshima City, Hiroshima, 739-8528, Japan
| | - Hiromu Ogi
- Graduate School of Integrated Sciences for Life, Hiroshima University, 1-4-4 Kagamiyama, Higashi-Hiroshima City, Hiroshima, 739-8528, Japan
| | - Tanee Sreewongchai
- Department of Agronomy, Faculty of Agriculture, Kasetsart University, 50 Ngam Wong Wan Road, Lat Yao, Chatuchak, 10900, Bangkok, Thailand
| | - Sho Nishida
- Faculty of Agriculture, Saga University, 1Honjo-Machi, Saga City, Saga, 840-8502, Japan
- United Graduate School of Agricultural Sciences, Kagoshima University, 1-21-24, Korimoto, Kagoshima City, Kagoshima, 890-0065, Japan
| | - Akihiro Ueda
- Graduate School of Integrated Sciences for Life, Hiroshima University, 1-4-4 Kagamiyama, Higashi-Hiroshima City, Hiroshima, 739-8528, Japan.
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3
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Ijaz U, Ahmed T, Rizwan M, Noman M, Shah AA, Azeem F, Alharby HF, Bamagoos AA, Alharbi BM, Ali S. Rice straw based silicon nanoparticles improve morphological and nutrient profile of rice plants under salinity stress by triggering physiological and genetic repair mechanisms. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2023; 201:107788. [PMID: 37302256 DOI: 10.1016/j.plaphy.2023.107788] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/24/2022] [Revised: 05/11/2023] [Accepted: 05/19/2023] [Indexed: 06/13/2023]
Abstract
The agricultural sector is facing numerous challenges worldwide, owing to global climate change and limited resources. Crop production is limited by numerous abiotic constraints. Among them, salinity stress as a combination of osmotic and ionic stress adversely influences the physiological and biochemical processes of the plant. Nanotechnology facilitates the production of crops either directly by eradicating the losses due to challenging environmental conditions or indirectly by improving tolerance against salinity stress. In this study, the protective role of silicon nanoparticles (SiNPs) was determined in two rice genotypes, N-22 and Super-Bas, differing in salinity tolerance. The SiNPs were confirmed through standard material characterization techniques, which showed the production of spherical-shaped crystalline SiNPs with a size in the range of 14.98-23.74 nm, respectively. Salinity stress adversely affected the morphological and physiological parameters of both varieties, with Super-Bas being more affected. Salt stress disturbed the ionic balance by minimizing the uptake of K+ and Ca2+ contents and increased the uptake of Na+ in plants. Exogenous SiNPs alleviated the toxic effects of salt stress and promoted the growth of both N-22 and Super-Bas, chlorophyll contents (16% and 13%), carotenoids (15% and 11%), total soluble protein contents (21% and 18%), and the activities of antioxidant enzymes. Expression analysis from quantitative real-time PCR showed that SiNPs relieved plants from oxidative bursts by triggering the expression of HKT genes. Overall, these findings demonstrate that SiNPs significantly alleviated salinity stress by triggering physiological and genetic repair mechanisms, offering a potential solution for food security.
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Affiliation(s)
- Usman Ijaz
- Department of Bioinformatics and Biotechnology, Government College University Faisalabd, Pakistan
| | - Temoor Ahmed
- State Key Laboratory of Rice Biology and Ministry of Agriculture Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of Biotechnology, Zhejiang University, Hangzhou, 310058, China
| | - Muhammad Rizwan
- Department of Environmental Sciences, Government College University, Faisalabad, Pakistan
| | - Muhammad Noman
- State Key Laboratory of Rice Biology and Ministry of Agriculture Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of Biotechnology, Zhejiang University, Hangzhou, 310058, China
| | - Anis Ali Shah
- Department of Botany, Division of Science and Technology, University of Education, Lahore, Pakistan
| | - Farrukh Azeem
- Department of Bioinformatics and Biotechnology, Government College University Faisalabd, Pakistan.
| | - Hesham F Alharby
- Department of Biological Sciences, Faculty of Science, King Abdulaziz University, Jeddah, 21589, Saudi Arabia; Plant Biology Research Group, Department of Biological Sciences, Faculty of Science, King Abdulaziz University, Jeddah, 21589, Saudi Arabia.
| | - Atif A Bamagoos
- Department of Biological Sciences, Faculty of Science, King Abdulaziz University, Jeddah, 21589, Saudi Arabia
| | - Basmah M Alharbi
- Biology Department, Faculty of Science, University of Tabuk, Tabuk, 71491, Saudi Arabia
| | - Shafaqat Ali
- Department of Environmental Sciences, Government College University, Faisalabad, Pakistan; Department of Biological Sciences and Technology, China Medical University, Taichung, 40402, Taiwan.
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4
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Cao Y, Song H, Zhang L. New Insight into Plant Saline-Alkali Tolerance Mechanisms and Application to Breeding. Int J Mol Sci 2022; 23:ijms232416048. [PMID: 36555693 PMCID: PMC9781758 DOI: 10.3390/ijms232416048] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2022] [Revised: 12/02/2022] [Accepted: 12/13/2022] [Indexed: 12/23/2022] Open
Abstract
Saline-alkali stress is a widespread adversity that severely affects plant growth and productivity. Saline-alkaline soils are characterized by high salt content and high pH values, which simultaneously cause combined damage from osmotic stress, ionic toxicity, high pH and HCO3-/CO32- stress. In recent years, many determinants of salt tolerance have been identified and their regulatory mechanisms are fairly well understood. However, the mechanism by which plants respond to comprehensive saline-alkali stress remains largely unknown. This review summarizes recent advances in the physiological, biochemical and molecular mechanisms of plants tolerance to salinity or salt- alkali stress. Focused on the progress made in elucidating the regulation mechanisms adopted by plants in response to saline-alkali stress and present some new views on the understanding of plants in the face of comprehensive stress. Plants generally promote saline-alkali tolerance by maintaining pH and Na+ homeostasis, while the plants responding to HCO3-/CO32- stress are not exactly the same as high pH stress. We proposed that pH-tolerant or sensitive plants have evolved distinct mechanisms to adapt to saline-alkaline stress. Finally, we highlight the areas that require further research to reveal the new components of saline-alkali tolerance in plants and present the current and potential application of key determinants in breed improvement and molecular breeding.
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Jiang W, Jin R, Wang D, Yang Y, Zhao P, Liu M, Zhang A, Tang Z. A Novel High-Affinity Potassium Transporter IbHKT-like Gene Enhances Low-Potassium Tolerance in Transgenic Roots of Sweet Potato ( Ipomoea batatas (L.) Lam.). PLANTS (BASEL, SWITZERLAND) 2022; 11:plants11111389. [PMID: 35684162 PMCID: PMC9182616 DOI: 10.3390/plants11111389] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/09/2022] [Revised: 05/13/2022] [Accepted: 05/17/2022] [Indexed: 05/27/2023]
Abstract
The high-affinity potassium transporters (HKT) mediate K+-Na+ homeostasis in plants. However, the function of enhancing low-potassium tolerance in sweet potato [Ipomoea batatas (L.) Lam.] remains unrevealed. In this study, a novel HKT transporter homolog IbHKT-like gene was cloned from sweet potato, which was significantly induced by potassium deficiency stress. IbHKT-like overexpressing transgenic roots were obtained from a sweet potato cultivar Xuzishu8 using an Agrobacterium rhizogenes-mediated root transgenic system in vivo. Compared with the CK, whose root cells did not overexpress the IbHKT-like gene, overexpression of the IbHKT-like gene protected cell ultrastructure from damage, and transgenic root meristem cells had intact mitochondria, endoplasmic reticulum, and Golgi dictyosomes. The steady-state K+ influx increased by 2.2 times in transgenic root meristem cells. Overexpression of the IbHKT-like gene also improved potassium content in the whole plant, which increased by 63.8% compared with the CK plants. These results could imply that the IbHKT-like gene, as a high-affinity potassium transporter gene, may play an important role in potassium deficiency stress responses.
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Affiliation(s)
- Wei Jiang
- Xuzhou Sweetpotato Research Center, Xuzhou Institute of Agricultural Sciences, Xuzhou 221121, China; (W.J.); (R.J.); (D.W.); (P.Z.); (M.L.); (A.Z.)
| | - Rong Jin
- Xuzhou Sweetpotato Research Center, Xuzhou Institute of Agricultural Sciences, Xuzhou 221121, China; (W.J.); (R.J.); (D.W.); (P.Z.); (M.L.); (A.Z.)
| | - Danfeng Wang
- Xuzhou Sweetpotato Research Center, Xuzhou Institute of Agricultural Sciences, Xuzhou 221121, China; (W.J.); (R.J.); (D.W.); (P.Z.); (M.L.); (A.Z.)
| | - Yufeng Yang
- Cereal Research Institute, Henan Academy of Agricultural Sciences, Zhengzhou 450002, China;
| | - Peng Zhao
- Xuzhou Sweetpotato Research Center, Xuzhou Institute of Agricultural Sciences, Xuzhou 221121, China; (W.J.); (R.J.); (D.W.); (P.Z.); (M.L.); (A.Z.)
| | - Ming Liu
- Xuzhou Sweetpotato Research Center, Xuzhou Institute of Agricultural Sciences, Xuzhou 221121, China; (W.J.); (R.J.); (D.W.); (P.Z.); (M.L.); (A.Z.)
| | - Aijun Zhang
- Xuzhou Sweetpotato Research Center, Xuzhou Institute of Agricultural Sciences, Xuzhou 221121, China; (W.J.); (R.J.); (D.W.); (P.Z.); (M.L.); (A.Z.)
| | - Zhonghou Tang
- Xuzhou Sweetpotato Research Center, Xuzhou Institute of Agricultural Sciences, Xuzhou 221121, China; (W.J.); (R.J.); (D.W.); (P.Z.); (M.L.); (A.Z.)
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Verma P, Sanyal SK, Pandey GK. Ca 2+-CBL-CIPK: a modulator system for efficient nutrient acquisition. PLANT CELL REPORTS 2021; 40:2111-2122. [PMID: 34415375 DOI: 10.1007/s00299-021-02772-8] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Accepted: 08/10/2021] [Indexed: 06/13/2023]
Abstract
Calcium (Ca2+) is a universal second messenger essential for the growth and development of plants in normal and stress situations. In plants, the proteins, CBL (calcineurin B-like) and CIPK (CBL-interacting protein kinase), form one of the important Ca2+ decoding complexes to decipher Ca2+ signals elicited by environmental challenges. Multiple interactors distinguish CBL and CIPK protein family members to form a signaling network for regulated perception and transduction of environmental signals, e.g., signals generated under nutrient stress conditions. Conservation of equilibrium in response to varying soil nutrient status is an important aspect for plant vigor and yield. Signaling processes have been reported to observe nutrient fluctuations as a signal responsible for regulated nutrient transport adaptation. Recent studies have identified downstream targets of CBL-CIPK modules as ion channels or transporters and their association in signaling nutrient disposal including potassium, nitrate, ammonium, magnesium, zinc, boron, and iron. Ca2+-CBL-CIPK pathway modulates ion transporters/channels and hence maintains a homeostasis of several important plant nutrients in the cytosol and sub-cellular compartments. In this article, we summarize recent literature to discuss the role of the Ca2+-CBL-CIPK pathway in cellular osmoregulation and homeostasis on exposure to nutrient excess or deprived soils. This further establishes a link between taking up the nutrient in the roots and its distribution and homeostasis during the generation of signal for the development and survival of plants.
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Affiliation(s)
- Pooja Verma
- Department of Plant Molecular Biology, University of Delhi South Campus, Benito Juarez Road, Dhaula Kuan, New Delhi, 110021, India
| | - Sibaji K Sanyal
- Department of Plant Molecular Biology, University of Delhi South Campus, Benito Juarez Road, Dhaula Kuan, New Delhi, 110021, India
| | - Girdhar K Pandey
- Department of Plant Molecular Biology, University of Delhi South Campus, Benito Juarez Road, Dhaula Kuan, New Delhi, 110021, India.
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Imran S, Tsuchiya Y, Tran STH, Katsuhara M. Identification and Characterization of Rice OsHKT1;3 Variants. PLANTS (BASEL, SWITZERLAND) 2021; 10:plants10102006. [PMID: 34685816 PMCID: PMC8537747 DOI: 10.3390/plants10102006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Revised: 09/20/2021] [Accepted: 09/21/2021] [Indexed: 05/23/2023]
Abstract
In rice, the high-affinity K+ transporter, OsHKT1;3, functions as a Na+-selective transporter. mRNA variants of OsHKT1;3 have been reported previously, but their functions remain unknown. In this study, five OsHKT1;3 variants (V1-V5) were identified from japonica rice (Nipponbare) in addition to OsHKT1;3_FL. Absolute quantification qPCR analyses revealed that the transcript level of OsHKT1;3_FL was significantly higher than other variants in both the roots and shoots. Expression levels of OsHKT1;3_FL, and some variants, increased after 24 h of salt stress. Two electrode voltage clamp experiments in a heterologous expression system using Xenopus laevis oocytes revealed that oocytes expressing OsHKT1;3_FL and all of its variants exhibited smaller Na+ currents. The presented data, together with previous data, provide insights to understanding how OsHKT family members are involved in the mechanisms of ion homeostasis and salt tolerance in rice.
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Affiliation(s)
- Shahin Imran
- Institute of Plant Science and Resources, Okayama University, 2-20-1 Chuo, Kurashiki 710-0046, Japan or (S.I.); (Y.T.); (S.T.H.T.)
- Department of Agronomy, Khulna Agricultural University, Khulna 9100, Bangladesh
| | - Yoshiyuki Tsuchiya
- Institute of Plant Science and Resources, Okayama University, 2-20-1 Chuo, Kurashiki 710-0046, Japan or (S.I.); (Y.T.); (S.T.H.T.)
| | - Sen Thi Huong Tran
- Institute of Plant Science and Resources, Okayama University, 2-20-1 Chuo, Kurashiki 710-0046, Japan or (S.I.); (Y.T.); (S.T.H.T.)
- Faculty of Agronomy, University of Agriculture and Forestry, Hue University, Hue 530000, Vietnam
| | - Maki Katsuhara
- Institute of Plant Science and Resources, Okayama University, 2-20-1 Chuo, Kurashiki 710-0046, Japan or (S.I.); (Y.T.); (S.T.H.T.)
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Tyerman SD, McGaughey SA, Qiu J, Yool AJ, Byrt CS. Adaptable and Multifunctional Ion-Conducting Aquaporins. ANNUAL REVIEW OF PLANT BIOLOGY 2021; 72:703-736. [PMID: 33577345 DOI: 10.1146/annurev-arplant-081720-013608] [Citation(s) in RCA: 43] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Aquaporins function as water and neutral solute channels, signaling hubs, disease virulence factors, and metabolon components. We consider plant aquaporins that transport ions compared to some animal counterparts. These are candidates for important, as yet unidentified, cation and anion channels in plasma, tonoplast, and symbiotic membranes. For those individual isoforms that transport ions, water, and gases, the permeability spans 12 orders of magnitude. This requires tight regulation of selectivity via protein interactions and posttranslational modifications. A phosphorylation-dependent switch between ion and water permeation in AtPIP2;1 might be explained by coupling between the gates of the four monomer water channels and the central pore of the tetramer. We consider the potential for coupling between ion and water fluxes that could form the basis of an electroosmotic transducer. A grand challenge in understanding the roles of ion transporting aquaporins is their multifunctional modes that are dependent on location, stress, time, and development.
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Affiliation(s)
- Stephen D Tyerman
- Australian Research Council (ARC) Centre of Excellence in Plant Energy Biology, School of Agriculture, Food and Wine, University of Adelaide, Glen Osmond, South Australia 5064, Australia; ,
| | - Samantha A McGaughey
- ARC Centre of Excellence for Translational Photosynthesis, Division of Plant Sciences, Research School of Biology, Australian National University, Acton, Australian Capital Territory 0200, Australia; ,
| | - Jiaen Qiu
- Australian Research Council (ARC) Centre of Excellence in Plant Energy Biology, School of Agriculture, Food and Wine, University of Adelaide, Glen Osmond, South Australia 5064, Australia; ,
| | - Andrea J Yool
- Adelaide Medical School, University of Adelaide, Adelaide, South Australia 5005, Australia;
| | - Caitlin S Byrt
- ARC Centre of Excellence for Translational Photosynthesis, Division of Plant Sciences, Research School of Biology, Australian National University, Acton, Australian Capital Territory 0200, Australia; ,
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9
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Dave A, Sanadhya P, Joshi PS, Agarwal P, Agarwal PK. Molecular cloning and characterization of high-affinity potassium transporter (AlHKT2;1) gene promoter from halophyte Aeluropus lagopoides. Int J Biol Macromol 2021; 181:1254-1264. [PMID: 33989688 DOI: 10.1016/j.ijbiomac.2021.05.038] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Revised: 03/20/2021] [Accepted: 05/04/2021] [Indexed: 11/19/2022]
Abstract
HKT subfamily II functions as Na+- K+ co-transporter and prevents plants from salinity stress. A 760 bp promoter region of AlHKT2;1 was isolated, sequenced and cloned. The full length promoter D1, has many cis-regulatory elements like MYB, MBS, W box, ABRE etc. involved in abiotic stress responses. D1 and subsequent 5' deletions were cloned into pCAMBIA1301 and studied for its efficacy in stress conditions in heterologous system. Blue colour staining was observed in flower petals, anther lobe, and dehiscence slit of anther in T0 plants. The T1 seedlings showed staining in leaf veins, shoot vasculature and root except root tip. T1 seedlings were subjected to NaCl, KCl, NaCl + KCl and ABA stresses. GUS activity was quantified by 4-methylumbelliferyl glucuronide (4-MUG) assay under control and stress conditions. The smallest deletion- D4 also showed GUS expression but highest activity was observed in D2 as compared to full length promoter and other deletions. The electrophoretic mobility shift assay using stress-induced protein with different promoter deletions revealed more prominent binding in D2. These results suggest that AlHKT2;1 promoter is involved in abiotic stress response and deletion D2 might be sufficient to drive the stress-inducible expression of various genes involved in providing stress tolerance in plants.
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Affiliation(s)
- Ankita Dave
- Division of Plant Omics, CSIR-Central Salt and Marine Chemicals Research Institute (CSIR-CSMCRI), Council of Scientific and Industrial Research (CSIR), Gijubhai Badheka Marg, Bhavnagar 364 002, Gujarat, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | - Payal Sanadhya
- Division of Plant Omics, CSIR-Central Salt and Marine Chemicals Research Institute (CSIR-CSMCRI), Council of Scientific and Industrial Research (CSIR), Gijubhai Badheka Marg, Bhavnagar 364 002, Gujarat, India
| | - Priyanka S Joshi
- Division of Plant Omics, CSIR-Central Salt and Marine Chemicals Research Institute (CSIR-CSMCRI), Council of Scientific and Industrial Research (CSIR), Gijubhai Badheka Marg, Bhavnagar 364 002, Gujarat, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | - Parinita Agarwal
- Division of Plant Omics, CSIR-Central Salt and Marine Chemicals Research Institute (CSIR-CSMCRI), Council of Scientific and Industrial Research (CSIR), Gijubhai Badheka Marg, Bhavnagar 364 002, Gujarat, India
| | - Pradeep K Agarwal
- Division of Plant Omics, CSIR-Central Salt and Marine Chemicals Research Institute (CSIR-CSMCRI), Council of Scientific and Industrial Research (CSIR), Gijubhai Badheka Marg, Bhavnagar 364 002, Gujarat, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India.
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10
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Plant HKT Channels: An Updated View on Structure, Function and Gene Regulation. Int J Mol Sci 2021; 22:ijms22041892. [PMID: 33672907 PMCID: PMC7918770 DOI: 10.3390/ijms22041892] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Revised: 01/29/2021] [Accepted: 02/09/2021] [Indexed: 12/28/2022] Open
Abstract
HKT channels are a plant protein family involved in sodium (Na+) and potassium (K+) uptake and Na+-K+ homeostasis. Some HKTs underlie salt tolerance responses in plants, while others provide a mechanism to cope with short-term K+ shortage by allowing increased Na+ uptake under K+ starvation conditions. HKT channels present a functionally versatile family divided into two classes, mainly based on a sequence polymorphism found in the sequences underlying the selectivity filter of the first pore loop. Physiologically, most class I members function as sodium uniporters, and class II members as Na+/K+ symporters. Nevertheless, even within these two classes, there is a high functional diversity that, to date, cannot be explained at the molecular level. The high complexity is also reflected at the regulatory level. HKT expression is modulated at the level of transcription, translation, and functionality of the protein. Here, we summarize and discuss the structure and conservation of the HKT channel family from algae to angiosperms. We also outline the latest findings on gene expression and the regulation of HKT channels.
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11
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Xu B, Hrmova M, Gilliham M. High affinity Na + transport by wheat HKT1;5 is blocked by K . PLANT DIRECT 2020; 4:e00275. [PMID: 33103046 PMCID: PMC7576878 DOI: 10.1002/pld3.275] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/12/2020] [Accepted: 09/21/2020] [Indexed: 05/11/2023]
Abstract
The wheat sodium transporters TmHKT1;5-A and TaHKT1;5-D are encoded by genes underlying the major shoot Na+ exclusion loci Nax2 and Kna1 from Triticum monococcum (Tm) and Triticum aestivum (Ta), respectively. In contrast to HKT2 transporters that have been shown to exhibit high affinity K+-dependent Na+ transport, HKT1 proteins have, with one exception, only been shown to catalyze low affinity Na+ transport and no K+ transport. Here, using heterologous expression in Xenopus laevis oocytes we uncover a novel property of HKT1 proteins, that both TmHKT1;5-A and TaHKT1;5-D encode dual (high and low) affinity Na+-transporters with the high-affinity component being abolished when external K+ is in excess of external Na+. Three-dimensional structural modeling suggested that, compared to Na+, K+ is bound more tightly in the selectivity filter region by means of additional van der Waals forces, which is likely to explain the K+ block at the molecular level. The low-affinity component for Na+ transport of TmHKT1;5-A had a lower K m than that of TaHKT1;5-D and was less sensitive to external K+. We propose that these properties contribute towards the improvements in shoot Na+-exclusion and crop plant salt tolerance following the introgression of TmHKT1;5-A into diverse wheat backgrounds.
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Affiliation(s)
- Bo Xu
- Australian Research Council Centre of Excellence in Plant Energy BiologyUniversity of AdelaideWaite Research PrecinctGlen OsmondSAAustralia
- School of Agriculture, Food and Wine, and Waite Research InstituteUniversity of AdelaideWaite Research PrecinctGlen OsmondSAAustralia
| | - Maria Hrmova
- School of Agriculture, Food and Wine, and Waite Research InstituteUniversity of AdelaideWaite Research PrecinctGlen OsmondSAAustralia
- School of Life ScienceHuaiyin Normal UniversityHuai’anChina
| | - Matthew Gilliham
- Australian Research Council Centre of Excellence in Plant Energy BiologyUniversity of AdelaideWaite Research PrecinctGlen OsmondSAAustralia
- School of Agriculture, Food and Wine, and Waite Research InstituteUniversity of AdelaideWaite Research PrecinctGlen OsmondSAAustralia
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12
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Ding B, Zhang X, Xu Y, An L, Liu X, Su Q. The bacterial potassium transporter gene MbtrkH improves K+ uptake in yeast and tobacco. PLoS One 2020; 15:e0236246. [PMID: 32804956 PMCID: PMC7430745 DOI: 10.1371/journal.pone.0236246] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2019] [Accepted: 07/01/2020] [Indexed: 11/19/2022] Open
Abstract
K+ is an essential nutrient for plant growth and is responsible for many important physiological processes. K+ deficiency leads to crop yield losses, and overexpression of K+ transporter genes has been proven to be an effective way to resolve this problem. However, current research on the overexpression of K+ transporter genes is limited to plant sources. TrkH is a bacterial K+ transporter whose function generally depends on the regulation of TrkA. To date, whether TrkH can improve K+ uptake in eukaryotic organisms is still unknown. In this study, a novel MbtrkH gene was cloned from marine microbial metagenomic DNA. Functional complementation and K+-depletion analyses revealed that MbTrkH functions in K+ uptake in the K+-deficient yeast strain CY162. Moreover, K+-depletion assays revealed that MbtrkH overexpression improves plant K+ uptake. K+ hydroponic culture experiments showed that, compared with WT tobacco lines, MbtrkH transgenic tobacco lines had significantly greater fresh weights, dry weights and K+ contents. These results indicate that MbTrkH promotes K+ uptake independently of TrkA in eukaryotes and provide a new strategy for improving K+-use efficiency in plants.
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Affiliation(s)
- Baojuan Ding
- School of Bioengineering, Dalian University of Technology, Dalian, P. R. China
| | - Xiaoyan Zhang
- School of Bioengineering, Dalian University of Technology, Dalian, P. R. China
| | - Yongsheng Xu
- School of Bioengineering, Dalian University of Technology, Dalian, P. R. China
| | - Lijia An
- School of Bioengineering, Dalian University of Technology, Dalian, P. R. China
| | - Xiangguo Liu
- Institute of Agricultural Biotechnology, Jilin Academy of Agricultural Sciences, Changchun, P. R. China
| | - Qiao Su
- School of Bioengineering, Dalian University of Technology, Dalian, P. R. China
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13
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Huang L, Wu DZ, Zhang GP. Advances in studies on ion transporters involved in salt tolerance and breeding crop cultivars with high salt tolerance. J Zhejiang Univ Sci B 2020; 21:426-441. [PMID: 32478490 PMCID: PMC7306632 DOI: 10.1631/jzus.b1900510] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2019] [Revised: 12/27/2019] [Accepted: 12/27/2019] [Indexed: 11/11/2022]
Abstract
Soil salinity is a global major abiotic stress threatening crop productivity. In salty conditions, plants may suffer from osmotic, ionic, and oxidative stresses, resulting in inhibition of growth and development. To deal with these stresses, plants have developed a series of tolerance mechanisms, including osmotic adjustment through accumulating compatible solutes in the cytoplasm, reactive oxygen species (ROS) scavenging through enhancing the activity of anti-oxidative enzymes, and Na+/K+ homeostasis regulation through controlling Na+ uptake and transportation. In this review, recent advances in studies of the mechanisms of salt tolerance in plants are described in relation to the ionome, transcriptome, proteome, and metabolome, and the main factor accounting for differences in salt tolerance among plant species or genotypes within a species is presented. We also discuss the application and roles of different breeding methodologies in developing salt-tolerant crop cultivars. In particular, we describe the advantages and perspectives of genome or gene editing in improving the salt tolerance of crops.
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14
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Hartley TN, Thomas AS, Maathuis FJM. A role for the OsHKT 2;1 sodium transporter in potassium use efficiency in rice. JOURNAL OF EXPERIMENTAL BOTANY 2020; 71:699-706. [PMID: 30854552 PMCID: PMC6946003 DOI: 10.1093/jxb/erz113] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/08/2019] [Accepted: 02/25/2019] [Indexed: 05/20/2023]
Abstract
Increasing the potassium use efficiency (KUE) of crops is important for agricultural sustainability. However, a greater understanding of this complex trait is required to develop new, high-KUE cultivars. To this end, a genome-wide association study (GWAS) was applied to diverse rice (Oryza sativa L.) genotypes grown under potassium-stressed and -replete conditions. Using high-stringency criteria, the genetic architecture of KUE was uncovered, together with the breadth of physiological responses to low-potassium stress. Specifically, three quantitative trait loci (QTLs) were identified, which contained >90 candidate genes. Of these, the sodium transporter gene OsHKT2;1 emerged as a key factor that impacts on KUE based on (i) the correlation between shoot Na+ and KUE, and (ii) higher levels of HKT2;1 expression in high-KUE lines.
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15
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Khan I, Mohamed S, Regnault T, Mieulet D, Guiderdoni E, Sentenac H, Véry AA. Constitutive Contribution by the Rice OsHKT1;4 Na + Transporter to Xylem Sap Desalinization and Low Na + Accumulation in Young Leaves Under Low as High External Na + Conditions. FRONTIERS IN PLANT SCIENCE 2020; 11:1130. [PMID: 32849692 PMCID: PMC7406799 DOI: 10.3389/fpls.2020.01130] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Accepted: 07/09/2020] [Indexed: 05/03/2023]
Abstract
HKT Na+ transporters correspond to major salt tolerance QTLs in different plant species and are targets of great interest for breeders. In rice, the HKT family is composed of seven or eight functional genes depending on cultivars. Three rice HKT genes, OsHKT1;1, OsHKT1;4 and OsHKT1;5, are known to contribute to salt tolerance by reducing Na+ accumulation in shoots upon salt stress. Here, we further investigate the mechanisms by which OsHKT1;4 contributes to this process and extend this analysis to the role of this transporter in plants in presence of low Na+ concentrations. By analyzing transgenic rice plants expressing a GUS reporter gene construct, we observed that OsHKT1;4 is mainly expressed in xylem parenchyma in both roots and leaves. Using mutant lines expressing artificial microRNA that selectively reduced OsHKT1;4 expression, the involvement of OsHKT1;4 in retrieving Na+ from the xylem sap in the roots upon salt stress was evidenced. Since OsHKT1;4 was found to be also well expressed in the roots in absence of salt stress, we extended the analysis of its role when plants were subjected to non-toxic Na+ conditions (0.5 and 5 mM). Our finding that the transporter, expressed in Xenopus oocytes, displayed a relatively high affinity for Na+, just above 1 mM, provided first support to the hypothesis that OsHKT1;4 could have a physiological role at low Na+ concentrations. We observed that progressive desalinization of the xylem sap along its ascent to the leaf blades still occurred in plants grown at submillimolar Na+ concentration, and that OsHKT1;4 was involved in reducing xylem sap Na+ concentration in roots in these conditions too. Its contribution to tissue desalinization from roots to young mature leaf blades appeared to be rather similar in the whole range of explored external Na+ concentrations, from submillimolar to salt stress conditions. Our data therefore indicate that HKT transporters can be involved in controlling Na+ translocation from roots to shoots in a much wider range of Na+ concentrations than previously thought. This asks questions about the roles of such a transporter-mediated maintaining of tissue Na+ content gradients in non-toxic conditions.
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Affiliation(s)
- Imran Khan
- BPMP, Univ Montpellier, CNRS, INRAE, Institut Agro, Montpellier, France
| | - Sonia Mohamed
- BPMP, Univ Montpellier, CNRS, INRAE, Institut Agro, Montpellier, France
| | - Thomas Regnault
- BPMP, Univ Montpellier, CNRS, INRAE, Institut Agro, Montpellier, France
| | - Delphine Mieulet
- CIRAD, UMR AGAP, Montpellier, France
- Université de Montpellier, CIRAD, INRAE, Institut Agro, Montpellier, France
| | - Emmanuel Guiderdoni
- CIRAD, UMR AGAP, Montpellier, France
- Université de Montpellier, CIRAD, INRAE, Institut Agro, Montpellier, France
| | - Hervé Sentenac
- BPMP, Univ Montpellier, CNRS, INRAE, Institut Agro, Montpellier, France
| | - Anne-Aliénor Véry
- BPMP, Univ Montpellier, CNRS, INRAE, Institut Agro, Montpellier, France
- *Correspondence: Anne-Aliénor Véry,
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16
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Chakraborty K, Chattaopadhyay K, Nayak L, Ray S, Yeasmin L, Jena P, Gupta S, Mohanty SK, Swain P, Sarkar RK. Ionic selectivity and coordinated transport of Na + and K + in flag leaves render differential salt tolerance in rice at the reproductive stage. PLANTA 2019; 250:1637-1653. [PMID: 31399792 DOI: 10.1007/s00425-019-03253-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2019] [Accepted: 08/01/2019] [Indexed: 05/27/2023]
Abstract
The present study shows that salt tolerance in the reproductive stage of rice is primarily governed by the selective Na+ and K+ transport from the root to upper plant parts. Ionic discrimination at the flag leaf, governed by differential expression of Na+- and K+-specific transporters/ion pumps, is associated with reduced spikelet sterility and reproductive stage salt tolerance. Reproductive stage salt tolerance is crucial in rice to guarantee yield under saline condition. In the present study, differential ionic selectivity and the coordinated transport (from root to flag leaf) of Na+ and K+ were investigated to assess their impact on reproductive stage salt tolerance. Four rice genotypes having differential salt sensitivity were subjected to reproductive stage salinity stress in pots. The selective Na+ and K+ transport from the root to upper plant parts was observed in tolerant genotypes. We noticed that prolonged salt exposure did not alter flag leaf greenness even up to 6 weeks; however, it had a detrimental effect on panicle development especially in the salt-susceptible genotype Sabita. But more precise chlorophyll fluorescence imaging analysis revealed salinity-induced damages in Sabita. The salt-tolerant genotype Pokkali (AC41585), a potential Na+ excluder, managed to sequester higher Na+ load in the roots with little upward transport as evident from greater expression of HKT1 and HKT2 transporters. In contrast, the moderately salt-tolerant Lunidhan was less selective in Na+ transport, but possessed a higher capacity to Na+ sequestration in leaves. Higher K+ uptake and tissue-specific redistribution mediated by HAK and AKT transporters showed robust control in selective K+ movement from the root to flag leaf and developing panicles. On the contrary, expressions of Na+-specific transporters in developing panicles were either down-regulated or unaffected in tolerant and moderately tolerant genotypes. Yet, in the panicles of the susceptible genotype Sabita, some of the Na+-specific transporter genes (SOS1, HKT1;5, HKT2;4) were upregulated. Apart from the ionic regulation strategy, cellular energy balance mediated by different plasma-membrane and tonoplastic H+-pumps were also associated with the reproductive stage salt tolerance in rice.
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Affiliation(s)
| | | | - Lopamudra Nayak
- ICAR, National Rice Research Institute, Cuttack, Odisha, 753006, India
| | - Soham Ray
- ICAR, National Rice Research Institute, Cuttack, Odisha, 753006, India
| | - Lucina Yeasmin
- ICAR, National Rice Research Institute, Cuttack, Odisha, 753006, India
| | - Priyanka Jena
- ICAR, National Rice Research Institute, Cuttack, Odisha, 753006, India
| | - Sunanda Gupta
- ICAR, National Rice Research Institute, Cuttack, Odisha, 753006, India
| | - Sangram K Mohanty
- ICAR, National Rice Research Institute, Cuttack, Odisha, 753006, India
| | - Padmini Swain
- ICAR, National Rice Research Institute, Cuttack, Odisha, 753006, India
| | - Ramani K Sarkar
- ICAR, National Rice Research Institute, Cuttack, Odisha, 753006, India
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17
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Hmidi D, Messedi D, Corratgï-Faillie C, Marhuenda TO, Fizames CC, Zorrig W, Abdelly C, Sentenac H, Vï Ry AAN. Investigation of Na+ and K+ Transport in Halophytes: Functional Analysis of the HmHKT2;1 Transporter from Hordeum maritimum and Expression under Saline Conditions. PLANT & CELL PHYSIOLOGY 2019; 60:2423-2435. [PMID: 31292634 DOI: 10.1093/pcp/pcz136] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2018] [Accepted: 07/04/2019] [Indexed: 06/09/2023]
Abstract
Control of K+ and Na+ transport plays a central role in plant adaptation to salinity. In the halophyte Hordeum maritimum, we have characterized a transporter gene, named HmHKT2;1, whose homolog HvHKT2;1 in cultivated barley, Hordeum vulgare, was known to give rise to increased salt tolerance when overexpressed. The encoded protein is strictly identical in two H. maritimum ecotypes, from two biotopes (Tunisian sebkhas) affected by different levels of salinity. These two ecotypes were found to display distinctive responses to salt stress in terms of biomass production, Na+ contents, K+ contents and K+ absorption efficiency. Electrophysiological analysis of HmHKT2;1 in Xenopus oocytes revealed distinctive properties when compared with HvHKT2;1 and other transporters from the same group, especially a much higher affinity for both Na+ and K+, and an Na+-K+ symporter behavior in a very broad range of Na+ and K+ concentrations, due to reduced K+ blockage of the transport pathway. Domain swapping experiments identified the region including the fifth transmembrane segment and the adjacent extracellular loop as playing a major role in the determination of the affinity for Na+ and the level of K+ blockage in these HKT2;1 transporters. The analysis (quantitative reverse transcription-PCR; qRT-PCR) of HmHKT2;1 expression in the two ecotypes submitted to saline conditions revealed that the levels of HmHKT2;1 transcripts were maintained constant in the most salt-tolerant ecotype whereas they decreased in the less tolerant one. Both the unique functional properties of HmHKT2;1 and the regulation of the expression of the encoding gene could contribute to H. maritimum adaptation to salinity.
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Affiliation(s)
- Dorsaf Hmidi
- Biochimie et Physiologie Mol�culaire des Plantes, Univ Montpellier, CNRS, INRA, SupAgro Montpellier, Campus SupAgro-INRA, Montpellier Cedex 2, France
- Laboratoire des Plantes Extr�mophiles, BP 901, Centre de Biotechnologie, Technopole de Borj C�dria, HammamLif, Tunisia
| | - Dorsaf Messedi
- Laboratoire des Plantes Extr�mophiles, BP 901, Centre de Biotechnologie, Technopole de Borj C�dria, HammamLif, Tunisia
| | - Claire Corratgï-Faillie
- Biochimie et Physiologie Mol�culaire des Plantes, Univ Montpellier, CNRS, INRA, SupAgro Montpellier, Campus SupAgro-INRA, Montpellier Cedex 2, France
| | - Thï O Marhuenda
- Biochimie et Physiologie Mol�culaire des Plantes, Univ Montpellier, CNRS, INRA, SupAgro Montpellier, Campus SupAgro-INRA, Montpellier Cedex 2, France
| | - Cï Cile Fizames
- Biochimie et Physiologie Mol�culaire des Plantes, Univ Montpellier, CNRS, INRA, SupAgro Montpellier, Campus SupAgro-INRA, Montpellier Cedex 2, France
| | - Walid Zorrig
- Laboratoire des Plantes Extr�mophiles, BP 901, Centre de Biotechnologie, Technopole de Borj C�dria, HammamLif, Tunisia
| | - Chedly Abdelly
- Laboratoire des Plantes Extr�mophiles, BP 901, Centre de Biotechnologie, Technopole de Borj C�dria, HammamLif, Tunisia
| | - Hervï Sentenac
- Biochimie et Physiologie Mol�culaire des Plantes, Univ Montpellier, CNRS, INRA, SupAgro Montpellier, Campus SupAgro-INRA, Montpellier Cedex 2, France
| | - Anne-Aliï Nor Vï Ry
- Biochimie et Physiologie Mol�culaire des Plantes, Univ Montpellier, CNRS, INRA, SupAgro Montpellier, Campus SupAgro-INRA, Montpellier Cedex 2, France
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18
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Park YC, Lim SD, Moon JC, Jang CS. A rice really interesting new gene H2-type E3 ligase, OsSIRH2-14, enhances salinity tolerance via ubiquitin/26S proteasome-mediated degradation of salt-related proteins. PLANT, CELL & ENVIRONMENT 2019; 42:3061-3076. [PMID: 31325169 DOI: 10.1111/pce.13619] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2019] [Accepted: 07/12/2019] [Indexed: 05/20/2023]
Abstract
Salinity is a deleterious abiotic stress factor that affects growth, productivity, and physiology of crop plants. Strategies for improving salinity tolerance in plants are critical for crop breeding programmes. Here, we characterized the rice (Oryza sativa) really interesting new gene (RING) H2-type E3 ligase, OsSIRH2-14 (previously named OsRFPH2-14), which plays a positive role in salinity tolerance by regulating salt-related proteins including an HKT-type Na+ transporter (OsHKT2;1). OsSIRH2-14 expression was induced in root and shoot tissues treated with NaCl. The OsSIRH2-14-EYFP fusion protein was predominately expressed in the cytoplasm, Golgi, and plasma membrane of rice protoplasts. In vitro pull-down assays and bimolecular fluorescence complementation assays revealed that OsSIRH2-14 interacts with salt-related proteins, including OsHKT2;1. OsSIRH2-14 E3 ligase regulates OsHKT2;1 via the 26S proteasome system under high NaCl concentrations but not under normal conditions. Compared with wild type plants, OsSIRH2-14-overexpressing rice plants showed significantly enhanced salinity tolerance and reduced Na+ accumulation in the aerial shoot and root tissues. These results suggest that the OsSIRH2-14 RING E3 ligase positively regulates the salinity stress response by modulating the stability of salt-related proteins.
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Affiliation(s)
- Yong Chan Park
- Plant Genomics Lab, Department of Applied Plant Sciences, Kangwon National University, Chuncheon, 24341, Republic of Korea
| | - Sung Don Lim
- Plant Genomics Lab, Department of Applied Plant Sciences, Kangwon National University, Chuncheon, 24341, Republic of Korea
| | - Jun-Cheol Moon
- Plant Genomics Lab, Department of Applied Plant Sciences, Kangwon National University, Chuncheon, 24341, Republic of Korea
| | - Cheol Seong Jang
- Plant Genomics Lab, Department of Applied Plant Sciences, Kangwon National University, Chuncheon, 24341, Republic of Korea
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19
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Cao Y, Liang X, Yin P, Zhang M, Jiang C. A domestication-associated reduction in K + -preferring HKT transporter activity underlies maize shoot K + accumulation and salt tolerance. THE NEW PHYTOLOGIST 2019; 222:301-317. [PMID: 30461018 DOI: 10.1111/nph.15605] [Citation(s) in RCA: 55] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2018] [Accepted: 11/10/2018] [Indexed: 05/26/2023]
Abstract
Maize was domesticated from Balsas teosinte c. 10 000 yr ago. Previous studies have suggested that increased tolerance to environmental stress occurred during maize domestication. However, the underlying genetic basis remains largely unknown. We used a maize (W22)-teosinte recombinant inbred line (RIL) to investigate the salt wild-type tolerance aspects of maize domestication. We revealed that ZmHKT2 is a major QTL that regulates K+ homeostasis in saline soils. ZmHKT2 encodes a K+ -preferring HKT family transporter and probably reduces shoot K+ content by removing K+ ions from root-to-shoot flowing xylem sap, ZmHKT2 deficiency increases xylem sap and shoot K+ concentrations, and increases salt tolerance. A coding sequence polymorphism in the ZmHKT2W22 allele (SNP389-G) confers an amino acid variant ZmHKT2 that increases xylem sap K+ concentration, thereby increasing shoot K+ content and salt tolerance. Additional analyses showed that SNP389-G first existed in teosinte (allele frequency 56% in assayed accessions), then swept through the maize population (allele frequency 98%), and that SNP389-G probably underwent positive selection during maize domestication. We conclude that a domestication-associated reduction in K+ transport activity in ZmHKT2 underlies maize shoot K+ content and salt tolerance, and propose that CRISPR-based editing of ZmHKT2 might provide a feasible strategy for improving maize salt tolerance.
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Affiliation(s)
- Yibo Cao
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing, 100094, China
| | - Xiaoyan Liang
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing, 100094, China
| | - Pan Yin
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing, 100094, China
| | - Ming Zhang
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing, 100094, China
| | - Caifu Jiang
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing, 100094, China
- Center for Crop Functional Genomics and Molecular Breeding, China Agricultural University, Beijing, 100094, China
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20
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Li N, Du C, Ma B, Gao Z, Wu Z, Zheng L, Niu Y, Wang Y. Functional Analysis of Ion Transport Properties and Salt Tolerance Mechanisms of RtHKT1 from the Recretohalophyte Reaumuria trigyna. PLANT & CELL PHYSIOLOGY 2019; 60:85-106. [PMID: 30239906 DOI: 10.1093/pcp/pcy187] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/06/2018] [Indexed: 05/13/2023]
Abstract
Reaumuria trigyna is an endangered recretohalophyte and a small archaic feral shrub that is endemic to arid and semi-arid plateau regions of Inner Mongolia, China. Based on transcriptomic data, we isolated a high-affinity potassium transporter gene (RtHKT1) from R. trigyna, which encoded a plasma membrane-localized protein. RtHKT1 was rapidly up-regulated by high Na+ or low K+ and exhibited different tissue-specific expression patterns before and after stress treatment. Transgenic yeast showed tolerance to high Na+ or low K+, while transgenic Arabidopsis exhibited tolerance to high Na+ and sensitivity to high K+, or high Na+-low K+, confirming that Na+ tolerance in transgenic Arabidopsis depends on a sufficient external K+ concentration. Under external high Na+, high K+ and low K+ conditions, transgenic yeast accumulated more Na+-K+, Na+ and K+, while transgenic Arabidopsis accumulated less Na+-more K+, more Na+ and more Na+-K+, respectively, indicating that the ion transport properties of RtHKT1 depend on the external Na+-K+ environment. Salt stress induced up-regulation of some ion transporter genes (AtSOS1/AtHAK5/AtKUP5-6), as well as down-regulation of some genes (AtNHX1/AtAVP1/AtKUP9-12), revealing that multi-ion-transporter synergism maintains Na+/K+ homeostasis under salt stress in transgenic Arabidopsis. Overexpression of RtHKT1 enhanced K+ accumulation and prevented Na+ transport from roots to shoots, improved biomass accumulation and Chl content in salt-stressed transgenic Arabidopsis. The proline content and relative water content increased significantly, and some proline biosynthesis genes (AtP5CS1 and AtP5CS2) were also up-regulated in salt-stressed transgenic plants. These results suggest that RtHKT1 confers salt tolerance on transgenic Arabidopsis by maintaining Na+/K+ homeostasis and osmotic homeostasis.
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Affiliation(s)
- Ningning Li
- Key Laboratory of Herbage and Endemic Crop Biotechnology (Inner Mongolia University), Ministry of Education, College of Life Sciences, Inner Mongolia University, 24 Zhaojun Road, Hohhot, China
| | - Chao Du
- Key Laboratory of Herbage and Endemic Crop Biotechnology (Inner Mongolia University), Ministry of Education, College of Life Sciences, Inner Mongolia University, 24 Zhaojun Road, Hohhot, China
| | - Binjie Ma
- Key Laboratory of Herbage and Endemic Crop Biotechnology (Inner Mongolia University), Ministry of Education, College of Life Sciences, Inner Mongolia University, 24 Zhaojun Road, Hohhot, China
| | - Ziqi Gao
- Key Laboratory of Herbage and Endemic Crop Biotechnology (Inner Mongolia University), Ministry of Education, College of Life Sciences, Inner Mongolia University, 24 Zhaojun Road, Hohhot, China
| | - Zhigang Wu
- Key Laboratory of Herbage and Endemic Crop Biotechnology (Inner Mongolia University), Ministry of Education, College of Life Sciences, Inner Mongolia University, 24 Zhaojun Road, Hohhot, China
| | - Linlin Zheng
- Key Laboratory of Herbage and Endemic Crop Biotechnology (Inner Mongolia University), Ministry of Education, College of Life Sciences, Inner Mongolia University, 24 Zhaojun Road, Hohhot, China
| | - Yiding Niu
- Key Laboratory of Herbage and Endemic Crop Biotechnology (Inner Mongolia University), Ministry of Education, College of Life Sciences, Inner Mongolia University, 24 Zhaojun Road, Hohhot, China
| | - Yingchun Wang
- Key Laboratory of Herbage and Endemic Crop Biotechnology (Inner Mongolia University), Ministry of Education, College of Life Sciences, Inner Mongolia University, 24 Zhaojun Road, Hohhot, China
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21
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Tada Y, Endo C, Katsuhara M, Horie T, Shibasaka M, Nakahara Y, Kurusu T. High-Affinity K+ Transporters from a Halophyte, Sporobolus virginicus, Mediate Both K+ and Na+ Transport in Transgenic Arabidopsis, X. laevis Oocytes and Yeast. PLANT & CELL PHYSIOLOGY 2019; 60:176-187. [PMID: 30325438 DOI: 10.1093/pcp/pcy202] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2018] [Accepted: 10/04/2018] [Indexed: 06/08/2023]
Abstract
Class II high-affinity potassium transporters (HKTs) have been proposed to mediate Na+-K+ co-transport in plants, as well as Na+ and K+ homeostasis under K+-starved and saline environments. We identified class II HKTs, namely SvHKT2;1 and SvHKT2;2 (SvHKTs), from the halophytic turf grass, Sporobolus virginicus. SvHKT2;2 expression in S. virginicus was up-regulated by NaCl treatment, while SvHKT2;1 expression was assumed to be up-regulated by K+ starvation and down-regulated by NaCl treatment. Localization analysis revealed SvHKTs predominantly targeted the plasma membrane. SvHKTs complemented K+ uptake deficiency in mutant yeast, and showed both inward and outward K+ and Na+ transport activity in Xenopus laevis oocytes. When constitutively expressed in Arabidopsis, SvHKTs mediated K+ and Na+ accumulation in shoots under K+-starved conditions, and the K+ concentration in xylem saps of transformants was also higher than in those of wild-type plants. These results suggest transporter-enhanced K+ and Na+ uploading to the xylem from xylem parenchyma cells. Together, our data demonstrate that SvHKTs mediate both outward and inward K+ and Na+ transport in X. laevis oocytes, and possibly in plant and yeast cells, depending on the ionic conditions.
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Affiliation(s)
- Yuichi Tada
- School of Bioscience and Biotechnology, Tokyo University of Technology, 1404-1 Katakura, Hachioji, Tokyo, Japan
| | - Chisato Endo
- School of Bioscience and Biotechnology, Tokyo University of Technology, 1404-1 Katakura, Hachioji, Tokyo, Japan
| | - Maki Katsuhara
- Institute of Plant Science and Resources, Okayama University, Chuo 2-20-1, Kurashiki, Okayama, Japan
| | - Tomoaki Horie
- Division of Applied Biology, Faculty of Textile Science and Technology, Shinshu University, 3-15-1 Tokida, Ueda, Nagano, Japan
| | - Mineo Shibasaka
- Institute of Plant Science and Resources, Okayama University, Chuo 2-20-1, Kurashiki, Okayama, Japan
| | - Yoshiki Nakahara
- Institute of Plant Science and Resources, Okayama University, Chuo 2-20-1, Kurashiki, Okayama, Japan
| | - Takamitsu Kurusu
- School of Bioscience and Biotechnology, Tokyo University of Technology, 1404-1 Katakura, Hachioji, Tokyo, Japan
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22
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Zhang Y, Fang J, Wu X, Dong L. Na +/K + Balance and Transport Regulatory Mechanisms in Weedy and Cultivated Rice (Oryza sativa L.) Under Salt Stress. BMC PLANT BIOLOGY 2018; 18:375. [PMID: 30594151 PMCID: PMC6311050 DOI: 10.1186/s12870-018-1586-9] [Citation(s) in RCA: 65] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2018] [Accepted: 12/03/2018] [Indexed: 05/20/2023]
Abstract
BACKGROUND Salinization is a primary abiotic stress constraining global plant growth and production. Weedy rice, though highly homologous to cultivated rice, is more salt tolerant during seed germination and seedling growth; we hypothesize that this is owing to ionic homeostasis and changes in the expression of genes encoding ion transport regulators. RESULTS The four different genotypes of weedy (JYGY-1 and JYFN-4) and cultivated (Nipponbare and 9311) rice have different salt-tolerance during seed germination and seedling vegetative growth under salt stress. In this study, Na+ and Ca2+content increased in weedy and cultivated rice genotypes under salt stress while K+ and Mg2+decreased; however, JYGY-1 had the lowest Na+/K+ ratio of assessed genotypes. Genes in the high-affinity K+ transporter (HKT) and tonoplast sodium-hydrogen exchanger (NHX) families, and salt overly sensitive 1 (OsSOS1) have more than 98% homology in amino acid sequences between weedy and cultivated rice genotypes. Under salt stress, the HKT family members were differentially expressed in the roots and shoots of four different genotypes. However, the NHX family transcripts were markedly up-regulated in all genotypes, but there are significant differences between different genotypes. OsSOS1 was significantly up-regulated in roots, especially in JYGY-1genotype. CONCLUSIONS The results showed that different genotypes had different germination and nutrient survival under salt stress, which was related to the difference of ion content and the difference of a series of ion transport gene expression. At the same time this study will provide new insight into the similarities and differences in ion homeostasis and gene regulatory mechanisms between weedy and cultivated rice under salt stress, which can aid in novel rice breeding and growth strategies.
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Affiliation(s)
- Yuhua Zhang
- College of Plant Protection, Nanjing Agricultural University, Nanjing, 210095, China
- Key Laboratory of Integrated Pest Management on Crops in East China, Ministry of Agriculture, Nanjing Agricultural University, Nanjing, 210095, China
| | - Jiapeng Fang
- College of Plant Protection, Nanjing Agricultural University, Nanjing, 210095, China
- Key Laboratory of Integrated Pest Management on Crops in East China, Ministry of Agriculture, Nanjing Agricultural University, Nanjing, 210095, China
| | - Xibao Wu
- College of Plant Protection, Nanjing Agricultural University, Nanjing, 210095, China
- Key Laboratory of Integrated Pest Management on Crops in East China, Ministry of Agriculture, Nanjing Agricultural University, Nanjing, 210095, China
| | - Liyao Dong
- College of Plant Protection, Nanjing Agricultural University, Nanjing, 210095, China.
- Key Laboratory of Integrated Pest Management on Crops in East China, Ministry of Agriculture, Nanjing Agricultural University, Nanjing, 210095, China.
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Han Y, Yin S, Huang L, Wu X, Zeng J, Liu X, Qiu L, Munns R, Chen ZH, Zhang G. A Sodium Transporter HvHKT1;1 Confers Salt Tolerance in Barley via Regulating Tissue and Cell Ion Homeostasis. PLANT & CELL PHYSIOLOGY 2018; 59:1976-1989. [PMID: 29917153 DOI: 10.1093/pcp/pcy116] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2018] [Accepted: 06/10/2018] [Indexed: 05/21/2023]
Abstract
Our previous studies showed that high salt tolerance in Tibetan wild barley accessions was associated with HvHKT1;1, a member of the high-affinity potassium transporter family. However, molecular mechanisms of HvHKT1;1 for salt tolerance and its roles in K+/Na+ homeostasis remain to be elucidated. Functional characterization of HvHKT1;1 was conducted in the present study. NaCl-induced transcripts of HvHKT1;1 were significantly higher in the roots of Tibetan wild barley XZ16 relative to other genotypes, being closely associated with its higher biomass and lower tissue Na+ content under salt stress. Heterologous expression of HvHKT1;1 in Saccharomyces cerevisiae (yeast) and Xenopus laevis oocytes showed that HvHKT1;1 had higher selectivity for Na+ over K+ and other monovalent cations. HvHKT1;1 was found to be localized at the cell plasma membrane of root stele and epidermis. Knock-down of HvHKT1;1 in barley led to higher Na+ accumulation in both roots and leaves, while overexpression of HvHKT1;1 in salt-sensitive Arabidopsis hkt1-4 and sos1-12 loss-of-function lines resulted in significantly less shoot and root Na+ accumulation. Additionally, microelectrode ion flux measurements and root elongation assay revealed that the transgenic Arabidopsis plants exhibited a remarkable capacity for regulation of Na+, K+, Ca2+ and H+ homeostasis under salt stress. These results indicate that HvHKT1;1 is critical in radial root Na+ transport, which eventually reduces shoot Na+ accumulation. Additionally, HvHKT1;1 may be indirectly involved in retention of K+ and Ca2+ in root cells, which also improves plant salt tolerance.
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Affiliation(s)
- Yong Han
- Agronomy Department, Key Laboratory of Crop Germplasm Resource of Zhejiang Province, Zhejiang University, Hangzhou, China
| | - Shuya Yin
- Agronomy Department, Key Laboratory of Crop Germplasm Resource of Zhejiang Province, Zhejiang University, Hangzhou, China
| | - Lu Huang
- Agronomy Department, Key Laboratory of Crop Germplasm Resource of Zhejiang Province, Zhejiang University, Hangzhou, China
| | - Xuelong Wu
- Agronomy Department, Key Laboratory of Crop Germplasm Resource of Zhejiang Province, Zhejiang University, Hangzhou, China
| | - Jianbin Zeng
- Agronomy Department, Key Laboratory of Crop Germplasm Resource of Zhejiang Province, Zhejiang University, Hangzhou, China
| | - Xiaohui Liu
- School of Science and Health, Hawkesbury Institute for the Environment, Western Sydney University, Penrith, NSW, Australia
| | - Long Qiu
- Agronomy Department, Key Laboratory of Crop Germplasm Resource of Zhejiang Province, Zhejiang University, Hangzhou, China
| | - Rana Munns
- Australian Research Council Centre of Excellence in Plant Energy Biology and School of Agriculture and Environment, University of Western Australia, Crawley, WA, Australia
| | - Zhong-Hua Chen
- Agronomy Department, Key Laboratory of Crop Germplasm Resource of Zhejiang Province, Zhejiang University, Hangzhou, China
- School of Science and Health, Hawkesbury Institute for the Environment, Western Sydney University, Penrith, NSW, Australia
| | - Guoping Zhang
- Agronomy Department, Key Laboratory of Crop Germplasm Resource of Zhejiang Province, Zhejiang University, Hangzhou, China
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Tounsi S, Feki K, Saïdi MN, Maghrebi S, Brini F, Masmoudi K. Promoter of the TmHKT1;4-A1 gene of Triticum monococcum directs stress inducible, developmental regulated and organ specific gene expression in transgenic Arbidopsis thaliana. World J Microbiol Biotechnol 2018; 34:99. [DOI: 10.1007/s11274-018-2485-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2018] [Accepted: 06/16/2018] [Indexed: 11/30/2022]
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25
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Hazzouri KM, Khraiwesh B, Amiri KMA, Pauli D, Blake T, Shahid M, Mullath SK, Nelson D, Mansour AL, Salehi-Ashtiani K, Purugganan M, Masmoudi K. Mapping of HKT1;5 Gene in Barley Using GWAS Approach and Its Implication in Salt Tolerance Mechanism. FRONTIERS IN PLANT SCIENCE 2018; 9:156. [PMID: 29515598 PMCID: PMC5826053 DOI: 10.3389/fpls.2018.00156] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/04/2017] [Accepted: 01/29/2018] [Indexed: 05/20/2023]
Abstract
Sodium (Na+) accumulation in the cytosol will result in ion homeostasis imbalance and toxicity of transpiring leaves. Studies of salinity tolerance in the diploid wheat ancestor Triticum monococcum showed that HKT1;5-like gene was a major gene in the QTL for salt tolerance, named Nax2. In the present study, we were interested in investigating the molecular mechanisms underpinning the role of the HKT1;5 gene in salt tolerance in barley (Hordeum vulgare). A USDA mini-core collection of 2,671 barley lines, part of a field trial was screened for salinity tolerance, and a Genome Wide Association Study (GWAS) was performed. Our results showed important SNPs that are correlated with salt tolerance that mapped to a region where HKT1;5 ion transporter located on chromosome four. Furthermore, sodium (Na+) and potassium (K+) content analysis revealed that tolerant lines accumulate more sodium in roots and leaf sheaths, than in the sensitive ones. In contrast, sodium concentration was reduced in leaf blades of the tolerant lines under salt stress. In the absence of NaCl, the concentration of Na+ and K+ were the same in the roots, leaf sheaths and leaf blades between the tolerant and the sensitive lines. In order to study the molecular mechanism behind that, alleles of the HKT1;5 gene from five tolerant and five sensitive barley lines were cloned and sequenced. Sequence analysis did not show the presence of any polymorphism that distinguishes between the tolerant and sensitive alleles. Our real-time RT-PCR experiments, showed that the expression of HKT1;5 gene in roots of the tolerant line was significantly induced after challenging the plants with salt stress. In contrast, in leaf sheaths the expression was decreased after salt treatment. In sensitive lines, there was no difference in the expression of HKT1;5 gene in leaf sheath under control and saline conditions, while a slight increase in the expression was observed in roots after salt treatment. These results provide stronger evidence that HKT1;5 gene in barley play a key role in withdrawing Na+ from the xylem and therefore reducing its transport to leaves. Given all that, these data support the hypothesis that HKT1;5 gene is responsible for Na+ unloading to the xylem and controlling its distribution in the shoots, which provide new insight into the understanding of this QTL for salinity tolerance in barley.
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Affiliation(s)
- Khaled M. Hazzouri
- Khalifa Center for Genetic Engineering and Biotechnology, United Arab Emirates University, Al Ain, United Arab Emirates
- Center for Genomics and Systems Biology, New York University of Abu Dhabi, Abu Dhabi, United Arab Emirates
- Khaled M. Hazzouri ;
| | - Basel Khraiwesh
- Laboratory of Algal and Systems Biology, New York University of Abu Dhabi, Abu Dhabi, United Arab Emirates
| | - Khaled M. A. Amiri
- Khalifa Center for Genetic Engineering and Biotechnology, United Arab Emirates University, Al Ain, United Arab Emirates
- Department of Biology, College of Science, United Arab Emirates University, Al Ain, United Arab Emirates
| | - Duke Pauli
- Plant Breeding and Genetics, School of Integrative Plant Science, Cornell University, Ithaca, NY, United States
| | - Tom Blake
- Department of Plant Sciences and Plant Pathology, Montana State University, Bozeman, MT, United States
| | - Mohammad Shahid
- International Center for Biosaline Agriculture, Dubai, United Arab Emirates
| | - Sangeeta K. Mullath
- Department of Arid Land Agriculture, College of Food and Agriculture, United Arab Emirates University, Al Ain, United Arab Emirates
| | - David Nelson
- Center for Genomics and Systems Biology, New York University of Abu Dhabi, Abu Dhabi, United Arab Emirates
| | - Alain L. Mansour
- Date Palm Tissue Culture, United Arab Emirates University, Al Ain, United Arab Emirates
| | - Kourosh Salehi-Ashtiani
- Laboratory of Algal and Systems Biology, New York University of Abu Dhabi, Abu Dhabi, United Arab Emirates
| | - Michael Purugganan
- Center for Genomics and Systems Biology, New York University of Abu Dhabi, Abu Dhabi, United Arab Emirates
| | - Khaled Masmoudi
- Department of Arid Land Agriculture, College of Food and Agriculture, United Arab Emirates University, Al Ain, United Arab Emirates
- *Correspondence: Khaled Masmoudi
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Uematsu S, Vandenhove H, Sweeck L, Hees MV, Wannijn J, Smolders E. Foliar uptake of radiocaesium from irrigation water by paddy rice (Oryza sativa): an overlooked pathway in contaminated environments. THE NEW PHYTOLOGIST 2017; 214:820-829. [PMID: 28102551 DOI: 10.1111/nph.14416] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/07/2016] [Accepted: 11/28/2016] [Indexed: 06/06/2023]
Abstract
Flooded (paddy) rice (Oryza sativa) can take up ions from the irrigation water by foliar uptake via the exposed stem base. We hypothesised that the stem base uptake of radiocaesium (RCs) is a pathway for rice grown in RCs-contaminated environments. We developed a bi-compartmental device which discriminates the stem base from root RCs uptake from solutions, thereby using RCs isotopes (137 Cs and 134 Cs) with < 2% solution leak between the compartments. Radiocaesium uptake was linear over time (0-24 h). Radiocaesium uptake to the entire plant, expressed per dry weight of the exposed parts, was sixfold higher for the roots than for the exposed stem base. At equal RCs concentrations in both compartments, the exposed stem base and root uptake contributed almost equally to the total shoot RCs concentrations. Reducing potassium supply to the roots not only increased the root RCs uptake but also increased RCs uptake by the stem base. This study was the first to experimentally demonstrate active and internally regulated RCs uptake by the stem base of rice. Scenario calculations for the Fukushima-affected area predict that RCs in irrigation water could be an important source of RCs in rice as indirectly suggested from field data.
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Affiliation(s)
- Shinichiro Uematsu
- Biosphere Impact Studies, SCK CEN, Belgian Nuclear Research Centre, Boeretang 200, B-2400, Mol, Belgium
- Division of Soil and Water Management, KU Leuven, Kasteelpark Arenberg 20, B-3001, Leuven, Belgium
| | - Hildegarde Vandenhove
- Biosphere Impact Studies, SCK CEN, Belgian Nuclear Research Centre, Boeretang 200, B-2400, Mol, Belgium
| | - Lieve Sweeck
- Biosphere Impact Studies, SCK CEN, Belgian Nuclear Research Centre, Boeretang 200, B-2400, Mol, Belgium
| | - May Van Hees
- Biosphere Impact Studies, SCK CEN, Belgian Nuclear Research Centre, Boeretang 200, B-2400, Mol, Belgium
| | - Jean Wannijn
- Biosphere Impact Studies, SCK CEN, Belgian Nuclear Research Centre, Boeretang 200, B-2400, Mol, Belgium
| | - Erik Smolders
- Division of Soil and Water Management, KU Leuven, Kasteelpark Arenberg 20, B-3001, Leuven, Belgium
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27
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Garriga M, Raddatz N, Véry AA, Sentenac H, Rubio-Meléndez ME, González W, Dreyer I. Cloning and functional characterization of HKT1 and AKT1 genes of Fragaria spp.-Relationship to plant response to salt stress. JOURNAL OF PLANT PHYSIOLOGY 2017; 210:9-17. [PMID: 28039842 DOI: 10.1016/j.jplph.2016.12.007] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2016] [Revised: 12/08/2016] [Accepted: 12/11/2016] [Indexed: 05/03/2023]
Abstract
Commercial strawberry, Fragaria x ananassa Duch., is a species sensitive to salinity. Under saline conditions, Na+ uptake by the plant is increased, while K+ uptake is significantly reduced. Maintaining an adequate K+/Na+ cytosolic ratio determines the ability of the plant to survive in saline environments. The goal of the present work was to clone and functionally characterize the genes AKT1 and HKT1 involved in K+ and Na+ transport in strawberry and to determine the relationship of these genes with the responses of three Fragaria spp. genotypes having different ecological adaptations to salt stress. FaHKT1 and FcHKT1 proteins from F. x ananassa and F. chiloensis have 98.1% of identity, while FaAKT1 and FcAKT1 identity is 99.7%. FaHKT1 and FaAKT1 from F. x ananassa, were functionally characterized in Xenopus oocytes. FaHKT1, belongs to the group I of HKT transporters and is selective for Na+. Expression of FaAKT1 in oocytes showed that the protein is a typical inward-rectifying and highly K+-selective channel. The relative expression of Fragaria HKT1 and AKT1 genes was studied in roots of F. x ananassa cv. Camarosa and of F. chiloensis (accessions Bau and Cucao) grown under salt stress. The expression of AKT1 was transiently increased in 'Camarosa', decreased in 'Cucao' and was not affected in 'Bau' upon salt stress. HKT1 expression was significantly increased in roots of 'Cucao' and was not affected in the other two genotypes. The increased relative expression of HKT1 and decreased expression of AKT1 in 'Cucao' roots correlates with the higher tolerance to salinity of this genotype in comparison with 'Camarosa' and 'Bau'.
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Affiliation(s)
- Miguel Garriga
- Facultad de Ciencias Agrarias, Universidad de Talca, Casilla 747, Talca, Chile.
| | - Natalia Raddatz
- Plant Biophysics, Centro de Biotecnología y Genómica de Plantas, Universidad Politécnica de Madrid (UPM), Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), E-28223 Pozuelo de Alarcón, Madrid, Spain
| | - Anne-Aliénor Véry
- Biochimie et Physiologie Moléculaire des Plantes, UMR 5004, ENSA.M INRA CNRS UMII, 34060 Montpellier, Cedex 2, France
| | - Hervé Sentenac
- Biochimie et Physiologie Moléculaire des Plantes, UMR 5004, ENSA.M INRA CNRS UMII, 34060 Montpellier, Cedex 2, France
| | - María E Rubio-Meléndez
- Facultad de Ciencias Agrarias, Universidad de Talca, Casilla 747, Talca, Chile; Instituto de Ciencias Biológicas, Universidad de Talca, Casilla 747, Talca, Chile
| | - Wendy González
- Centro de Bioinformática y Simulación Molecular, Universidad de Talca, Casilla 721, Talca, Chile
| | - Ingo Dreyer
- Plant Biophysics, Centro de Biotecnología y Genómica de Plantas, Universidad Politécnica de Madrid (UPM), Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), E-28223 Pozuelo de Alarcón, Madrid, Spain; Centro de Bioinformática y Simulación Molecular, Universidad de Talca, Casilla 721, Talca, Chile.
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28
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Zhang C, Li H, Wang J, Zhang B, Wang W, Lin H, Luan S, Gao J, Lan W. The Rice High-Affinity K + Transporter OsHKT2;4 Mediates Mg 2+ Homeostasis under High-Mg 2+ Conditions in Transgenic Arabidopsis. FRONTIERS IN PLANT SCIENCE 2017; 8:1823. [PMID: 29114257 PMCID: PMC5660728 DOI: 10.3389/fpls.2017.01823] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2017] [Accepted: 10/10/2017] [Indexed: 05/13/2023]
Abstract
Rice (Oryza sativa; background Nipponbare) contains nine HKT (high-affinity K+ transport)-like genes encoding membrane proteins belonging to the superfamily of Ktr/TRK/HKT. OsHKTs have been proposed to include four selectivity filter-pore-forming domains homologous to the bacterial K+ channel KcsA, and are separated into OsHKT1s with Na+-selective activity and OsHKT2s with Na+-K+ symport activity. As a member of the OsHKT2 subfamily, OsHKT2;4 renders Mg2+ and Ca2+ permeability for yeast cells and Xenopus laevis oocytes, besides K+ and Na+. However, physiological functions related to Mg2+in planta have not yet been identified. Here we report that OsHKT2;4 from rice (O. sativa; background Nipponbare) functions as a low-affinity Mg2+ transporter to mediate Mg2+ homeostasis in plants under high-Mg2+ environments. Using the functional complementation assay in Mg2+-uptake deficient Salmonella typhimurium strains MM281 and electrophysiological analysis in X. laevis oocytes, we found that OsHKT2;4 could rescue the growth of MM281 in Mg2+-deficient conditions and induced the Mg2+ currents in oocytes at millimolar range of Mg2+. Additionally, overexpression of OsHKT2;4 to Arabidopsis mutant lines with a knockout of AtMGT6, a gene encoding the transporter protein necessary for Mg2+ adaptation in Arabidopsis, caused the Mg2+ toxicity to the leaves under the high-Mg2+ stress, but not under low-Mg2+ environments. Moreover, this Mg2+ toxicity symptom resulted from the excessive Mg2+ translocation from roots to shoots, and was relieved by the increase in supplemental Ca2+. Together, our results demonstrated that OsHKT2;4 is a low-affinity Mg2+ transporter responsible for Mg2+ transport to aerials in plants under high-Mg2+ conditions.
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Affiliation(s)
- Chi Zhang
- State Key Laboratory for Pharmaceutical Biotechnology, NJU–NFU Joint Institute for Plant Molecular Biology, College of Life Sciences, Nanjing University, Nanjing, China
| | - Hejuan Li
- State Key Laboratory for Pharmaceutical Biotechnology, NJU–NFU Joint Institute for Plant Molecular Biology, College of Life Sciences, Nanjing University, Nanjing, China
| | - Jiayuan Wang
- State Key Laboratory for Pharmaceutical Biotechnology, NJU–NFU Joint Institute for Plant Molecular Biology, College of Life Sciences, Nanjing University, Nanjing, China
| | - Bin Zhang
- State Key Laboratory for Pharmaceutical Biotechnology, NJU–NFU Joint Institute for Plant Molecular Biology, College of Life Sciences, Nanjing University, Nanjing, China
| | - Wei Wang
- National Key Laboratory of Plant Molecular Genetics, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Hongxuan Lin
- National Key Laboratory of Plant Molecular Genetics, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Sheng Luan
- Department of Plant and Microbial Biology, University of California, Berkeley, Berkeley, CA, United States
| | - Jiping Gao
- National Key Laboratory of Plant Molecular Genetics, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
- *Correspondence: Jiping Gao, Wenzhi Lan,
| | - Wenzhi Lan
- State Key Laboratory for Pharmaceutical Biotechnology, NJU–NFU Joint Institute for Plant Molecular Biology, College of Life Sciences, Nanjing University, Nanjing, China
- *Correspondence: Jiping Gao, Wenzhi Lan,
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Tounsi S, Ben Amar S, Masmoudi K, Sentenac H, Brini F, Véry AA. Characterization of Two HKT1;4 Transporters from Triticum monococcum to Elucidate the Determinants of the Wheat Salt Tolerance Nax1 QTL. PLANT & CELL PHYSIOLOGY 2016; 57:2047-2057. [PMID: 27440547 DOI: 10.1093/pcp/pcw123] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2016] [Accepted: 07/06/2016] [Indexed: 05/20/2023]
Abstract
TmHKT1;4-A1 and TmHKT1;4-A2 are two Na+ transporter genes that have been identified as associated with the salt tolerance Nax1 locus found in a durum wheat (Triticum turgidum L. subsp. durum) line issued from a cross with T. monococcum. In the present study, we were interested in getting clues on the molecular mechanisms underpinning this salt tolerance quantitative trait locus (QTL). By analyzing the phylogenetic relationships between wheat and T. monococcum HKT1;4-type genes, we found that durum and bread wheat genomes possess a close homolog of TmHKT1;4-A1, but no functional close homolog of TmHKT1;4-A2. Furthermore, performing real-time reverse transcription-PCR experiments, we showed that TmHKT1;4-A1 and TmHKT1;4-A2 are similarly expressed in the leaves but that TmHKT1;4-A2 is more strongly expressed in the roots, which would enable it to contribute more to the prevention of Na+ transfer to the shoots upon salt stress. We also functionally characterized the TmHKT1;4-A1 and TmHKT1;4-A2 transporters by expressing them in Xenopus oocytes. The two transporters displayed close functional properties (high Na+/K+ selectivity, low affinity for Na+, stimulation by external K+ of Na+ transport), but differed in some quantitative parameters: Na+ affinity was 3-fold lower and the maximal inward conductance was 3-fold higher in TmHKT1;4-A2 than in TmHKT1;4-A1. The conductance of TmHKT1;4-A2 at high Na+ concentration (>10 mM) was also shown to be higher than that of the two durum wheat HKT1;4-type transporters so far characterized. Altogether, these data support the hypothesis that TmHKT1;4-A2 is responsible for the Nax1 trait and provide new insight into the understanding of this QTL.
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Affiliation(s)
- Sana Tounsi
- Biotechnology and Plant Improvement Laboratory, Centre of Biotechnology of Sfax (CBS)/University of Sfax, BP '1177', 3018 Sfax, Tunisia
- Biochimie & Physiologie Moléculaire des plantes, UMR 5004 CNRS/386 INRA/SupAgro Montpellier/Université Montpellier, Campus SupAgro-INRA, 34060 Montpellier Cedex 2, France
| | - Siwar Ben Amar
- Biotechnology and Plant Improvement Laboratory, Centre of Biotechnology of Sfax (CBS)/University of Sfax, BP '1177', 3018 Sfax, Tunisia
- Biochimie & Physiologie Moléculaire des plantes, UMR 5004 CNRS/386 INRA/SupAgro Montpellier/Université Montpellier, Campus SupAgro-INRA, 34060 Montpellier Cedex 2, France
| | - Khaled Masmoudi
- Biotechnology and Plant Improvement Laboratory, Centre of Biotechnology of Sfax (CBS)/University of Sfax, BP '1177', 3018 Sfax, Tunisia
- Present address: International Center for Biosaline Agriculture (ICBA), PO Box 14660, Dubai-United Arab Emirates
| | - Hervé Sentenac
- Biochimie & Physiologie Moléculaire des plantes, UMR 5004 CNRS/386 INRA/SupAgro Montpellier/Université Montpellier, Campus SupAgro-INRA, 34060 Montpellier Cedex 2, France
| | - Faiçal Brini
- Biotechnology and Plant Improvement Laboratory, Centre of Biotechnology of Sfax (CBS)/University of Sfax, BP '1177', 3018 Sfax, Tunisia
| | - Anne-Aliénor Véry
- Biochimie & Physiologie Moléculaire des plantes, UMR 5004 CNRS/386 INRA/SupAgro Montpellier/Université Montpellier, Campus SupAgro-INRA, 34060 Montpellier Cedex 2, France
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30
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Nieves-Cordones M, Al Shiblawi FR, Sentenac H. Roles and Transport of Sodium and Potassium in Plants. Met Ions Life Sci 2016; 16:291-324. [PMID: 26860305 DOI: 10.1007/978-3-319-21756-7_9] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The two alkali cations Na(+) and K(+) have similar relative abundances in the earth crust but display very different distributions in the biosphere. In all living organisms, K(+) is the major inorganic cation in the cytoplasm, where its concentration (ca. 0.1 M) is usually several times higher than that of Na(+). Accumulation of Na(+) at high concentrations in the cytoplasm results in deleterious effects on cell metabolism, e.g., on photosynthetic activity in plants. Thus, Na(+) is compartmentalized outside the cytoplasm. In plants, it can be accumulated at high concentrations in vacuoles, where it is used as osmoticum. Na(+) is not an essential element in most plants, except in some halophytes. On the other hand, it can be a beneficial element, by replacing K(+) as vacuolar osmoticum for instance. In contrast, K(+) is an essential element. It is involved in electrical neutralization of inorganic and organic anions and macromolecules, pH homeostasis, control of membrane electrical potential, and the regulation of cell osmotic pressure. Through the latter function in plants, it plays a role in turgor-driven cell and organ movements. It is also involved in the activation of enzymes, protein synthesis, cell metabolism, and photosynthesis. Thus, plant growth requires large quantities of K(+) ions that are taken up by roots from the soil solution, and then distributed throughout the plant. The availability of K(+) ions in the soil solution, slowly released by soil particles and clays, is often limiting for optimal growth in most natural ecosystems. In contrast, due to natural salinity or irrigation with poor quality water, detrimental Na(+) concentrations, toxic for all crop species, are present in many soils, representing 6 % to 10 % of the earth's land area. Three families of ion channels (Shaker, TPK/KCO, and TPC) and 3 families of transporters (HAK, HKT, and CPA) have been identified so far as contributing to K(+) and Na(+) transport across the plasmalemma and internal membranes, with high or low ionic selectivity. In the model plant Arabidopsis thaliana, these families gather at least 70 members. Coordination of the activities of these systems, at the cell and whole plant levels, ensures plant K(+) nutrition, use of Na(+) as a beneficial element, and adaptation to saline conditions.
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Affiliation(s)
- Manuel Nieves-Cordones
- Laboratory of Plant Biochemistry and Molecular Physiology, UMR BPMP CNRS/INRA/MontpellierSupAgro, University of Montpellier, INRA, Place Viala, F-34060, Montpellier cedex 1, France
| | - Fouad Razzaq Al Shiblawi
- Laboratory of Plant Biochemistry and Molecular Physiology, UMR BPMP CNRS/INRA/MontpellierSupAgro, University of Montpellier, INRA, Place Viala, F-34060, Montpellier cedex 1, France
| | - Hervé Sentenac
- Laboratory of Plant Biochemistry and Molecular Physiology, UMR BPMP CNRS/INRA/MontpellierSupAgro, University of Montpellier, INRA, Place Viala, F-34060, Montpellier cedex 1, France.
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Ariyarathna HACK, Francki MG. Phylogenetic relationships and protein modelling revealed two distinct subfamilies of group II HKT genes between crop and model grasses. Genome 2016; 59:509-17. [PMID: 27203707 DOI: 10.1139/gen-2016-0035] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Molecular evolution of large protein families in closely related species can provide useful insights on structural functional relationships. Phylogenetic analysis of the grass-specific group II HKT genes identified two distinct subfamilies, I and II. Subfamily II was represented in all species, whereas subfamily I was identified only in the small grain cereals and possibly originated from an ancestral gene duplication post divergence from the coarse grain cereal lineage. The core protein structures were highly analogous despite there being no more than 58% amino acid identity between members of the two subfamilies. Distinctly variable regions in known functional domains, however, indicated functional divergence of the two subfamilies. The subsets of codons residing external to known functional domains predicted signatures of positive Darwinian selection potentially identifying new domains of functional divergence and providing new insights on the structural function and relationships between protein members of the two subfamilies.
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Affiliation(s)
- H A Chandima K Ariyarathna
- a School of Plant Biology and Institute of Agriculture, The University of Western Australia, Crawley WA 6009, Australia.,b State Agricultural Biotechnology Centre, Murdoch University, Murdoch WA 6150, Australia
| | - Michael G Francki
- b State Agricultural Biotechnology Centre, Murdoch University, Murdoch WA 6150, Australia.,c Department of Agriculture and Food Western Australia, 3 Baron Hay Ct, South Perth WA 6151, Australia
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Ariyarathna HACK, Oldach KH, Francki MG. A comparative gene analysis with rice identified orthologous group II HKT genes and their association with Na(+) concentration in bread wheat. BMC PLANT BIOLOGY 2016; 16:21. [PMID: 26786911 PMCID: PMC4719669 DOI: 10.1186/s12870-016-0714-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2015] [Accepted: 01/14/2016] [Indexed: 05/08/2023]
Abstract
BACKGROUND Although the HKT transporter genes ascertain some of the key determinants of crop salt tolerance mechanisms, the diversity and functional role of group II HKT genes are not clearly understood in bread wheat. The advanced knowledge on rice HKT and whole genome sequence was, therefore, used in comparative gene analysis to identify orthologous wheat group II HKT genes and their role in trait variation under different saline environments. RESULTS The four group II HKTs in rice identified two orthologous gene families from bread wheat, including the known TaHKT2;1 gene family and a new distinctly different gene family designated as TaHKT2;2. A single copy of TaHKT2;2 was found on each homeologous chromosome arm 7AL, 7BL and 7DL and each gene was expressed in leaf blade, sheath and root tissues under non-stressed and at 200 mM salt stressed conditions. The proteins encoded by genes of the TaHKT2;2 family revealed more than 93% amino acid sequence identity but ≤52% amino acid identity compared to the proteins encoded by TaHKT2;1 family. Specifically, variations in known critical domains predicted functional differences between the two protein families. Similar to orthologous rice genes on chromosome 6L, TaHKT2;1 and TaHKT2;2 genes were located approximately 3 kb apart on wheat chromosomes 7AL, 7BL and 7DL, forming a static syntenic block in the two species. The chromosomal region on 7AL containing TaHKT2;1 7AL-1 co-located with QTL for shoot Na(+) concentration and yield in some saline environments. CONCLUSION The differences in copy number, genes sequences and encoded proteins between TaHKT2;2 homeologous genes and other group II HKT gene families within and across species likely reflect functional diversity for ion selectivity and transport in plants. Evidence indicated that neither TaHKT2;2 nor TaHKT2;1 were associated with primary root Na(+) uptake but TaHKT2;1 may be associated with trait variation for Na(+) exclusion and yield in some but not all saline environments.
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Affiliation(s)
- H A Chandima K Ariyarathna
- School of Plant Biology and Institute of Agriculture, The University of Western Australia, Crawley, 6009, Western Australia.
- State Agricultural Biotechnology Centre, Murdoch University, Murdoch, 6150, Western Australia.
| | - Klaus H Oldach
- South Australia Research Development Institute, Plant Genomics Centre, Waite Research Precinct, Urrbrae, 5064, South Australia.
| | - Michael G Francki
- State Agricultural Biotechnology Centre, Murdoch University, Murdoch, 6150, Western Australia.
- Department of Agriculture and Food Western Australia, South Perth, 6151, Western Australia.
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Domingo C, Lalanne E, Catalá MM, Pla E, Reig-Valiente JL, Talón M. Physiological Basis and Transcriptional Profiling of Three Salt-Tolerant Mutant Lines of Rice. FRONTIERS IN PLANT SCIENCE 2016; 7:1462. [PMID: 27733859 PMCID: PMC5039197 DOI: 10.3389/fpls.2016.01462] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/2016] [Accepted: 09/13/2016] [Indexed: 05/15/2023]
Abstract
Salinity is a complex trait that affects growth and productivity in many crops, including rice. Mutation induction, a useful tool to generate salt tolerant plants, enables the analysis of plants with similar genetic background, facilitating the understanding of the salt tolerance mechanisms. In this work, we generated three salt tolerant mutant lines by irradiation of a salt-sensitive cultivar plants and screened M2 plants at seedling stage in the presence of high salinity. These three lines, SaT20, SaS62, and SaT58, showed different responses to salinity, but exhibited similar phenotype to wild type plants, except SaT20 that displayed shorter height when grown in the absence of salt. Under salt conditions, all three mutants and the parental line showed similar reduction in yield, although relevant differences in other physiological parameters, such as Na+ accumulation in healthy leaves of SaT20, were registered. Microarray analyses of gene expression profiles in roots revealed the occurrence of common and specific responses in the mutants. The three mutants showed up-regulation of responsive genes, the activation of oxido-reduction process and the inhibition of ion transport. The participation of jasmonate in the plant response to salt was evident by down-regulation of a gene coding for a jasmonate O-methyltransferase. Genes dealing with lipid transport and metabolism were, in general, up-regulated except in SaS62, that also exhibited down-regulation of genes involved in ion transport and Ca2+ signal transduction. The two most tolerant varieties, SaS62 and SaT20, displayed lower levels of transcripts involved in K+ uptake. The physiological study and the description of the expression analysis evidenced that the three lines showed different responses to salt: SaT20 showed a high Na+ content in leaves, SaS62 presented an inhibition of lipid metabolism and ion transport and SaT58 differs in both features in the response to salinity. The analysis of these salt tolerant mutants illustrates the complexity of this trait evidencing the breadth of the plant responses to salinity including simultaneous cooperation of alternative or complementary mechanisms.
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Affiliation(s)
- Concha Domingo
- Genomics Department, Instituto Valenciano de Investigaciones AgrariasValencia, Spain
- *Correspondence: Concha Domingo
| | - Eric Lalanne
- Oryzon Genomics Diagnóstico SLCornellà de Llobregat–Barcelona, Spain
| | - María M. Catalá
- Ebre Field Station, Institut de Recerca i Tecnologia AgroalimentariesAmposta, Spain
| | - Eva Pla
- Ebre Field Station, Institut de Recerca i Tecnologia AgroalimentariesAmposta, Spain
| | - Juan L. Reig-Valiente
- Genomics Department, Instituto Valenciano de Investigaciones AgrariasValencia, Spain
| | - Manuel Talón
- Genomics Department, Instituto Valenciano de Investigaciones AgrariasValencia, Spain
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Nieves-Cordones M, Martínez V, Benito B, Rubio F. Comparison between Arabidopsis and Rice for Main Pathways of K(+) and Na(+) Uptake by Roots. FRONTIERS IN PLANT SCIENCE 2016; 7:992. [PMID: 27458473 PMCID: PMC4932104 DOI: 10.3389/fpls.2016.00992] [Citation(s) in RCA: 65] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2016] [Accepted: 06/22/2016] [Indexed: 05/22/2023]
Abstract
K(+) is an essential macronutrient for plants. It is acquired by specific uptake systems located in roots. Although the concentrations of K(+) in the soil solution are widely variable, K(+) nutrition is secured by uptake systems that exhibit different affinities for K(+). Two main systems have been described for root K(+) uptake in several species: the high-affinity HAK5-like transporter and the inward-rectifier AKT1-like channel. Other unidentified systems may be also involved in root K(+) uptake, although they only seem to operate when K(+) is not limiting. The use of knock-out lines has allowed demonstrating their role in root K(+) uptake in Arabidopsis and rice. Plant adaptation to the different K(+) supplies relies on the finely tuned regulation of these systems. Low K(+)-induced transcriptional up-regulation of the genes encoding HAK5-like transporters occurs through a signal cascade that includes changes in the membrane potential of root cells and increases in ethylene and reactive oxygen species concentrations. Activation of AKT1 channels occurs through phosphorylation by the CIPK23/CBL1 complex. Recently, activation of the Arabidopsis HAK5 by the same complex has been reported, pointing to CIPK23/CBL as a central regulator of the plant's adaptation to low K(+). Na(+) is not an essential plant nutrient but it may be beneficial for some plants. At low concentrations, Na(+) improves growth, especially under K(+) deficiency. Thus, high-affinity Na(+) uptake systems have been described that belong to the HKT and HAK families of transporters. At high concentrations, typical of saline environments, Na(+) accumulates in plant tissues at high concentrations, producing alterations that include toxicity, water deficit and K(+) deficiency. Data concerning pathways for Na(+) uptake into roots under saline conditions are still scarce, although several possibilities have been proposed. The apoplast is a significant pathway for Na(+) uptake in rice grown under salinity conditions, but in other plant species different mechanisms involving non-selective cation channels or transporters are under discussion.
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Affiliation(s)
- Manuel Nieves-Cordones
- Biochimie et Physiologie Moléculaire des Plantes, Institut de Biologie Intégrative des Plantes, UMR 5004 CNRS/UMR 0386 INRA/Montpellier SupAgro/Université Montpellier 2Montpellier, France
| | - Vicente Martínez
- Departamento de Nutrición Vegetal, Centro de Edafología y Biología Aplicada del Segura – Consejo Superior de Investigaciones CientíficasMurcia, Spain
| | - Begoña Benito
- Centro de Biotecnología y Genómica de Plantas, Universidad Politécnica de MadridMadrid, Spain
| | - Francisco Rubio
- Departamento de Nutrición Vegetal, Centro de Edafología y Biología Aplicada del Segura – Consejo Superior de Investigaciones CientíficasMurcia, Spain
- *Correspondence: Francisco Rubio,
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Suzuki K, Costa A, Nakayama H, Katsuhara M, Shinmyo A, Horie T. OsHKT2;2/1-mediated Na(+) influx over K(+) uptake in roots potentially increases toxic Na(+) accumulation in a salt-tolerant landrace of rice Nona Bokra upon salinity stress. JOURNAL OF PLANT RESEARCH 2016; 129:67-77. [PMID: 26578190 DOI: 10.1007/s10265-015-0764-1] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/17/2015] [Accepted: 07/18/2015] [Indexed: 05/10/2023]
Abstract
HKT transporters are Na(+)-permeable membrane proteins, which mediate Na(+) and K(+) homeostasis in K(+)-depleted and saline environments in plants. Class II HKT transporters, a distinct subgroup found predominantly in monocots, are known to mediate Na(+)-K(+) co-transport in principle. Here we report features of ion transport functions of No-OsHKT2;2/1, a class II transporter identified in a salt tolerant landrace of indica rice, Nona Bokra. We profiled No-OsHKT2;2/1 expression in organs of Nona Bokra plants with or without salinity stress. Dominant accumulation of the No-OsHKT2;2/1 transcript in K(+)-starved roots of Nona Bokra plants largely disappeared in response to 50 mM NaCl. We found that No-OsHKT2;2/1 expressed in the high-affinity K(+) uptake deficient mutant of Saccharomyces cerevisiae and Xenopus laevis oocytes shows robust K(+) selectivity even in the presence of a large amount of NaCl as reported previously. However, No-OsHKT2;2/1-expressing yeast cells exhibited Na(+) hypersensitive growth under various concentrations of K(+) and Na(+) as the cells expressing Po-OsHKT2;2, a similar class II transporter from another salt tolerant indica rice Pokkali, when compared with the growth of cells harboring empty vector or cells expressing OsHKT2;4. The OsHKT2;4 protein expressed in Xenopus oocytes showed strong K(+) selectivity in the presence of 50 mM NaCl in comparison with No-OsHKT2;2/1 and Po-OsHKT2;2. Together with apparent plasma membrane-localization of No-OsHKT2;2/1, these results point to possibilities that No-OsHKT2;2/1 could mediate destructive Na(+) influx over K(+) uptake in Nona Bokra plants upon salinity stress, and that a predominant physiological function of No-OsHKT2;2/1 might be the acquisition of Na(+) and K(+) in K(+)-limited environments.
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Affiliation(s)
- Kei Suzuki
- Division of Applied Biology, Faculty of Textile Science and Technology, Shinshu University, 3-15-1, Tokida, Ueda, Nagano, 386-8567, Japan
| | - Alex Costa
- Department of Biosciences, University of Milan, Via G. Celoria 26, 20133, Milan, Italy
- Institute of Biophysics, Consiglio Nazionale delle Ricerche, Via G. Celoria 26, 20133, Milan, Italy
| | - Hideki Nakayama
- Institute of Environmental Studies, Graduate School of Fisheries Science and Environmental Studies, Nagasaki University, 1-14 Bunkyo-machi, Nagasaki, 852-8521, Japan
| | - Maki Katsuhara
- Institute of Plant Science and Resources, Okayama University, Chuo 2-20-1, Kurashiki, 710-0046, Japan
| | - Atsuhiko Shinmyo
- Nara Institute of Science and Technology, 8916-5 Takayama-cho, Ikoma, Nara, 630-0192, Japan
| | - Tomoaki Horie
- Division of Applied Biology, Faculty of Textile Science and Technology, Shinshu University, 3-15-1, Tokida, Ueda, Nagano, 386-8567, Japan.
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Volkov V. Salinity tolerance in plants. Quantitative approach to ion transport starting from halophytes and stepping to genetic and protein engineering for manipulating ion fluxes. FRONTIERS IN PLANT SCIENCE 2015; 6:873. [PMID: 26579140 PMCID: PMC4621421 DOI: 10.3389/fpls.2015.00873] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2015] [Accepted: 10/01/2015] [Indexed: 05/18/2023]
Abstract
Ion transport is the fundamental factor determining salinity tolerance in plants. The Review starts from differences in ion transport between salt tolerant halophytes and salt-sensitive plants with an emphasis on transport of potassium and sodium via plasma membranes. The comparison provides introductory information for increasing salinity tolerance. Effects of salt stress on ion transport properties of membranes show huge opportunities for manipulating ion fluxes. Further steps require knowledge about mechanisms of ion transport and individual genes of ion transport proteins. Initially, the Review describes methods to measure ion fluxes, the independent set of techniques ensures robust and reliable basement for quantitative approach. The Review briefly summarizes current data concerning Na(+) and K(+) concentrations in cells, refers to primary thermodynamics of ion transport and gives special attention to individual ion channels and transporters. Simplified scheme of a plant cell with known transport systems at the plasma membrane and tonoplast helps to imagine the complexity of ion transport and allows choosing specific transporters for modulating ion transport. The complexity is enhanced by the influence of cell size and cell wall on ion transport. Special attention is given to ion transporters and to potassium and sodium transport by HKT, HAK, NHX, and SOS1 proteins. Comparison between non-selective cation channels and ion transporters reveals potential importance of ion transporters and the balance between the two pathways of ion transport. Further on the Review describes in detail several successful attempts to overexpress or knockout ion transporters for changing salinity tolerance. Future perspectives are questioned with more attention given to promising candidate ion channels and transporters for altered expression. Potential direction of increasing salinity tolerance by modifying ion channels and transporters using single point mutations is discussed and questioned. An alternative approach from synthetic biology is to create new regulation networks using novel transport proteins with desired properties for transforming agricultural crops. The approach had not been widely used earlier; it leads also to theoretical and pure scientific aspects of protein chemistry, structure-function relations of membrane proteins, systems biology and physiology of stress and ion homeostasis. Summarizing, several potential ways are aimed at required increase in salinity tolerance of plants of interest.
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Affiliation(s)
- Vadim Volkov
- Faculty of Life Sciences and Computing, London Metropolitan UniversityLondon, UK
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37
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Wang R, Jing W, Xiao L, Jin Y, Shen L, Zhang W. The Rice High-Affinity Potassium Transporter1;1 Is Involved in Salt Tolerance and Regulated by an MYB-Type Transcription Factor. PLANT PHYSIOLOGY 2015; 168:1076-90. [PMID: 25991736 PMCID: PMC4741328 DOI: 10.1104/pp.15.00298] [Citation(s) in RCA: 148] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/25/2015] [Accepted: 05/18/2015] [Indexed: 05/18/2023]
Abstract
Sodium transporters play key roles in plant tolerance to salt stress. Here, we report that a member of the High-Affinity K(+) Transporter (HKT) family, OsHKT1;1, in rice (Oryza sativa 'Nipponbare') plays an important role in reducing Na(+) accumulation in shoots to cope with salt stress. The oshkt1;1 mutant plants displayed hypersensitivity to salt stress. They contained less Na(+) in the phloem sap and accumulated more Na(+) in the shoots compared with the wild type. OsHKT1;1 was expressed mainly in the phloem of leaf blades and up-regulated in response to salt stress. Using a yeast one-hybrid approach, a novel MYB coiled-coil type transcription factor, OsMYBc, was found to bind to the OsHKT1;1 promoter. In vivo chromatin immunoprecipitation and in vitro electrophoresis mobility shift assays demonstrated that OsMYBc binds to AAANATNC(C/T) fragments within the OsHKT1;1 promoter. Mutation of the OsMYBc-binding nucleotides resulted in a decrease in promoter activity of OsHKT1;1. Knockout of OsMYBc resulted in a reduction in NaCl-induced expression of OsHKT1;1 and salt sensitivity. Taken together, these results suggest that OsHKT1;1 has a role in controlling Na(+) concentration and preventing sodium toxicity in leaf blades and is regulated by the OsMYBc transcription factor.
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Affiliation(s)
- Rong Wang
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, People's Republic of China
| | - Wen Jing
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, People's Republic of China
| | - Longyun Xiao
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, People's Republic of China
| | - Yakang Jin
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, People's Republic of China
| | - Like Shen
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, People's Republic of China
| | - Wenhua Zhang
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, People's Republic of China
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38
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Shahzad K, Rauf M, Ahmed M, Malik ZA, Habib I, Ahmed Z, Mahmood K, Ali R, Masmoudi K, Lemtiri-Chlieh F, Gehring C, Berkowitz GA, Saeed NA. Functional characterisation of an intron retaining K(+) transporter of barley reveals intron-mediated alternate splicing. PLANT BIOLOGY (STUTTGART, GERMANY) 2015; 17:840-51. [PMID: 25631371 DOI: 10.1111/plb.12290] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2014] [Accepted: 11/19/2014] [Indexed: 06/04/2023]
Abstract
Intron retention in transcripts and the presence of 5' and 3' splice sites within these introns mediate alternate splicing, which is widely observed in animals and plants. Here, functional characterisation of the K(+) transporter, HvHKT2;1, with stably retained introns from barley (Hordeum vulgare) in yeast (Saccharomyces cerevisiae), and transcript profiling in yeast and transgenic tobacco (Nicotiana tabacum) is presented. Expression of intron-retaining HvHKT2;1 cDNA (HvHKT2;1-i) in trk1, trk2 yeast strain defective in K(+) uptake restored growth in medium containing hygromycin in the presence of different concentrations of K(+) and mediated hypersensitivity to Na(+) . HvHKT2;1-i produces multiple transcripts via alternate splicing of two regular introns and three exons in different compositions. HKT isoforms with retained introns and exon skipping variants were detected in relative expression analysis of (i) HvHKT2;1-i in barley under native conditions, (ii) in transgenic tobacco plants constitutively expressing HvHKT2;1-i, and (iii) in trk1, trk2 yeast expressing HvHKT2;1-i under control of an inducible promoter. Mixed proportions of three HKT transcripts: HvHKT2;1-e (first exon region), HvHKT2;1-i1 (first intron) and HvHKT2;1-i2 (second intron) were observed. The variation in transcript accumulation in response to changing K(+) and Na(+) concentrations was observed in both heterologous and plant systems. These findings suggest a link between intron-retaining transcripts and different splice variants to ion homeostasis, and their possible role in salt stress.
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Affiliation(s)
- K Shahzad
- National Institute for Biotechnology and Genetic Engineering, Faisalabad, Pakistan
- Pakistan Institute of Engineering and Applied Sciences, Nilore, Islamabad, Pakistan
| | - M Rauf
- National Institute for Biotechnology and Genetic Engineering, Faisalabad, Pakistan
- Pakistan Institute of Engineering and Applied Sciences, Nilore, Islamabad, Pakistan
| | - M Ahmed
- National Institute for Biotechnology and Genetic Engineering, Faisalabad, Pakistan
| | - Z A Malik
- National Institute for Biotechnology and Genetic Engineering, Faisalabad, Pakistan
| | - I Habib
- National Institute for Biotechnology and Genetic Engineering, Faisalabad, Pakistan
| | - Z Ahmed
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON, Canada
| | - K Mahmood
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON, Canada
| | - R Ali
- Agricultural Biotechnology Laboratory, Department of Plant Science, University of Connecticut, Storrs, CT, USA
| | - K Masmoudi
- International Centre for Biosaline Agriculture (ICBA), Dubai, UAE
| | - F Lemtiri-Chlieh
- Division of Biological and Environmental Science and Engineering, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
| | - C Gehring
- Division of Biological and Environmental Science and Engineering, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
| | - G A Berkowitz
- Agricultural Biotechnology Laboratory, Department of Plant Science, University of Connecticut, Storrs, CT, USA
| | - N A Saeed
- National Institute for Biotechnology and Genetic Engineering, Faisalabad, Pakistan
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Pinto E, Ferreira IMPLVO. Cation transporters/channels in plants: Tools for nutrient biofortification. JOURNAL OF PLANT PHYSIOLOGY 2015; 179:64-82. [PMID: 25841207 DOI: 10.1016/j.jplph.2015.02.010] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2014] [Revised: 02/11/2015] [Accepted: 02/11/2015] [Indexed: 05/07/2023]
Abstract
Cation transporters/channels are key players in a wide range of physiological functions in plants, including cell signaling, osmoregulation, plant nutrition and metal tolerance. The recent identification of genes encoding some of these transport systems has allowed new studies toward further understanding of their integrated roles in plant. This review summarizes recent discoveries regarding the function and regulation of the multiple systems involved in cation transport in plant cells. The role of membrane transport in the uptake, distribution and accumulation of cations in plant tissues, cell types and subcellular compartments is described. We also discuss how the knowledge of inter- and intra-species variation in cation uptake, transport and accumulation as well as the molecular mechanisms responsible for these processes can be used to increase nutrient phytoavailability and nutrients accumulation in the edible tissues of plants. The main trends for future research in the field of biofortification are proposed.
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Affiliation(s)
- Edgar Pinto
- REQUIMTE/Department of Chemical Sciences, Laboratory of Bromatology and Hydrology, Faculty of Pharmacy - University of Porto, Portugal; CISA - Research Centre on Environment and Health, School of Allied Health Sciences, Polytechnic Institute of Porto, Portugal.
| | - Isabel M P L V O Ferreira
- REQUIMTE/Department of Chemical Sciences, Laboratory of Bromatology and Hydrology, Faculty of Pharmacy - University of Porto, Portugal
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40
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Rosas-Santiago P, Lagunas-Gómez D, Barkla BJ, Vera-Estrella R, Lalonde S, Jones A, Frommer WB, Zimmermannova O, Sychrová H, Pantoja O. Identification of rice cornichon as a possible cargo receptor for the Golgi-localized sodium transporter OsHKT1;3. JOURNAL OF EXPERIMENTAL BOTANY 2015; 66:2733-48. [PMID: 25750424 PMCID: PMC4986874 DOI: 10.1093/jxb/erv069] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Membrane proteins are synthesized and folded in the endoplasmic reticulum (ER), and continue their path to their site of residence along the secretory pathway. The COPII system has been identified as a key player for selecting and directing the fate of membrane and secretory cargo proteins. Selection of cargo proteins within the COPII vesicles is achieved by cargo receptors. The cornichon cargo receptor belongs to a conserved protein family found in eukaryotes that has been demonstrated to participate in the selection of integral membrane proteins as cargo for their correct targeting. Here it is demonstrated at the cellular level that rice cornichon OsCNIH1 interacts with OsHKT1;3 and, in yeast cells, enables the expression of the sodium transporter to the Golgi apparatus. Physical and functional HKT-cornichon interactions are confirmed by the mating-based split ubiquitin system, bimolecular fluorescence complementation, and Xenopus oocyte and yeast expression systems. The interaction between the two proteins occurs in the ER of plant cells and their co-expression in oocytes leads to the sequestration of the transporter in the ER. In the yeast cornichon mutant erv14, OsHKT1;3 is mistargeted, preventing the toxic effects of sodium transport in the cell observed in wild-type cells or in the erv14 mutant that co-expressed OsHKT1;3 with either OsCNIH1 or Erv14p. Identification and characterization of rice cornichon as a possible cargo receptor opens up the opportunity to improve our knowledge on membrane protein targeting in plant cells.
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Affiliation(s)
- Paul Rosas-Santiago
- Instituto de Biotecnología, Universidad Nacional de Autónoma de México, Cuernavaca, Morelos 62250, México Department of Plant Biology, Carnegie Institution for Science, Stanford, CA 94305, USA
| | - Daniel Lagunas-Gómez
- Instituto de Biotecnología, Universidad Nacional de Autónoma de México, Cuernavaca, Morelos 62250, México
| | - Bronwyn J Barkla
- Southern Cross Plant Science, Southern Cross University, Lismore, Australia
| | - Rosario Vera-Estrella
- Instituto de Biotecnología, Universidad Nacional de Autónoma de México, Cuernavaca, Morelos 62250, México
| | - Sylvie Lalonde
- Department of Plant Biology, Carnegie Institution for Science, Stanford, CA 94305, USA
| | - Alexander Jones
- Department of Plant Biology, Carnegie Institution for Science, Stanford, CA 94305, USA
| | - Wolf B Frommer
- Department of Plant Biology, Carnegie Institution for Science, Stanford, CA 94305, USA
| | - Olga Zimmermannova
- Southern Cross Plant Science, Southern Cross University, Lismore, Australia
| | - Hana Sychrová
- Department of Membrane Transport, Institute of Physiology, Academy of Sciences of the Czech Republic, v.v.i., 142 20 Prague 4, Czech Republic
| | - Omar Pantoja
- Instituto de Biotecnología, Universidad Nacional de Autónoma de México, Cuernavaca, Morelos 62250, México
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Sanadhya P, Agarwal P, Khedia J, Agarwal PK. A Low-Affinity K+ Transporter AlHKT2;1 from Recretohalophyte Aeluropus lagopoides Confers Salt Tolerance in Yeast. Mol Biotechnol 2015; 57:489-98. [DOI: 10.1007/s12033-015-9842-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Model of Cation Transportation Mediated by High-Affinity Potassium Transporters (HKTs) in Higher Plants. Biol Proced Online 2015; 17:1. [PMID: 25698907 PMCID: PMC4334588 DOI: 10.1186/s12575-014-0013-3] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2014] [Accepted: 12/06/2014] [Indexed: 01/18/2023] Open
Abstract
Trk/Ktr/HKT transporters probably were evolved from simple K+ channels KcsA. HKT transporters, which mediate Na+-uniport or Na+/K+-symport, maintain K+/Na+ homeostasis and increase salinity tolerance, can be classified into three subfamilies in higher plants. In this review, we systematically analyzed the characteristics of amino acids sequences and physiological functions of HKT transporters in higher plant. Furthermore, we depicted the hypothetical models of cations selection and transportation mediated by HKT transporters according to the highly conserved structure for the goal of better understanding the cations transportation processes.
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Ariyarathna HACK, Ul-Haq T, Colmer TD, Francki MG. Characterization of the multigene family TaHKT 2;1 in bread wheat and the role of gene members in plant Na(+) and K(+) status. BMC PLANT BIOLOGY 2014; 14:159. [PMID: 24920193 PMCID: PMC4079177 DOI: 10.1186/1471-2229-14-159] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2014] [Accepted: 06/04/2014] [Indexed: 05/20/2023]
Abstract
BACKGROUND A member of the TaHKT2;1 multigene family was previously identified as a Na(+) transporter with a possible role in root Na(+) uptake. In the present study, the existing full-length cDNA of this member was used as a basis to query the International Wheat Genome Survey Sequence to identify all members of the TaHKT2;1 family. Individual TaHKT2;1 genes were subsequently studied for gene and predicted protein structures, promoter variability, tissue expression and their role in Na(+) and K(+) status of wheat. RESULTS Six TaHKT2;1 genes were characterized which included four functional genes (TaHKT2;1 7AL-1, TaHKT2;1 7BL-1, TaHKT2;1 7BL-2 and TaHKT2;1 7DL-1) and two pseudogenes (TaHKT2;1 7AL-2 and TaHKT2;1 7AL-3), on chromosomes 7A, 7B and 7D of hexaploid wheat. Variability in protein domains for cation specificity and in cis-regulatory elements for salt response in gene promoters, were identified amongst the functional TaHKT2;1 members. The functional genes were expressed under low and high NaCl conditions in roots and leaf sheaths, but were down regulated in leaf blades. Alternative splicing events were evident in TaHKT2;1 7AL-1. Aneuploid lines null for each functional gene were grown in high NaCl nutrient solution culture to identify potential role of each TaHKT2;1 member. Aneuploid lines null for TaHKT2;1 7AL-1, TaHKT2;1 7BL-1 and TaHKT2;1 7BL-2 showed no difference in Na(+) concentration between Chinese Spring except for higher Na(+) in sheaths. The same aneuploid lines had lower K(+) in roots, sheath and youngest fully expanded leaf but only under high (200 mM) NaCl in the external solution. There was no difference in Na(+) or K(+) concentration for any treatment between aneuploid line null for the TaHKT2;1 7DL-1 gene and Chinese Spring. CONCLUSIONS TaHKT2;1 is a complex family consisting of pseudogenes and functional members. TaHKT2;1 genes do not have an apparent role in controlling root Na(+) uptake in bread wheat seedlings under experimental conditions in this study, contrary to existing hypotheses. However, TaHKT2;1 genes or, indeed other genes in the same chromosome region on 7AL, are candidates that may control Na(+) transport from root to sheath and regulate K(+) levels in different plant tissues.
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Affiliation(s)
- HA Chandima K Ariyarathna
- School of Plant Biology and Institute of Agriculture, The University of Western Australia, Crawley 6009, Western Australia
- State Agricultural Biotechnology Centre, Murdoch University, Murdoch 6150, Western Australia
| | - Tanveer Ul-Haq
- School of Plant Biology and Institute of Agriculture, The University of Western Australia, Crawley 6009, Western Australia
- State Agricultural Biotechnology Centre, Murdoch University, Murdoch 6150, Western Australia
- College of Agriculture, D. G. Khan, University of Agriculture Faisalabad, Faisalabad 38040, Pakistan
| | - Timothy D Colmer
- School of Plant Biology and Institute of Agriculture, The University of Western Australia, Crawley 6009, Western Australia
| | - Michael G Francki
- State Agricultural Biotechnology Centre, Murdoch University, Murdoch 6150, Western Australia
- Department of Agriculture and Food Western Australia, South Perth 6151, Western Australia
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Véry AA, Nieves-Cordones M, Daly M, Khan I, Fizames C, Sentenac H. Molecular biology of K+ transport across the plant cell membrane: what do we learn from comparison between plant species? JOURNAL OF PLANT PHYSIOLOGY 2014; 171:748-69. [PMID: 24666983 DOI: 10.1016/j.jplph.2014.01.011] [Citation(s) in RCA: 175] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2014] [Accepted: 01/30/2014] [Indexed: 05/20/2023]
Abstract
Cloning and characterizations of plant K(+) transport systems aside from Arabidopsis have been increasing over the past decade, favored by the availability of more and more plant genome sequences. Information now available enables the comparison of some of these systems between species. In this review, we focus on three families of plant K(+) transport systems that are active at the plasma membrane: the Shaker K(+) channel family, comprised of voltage-gated channels that dominate the plasma membrane conductance to K(+) in most environmental conditions, and two families of transporters, the HAK/KUP/KT K(+) transporter family, which includes some high-affinity transporters, and the HKT K(+) and/or Na(+) transporter family, in which K(+)-permeable members seem to be present in monocots only. The three families are briefly described, giving insights into the structure of their members and on functional properties and their roles in Arabidopsis or rice. The structure of the three families is then compared between plant species through phylogenic analyses. Within clusters of ortologues/paralogues, similarities and differences in terms of expression pattern, functional properties and, when known, regulatory interacting partners, are highlighted. The question of the physiological significance of highlighted differences is also addressed.
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Affiliation(s)
- Anne-Aliénor Véry
- Biochimie & Physiologie Moléculaire des Plantes, UMR 5004 CNRS/386 INRA/SupAgro Montpellier/Université Montpellier 2, Campus SupAgro-INRA, 34060 Montpellier Cedex 2, France.
| | - Manuel Nieves-Cordones
- Biochimie & Physiologie Moléculaire des Plantes, UMR 5004 CNRS/386 INRA/SupAgro Montpellier/Université Montpellier 2, Campus SupAgro-INRA, 34060 Montpellier Cedex 2, France
| | - Meriem Daly
- Biochimie & Physiologie Moléculaire des Plantes, UMR 5004 CNRS/386 INRA/SupAgro Montpellier/Université Montpellier 2, Campus SupAgro-INRA, 34060 Montpellier Cedex 2, France; Laboratoire d'Ecologie et d'Environnement, Faculté des Sciences Ben M'sik, Université Hassan II-Mohammedia, Avenue Cdt Driss El Harti, BP 7955, Sidi Othmane, Casablanca, Morocco
| | - Imran Khan
- Biochimie & Physiologie Moléculaire des Plantes, UMR 5004 CNRS/386 INRA/SupAgro Montpellier/Université Montpellier 2, Campus SupAgro-INRA, 34060 Montpellier Cedex 2, France; Department of Agronomy, University of Agriculture, Faisalabad, Pakistan
| | - Cécile Fizames
- Biochimie & Physiologie Moléculaire des Plantes, UMR 5004 CNRS/386 INRA/SupAgro Montpellier/Université Montpellier 2, Campus SupAgro-INRA, 34060 Montpellier Cedex 2, France
| | - Hervé Sentenac
- Biochimie & Physiologie Moléculaire des Plantes, UMR 5004 CNRS/386 INRA/SupAgro Montpellier/Université Montpellier 2, Campus SupAgro-INRA, 34060 Montpellier Cedex 2, France
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Benito B, Haro R, Amtmann A, Cuin TA, Dreyer I. The twins K+ and Na+ in plants. JOURNAL OF PLANT PHYSIOLOGY 2014; 171:723-31. [PMID: 24810769 DOI: 10.1016/j.jplph.2013.10.014] [Citation(s) in RCA: 127] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2013] [Revised: 10/01/2013] [Accepted: 10/02/2013] [Indexed: 05/02/2023]
Abstract
In the earth's crust and in seawater, K(+) and Na(+) are by far the most available monovalent inorganic cations. Physico-chemically, K(+) and Na(+) are very similar, but K(+) is widely used by plants whereas Na(+) can easily reach toxic levels. Indeed, salinity is one of the major and growing threats to agricultural production. In this article, we outline the fundamental bases for the differences between Na(+) and K(+). We present the foundation of transporter selectivity and summarize findings on transporters of the HKT type, which are reported to transport Na(+) and/or Na(+) and K(+), and may play a central role in Na(+) utilization and detoxification in plants. Based on the structural differences in the hydration shells of K(+) and Na(+), and by comparison with sodium channels, we present an ad hoc mechanistic model that can account for ion permeation through HKTs.
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Affiliation(s)
- Begoña Benito
- Centro de Biotecnología y Genómica de Plantas, Universidad Politécnica de Madrid, Madrid, Spain
| | - Rosario Haro
- Centro de Biotecnología y Genómica de Plantas, Universidad Politécnica de Madrid, Madrid, Spain
| | - Anna Amtmann
- Institute of Molecular, Cellular and Systems Biology (MCSB), College of Medical, Veterinary and Life Sciences (MVLS), University of Glasgow, Glasgow, UK
| | - Tracey Ann Cuin
- Biochimie et Physiologie Moléculaire des Plantes, Institut de Biologie Intégrative des Plantes, UMR 5004 CNRS/UMR 0386 INRA/Montpellier SupAgro/Université Montpellier 2, Montpellier, France
| | - Ingo Dreyer
- Centro de Biotecnología y Genómica de Plantas, Universidad Politécnica de Madrid, Madrid, Spain.
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Chérel I, Lefoulon C, Boeglin M, Sentenac H. Molecular mechanisms involved in plant adaptation to low K(+) availability. JOURNAL OF EXPERIMENTAL BOTANY 2014; 65:833-48. [PMID: 24293613 DOI: 10.1093/jxb/ert402] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
Potassium is a major inorganic constituent of the living cell and the most abundant cation in the cytosol. It plays a role in various functions at the cell level, such as electrical neutralization of anionic charges, protein synthesis, long- and short-term control of membrane polarization, and regulation of the osmotic potential. Through the latter function, K(+) is involved at the whole-plant level in osmotically driven functions such as cell movements, regulation of stomatal aperture, or phloem transport. Thus, plant growth and development require that large amounts of K(+) are taken up from the soil and translocated to the various organs. In most ecosystems, however, soil K(+) availability is low and fluctuating, so plants have developed strategies to take up K(+) more efficiently and preserve vital functions and growth when K(+) availability is becoming limited. These strategies include increased capacity for high-affinity K(+) uptake from the soil, K(+) redistribution between the cytosolic and vacuolar pools, ensuring cytosolic homeostasis, and modification of root system development and architecture. Our knowledge about the mechanisms and signalling cascades involved in these different adaptive responses has been rapidly growing during the last decade, revealing a highly complex network of interacting processes. This review is focused on the different physiological responses induced by K(+) deprivation, their underlying molecular events, and the present knowledge and hypotheses regarding the mechanisms responsible for K(+) sensing and signalling.
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Affiliation(s)
- Isabelle Chérel
- Biochimie et Physiologie Moléculaire des Plantes, Institut de Biologie Intégrative des Plantes, UMR 5004 CNRS/UMR 0386 INRA/Montpellier SupAgro/Université Montpellier 2, F-34060 Montpellier Cedex 1, France
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Schmidt R, Caldana C, Mueller-Roeber B, Schippers JHM. The contribution of SERF1 to root-to-shoot signaling during salinity stress in rice. PLANT SIGNALING & BEHAVIOR 2014; 9:e27540. [PMID: 24451326 PMCID: PMC4091250 DOI: 10.4161/psb.27540] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/06/2013] [Revised: 12/15/2013] [Accepted: 12/16/2013] [Indexed: 05/20/2023]
Abstract
Stress perception and communication play important roles in the adaptation of plants to changing environmental conditions. Plant roots are the first organs to detect changes in the soil water potential induced by salt stress. In the presence of salinity stress, root-to-shoot communication occurs to adjust the growth of the whole plant. So far, the phytohormone abscisic acid (ABA), hydraulic signals and reactive oxygen species (ROS) have been proposed to mediate this communication under salt stress. Recently, we identified the rice transcription factor SALT-RESPONSIVE ERF1 (SERF1), which regulates a ROS-dependent transcriptional cascade in roots required for salinity tolerance. Upon salt stress, SERF1 knockout mutant plants show an increased leaf temperature as compared with wild type. As this occurs within the first 20 min of salt stress, we here evaluated the involvement of SERF1 in the perception of salt stress in the shoot. By metabolic profiling and expression analysis we show that the action of SERF1 in signal communication to the shoot is independent from ABA, but does affect the accumulation of ROS-related metabolites and transcripts under short-term salt stress.
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Affiliation(s)
- Romy Schmidt
- Institute of Biochemistry and Biology; University of Potsdam; Potsdam, Germany
- Max Planck Institute of Molecular Plant Physiology; Potsdam, Germany
| | - Camila Caldana
- Max Planck Institute of Molecular Plant Physiology; Potsdam, Germany
| | - Bernd Mueller-Roeber
- Institute of Biochemistry and Biology; University of Potsdam; Potsdam, Germany
- Max Planck Institute of Molecular Plant Physiology; Potsdam, Germany
| | - Jos HM Schippers
- Institute of Biochemistry and Biology; University of Potsdam; Potsdam, Germany
- Max Planck Institute of Molecular Plant Physiology; Potsdam, Germany
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48
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Ben Amar S, Brini F, Sentenac H, Masmoudi K, Véry AA. Functional characterization in Xenopus oocytes of Na+ transport systems from durum wheat reveals diversity among two HKT1;4 transporters. JOURNAL OF EXPERIMENTAL BOTANY 2014; 65:213-22. [PMID: 24192995 PMCID: PMC3883290 DOI: 10.1093/jxb/ert361] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Plant tolerance to salinity constraint involves complex and integrated functions including control of Na(+) uptake, translocation, and compartmentalization. Several members of the high-affinity K(+) transporter (HKT) family, which comprises plasma-membrane transporters permeable to K(+) and Na(+) or to Na(+) only, have been shown to play major roles in plant Na(+) and K(+) homeostasis. Among them, HKT1;4 has been identified as corresponding to a quantitative trait locus (QTL) of salt tolerance in wheat but was not functionally characterized. Here, we isolated two HKT1;4-type cDNAs from a salt-tolerant durum wheat (Triticum turgidum L. subsp. durum) cultivar, Om Rabia3, and investigated the functional properties of the encoded transporters using a two-electrode voltage-clamp technique, after expression in Xenopus oocytes. Both transporters displayed high selectivity for Na(+), their permeability to other monovalent cations (K(+), Li(+), Cs(+), and Rb(+)) being ten times lower than that to Na(+). Both TdHKT1;4-1 and TdHKT1;4-2 transported Na(+) with low affinity, although the half-saturation of the conductance was observed at a Na(+) concentration four times lower in TdHKT1;4-1 than in TdHKT1;4-2. External K(+) did not inhibit Na(+) transport through these transporters. Quinine slightly inhibited TdHKT1;4-2 but not TdHKT1;4-1. Overall, these data identified TdHKT1;4 transporters as new Na(+)-selective transporters within the HKT family, displaying their own functional features. Furthermore, they showed that important differences in affinity exist among durum wheat HKT1;4 transporters. This suggests that the salt tolerance QTL involving HKT1;4 may be at least in part explained by functional variability among wheat HKT1;4-type transporters.
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Affiliation(s)
- Siwar Ben Amar
- Plant Protection and Improvement Laboratory, Center of Biotechnology of Sfax (CBS)/University of Sfax, B.P. ‘1177’ 3018, Sfax, Tunisia
- Biochimie & Physiologie Moléculaire des Plantes, UMR 5004 CNRS/ 386 INRA/SupAgro Montpellier/Université Montpellier 2, Campus SupAgro-INRA, 34060 Montpellier Cedex 2, France
| | - Faiçal Brini
- Plant Protection and Improvement Laboratory, Center of Biotechnology of Sfax (CBS)/University of Sfax, B.P. ‘1177’ 3018, Sfax, Tunisia
| | - Hervé Sentenac
- Biochimie & Physiologie Moléculaire des Plantes, UMR 5004 CNRS/ 386 INRA/SupAgro Montpellier/Université Montpellier 2, Campus SupAgro-INRA, 34060 Montpellier Cedex 2, France
| | - Khaled Masmoudi
- Plant Protection and Improvement Laboratory, Center of Biotechnology of Sfax (CBS)/University of Sfax, B.P. ‘1177’ 3018, Sfax, Tunisia
| | - Anne-Aliénor Véry
- Biochimie & Physiologie Moléculaire des Plantes, UMR 5004 CNRS/ 386 INRA/SupAgro Montpellier/Université Montpellier 2, Campus SupAgro-INRA, 34060 Montpellier Cedex 2, France
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HKT transporters--state of the art. Int J Mol Sci 2013; 14:20359-85. [PMID: 24129173 PMCID: PMC3821619 DOI: 10.3390/ijms141020359] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2013] [Revised: 08/15/2013] [Accepted: 09/18/2013] [Indexed: 12/18/2022] Open
Abstract
The increase in soil salinity poses a serious threat to agricultural yields. Under salinity stress, several Na⁺ transporters play an essential role in Na⁺ tolerance in plants. Amongst all Na+ transporters, HKT has been shown to have a crucial role in both mono and dicotyledonous plants in the tolerance to salinity stress. Here we present an overview of the physiological role of HKT transporters in plant Na⁺ homeostasis. HKT regulation and amino acids important to the correct function of HKT transporters are reviewed. The functions of the most recently characterized HKT members from both HKT1 and HKT2 subfamilies are also discussed. Topics that still need to be studied in future research (e.g., HKT regulation) as well as research suggestions (e.g., generation of HKT mutants) are addressed.
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50
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Swarbreck SM, Colaço R, Davies JM. Plant calcium-permeable channels. PLANT PHYSIOLOGY 2013; 163:514-22. [PMID: 23860348 PMCID: PMC3793033 DOI: 10.1104/pp.113.220855] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2013] [Accepted: 07/14/2013] [Indexed: 05/19/2023]
Abstract
Experimental and modeling breakthroughs will help establish the genetic identities of plant calcium channels.
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