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Wang P, Yamaji N, Mitani-Ueno N, Ge J, Ma JF. Knockout of a rice K5.2 gene increases Ca accumulation in the grain. JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2024; 66:252-264. [PMID: 38018375 DOI: 10.1111/jipb.13587] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2023] [Revised: 11/20/2023] [Accepted: 11/27/2023] [Indexed: 11/30/2023]
Abstract
Rice is a staple food for half of the world's population, but it is a poor dietary source of calcium (Ca) due to the low concentration. It is an important issue to boost Ca concentration in this grain to improve Ca deficiency risk, but the mechanisms underlying Ca accumulation are poorly understood. Here, we obtained a rice (Oryza sativa) mutant with high shoot Ca accumulation. The mutant exhibited 26%-53% higher Ca in shoots than did wild-type rice (WT) at different Ca supplies. Ca concentration in the xylem sap was 36% higher in the mutant than in the WT. There was no difference in agronomic traits between the WT and mutant, but the mutant showed 25% higher Ca in the polished grain compared with the WT. Map-based cloning combined with a complementation test revealed that the mutant phenotype was caused by an 18-bp deletion of a gene, OsK5.2, belonging to the Shaker-like K+ channel family. OsK5.2 was highly expressed in the mature region of the roots and its expression in the roots was not affected by Ca levels, but upregulated by low K. Immunostaining showed that OsK5.2 was mainly expressed in the pericycle of the roots. Taken together, our results revealed a novel role for OsK5.2 in Ca translocation in rice, and will be a good target for Ca biofortification in rice.
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Affiliation(s)
- Peitong Wang
- National Key Laboratory of Crop Genetics & Germplasm Enhancement and Utilization, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, 210095, China
- Institute of Plant Science and Resources, Okayama University, Kurashiki, 710-0046, Japan
| | - Naoki Yamaji
- Institute of Plant Science and Resources, Okayama University, Kurashiki, 710-0046, Japan
| | - Namiki Mitani-Ueno
- Institute of Plant Science and Resources, Okayama University, Kurashiki, 710-0046, Japan
| | - Jun Ge
- Institute of Plant Science and Resources, Okayama University, Kurashiki, 710-0046, Japan
| | - Jian Feng Ma
- Institute of Plant Science and Resources, Okayama University, Kurashiki, 710-0046, Japan
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2
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Mei C, Yan P, Feng B, Mamat A, Wang J. The apple Ca 2+/H + exchanger MdCAX2L-2 functions positively in modulation of Ba 2+ tolerance. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2024; 207:108314. [PMID: 38184884 DOI: 10.1016/j.plaphy.2023.108314] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2023] [Revised: 12/21/2023] [Accepted: 12/23/2023] [Indexed: 01/09/2024]
Abstract
Calcium is an essential element for plant growth and development, and it plays an important role in the responses of plants to abiotic stress. High concentrations of heavy metal ions in soil significantly affect the yield and quality of crops and pose human health threats when these ions accumulate in edible organs. The Ca2+/H+ exchanger (CAX) family is a class of transporters that mediate the transmembrane transport of both Ca2+ and metal ions, and they are widely involved in regulating plant growth and development and stress responses. Here, we cloned an AtCAX2 ortholog, MdCAX2L-2, from apple. It is constitutively expressed in various apple tissues and significantly induced by Ca2+ and Ba2+ treatments. The MdCAX2L-2 protein is located in the vacuolar membrane in both plant and yeast cells. Overexpression of MdCAX2L-2 enhanced the tolerance of the yeast mutant K667 to high concentrations of Ca2+ and Ba2+. In addition, the role of MdCAX2L-2 in modulating Ba2+ tolerance was identified using MdCAX2L-2-overexpressing transgenic Arabidopsis plants and apple calli. Comparison of growth phenotypes and stress-related physiological indexes under BaCl2 treatment indicated that MdCAX2L-2 could enhance the Ba2+ tolerance of plants by promoting Ba2+ compartmentalization into the vacuoles and eliminating excess ROS. Our results provide insights that will aid future studies examining the function of CAX proteins in regulating stress tolerance in fruit crops, as well as their underlying mechanisms.
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Affiliation(s)
- Chuang Mei
- The State Key Laboratory of Genetic Improvement and Germplasm Innovation of Crop Resistance in Arid Desert Regions (Preparation), Key Laboratory of Genome Research and Genetic Improvement of Xinjiang Characteristic Fruits and Vegetables, Institute of Horticultural Crops, Xinjiang Academy of Agricultural Sciences, Urumqi, China
| | - Peng Yan
- The State Key Laboratory of Genetic Improvement and Germplasm Innovation of Crop Resistance in Arid Desert Regions (Preparation), Key Laboratory of Genome Research and Genetic Improvement of Xinjiang Characteristic Fruits and Vegetables, Institute of Horticultural Crops, Xinjiang Academy of Agricultural Sciences, Urumqi, China
| | - Beibei Feng
- The State Key Laboratory of Genetic Improvement and Germplasm Innovation of Crop Resistance in Arid Desert Regions (Preparation), Key Laboratory of Genome Research and Genetic Improvement of Xinjiang Characteristic Fruits and Vegetables, Institute of Horticultural Crops, Xinjiang Academy of Agricultural Sciences, Urumqi, China
| | - Aisajan Mamat
- The State Key Laboratory of Genetic Improvement and Germplasm Innovation of Crop Resistance in Arid Desert Regions (Preparation), Key Laboratory of Genome Research and Genetic Improvement of Xinjiang Characteristic Fruits and Vegetables, Institute of Horticultural Crops, Xinjiang Academy of Agricultural Sciences, Urumqi, China
| | - Jixun Wang
- The State Key Laboratory of Genetic Improvement and Germplasm Innovation of Crop Resistance in Arid Desert Regions (Preparation), Key Laboratory of Genome Research and Genetic Improvement of Xinjiang Characteristic Fruits and Vegetables, Institute of Horticultural Crops, Xinjiang Academy of Agricultural Sciences, Urumqi, China.
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3
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Liu J, Feng X, Qiu G, Li H, Wang Y, Chen X, Fu Q, Guo B. Inhibition Roles of Calcium in Cadmium Uptake and Translocation in Rice: A Review. Int J Mol Sci 2023; 24:11587. [PMID: 37511349 PMCID: PMC10380254 DOI: 10.3390/ijms241411587] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2023] [Revised: 07/14/2023] [Accepted: 07/16/2023] [Indexed: 07/30/2023] Open
Abstract
Cadmium (Cd) contamination in rice grains is posing a significant threat to global food security. To restrict the transport of Cd in the soil-rice system, an efficient way is to use the ionomics strategy. Since calcium (Ca) and Cd have similar ionic radii, their uptake and translocation may be linked in multiple aspects in rice. However, the underlying antagonistic mechanisms are still not fully understood. Therefore, we first summarized the current knowledge on the physiological and molecular footprints of Cd translocation in plants and then explored the potential antagonistic points between Ca and Cd in rice, including exchange adsorption on roots, plant cell-wall composition, co-transporter gene expression, and transpiration inhibition. This review provides suggestions for Ca/Cd interaction studies on rice and introduces ionomics research as a means of better controlling the accumulation of Cd in plants.
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Affiliation(s)
- Junli Liu
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-Products, Institute of Environment, Resource, Soil and Fertilizer, Zhejiang Academy of Agricultural Sciences, Hangzhou 310021, China; (J.L.); (X.F.); (G.Q.); (H.L.); (Y.W.); (X.C.); (Q.F.)
| | - Xiaoyu Feng
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-Products, Institute of Environment, Resource, Soil and Fertilizer, Zhejiang Academy of Agricultural Sciences, Hangzhou 310021, China; (J.L.); (X.F.); (G.Q.); (H.L.); (Y.W.); (X.C.); (Q.F.)
- Key Laboratory of Environment Remediation and Ecological Health, Ministry of Education, College of Environmental Resource Sciences, Zhejiang University, Hangzhou 310058, China
| | - Gaoyang Qiu
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-Products, Institute of Environment, Resource, Soil and Fertilizer, Zhejiang Academy of Agricultural Sciences, Hangzhou 310021, China; (J.L.); (X.F.); (G.Q.); (H.L.); (Y.W.); (X.C.); (Q.F.)
- Key Laboratory of Environment Remediation and Ecological Health, Ministry of Education, College of Environmental Resource Sciences, Zhejiang University, Hangzhou 310058, China
| | - Hua Li
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-Products, Institute of Environment, Resource, Soil and Fertilizer, Zhejiang Academy of Agricultural Sciences, Hangzhou 310021, China; (J.L.); (X.F.); (G.Q.); (H.L.); (Y.W.); (X.C.); (Q.F.)
| | - Yuan Wang
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-Products, Institute of Environment, Resource, Soil and Fertilizer, Zhejiang Academy of Agricultural Sciences, Hangzhou 310021, China; (J.L.); (X.F.); (G.Q.); (H.L.); (Y.W.); (X.C.); (Q.F.)
| | - Xiaodong Chen
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-Products, Institute of Environment, Resource, Soil and Fertilizer, Zhejiang Academy of Agricultural Sciences, Hangzhou 310021, China; (J.L.); (X.F.); (G.Q.); (H.L.); (Y.W.); (X.C.); (Q.F.)
| | - Qinglin Fu
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-Products, Institute of Environment, Resource, Soil and Fertilizer, Zhejiang Academy of Agricultural Sciences, Hangzhou 310021, China; (J.L.); (X.F.); (G.Q.); (H.L.); (Y.W.); (X.C.); (Q.F.)
| | - Bin Guo
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-Products, Institute of Environment, Resource, Soil and Fertilizer, Zhejiang Academy of Agricultural Sciences, Hangzhou 310021, China; (J.L.); (X.F.); (G.Q.); (H.L.); (Y.W.); (X.C.); (Q.F.)
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Gan Q, Song F, Zhang C, Han Z, Teng B, Lin C, Gu D, Wang J, Pei H, Wu J, Fang J, Ni D. Ca 2+ deficiency triggers panicle degeneration in rice mediated by Ca 2+ /H + exchanger OsCAX1a. PLANT, CELL & ENVIRONMENT 2023; 46:1610-1628. [PMID: 36694306 DOI: 10.1111/pce.14550] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/09/2022] [Revised: 01/20/2023] [Accepted: 01/21/2023] [Indexed: 06/17/2023]
Abstract
Increasing rice yield has always been one of the primary objectives of rice breeding. However, panicle degeneration often occurs in rice-growing regions and severely curbs rice yield. In this study, we obtained a new apical panicle degeneration mutant, which induces a marked degeneration rate and diminishes the final grain yield. Cellular and physiological analyses revealed that the apical panicle undergoes programmed cell death, accompanied by excessive accumulations of peroxides. Following, the panicle degeneration gene OsCAX1a was identified in the mutant, which was involved in Ca2+ transport. Hydroponics assays and Ca2+ quantification confirmed that Ca2+ transport and distribution to apical tissues were restricted and over-accumulated in the mutant sheath. Ca2+ transport between cytoplasm and vacuole was affected, and the reduced Ca2+ content in the vacuole and cell wall of the apical panicle and the decreased Ca2+ absorption appeared in the mutant. RNA-Seq data indicated that the abnormal CBL (calcineurin b-like proteins) pathway mediated by deficient Ca2+ might occur in the mutant, resulting in the burst of ROS and programmed cell death in panicles. Our results explained the key role of OsCAX1a in Ca2+ transport and distribution and laid a foundation to further explore the genetic and molecular mechanisms of panicle degeneration in rice.
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Affiliation(s)
- Quan Gan
- Rice Research Institute, Anhui Academy of Agricultural Sciences, Hefei, China
- Key Laboratory of Rice Genetics and Breeding in Anhui Province, Hefei, China
| | - Fengshun Song
- Rice Research Institute, Anhui Academy of Agricultural Sciences, Hefei, China
- Key Laboratory of Rice Genetics and Breeding in Anhui Province, Hefei, China
| | - Chuanzhong Zhang
- Key Laboratory of Soybean Molecular Design Breeding, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Harbin, China
| | - Zhongmin Han
- Key Laboratory of Soybean Molecular Design Breeding, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Harbin, China
| | - Bin Teng
- Rice Research Institute, Anhui Academy of Agricultural Sciences, Hefei, China
- Key Laboratory of Rice Genetics and Breeding in Anhui Province, Hefei, China
| | - Cuixiang Lin
- Rice Research Institute, Anhui Academy of Agricultural Sciences, Hefei, China
- Key Laboratory of Rice Genetics and Breeding in Anhui Province, Hefei, China
| | - Dongfang Gu
- Rice Research Institute, Anhui Academy of Agricultural Sciences, Hefei, China
- Key Laboratory of Rice Genetics and Breeding in Anhui Province, Hefei, China
| | - Jiajia Wang
- Soil and Fertilizer Research Institute, Anhui Academy of Agricultural Sciences, Hefei, China
| | - Huan Pei
- Soil and Fertilizer Research Institute, Anhui Academy of Agricultural Sciences, Hefei, China
| | - Ji Wu
- Soil and Fertilizer Research Institute, Anhui Academy of Agricultural Sciences, Hefei, China
| | - Jun Fang
- Key Laboratory of Soybean Molecular Design Breeding, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Harbin, China
| | - Dahu Ni
- Rice Research Institute, Anhui Academy of Agricultural Sciences, Hefei, China
- Key Laboratory of Rice Genetics and Breeding in Anhui Province, Hefei, China
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Liu Y, He G, He Y, Tang Y, Zhao F, He T. Discovery of cadmium-tolerant biomacromolecule (StCAX1/4 transportproteins) in potato and its potential regulatory relationship with WRKY transcription factors. Int J Biol Macromol 2023; 228:385-399. [PMID: 36581029 DOI: 10.1016/j.ijbiomac.2022.12.232] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2022] [Revised: 09/04/2022] [Accepted: 12/16/2022] [Indexed: 12/27/2022]
Abstract
The cation/H+ exchanger (CAX) involved in Ca2+, Mg2+ and Mn2+ transport is a special class of vacuolar transporters that play an important role in maintaining ion homeostasis in plant cells. However, it has been rarely reported whether CAX proteins have unique tolerance to cadmium stress. In our research, the cadmium-resistant potato variety "Yunshu 505" was taken as the object, through biological etc. methods, explored 1: response mode of StCAXs to cadmium stress; 2: the evolutionary characteristics and Cd ion binding sites of StCAXs; and 3: possible upstream regulatory pathways of StCAXs. The results showed that cadmium stress significantly induced the expression of StCAX1/4, and there were specific mutations in the evolution process, thus the possible main binding site of Cd ion (EDEE/DH/GxxxxxS/EEEE) was speculated. StCAX1/4 interacts with several proteins, and be regulated by transcription factors, especially the WRKY6. This synergistic regulation through WRKY6 may be an important pathway through which StCAX1/4 imparts high cadmium tolerance to potato. These results provide certain support for understanding the binding sites and specific evolutionary mechanisms of key amino acid residues of cadmium ion in StCAXs, also provide new clues for the identification and regulatory model of potato CAX key positive stress-responsive proteins under cadmium stress.
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Affiliation(s)
- Yao Liu
- College of Agricultural, Guizhou University, Guiyang 550025, PR China.
| | - Guandi He
- College of Agricultural, Guizhou University, Guiyang 550025, PR China; Key Laboratory of Plant Resource Conservation and Germplasm Innovation in Mountainous Region (Ministry of Education), Key Laboratory of Animal Genetics, Breeding and Reproduction in the Plateau Mountainous Region, Ministry of Education, Guizhou University, Guiyang 550025, PR China.
| | - Yeqing He
- College of Agricultural, Guizhou University, Guiyang 550025, PR China.
| | - Yueyue Tang
- College of Agricultural, Guizhou University, Guiyang 550025, PR China.
| | - Fulin Zhao
- College of Agricultural, Guizhou University, Guiyang 550025, PR China.
| | - Tengbing He
- College of Agricultural, Guizhou University, Guiyang 550025, PR China; Key Laboratory of Plant Resource Conservation and Germplasm Innovation in Mountainous Region (Ministry of Education), Key Laboratory of Animal Genetics, Breeding and Reproduction in the Plateau Mountainous Region, Ministry of Education, Guizhou University, Guiyang 550025, PR China; Institute of New Rural Development of Guizhou University, Guiyang 550025, PR China.
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6
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Metalloprotein-Specific or Critical Amino Acid Residues: Perspectives on Plant-Precise Detoxification and Recognition Mechanisms under Cadmium Stress. Int J Mol Sci 2022; 23:ijms23031734. [PMID: 35163656 PMCID: PMC8836122 DOI: 10.3390/ijms23031734] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2021] [Revised: 01/26/2022] [Accepted: 02/02/2022] [Indexed: 12/15/2022] Open
Abstract
Cadmium (Cd) pollution in cultivated land is caused by irresistible geological factors and human activities; intense diffusion and migration have seriously affected the safety of food crops. Plants have evolved mechanisms to control excessive influx of Cd in the environment, such as directional transport, chelation and detoxification. This is done by some specific metalloproteins, whose key amino acid motifs have been investigated by scientists one by one. The application of powerful cell biology, crystal structure science, and molecular probe targeted labeling technology has identified a series of protein families involved in the influx, transport and detoxification of the heavy metal Cd. This review summarizes them as influx proteins (NRAMP, ZIP), chelating proteins (MT, PDF), vacuolar proteins (CAX, ABCC, MTP), long-distance transport proteins (OPT, HMA) and efflux proteins (PCR, ABCG). We selected representative proteins from each family, and compared their amino acid sequence, motif structure, subcellular location, tissue specific distribution and other characteristics of differences and common points, so as to summarize the key residues of the Cd binding target. Then, we explain its special mechanism of action from the molecular structure. In conclusion, this review is expected to provide a reference for the exploration of key amino acid targets of Cd, and lay a foundation for the intelligent design and breeding of crops with high/low Cd accumulation.
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7
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Description of AtCAX4 in Response to Abiotic Stress in Arabidopsis. Int J Mol Sci 2021; 22:ijms22020856. [PMID: 33467091 PMCID: PMC7830611 DOI: 10.3390/ijms22020856] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2020] [Revised: 01/13/2021] [Accepted: 01/14/2021] [Indexed: 02/04/2023] Open
Abstract
High-capacity tonoplast cation/H+ antiport in plants is partially mediated by a family of CAX transporters. Previous studies have reported that CAX activity is affected by an N-terminal autoinhibitory region. CAXs may be present as heterodimers in plant cells, and this phenomenon necessitates further study. In this study, we demonstrate that there is an interaction between CAX4 and CAX1 as determined by the use of a yeast two-hybrid system and a bimolecular fluorescence complementation assay. More specifically, the N-terminal of CAX4 interacts with CAX1. We further observed the over-expression and either a single or double mutant of CAX1 and CAX4 in response to abiotic stress in Arabidopsis. These results suggest that CAX1 and CAX4 can interact to form a heterodimer, and the N-terminal regions of CAX4 play important roles in vivo; this may provide a foundation for a deep study of CAX4 function in the future.
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Chen S, Liu Y, Deng Y, Liu Y, Dong M, Tian Y, Sun H, Li Y. Cloning and functional analysis of the VcCXIP4 and VcYSL6 genes as Cd-regulating genes in blueberry. Gene 2019; 686:104-117. [PMID: 30391441 DOI: 10.1016/j.gene.2018.10.078] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2018] [Revised: 10/11/2018] [Accepted: 10/27/2018] [Indexed: 11/26/2022]
Abstract
Blueberries (Vaccinium ssp.) show relatively high resistance to pollution and have been reported to successfully colonize acid and heavy metal-contaminated soils. Blueberries were subjected to cadmium stress using a simulated pot-culture method. The intact CDS regions of VcCXIP4 and VcYSL6 were obtained, VcCXIP4 was located in the nucleus, while VcYSL6 was located in the chloroplast. Both genes were constructed into a modified plant expression vector pCambia1301 for tobacco transformation with agrobacterium infection methods. Results showed that VcCXIP4 did not function alone in regulating cadmium (Cd) transport. Cd content of Cd in the leaves of VcYSL6 transgenic tobacco by 15.57% under high Cd concentration. Both, VcCXIP4 and VcYSL6 genes were up-regulated under Cd stress. Blueberry primarily accumulated excess Cd in the root, but Cd content in the fruit was almost independent of Cd content in the soil. Further, the effect of soil Cd content on fruit Cd content was not significant. VcCXIP4 is likely to interact with other proteins to regulate excess Cd in blueberry, while VcYSL6 is a Cd transporter required for excess Cd detoxification in blueberry.
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Affiliation(s)
- Shaopeng Chen
- College of Life Science, Jilin Agricultural University, Changchun 130118, PR China; College of Agriculture, Jilin Agricultural Science and Technology University, Jilin 132101, PR China
| | - Yushan Liu
- College of Life Science, Jilin Agricultural University, Changchun 130118, PR China
| | - Yu Deng
- College of Life Science, Jilin Agricultural University, Changchun 130118, PR China
| | - Yue Liu
- College of Life Science, Jilin Agricultural University, Changchun 130118, PR China
| | - Mei Dong
- College of Horticulture, Jilin Agricultural University, Changchun 130118, PR China
| | - Youwen Tian
- College of Life Science, Jilin Agricultural University, Changchun 130118, PR China
| | - Haiyue Sun
- College of Horticulture, Jilin Agricultural University, Changchun 130118, PR China.
| | - Yadong Li
- College of Horticulture, Jilin Agricultural University, Changchun 130118, PR China.
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Ahmadi H, Corso M, Weber M, Verbruggen N, Clemens S. CAX1 suppresses Cd-induced generation of reactive oxygen species in Arabidopsis halleri. PLANT, CELL & ENVIRONMENT 2018; 41:2435-2448. [PMID: 29879753 DOI: 10.1111/pce.13362] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2018] [Revised: 04/12/2018] [Accepted: 05/25/2018] [Indexed: 05/11/2023]
Abstract
The molecular analysis of metal hyperaccumulation in species such as Arabidopsis halleri offers the chance to gain insights into metal homeostasis and into the evolution of adaptation to extreme habitats. A prerequisite of metal hyperaccumulation is metal hypertolerance. Genetic analysis of a backcross population derived from Arabidopsis lyrata × A. halleri crosses revealed three quantitative trait loci for Cd hypertolerance. A candidate gene for Cdtol2 is AhCAX1, encoding a vacuolar Ca2+ /H+ antiporter. We developed a method for the transformation of vegetatively propagated A. halleri plants and generated AhCAX1-silenced lines. Upon Cd2+ exposure, several-fold higher accumulation of reactive oxygen species (ROS) was detectable in roots of AhCAX1-silenced plants. In accordance with the dependence of Cdtol2 on external Ca2+ concentration, this phenotype was exclusively observed in low Ca2+ conditions. The effects of external Ca2+ on Cd accumulation cannot explain the phenotype as they were not influenced by the genotype. Our data strongly support the hypothesis that higher expression of CAX1 in A. halleri relative to other Arabidopsis species represents a Cd hypertolerance factor. We propose a function of AhCAX1 in preventing a positive feedback loop of Cd-elicited ROS production triggering further Ca2+ -dependent ROS accumulation.
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Affiliation(s)
- Hassan Ahmadi
- University of Bayreuth, Department of Plant Physiology, and Bayreuth Center of Ecology and Environmental Research, Bayreuth, Germany
| | - Massimiliano Corso
- Université Libre de Bruxelles, Laboratory of Plant Physiology and Molecular Genetics, Brussels, Belgium
| | - Michael Weber
- University of Bayreuth, Department of Plant Physiology, and Bayreuth Center of Ecology and Environmental Research, Bayreuth, Germany
| | - Nathalie Verbruggen
- Université Libre de Bruxelles, Laboratory of Plant Physiology and Molecular Genetics, Brussels, Belgium
| | - Stephan Clemens
- University of Bayreuth, Department of Plant Physiology, and Bayreuth Center of Ecology and Environmental Research, Bayreuth, Germany
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Martins V, Carneiro F, Conde C, Sottomayor M, Gerós H. The grapevine VvCAX3 is a cation/H + exchanger involved in vacuolar Ca 2+ homeostasis. PLANTA 2017; 246:1083-1096. [PMID: 28801786 DOI: 10.1007/s00425-017-2754-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/18/2017] [Accepted: 08/03/2017] [Indexed: 05/05/2023]
Abstract
The grapevine VvCAX3 mediates calcium transport in the vacuole and is mostly expressed in green grape berries and upregulated by Ca 2+ , Na + and methyl jasmonate. Calcium is an essential plant nutrient with important regulatory and structural roles in the berries of grapevine (Vitis vinifera L.). On the other hand, the proton-cation exchanger CAX proteins have been shown to impact Ca2+ homeostasis with important consequences for fruit integrity and resistance to biotic/abiotic stress. Here, the CAX gene found in transcriptomic databases as having one of the highest expressions in grapevine tissues, VvCAX3, was cloned and functionally characterized. Heterologous expression in yeast showed that a truncated version of VvCAX3 lacking its NNR autoinhibitory domain (sCAX3) restored the ability of the yeast strain to grow in 100-200 mM Ca2+, demonstrating a role in Ca2+ transport. The truncated VvCAX3 was further shown to be involved in the transport of Na+, Li+, Mn2+ and Cu2+ in yeast cells. Subcellular localization studies using fluorescently tagged proteins confirmed VvCAX3 as a tonoplast transporter. VvCAX3 is expressed in grapevine stems, leaves, roots, and berries, especially at pea size, decreasing gradually throughout development, in parallel with the pattern of calcium accumulation in the fruit. The transcript abundance of VvCAX3 was shown to be regulated by methyl jasmonate (MeJA), Ca2+, and Na+ in grape cell suspensions, and the VvCAX3 promotor contains several predicted cis-acting elements related to developmental and stress response processes. As a whole, the results obtained add new insights on the mechanisms involved in calcium homeostasis and intracellular compartmentation in grapevine, and indicate that VvCAX3 may be an interesting target towards the development of strategies for enhancement of grape berry properties.
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Affiliation(s)
- Viviana Martins
- Centro de Investigação e de Tecnologias Agro-ambientais e Biológicas, CITAB-UMinho Pole, Departamento de Biologia, Escola de Ciências, Universidade do Minho, Braga, Portugal.
| | - Filipa Carneiro
- Centro de Investigação e de Tecnologias Agro-ambientais e Biológicas, CITAB-UMinho Pole, Departamento de Biologia, Escola de Ciências, Universidade do Minho, Braga, Portugal
| | - Carlos Conde
- i3S-Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal
- IBMC, Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal
| | - Mariana Sottomayor
- CIBIO-InBIO, Universidade do Porto, Campus de Vairão, Rua Padre Armando Quintas, Vairão, Portugal
- Departamento de Biologia, Faculdade de Ciências, Universidade do Porto, Porto, Portugal
| | - Hernâni Gerós
- Centro de Investigação e de Tecnologias Agro-ambientais e Biológicas, CITAB-UMinho Pole, Departamento de Biologia, Escola de Ciências, Universidade do Minho, Braga, Portugal
- Centro de Biologia Molecular e Ambiental (CBMA), Departamento de Biologia, Escola de Ciências, Universidade do Minho, Braga, Portugal
- Centro de Engenharia Biológica (CEB), Universidade do Minho, Braga, Portugal
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11
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Colinet AS, Thines L, Deschamps A, Flémal G, Demaegd D, Morsomme P. Acidic and uncharged polar residues in the consensus motifs of the yeast Ca2+
transporter Gdt1p are required for calcium transport. Cell Microbiol 2017; 19. [DOI: 10.1111/cmi.12729] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2016] [Revised: 12/12/2016] [Accepted: 01/18/2017] [Indexed: 11/29/2022]
Affiliation(s)
- Anne-Sophie Colinet
- Institut des Sciences de la Vie; Université catholique de Louvain; Louvain-la-Neuve Belgium
| | - Louise Thines
- Institut des Sciences de la Vie; Université catholique de Louvain; Louvain-la-Neuve Belgium
| | - Antoine Deschamps
- Institut des Sciences de la Vie; Université catholique de Louvain; Louvain-la-Neuve Belgium
| | - Gaëlle Flémal
- Institut des Sciences de la Vie; Université catholique de Louvain; Louvain-la-Neuve Belgium
| | - Didier Demaegd
- Institut des Sciences de la Vie; Université catholique de Louvain; Louvain-la-Neuve Belgium
| | - Pierre Morsomme
- Institut des Sciences de la Vie; Université catholique de Louvain; Louvain-la-Neuve Belgium
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12
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Chen ZH, Chen G, Dai F, Wang Y, Hills A, Ruan YL, Zhang G, Franks PJ, Nevo E, Blatt MR. Molecular Evolution of Grass Stomata. TRENDS IN PLANT SCIENCE 2017; 22:124-139. [PMID: 27776931 DOI: 10.1016/j.tplants.2016.09.005] [Citation(s) in RCA: 136] [Impact Index Per Article: 19.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2016] [Revised: 09/29/2016] [Accepted: 09/30/2016] [Indexed: 05/18/2023]
Abstract
Grasses began to diversify in the late Cretaceous Period and now dominate more than one third of global land area, including three-quarters of agricultural land. We hypothesize that their success is likely attributed to the evolution of highly responsive stomata capable of maximizing productivity in rapidly changing environments. Grass stomata harness the active turgor control mechanisms present in stomata of more ancient plant lineages, maximizing several morphological and developmental features to ensure rapid responses to environmental inputs. The evolutionary development of grass stomata appears to have been a gradual progression. Therefore, understanding the complex structures, developmental events, regulatory networks, and combinations of ion transporters necessary to drive rapid stomatal movement may inform future efforts towards breeding new crop varieties.
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Affiliation(s)
- Zhong-Hua Chen
- College of Agriculture and Biotechnology, Zhejiang University, Hangzhou 310058, China; School of Science and Health, Western Sydney University, Penrith, NSW 2751, Australia.
| | - Guang Chen
- College of Agriculture and Biotechnology, Zhejiang University, Hangzhou 310058, China
| | - Fei Dai
- College of Agriculture and Biotechnology, Zhejiang University, Hangzhou 310058, China
| | - Yizhou Wang
- Laboratory of Plant Physiology and Biophysics, University of Glasgow, Glasgow G12 8QQ, United Kingdom
| | - Adrian Hills
- Laboratory of Plant Physiology and Biophysics, University of Glasgow, Glasgow G12 8QQ, United Kingdom
| | - Yong-Ling Ruan
- School of Environmental and Life Sciences, University of Newcastle, Callaghan, NSW 2308, Australia
| | - Guoping Zhang
- College of Agriculture and Biotechnology, Zhejiang University, Hangzhou 310058, China
| | - Peter J Franks
- Faculty of Agriculture and Environment, The University of Sydney, Sydney, NSW 2006, Australia
| | - Eviatar Nevo
- Institute of Evolution, University of Haifa, Mount Carmel, Haifa 31905, Israel
| | - Michael R Blatt
- Laboratory of Plant Physiology and Biophysics, University of Glasgow, Glasgow G12 8QQ, United Kingdom
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Taneja M, Tyagi S, Sharma S, Upadhyay SK. Ca 2+/Cation Antiporters (CaCA): Identification, Characterization and Expression Profiling in Bread Wheat ( Triticum aestivum L.). FRONTIERS IN PLANT SCIENCE 2016; 7:1775. [PMID: 27965686 PMCID: PMC5124604 DOI: 10.3389/fpls.2016.01775] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2016] [Accepted: 11/10/2016] [Indexed: 05/05/2023]
Abstract
The Ca2+/cation antiporters (CaCA) superfamily proteins play vital function in Ca2+ ion homeostasis, which is an important event during development and defense response. Molecular characterization of these proteins has been performed in certain plants, but they are still not characterized in Triticum aestivum (bread wheat). Herein, we identified 34 TaCaCA superfamily proteins, which were classified into TaCAX, TaCCX, TaNCL, and TaMHX protein families based on their structural organization and evolutionary relation with earlier reported proteins. Since the T. aestivum comprises an allohexaploid genome, TaCaCA genes were derived from each A, B, and D subgenome and homeologous chromosome (HC), except chromosome-group 1. Majority of genes were derived from more than one HCs in each family that were considered as homeologous genes (HGs) due to their high similarity with each other. These HGs showed comparable gene and protein structures in terms of exon/intron organization and domain architecture. Majority of TaCaCA proteins comprised two Na_Ca_ex domains. However, TaNCLs consisted of an additional EF-hand domain with calcium binding motifs. Each TaCaCA protein family consisted of about 10 transmembrane and two α-repeat regions with specifically conserved signature motifs except TaNCL, which had single α-repeat. Variable expression of most of the TaCaCA genes during various developmental stages suggested their specified role in development. However, constitutively high expression of a few genes like TaCAX1-A and TaNCL1-B indicated their role throughout the plant growth and development. The modulated expression of certain genes during biotic (fungal infections) and abiotic stresses (heat, drought, salt) suggested their role in stress response. Majority of TaCCX and TaNCL family genes were found highly affected during various abiotic stresses. However, the role of individual gene needs to be established. The present study unfolded the opportunity for detail functional characterization of TaCaCA proteins and their utilization in future crop improvement programs.
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Affiliation(s)
- Mehak Taneja
- Department of Botany, Panjab UniversityChandigarh, India
| | - Shivi Tyagi
- Department of Botany, Panjab UniversityChandigarh, India
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Singh AK, Kumar R, Tripathi AK, Gupta BK, Pareek A, Singla-Pareek SL. Genome-wide investigation and expression analysis of Sodium/Calcium exchanger gene family in rice and Arabidopsis. RICE (NEW YORK, N.Y.) 2015; 8:54. [PMID: 26134707 PMCID: PMC4488139 DOI: 10.1186/s12284-015-0054-5] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2015] [Accepted: 06/09/2015] [Indexed: 05/20/2023]
Abstract
BACKGROUND The Na(+)/Ca(2+) Exchanger (NCX) protein family is a member of the Cation/Ca(2+) exchanger superfamily and its members play important roles in cellular Ca(2+) homeostasis. While the functions of NCX family of proteins is well understood in humans, not much is known about the total complement of Na(+)/Ca(2+) exchangers in plants and their role in various physiological and developmental processes. In the present study, we have identified all the NCX proteins encoded in the genomes of rice and Arabidopsis and studied their phylogeny, domain architecture and expression profiles across different tissues, at various developmental stages and under stress conditions. RESULTS Through whole genome investigation, we identified twenty-two NCX proteins encoded by fifteen genes in rice and sixteen NCX proteins encoded by thirteen genes in Arabidopsis. Based on phylogenetic reconstruction, these could be classified into five clades, members of most of which were found to possess distinct domain architecture. Expression profiling of the identified NCX genes using publicly available MPSS and microarray data showed differential expression patterns under abiotic stresses, and at various development stages. In rice, OsNCX1, OsNCX8, OsNCX9 and OsNCX15 were found to be highly expressed in all the plant parts and various developmental stages. qRT-PCR based expression analysis revealed that OsNCX3, OsNCX10 and OsNCX15 were highly induced by salt and dehydration stress. Besides, expression profiling showed differential regulation of rice NCX genes in response to calcium and EGTA. Interestingly, expression of none of the NCX genes was found to be co-regulated by NaCl and calcium. CONCLUSIONS Together, our results present insights into the potential role of NCX family of proteins in abiotic stresses and development. Findings of the present investigation should serve as a starting point for future studies aiming functional characterization of plant NCX family proteins.
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Affiliation(s)
- Anil Kumar Singh
- />Plant Molecular Biology Group, International Centre for Genetic Engineering & Biotechnology (ICGEB), Aruna Asaf Ali Marg, New Delhi, 110067 India
- />Present address: Division of Biotechnology, CSIR-Institute of Himalayan Bioresource Technology, Palampur -, 176061, H.P. India
| | - Ritesh Kumar
- />Plant Molecular Biology Group, International Centre for Genetic Engineering & Biotechnology (ICGEB), Aruna Asaf Ali Marg, New Delhi, 110067 India
- />Present address: Division of Applied Life Science, Plant Molecular Biology and Biotechnology Research Center, Gyeongsang National University, Jinju, 660-701 Korea
| | - Amit K. Tripathi
- />Plant Molecular Biology Group, International Centre for Genetic Engineering & Biotechnology (ICGEB), Aruna Asaf Ali Marg, New Delhi, 110067 India
| | - Brijesh K. Gupta
- />Plant Molecular Biology Group, International Centre for Genetic Engineering & Biotechnology (ICGEB), Aruna Asaf Ali Marg, New Delhi, 110067 India
| | - Ashwani Pareek
- />Stress Physiology and Molecular Biology Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi, 110067 India
| | - Sneh L. Singla-Pareek
- />Plant Molecular Biology Group, International Centre for Genetic Engineering & Biotechnology (ICGEB), Aruna Asaf Ali Marg, New Delhi, 110067 India
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15
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Yadav AK, Shankar A, Jha SK, Kanwar P, Pandey A, Pandey GK. A rice tonoplastic calcium exchanger, OsCCX2 mediates Ca2+/cation transport in yeast. Sci Rep 2015; 5:17117. [PMID: 26607171 PMCID: PMC4660821 DOI: 10.1038/srep17117] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2015] [Accepted: 10/26/2015] [Indexed: 12/14/2022] Open
Abstract
In plant cell, cations gradient in cellular compartments is maintained by synergistic action of various exchangers, pumps and channels. The Arabidopsis exchanger family members (AtCCX3 and AtCCX5) were previously studied and belong to CaCA (calcium cation exchangers) superfamily while none of the rice CCXs has been functionally characterized for their cation transport activities till date. Rice genome encode four CCXs and only OsCCX2 transcript showed differential expression under abiotic stresses and Ca(2+) starvation conditions. The OsCCX2 localized to tonoplast and suppresses the Ca(2+) sensitivity of K667 (low affinity Ca(2+) uptake deficient) yeast mutant under excess CaCl2 conditions. In contrast to AtCCXs, OsCCX2 expressing K667 yeast cells show tolerance towards excess Na(+), Li(+), Fe(2+), Zn(2+) and Co(2+) and suggest its ability to transport both mono as well as divalent cations in yeast. Additionally, in contrast to previously characterized AtCCXs, OsCCX2 is unable to complement yeast trk1trk2 double mutant suggesting inability to transport K(+) in yeast system. These finding suggest that OsCCX2 having distinct metal transport properties than previously characterized plant CCXs. OsCCX2 can be used as potential candidate for enhancing the abiotic stress tolerance in plants as well as for phytoremediation of heavy metal polluted soil.
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Affiliation(s)
- Akhilesh K. Yadav
- Department of Plant Molecular Biology, University of Delhi South Campus, Benito Juarez Road, Dhaula Kuan, New Delhi-110021, India
| | - Alka Shankar
- Department of Plant Molecular Biology, University of Delhi South Campus, Benito Juarez Road, Dhaula Kuan, New Delhi-110021, India
| | - Saroj K. Jha
- Department of Plant Molecular Biology, University of Delhi South Campus, Benito Juarez Road, Dhaula Kuan, New Delhi-110021, India
| | - Poonam Kanwar
- Department of Plant Molecular Biology, University of Delhi South Campus, Benito Juarez Road, Dhaula Kuan, New Delhi-110021, India
| | - Amita Pandey
- 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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Zhang L, Hao J, Bao M, Hasi A, Niu Y. Cloning and characterization of a Ca(2+)/H(+) exchanger from the halophyte Salicornia europaea L. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2015; 96:321-328. [PMID: 26332662 DOI: 10.1016/j.plaphy.2015.08.011] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2015] [Revised: 08/17/2015] [Accepted: 08/17/2015] [Indexed: 06/05/2023]
Abstract
The calcium ion (Ca(2+)), which functions as a second messenger, plays an important role in plants' responses to various abiotic stresses, and Ca(2+)/H(+) exchangers (CAXs) are an important part of this process. In this study, we isolated and characterized a putative Ca(2+)/H(+) exchanger gene (SeCAX3) from Salicornia europaea L., a succulent, leafless euhalophyte. The SeCAX3 open reading frame was 1368 bp long and encoded a 455-amino-acid polypeptide that showed 67.9% similarity to AtCAX3. SeCAX3 was expressed in the shoots and roots of S. europaea. Expression of SeCAX3 was up-regulated by Ca(2+), Na(+), sorbitol, Li(+), abscisic acid, and cold treatments in shoots, but down-regulated by Ca(2+), sorbitol, abscisic acid, and cold treatments in roots. When SeCAX3 was transformed into a Ca-sensitive yeast strain, the transformed cells were able to grow in the presence of 200 mM Ca(2+). Furthermore, SeCAX3 conferred drought, salt, and cold tolerance in yeast. Compared with the control strains, the yeast transformants expressing SeCAX3 were able to grow well in the presence of 30 mM Li(+), 150 mM Mg(2+), or 6 mM Ba(2+). These results showed that the expression of SeCAX3 in yeast suppressed its Ca(2+) hypersensitivity and conferred tolerance to Mg(2+) and Ba(2+). Together, these findings suggest that SeCAX3 might be a Ca(2+) transporter that plays a role in regulating cation tolerance and the responses of S. europaea to various abiotic stresses.
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Affiliation(s)
- Liquan Zhang
- Inner Mongolia Key Laboratory of Herbage & Endemic Crop Biotechnology, College of Life Sciences, Inner Mongolia University, Hohhot 010021, PR China
| | - Jinfeng Hao
- Inner Mongolia Key Laboratory of Herbage & Endemic Crop Biotechnology, College of Life Sciences, Inner Mongolia University, Hohhot 010021, PR China
| | - Mulan Bao
- Inner Mongolia Key Laboratory of Herbage & Endemic Crop Biotechnology, College of Life Sciences, Inner Mongolia University, Hohhot 010021, PR China
| | - Agula Hasi
- Inner Mongolia Key Laboratory of Herbage & Endemic Crop Biotechnology, College of Life Sciences, Inner Mongolia University, Hohhot 010021, PR China
| | - Yiding Niu
- Inner Mongolia Key Laboratory of Herbage & Endemic Crop Biotechnology, College of Life Sciences, Inner Mongolia University, Hohhot 010021, PR China.
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17
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Singh UM, Metwal M, Singh M, Taj G, Kumar A. Identification and characterization of calcium transporter gene family in finger millet in relation to grain calcium content. Gene 2015; 566:37-46. [PMID: 25869323 DOI: 10.1016/j.gene.2015.04.021] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2014] [Revised: 04/06/2015] [Accepted: 04/08/2015] [Indexed: 02/08/2023]
Abstract
Calcium (Ca) is an essential mineral for proper growth and development of plants as well as animals. In plants including cereals, calcium is deposited in seed during its development which is mediated by specialized Ca transporters. Common cereal seeds contain very low amounts of Ca while the finger millet (Eleusine coracana) contains exceptionally high amounts of Ca in seed. In order to understand the role of Ca transporters in grain Ca accumulation, developing seed transcriptome of two finger millet genotypes (GP-1, low Ca and GP-45 high Ca) differing in seed Ca content was sequenced using Illumina paired-end sequencing technology and members of Ca transporter gene family were identified. Out of 109,218 and 120,130 contigs, 86 and 81 contigs encoding Ca transporters were identified in GP-1 and GP-45, respectively. After removal of redundant sequences, a total of 19 sequences were confirmed as Ca transporter genes, which includes 11 Ca(2+) ATPases, 07 Ca(2+)/cation exchangers and 01 Ca(2+) channel. The differential expressions of all genes were analyzed from transcriptome data and it was observed that 9 and 3 genes were highly expressed in GP-45 and GP-1 genotypes respectively. Validation of transcriptome expression data of selected Ca transporter genes was performed on different stages of developing spikes of both genotypes grown under different concentrations of exogenous Ca. In both genotypes, significant correlation was observed between the expression of these genes, especially EcCaX3, and on the amount of Ca accumulated in seed. The positive correlation of seed mass with the amount of Ca concentration was also observed. The efficient Ca transport property and responsiveness of EcCAX3 towards exogenous Ca could be utilized in future biofortification program.
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Affiliation(s)
- Uma M Singh
- Department of Molecular Biology & Genetic Engineering, College of Basic Science & Humanities, G.B. Pant University of Agriculture & Technology, Pantnagar 263145, Uttarakhand, India; IRRI-South Asia Hub, International Crops Research Institute for the Semi-Arid Tropics, Patancheru 502 324, Telangana State, India
| | - Mamta Metwal
- Department of Molecular Biology & Genetic Engineering, College of Basic Science & Humanities, G.B. Pant University of Agriculture & Technology, Pantnagar 263145, Uttarakhand, India
| | - Manoj Singh
- Department of Molecular Biology & Genetic Engineering, College of Basic Science & Humanities, G.B. Pant University of Agriculture & Technology, Pantnagar 263145, Uttarakhand, India
| | - Gohar Taj
- Department of Molecular Biology & Genetic Engineering, College of Basic Science & Humanities, G.B. Pant University of Agriculture & Technology, Pantnagar 263145, Uttarakhand, India
| | - Anil Kumar
- Department of Molecular Biology & Genetic Engineering, College of Basic Science & Humanities, G.B. Pant University of Agriculture & Technology, Pantnagar 263145, Uttarakhand, India.
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18
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Towards Understanding the Role of the Na+-Ca2+ Exchanger Isoform 3. Rev Physiol Biochem Pharmacol 2015; 168:31-57. [DOI: 10.1007/112_2015_23] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
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19
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Sodium recognition by the Na+/Ca2+ exchanger in the outward-facing conformation. Proc Natl Acad Sci U S A 2014; 111:E5354-62. [PMID: 25468964 DOI: 10.1073/pnas.1415751111] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Na(+)/Ca(2+) exchangers (NCXs) are ubiquitous membrane transporters with a key role in Ca(2+) homeostasis and signaling. NCXs mediate the bidirectional translocation of either Na(+) or Ca(2+), and thus can catalyze uphill Ca(2+) transport driven by a Na(+) gradient, or vice versa. In a major breakthrough, a prokaryotic NCX homolog (NCX_Mj) was recently isolated and its crystal structure determined at atomic resolution. The structure revealed an intriguing architecture consisting of two inverted-topology repeats, each comprising five transmembrane helices. These repeats adopt asymmetric conformations, yielding an outward-facing occluded state. The crystal structure also revealed four putative ion-binding sites, but the occupancy and specificity thereof could not be conclusively established. Here, we use molecular-dynamics simulations and free-energy calculations to identify the ion configuration that best corresponds to the crystallographic data and that is also thermodynamically optimal. In this most probable configuration, three Na(+) ions occupy the so-called Sext, SCa, and Sint sites, whereas the Smid site is occupied by one water molecule and one H(+), which protonates an adjacent aspartate side chain (D240). Experimental measurements of Na(+)/Ca(2+) and Ca(2+)/Ca(2+) exchange by wild-type and mutagenized NCX_Mj confirm that transport of both Na(+) and Ca(2+) requires protonation of D240, and that this side chain does not coordinate either ion at Smid. These results imply that the ion exchange stoichiometry of NCX_Mj is 3:1 and that translocation of Na(+) across the membrane is electrogenic, whereas transport of Ca(2+) is not. Altogether, these findings provide the basis for further experimental and computational studies of the conformational mechanism of this exchanger.
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20
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Yamada N, Theerawitaya C, Cha-um S, Kirdmanee C, Takabe T. Expression and functional analysis of putative vacuolar Ca2+-transporters (CAXs and ACAs) in roots of salt tolerant and sensitive rice cultivars. PROTOPLASMA 2014; 251:1067-75. [PMID: 24482191 DOI: 10.1007/s00709-014-0615-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2013] [Accepted: 01/16/2014] [Indexed: 05/05/2023]
Abstract
Vacuolar Ca2+-transporters could play an important role for salt tolerance in rice (Oryza sativa L.) root. Here, we compared the expression profiles of putative vacuolar cation/H+ exchanger (CAX) and calmodulin-regulated autoinhibited Ca2+-ATPase (ACA) in rice roots of salt tolerant cv. Pokkali and salt sensitive cv. IR29. In addition to five putative vacuolar CAX genes in the rice genome, a new CAX gene (OsCAX4) has been annotated. In the present study, we isolated the OsCAX4 gene and showed that its encoded protein possesses a unique transmembrane structure and is potentially involved in transporting not only Ca2+ but also Mn2+ and Cu2+. These six OsCAX genes differed in their mRNA expression pattern in roots of tolerant versus sensitive rice cultivars exposed to salt stress. For example, OsCAX4 showed abundant expression in IR29 (sensitive) upon prolonged salt stress. The mRNA expression profile of four putative vacuolar Ca2+-ATPases (OsACA4-7) was also examined. Under control conditions, the mRNA levels of OsACA4, OsACA5, and OsACA7 were relatively high and similar among IR29 and Pokkali. Upon salt stress, only OsACA4 showed first a decrease in its expression in Pokkali (tolerant), followed by a significant increase. Based on these results, a role of vacuolar Ca2+ transporter for salt tolerance in rice root was discussed.
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Affiliation(s)
- Nana Yamada
- Plant Physiology and Biochemistry Laboratory, National Center for Genetic Engineering and Biotechnology (BIOTEC), National Science and Technology Development Agency (NSTDA), Khlong Nueng, Khlong Luang, Pathum Thani, 12120, Thailand
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21
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Siemianowski O, Barabasz A, Kendziorek M, Ruszczyńska A, Bulska E, Williams LE, Antosiewicz DM. HMA4 expression in tobacco reduces Cd accumulation due to the induction of the apoplastic barrier. JOURNAL OF EXPERIMENTAL BOTANY 2014; 65:1125-39. [PMID: 24420575 PMCID: PMC3935570 DOI: 10.1093/jxb/ert471] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Ectopic expression in tobacco (Nicotiana tabacum v. Xanthi) of the export protein AtHMA4 (responsible in Arabidopsis for the control of Zn/Cd root to shoot translocation) resulted in decreased Cd uptake/accumulation in roots and shoots. This study contributes to understanding the mechanisms underlying this Cd-dependent phenotype to help predict the consequences of transgene expression for potential phytoremediation/biofortification-based strategies. Microarray analysis was performed to identify metal homeostasis genes that were differentially expressed in roots of Cd-exposed AtHMA4-expressing tobacco relative to the wild type. It was established that down-regulation of genes known to mediate Cd uptake was not responsible for reduced Cd uptake/accumulation in AtHMA4 transformants. The transcript levels of NtIRT1 and NtZIP1 were higher in transgenic plants, indicating an induction of the Fe and Zn deficiency status due to AtHMA4 expression. Interestingly, upon exposure to Cd, genes involved in cell wall lignification (NtHCT, NtOMET, and NtPrx11a) were up-regulated in transformants. Microscopic analysis of roots demonstrated that expression of AtHMA4 caused an induction of cell wall lignification in the external cell layers that was accompanied by enhanced H2O2 accumulation. Further study showed that the concentration of other elements (B, Co, Cu, Ni, Mo, and Zn) was reduced in AtHMA4 transformants in the presence of Cd. In conclusion, due to ectopic expression of 35S::AtHMA4, the physical apoplastic barrier within the external cell layer developed, which is likely to be responsible for the reduction of Cd uptake/accumulation.
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Affiliation(s)
- Oskar Siemianowski
- University of Warsaw, Faculty of Biology, Institute of Experimental Plant Biology and Biotechnology, Miecznikowa str. 1, 02-096 Warszawa, Poland
| | - Anna Barabasz
- University of Warsaw, Faculty of Biology, Institute of Experimental Plant Biology and Biotechnology, Miecznikowa str. 1, 02-096 Warszawa, Poland
| | - Maria Kendziorek
- University of Warsaw, Faculty of Biology, Institute of Experimental Plant Biology and Biotechnology, Miecznikowa str. 1, 02-096 Warszawa, Poland
| | - Anna Ruszczyńska
- University of Warsaw, Faculty of Chemistry, Pasteura str. 1, 02-093 Warszawa, Poland
| | - Ewa Bulska
- University of Warsaw, Faculty of Chemistry, Pasteura str. 1, 02-093 Warszawa, Poland
| | | | - Danuta Maria Antosiewicz
- University of Warsaw, Faculty of Biology, Institute of Experimental Plant Biology and Biotechnology, Miecznikowa str. 1, 02-096 Warszawa, Poland
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22
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Socha AL, Guerinot ML. Mn-euvering manganese: the role of transporter gene family members in manganese uptake and mobilization in plants. FRONTIERS IN PLANT SCIENCE 2014; 5:106. [PMID: 24744764 PMCID: PMC3978347 DOI: 10.3389/fpls.2014.00106] [Citation(s) in RCA: 131] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2013] [Accepted: 03/05/2014] [Indexed: 05/18/2023]
Abstract
Manganese (Mn), an essential trace element, is important for plant health. In plants, Mn serves as a cofactor in essential processes such as photosynthesis, lipid biosynthesis and oxidative stress. Mn deficient plants exhibit decreased growth and yield and are more susceptible to pathogens and damage at freezing temperatures. Mn deficiency is most prominent on alkaline soils with approximately one third of the world's soils being too alkaline for optimal crop production. Despite the importance of Mn in plant development, relatively little is known about how it traffics between plant tissues and into and out of organelles. Several gene transporter families have been implicated in Mn transport in plants. These transporter families include NRAMP (natural resistance associated macrophage protein), YSL (yellow stripe-like), ZIP (zinc regulated transporter/iron-regulated transporter [ZRT/IRT1]-related protein), CAX (cation exchanger), CCX (calcium cation exchangers), CDF/MTP (cation diffusion facilitator/metal tolerance protein), P-type ATPases and VIT (vacuolar iron transporter). A combination of techniques including mutant analysis and Synchrotron X-ray Fluorescence Spectroscopy can assist in identifying essential transporters of Mn. Such knowledge would vastly improve our understanding of plant Mn homeostasis.
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Affiliation(s)
- Amanda L. Socha
- *Correspondence: Amanda L. Socha, Department of Biological Sciences, Dartmouth College, 78 College Street, Hanover, NH 03766, USA e-mail:
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Kumar K, Kumar M, Kim SR, Ryu H, Cho YG. Insights into genomics of salt stress response in rice. RICE (NEW YORK, N.Y.) 2013; 6:27. [PMID: 24280112 PMCID: PMC4883734 DOI: 10.1186/1939-8433-6-27] [Citation(s) in RCA: 102] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/06/2013] [Accepted: 08/29/2013] [Indexed: 05/18/2023]
Abstract
Plants, as sessile organisms experience various abiotic stresses, which pose serious threat to crop production. Plants adapt to environmental stress by modulating their growth and development along with the various physiological and biochemical changes. This phenotypic plasticity is driven by the activation of specific genes encoding signal transduction, transcriptional regulation, ion transporters and metabolic pathways. Rice is an important staple food crop of nearly half of the world population and is well known to be a salt sensitive crop. The completion and enhanced annotations of rice genome sequence has provided the opportunity to study functional genomics of rice. Functional genomics aids in understanding the molecular and physiological basis to improve the salinity tolerance for sustainable rice production. Salt tolerant transgenic rice plants have been produced by incorporating various genes into rice. In this review we present the findings and investigations in the field of rice functional genomics that includes supporting genes and networks (ABA dependent and independent), osmoprotectants (proline, glycine betaine, trehalose, myo-inositol, and fructans), signaling molecules (Ca2+, abscisic acid, jasmonic acid, brassinosteroids) and transporters, regulating salt stress response in rice.
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Affiliation(s)
- Kundan Kumar
- />Department of Biological Sciences, Birla Institute of Technology & Science, K. K. Birla Goa Campus, Goa 403726 India
| | - Manu Kumar
- />Department of Life Science, Sogang University, Seoul, 121-742 Korea
| | - Seong-Ryong Kim
- />Department of Life Science, Sogang University, Seoul, 121-742 Korea
| | - Hojin Ryu
- />Department of Life Science, Pohang University of Science & Technology, Pohang, Korea
| | - Yong-Gu Cho
- />Department of Crop Science, Chungbuk National University, Cheongju, 361-763 Korea
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Ullah A, Kemp G, Lee B, Alves C, Young H, Sykes BD, Fliegel L. Structural and functional analysis of transmembrane segment IV of the salt tolerance protein Sod2. J Biol Chem 2013; 288:24609-24. [PMID: 23836910 DOI: 10.1074/jbc.m113.483065] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Sod2 is the plasma membrane Na(+)/H(+) exchanger of the fission yeast Schizosaccharomyces pombe. It provides salt tolerance by removing excess intracellular sodium (or lithium) in exchange for protons. We examined the role of amino acid residues of transmembrane segment IV (TM IV) ((126)FPQINFLGSLLIAGCITSTDPVLSALI(152)) in activity by using alanine scanning mutagenesis and examining salt tolerance in sod2-deficient S. pombe. Two amino acids were critical for function. Mutations T144A and V147A resulted in defective proteins that did not confer salt tolerance when reintroduced into S. pombe. Sod2 protein with other alanine mutations in TM IV had little or no effect. T144D and T144K mutant proteins were inactive; however, a T144S protein was functional and provided lithium, but not sodium, tolerance and transport. Analysis of sensitivity to trypsin indicated that the mutations caused a conformational change in the Sod2 protein. We expressed and purified TM IV (amino acids 125-154). NMR analysis yielded a model with two helical regions (amino acids 128-142 and 147-154) separated by an unwound region (amino acids 143-146). Molecular modeling of the entire Sod2 protein suggested that TM IV has a structure similar to that deduced by NMR analysis and an overall structure similar to that of Escherichia coli NhaA. TM IV of Sod2 has similarities to TM V of the Zygosaccharomyces rouxii Na(+)/H(+) exchanger and TM VI of isoform 1 of mammalian Na(+)/H(+) exchanger. TM IV of Sod2 is critical to transport and may be involved in cation binding or conformational changes of the protein.
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Affiliation(s)
- Asad Ullah
- Department of Biochemistry, University of Alberta, Edmonton, Alberta T6G 2H7, Canada
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Crystal structure of Ca2+/H+ antiporter protein YfkE reveals the mechanisms of Ca2+ efflux and its pH regulation. Proc Natl Acad Sci U S A 2013; 110:11367-72. [PMID: 23798403 DOI: 10.1073/pnas.1302515110] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Ca(2+) efflux by Ca(2+) cation antiporter (CaCA) proteins is important for maintenance of Ca(2+) homeostasis across the cell membrane. Recently, the monomeric structure of the prokaryotic Na(+)/Ca(2+) exchanger (NCX) antiporter NCX_Mj protein from Methanococcus jannaschii shows an outward-facing conformation suggesting a hypothesis of alternating substrate access for Ca(2+) efflux. To demonstrate conformational changes essential for the CaCA mechanism, we present the crystal structure of the Ca(2+)/H(+) antiporter protein YfkE from Bacillus subtilis at 3.1-Å resolution. YfkE forms a homotrimer, confirmed by disulfide crosslinking. The protonated state of YfkE exhibits an inward-facing conformation with a large hydrophilic cavity opening to the cytoplasm in each protomer and ending in the middle of the membrane at the Ca(2+)-binding site. A hydrophobic "seal" closes its periplasmic exit. Four conserved α-repeat helices assemble in an X-like conformation to form a Ca(2+)/H(+) exchange pathway. In the Ca(2+)-binding site, two essential glutamate residues exhibit different conformations compared with their counterparts in NCX_Mj, whereas several amino acid substitutions occlude the Na(+)-binding sites. The structural differences between the inward-facing YfkE and the outward-facing NCX_Mj suggest that the conformational transition is triggered by the rotation of the kink angles of transmembrane helices 2 and 7 and is mediated by large conformational changes in their adjacent transmembrane helices 1 and 6. Our structural and mutational analyses not only establish structural bases for mechanisms of Ca(2+)/H(+) exchange and its pH regulation but also shed light on the evolutionary adaptation to different energy modes in the CaCA protein family.
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Waight AB, Pedersen BP, Schlessinger A, Bonomi M, Chau BH, Roe-Zurz Z, Risenmay AJ, Sali A, Stroud RM. Structural basis for alternating access of a eukaryotic calcium/proton exchanger. Nature 2013; 499:107-10. [PMID: 23685453 PMCID: PMC3702627 DOI: 10.1038/nature12233] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2012] [Accepted: 04/30/2013] [Indexed: 12/01/2022]
Affiliation(s)
- Andrew B Waight
- Department of Biochemistry and Biophysics, University of California, San Francisco, California 94158, USA
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The Plasmodium berghei Ca(2+)/H(+) exchanger, PbCAX, is essential for tolerance to environmental Ca(2+) during sexual development. PLoS Pathog 2013; 9:e1003191. [PMID: 23468629 PMCID: PMC3585132 DOI: 10.1371/journal.ppat.1003191] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2012] [Accepted: 12/28/2012] [Indexed: 12/15/2022] Open
Abstract
Ca(2+) contributes to a myriad of important cellular processes in all organisms, including the apicomplexans, Plasmodium and Toxoplasma. Due to its varied and essential roles, free Ca(2+) is tightly regulated by complex mechanisms. These mechanisms are therefore of interest as putative drug targets. One pathway in Ca(2+) homeostatic control in apicomplexans uses a Ca(2+)/H(+) exchanger (a member of the cation exchanger family, CAX). The P. falciparum CAX (PfCAX) has recently been characterised in asexual blood stage parasites. To determine the physiological importance of apicomplexan CAXs, tagging and knock-out strategies were undertaken in the genetically tractable T. gondii and P. berghei parasites. In addition, a yeast heterologous expression system was used to study the function of apicomplexan CAXs. Tagging of T. gondii and P. berghei CAXs (TgCAX and PbCAX) under control of their endogenous promoters could not demonstrate measureable expression of either CAX in tachyzoites and asexual blood stages, respectively. These results were consistent with the ability of parasites to tolerate knock-outs of the genes for TgCAX and PbCAX at these developmental stages. In contrast, PbCAX expression was detectable during sexual stages of development in female gametocytes/gametes, zygotes and ookinetes, where it was dispersed in membranous networks within the cytosol (with minimal mitochondrial localisation). Furthermore, genetically disrupted parasites failed to develop further from "round" form zygotes, suggesting that PbCAX is essential for ookinete development and differentiation. This impeded phenotype could be rescued by removal of extracellular Ca(2+). Therefore, PbCAX provides a mechanism for free living parasites to multiply within the ionic microenvironment of the mosquito midgut. Ca(2+) homeostasis mediated by PbCAX is critical and suggests plasmodial CAXs may be targeted in approaches designed to block parasite transmission.
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Emery L, Whelan S, Hirschi KD, Pittman JK. Protein Phylogenetic Analysis of Ca(2+)/cation Antiporters and Insights into their Evolution in Plants. FRONTIERS IN PLANT SCIENCE 2012; 3:1. [PMID: 22645563 PMCID: PMC3355786 DOI: 10.3389/fpls.2012.00001] [Citation(s) in RCA: 100] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2011] [Accepted: 01/01/2012] [Indexed: 05/19/2023]
Abstract
Cation transport is a critical process in all organisms and is essential for mineral nutrition, ion stress tolerance, and signal transduction. Transporters that are members of the Ca(2+)/cation antiporter (CaCA) superfamily are involved in the transport of Ca(2+) and/or other cations using the counter exchange of another ion such as H(+) or Na(+). The CaCA superfamily has been previously divided into five transporter families: the YRBG, Na(+)/Ca(2+) exchanger (NCX), Na(+)/Ca(2+), K(+) exchanger (NCKX), H(+)/cation exchanger (CAX), and cation/Ca(2+) exchanger (CCX) families, which include the well-characterized NCX and CAX transporters. To examine the evolution of CaCA transporters within higher plants and the green plant lineage, CaCA genes were identified from the genomes of sequenced flowering plants, a bryophyte, lycophyte, and freshwater and marine algae, and compared with those from non-plant species. We found evidence of the expansion and increased diversity of flowering plant genes within the CAX and CCX families. Genes related to the NCX family are present in land plant though they encode distinct MHX homologs which probably have an altered transport function. In contrast, the NCX and NCKX genes which are absent in land plants have been retained in many species of algae, especially the marine algae, indicating that these organisms may share "animal-like" characteristics of Ca(2+) homeostasis and signaling. A group of genes encoding novel CAX-like proteins containing an EF-hand domain were identified from plants and selected algae but appeared to be lacking in any other species. Lack of functional data for most of the CaCA proteins make it impossible to reliably predict substrate specificity and function for many of the groups or individual proteins. The abundance and diversity of CaCA genes throughout all branches of life indicates the importance of this class of cation transporter, and that many transporters with novel functions are waiting to be discovered.
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Affiliation(s)
- Laura Emery
- Faculty of Life Sciences, University of ManchesterManchester, UK
| | - Simon Whelan
- Faculty of Life Sciences, University of ManchesterManchester, UK
| | - Kendal D. Hirschi
- Children’s Nutrition Research Center, Baylor College of MedicineHouston, TX, USA
| | - Jon K. Pittman
- Faculty of Life Sciences, University of ManchesterManchester, UK
- *Correspondence: Jon K. Pittman, Faculty of Life Sciences, University of Manchester, Michael Smith Building, Oxford Road, Manchester M13 9PT, UK. e-mail:
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29
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Punshon T, Hirschi K, Yang J, Lanzirotti A, Lai B, Guerinot ML. The role of CAX1 and CAX3 in elemental distribution and abundance in Arabidopsis seed. PLANT PHYSIOLOGY 2012; 158:352-62. [PMID: 22086421 PMCID: PMC3252103 DOI: 10.1104/pp.111.184812] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/26/2011] [Accepted: 11/13/2011] [Indexed: 05/04/2023]
Abstract
The ability to alter nutrient partitioning within plants cells is poorly understood. In Arabidopsis (Arabidopsis thaliana), a family of endomembrane cation exchangers (CAXs) transports Ca(2+) and other cations. However, experiments have not focused on how the distribution and partitioning of calcium (Ca) and other elements within seeds are altered by perturbed CAX activity. Here, we investigate Ca distribution and abundance in Arabidopsis seed from cax1 and cax3 loss-of-function lines and lines expressing deregulated CAX1 using synchrotron x-ray fluorescence microscopy. We conducted 7- to 10-μm resolution in vivo x-ray microtomography on dry mature seed and 0.2-μm resolution x-ray microscopy on embryos from lines overexpressing deregulated CAX1 (35S-sCAX1) and cax1cax3 double mutants only. Tomograms showed an increased concentration of Ca in both the seed coat and the embryo in cax1, cax3, and cax1cax3 lines compared with the wild type. High-resolution elemental images of the mutants showed that perturbed CAX activity altered Ca partitioning within cells, reducing Ca partitioning into organelles and/or increasing Ca in the cytosol and abolishing tissue-level Ca gradients. In comparison with traditional volume-averaged metal analysis, which confirmed subtle changes in seed elemental composition, the collection of spatially resolved data at varying resolutions provides insight into the impact of altered CAX activity on seed metal distribution and indicates a cell type-specific function of CAX1 and CAX3 in partitioning Ca into organelles. This work highlights a powerful technology for inferring transport function and quantifying nutrient changes.
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Affiliation(s)
- Tracy Punshon
- Department of Biological Sciences, Dartmouth College, Hanover, New Hampshire 03755, USA.
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Mackinder L, Wheeler G, Schroeder D, von Dassow P, Riebesell U, Brownlee C. Expression of biomineralization-related ion transport genes in Emiliania huxleyi. Environ Microbiol 2011; 13:3250-65. [PMID: 21902794 DOI: 10.1111/j.1462-2920.2011.02561.x] [Citation(s) in RCA: 72] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Biomineralization in the marine phytoplankton Emiliania huxleyi is a stringently controlled intracellular process. The molecular basis of coccolith production is still relatively unknown although its importance in global biogeochemical cycles and varying sensitivity to increased pCO₂ levels has been well documented. This study looks into the role of several candidate Ca²⁺, H⁺ and inorganic carbon transport genes in E. huxleyi, using quantitative reverse transcriptase PCR. Differential gene expression analysis was investigated in two isogenic pairs of calcifying and non-calcifying strains of E. huxleyi and cultures grown at various Ca²⁺ concentrations to alter calcite production. We show that calcification correlated to the consistent upregulation of a putative HCO₃⁻ transporter belonging to the solute carrier 4 (SLC4) family, a Ca²⁺/H⁺ exchanger belonging to the CAX family of exchangers and a vacuolar H⁺-ATPase. We also show that the coccolith-associated protein, GPA is downregulated in calcifying cells. The data provide strong evidence that these genes play key roles in E. huxleyi biomineralization. Based on the gene expression data and the current literature a working model for biomineralization-related ion transport in coccolithophores is presented.
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Affiliation(s)
- Luke Mackinder
- The Laboratory, Marine Biological Association of the UK, Citadel Hill, Plymouth PL1 2PB, UK.
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31
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Pittman JK. Vacuolar Ca(2+) uptake. Cell Calcium 2011; 50:139-46. [PMID: 21310481 DOI: 10.1016/j.ceca.2011.01.004] [Citation(s) in RCA: 93] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2010] [Revised: 12/31/2010] [Accepted: 01/03/2011] [Indexed: 12/22/2022]
Abstract
Calcium transporters that mediate the removal of Ca(2+) from the cytosol and into internal stores provide a critical role in regulating Ca(2+) signals following stimulus induction and in preventing calcium toxicity. The vacuole is a major calcium store in many organisms, particularly plants and fungi. Two main pathways facilitate the accumulation of Ca(2+) into vacuoles, Ca(2+)-ATPases and Ca(2+)/H(+) exchangers. Here I review the biochemical and regulatory features of these transporters that have been characterised in yeast and plants. These Ca(2+) transport mechanisms are compared with those being identified from other vacuolated organisms including algae and protozoa. Studies suggest that Ca(2+) uptake into vacuoles and other related acidic Ca(2+) stores occurs by conserved mechanisms which developed early in evolution.
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Affiliation(s)
- Jon K Pittman
- Faculty of Life Sciences, University of Manchester, Michael Smith Building, Oxford Road, Manchester M13 9PT, UK.
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32
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Ca2+ Pumps and Ca2+ Antiporters in Plant Development. SIGNALING AND COMMUNICATION IN PLANTS 2011. [DOI: 10.1007/978-3-642-14369-4_5] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/08/2022]
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33
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Migeon A, Blaudez D, Wilkins O, Montanini B, Campbell MM, Richaud P, Thomine S, Chalot M. Genome-wide analysis of plant metal transporters, with an emphasis on poplar. Cell Mol Life Sci 2010; 67:3763-84. [PMID: 20623158 PMCID: PMC11115807 DOI: 10.1007/s00018-010-0445-0] [Citation(s) in RCA: 72] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2010] [Revised: 06/15/2010] [Accepted: 06/23/2010] [Indexed: 11/27/2022]
Abstract
The specific transport of metal ions, mediated by membrane-localized metal transporters, is of fundamental importance in all eukaryotes. Genome-wide analysis of metal transporters was undertaken, making use of whole genome sequences of the green alga Chlamydomonas reinhardtii, the moss Physcomitrella patens, the lycophyte Selaginella moellendorffii, the monocots rice and sorghum, and the dicots Arabidopsis thaliana, poplar, grapevine, as well as of the yeast Saccharomyces cerevisiae. A repertoire of 430 metal transporters was found in total across eight photosynthetic plants, as well as in S. cerevisiae. Seventy-two full-length metal transporter genes were identified in the Populus genome alone, which is the largest number of metal transporters genes identified in any single species to date. Diversification of some transporter family gene clusters appears to have occurred in a lineage-specific manner. Expression analysis of Populus metal transporters indicates that some family members show tissue-specific transcript abundance. Taken together, the data provide a picture into the diversification of these important gene families.
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Affiliation(s)
- Aude Migeon
- UMR INRA/UHP 1136 “Tree–microbe Interactions”, Faculty of Sciences and Technology, Nancy-University, BP 70239, 54506 Vandoeuvre-les-Nancy, France
| | - Damien Blaudez
- UMR INRA/UHP 1136 “Tree–microbe Interactions”, Faculty of Sciences and Technology, Nancy-University, BP 70239, 54506 Vandoeuvre-les-Nancy, France
| | - Olivia Wilkins
- Department of Cell and Systems Biology and Centre for the Analysis of Genome Evolution and Function, University of Toronto, Toronto, ON M5S 3B2 Canada
| | - Barbara Montanini
- Dipartimento di Biochimica e Biologia Molecolare, Università degli Studi di Parma, Parma, Italy
| | - Malcolm M. Campbell
- Department of Cell and Systems Biology and Centre for the Analysis of Genome Evolution and Function, University of Toronto, Toronto, ON M5S 3B2 Canada
| | - Pierre Richaud
- Laboratoire des Echanges Membranaires et Signalisation, CEA, DSV, iBEB, 13108 St. Paul les Durance, France
- CNRS, UMR 6191, 13108 St. Paul les Durance, France
- Université Aix-Marseille, 13108 St. Paul les Durance, France
| | - Sébastien Thomine
- Institut des Sciences du Végétal, CNRS, Avenue de la Terrasse, Gif-sur-Yvette, France
| | - Michel Chalot
- UMR INRA/UHP 1136 “Tree–microbe Interactions”, Faculty of Sciences and Technology, Nancy-University, BP 70239, 54506 Vandoeuvre-les-Nancy, France
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Cagnac O, Aranda-Sicilia MN, Leterrier M, Rodriguez-Rosales MP, Venema K. Vacuolar cation/H+ antiporters of Saccharomyces cerevisiae. J Biol Chem 2010; 285:33914-22. [PMID: 20709757 DOI: 10.1074/jbc.m110.116590] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
We previously demonstrated that Saccharomyces cerevisiae vnx1Δ mutant strains displayed an almost total loss of Na(+) and K(+)/H(+) antiporter activity in a vacuole-enriched fraction. However, using different in vitro transport conditions, we were able to reveal additional K(+)/H(+) antiporter activity. By disrupting genes encoding transporters potentially involved in the vnx1 mutant strain, we determined that Vcx1p is responsible for this activity. This result was further confirmed by complementation of the vnx1Δvcx1Δ nhx1Δ triple mutant with Vcx1p and its inactivated mutant Vcx1p-H303A. Like the Ca(2+)/H(+) antiporter activity catalyzed by Vcx1p, the K(+)/H(+) antiporter activity was strongly inhibited by Cd(2+) and to a lesser extend by Zn(2+). Unlike as previously observed for NHX1 or VNX1, VCX1 overexpression only marginally improved the growth of yeast strain AXT3 in the presence of high concentrations of K(+) and had no effect on hygromycin sensitivity. Subcellular localization showed that Vcx1p and Vnx1p are targeted to the vacuolar membrane, whereas Nhx1p is targeted to prevacuoles. The relative importance of Nhx1p, Vnx1p, and Vcx1p in the vacuolar accumulation of monovalent cations will be discussed.
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Affiliation(s)
- Olivier Cagnac
- Departamento de Bioquímica, Biología Celular y Molecular de Plantas, Estacion Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, Apartado 419, E-18080 Granada, Spain.
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Manohar M, Mei H, Franklin AJ, Sweet EM, Shigaki T, Riley BB, MacDiarmid CW, Hirschi K. Zebrafish (Danio rerio) Endomembrane Antiporter Similar to a Yeast Cation/H+ Transporter Is Required for Neural Crest Development. Biochemistry 2010; 49:6557-66. [DOI: 10.1021/bi100362k] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Affiliation(s)
- Murli Manohar
- Vegetable and Fruit Improvement Center, Texas A&M University, College Station, Texas 77845
- United States Department of Agriculture/Agricultural Research Service, Children’s Nutrition Research Center, Baylor College of Medicine, Houston, Texas 77030
| | - Hui Mei
- Vegetable and Fruit Improvement Center, Texas A&M University, College Station, Texas 77845
| | - Andrew J. Franklin
- Department of Surgery, Washington University School of Medicine, St. Louis, Missouri
| | - Elly M. Sweet
- Department of Biology, Texas A&M University, College Station, Texas 77843
| | - Toshiro Shigaki
- United States Department of Agriculture/Agricultural Research Service, Children’s Nutrition Research Center, Baylor College of Medicine, Houston, Texas 77030
| | - Bruce B. Riley
- Department of Biology, Texas A&M University, College Station, Texas 77843
| | - Colin W. MacDiarmid
- Department of Nutritional Sciences, University of Wisconsin—Madison, Madison, Wisconsin 53562
| | - Kendal Hirschi
- Vegetable and Fruit Improvement Center, Texas A&M University, College Station, Texas 77845
- United States Department of Agriculture/Agricultural Research Service, Children’s Nutrition Research Center, Baylor College of Medicine, Houston, Texas 77030
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Liu H, Zhang X, Takano T, Liu S. Characterization of a PutCAX1 gene from Puccinellia tenuiflora that confers Ca2+ and Ba2+ tolerance in yeast. Biochem Biophys Res Commun 2009; 383:392-6. [PMID: 19379714 DOI: 10.1016/j.bbrc.2009.04.042] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2009] [Accepted: 04/02/2009] [Indexed: 10/20/2022]
Abstract
The gene for a novel cation/H+ antiporter from Puccinellia tenuiflora, PutCAX1, was cloned from a cDNA library. The PutCAX protein was localized in the vacuolar membrane using a GFP marker. Several yeast transformants were created using full-length and truncated form of PutCAX1 and their growths in the presence of various cations (Mg2+, Ca2+, Mn2+, Ni2+, Cu2+, Zn2+, Se2+, and Ba2+) were analyzed. PutCAX1 expression was found to affect the response to Ca2+ and Ba2+ in yeast. The PutCAX1 and C-terminally truncated PutCAX1 (DeltaCPutCAX1) transformants grew in the presence of 70 mM Ca2+ as well as in the presence of 8 mM Ba2+. However, the DeltaCPutCAX1 transformant was able to grow in the presence of 20 mM Ba2+ while the PutCAX1 transformant could not. On the other hand, expression of the N-terminally truncated form and the N- and C-terminally truncated form failed to suppress the Ca2+ or Ba2+ sensitivity of yeast. These results suggest that PutCAX1 can complement the active Ca2+ transporters at some level and confer yeast Ba2+ tolerance, and that the N- and C-terminal regions of PutCAX1 play important roles in increasing the Ca2+ or Ba2+ tolerance of yeast.
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Affiliation(s)
- Hua Liu
- Alkali Soil Natural Environmental Science Center (ASNESC), Stress Molecular Biology Laboratory, Northeast Forestry University, Harbin, Heilongjiang Province 150040, PR China
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Comparative analysis of CAX2-like cation transporters indicates functional and regulatory diversity. Biochem J 2009; 418:145-54. [PMID: 18950291 DOI: 10.1042/bj20081814] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Internal compartmentalization of metals is an important metal tolerance mechanism in many organisms. In plants and fungi, sequestration into the vacuole is a major detoxification mechanism for metals. Cation transport into the vacuole can be mediated by CAX (cation exchanger) transporters. The Arabidopsis thaliana AtCAX2 transporter was shown previously to transport Ca(2+), Cd(2+) and Mn(2+). To assess the conservation of the functional and regulatory characteristics of CAX2-like transporters in higher plants, we have characterized AtCAX2 orthologues from Arabidopsis (AtCAX5), tomato (LeCAX2) and barley (HvCAX2). Substrate specificity and regulatory activity were assessed using a yeast heterologous-expression assay. Each CAX could transport Ca(2+) and Mn(2+) into the yeast vacuole, but they each had different cation transport kinetics. Most notably, there was variation in the regulation of the transporters. As found with AtCAX2 previously, only expression of an N-terminally truncated form of AtCAX5 in yeast was able to mediate Ca(2+) and Mn(2+) transport, indicating that activity may be controlled by an autoregulatory region at the N-terminus. In contrast, either full-length or truncated LeCAX2 could efficiently transport Ca(2+), although Mn(2+) transport was controlled by the N-terminus. HvCAX2 did not appear to possess an N-terminal regulatory domain. Expression of AtCAX2 was not significantly modulated by metal stress; however, AtCAX5 and HvCAX2 were transcriptionally up-regulated by high Mn(2+) treatment, and by Ca(2+) and Na(+) stress respectively. It is therefore apparent that, despite the high sequence identity between plant CAX2 orthologues, there is significant diversity in their functional characteristics, particularly with regard to regulatory mechanisms.
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Zhang L, Lavery L, Gill U, Gill K, Steffenson B, Yan G, Chen X, Kleinhofs A. A cation/proton-exchanging protein is a candidate for the barley NecS1 gene controlling necrosis and enhanced defense response to stem rust. TAG. THEORETICAL AND APPLIED GENETICS. THEORETISCHE UND ANGEWANDTE GENETIK 2009; 118:385-97. [PMID: 18956175 DOI: 10.1007/s00122-008-0910-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2008] [Accepted: 10/02/2008] [Indexed: 05/08/2023]
Abstract
We characterized three lesion mimic necS1 (necrotic Steptoe) mutants, induced by fast neutron (FN) treatment of barley cultivar Steptoe. The three mutants are recessive and allelic. When infected with Puccinia graminis f. sp. tritici pathotypes MCC and QCC and P. graminis f. sp. secalis isolate 92-MN-90, all three mutants exhibited enhanced resistance compared to parent cultivar Steptoe. These results suggested that the lesion mimic mutants carry broad-spectrum resistance to stem rust. In order to identify the mutated gene responsible for the phenotype, transcript-based cloning was used. Two genes, represented by three Barley1 probesets (Contig4211_at and Contig4212_s_at, representing the same gene, and Contig10850_s_at), were deleted in all three mutants. Genetic analysis suggested that the lesion mimic phenotype was due to a mutation in one or both of these genes, named NecS1. Consistent with the increased disease resistance, all three mutants constitutively accumulated elevated transcript levels of pathogenesis-related (PR) genes. Barley stripe mosaic virus (BSMV) has been developed as a virus-induced gene-silencing (VIGS) vector for monocots. We utilized BSMV-VIGS to demonstrate that silencing of the gene represented by Contig4211_at, but not Contig10850_s_at caused the necrotic lesion mimic phenotype on barley seedling leaves. Therefore, Contig4211_at is a strong candidate for the NecS1 gene, which encodes a cation/proton exchanging protein (HvCAX1).
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Affiliation(s)
- Ling Zhang
- Department of Crop and Soil Sciences, Washington State University, Pullman, WA, 99164, USA
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39
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Pittman JK, Edmond C, Sunderland PA, Bray CM. A cation-regulated and proton gradient-dependent cation transporter from Chlamydomonas reinhardtii has a role in calcium and sodium homeostasis. J Biol Chem 2008; 284:525-533. [PMID: 19001368 DOI: 10.1074/jbc.m807173200] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The CrCAX1 gene encoding a Ca2+/H+ and Na+/H+ exchanger was cloned and characterized from the unicellular green alga Chlamydomonas reinhardtii to begin to understand the mechanisms of cation homeostasis in this model organism. CrCAX1 was more closely related to fungal cation exchanger (CAX) genes than those from higher plants but has structural characteristics similar to plant Ca2+/H+ exchangers including a long N-terminal tail. When CrCAX1-GFP was expressed in Saccharomyces cerevisiae, it localized at the vacuole. CrCAX1 could suppress the Ca2+-hypersensitive phenotype of a yeast mutant and mediated proton gradient-dependent Ca2+/H+ exchange activity in vacuolar membrane vesicles. Ca2+ transport activity was increased following N-terminal truncation of CrCAX1, suggesting the existence of an N-terminal auto-regulatory mechanism. CrCAX1 could also provide tolerance to Na+ stress when expressed in yeast or Arabidopsis thaliana because of Na+/H+ exchange activity. This Na+/H+ exchange activity was not regulated by the N terminus of the CrCAX1 protein. A subtle tolerance by CrCAX1 in yeast to Co2+ stress was also observed. CrCAX1 was transcriptionally regulated in Chlamydomonas cells grown in elevated Ca2+ or Na+. This study has thus uncovered a novel eukaryotic proton-coupled transporter, CrCAX1, that can transport both monovalent and divalent cations and that appears to play a role in cellular cation homeostasis by the transport of Ca2+ and Na+ into the vacuole.
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Affiliation(s)
- Jon K Pittman
- Faculty of Life Sciences, University of Manchester, Manchester, M13 9PT, United Kingdom.
| | - Clare Edmond
- Faculty of Life Sciences, University of Manchester, Manchester, M13 9PT, United Kingdom
| | - Paul A Sunderland
- Faculty of Life Sciences, University of Manchester, Manchester, M13 9PT, United Kingdom
| | - Clifford M Bray
- Faculty of Life Sciences, University of Manchester, Manchester, M13 9PT, United Kingdom
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40
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Morris J, Tian H, Park S, Sreevidya CS, Ward JM, Hirschi KD. AtCCX3 is an Arabidopsis endomembrane H+ -dependent K+ transporter. PLANT PHYSIOLOGY 2008; 148:1474-86. [PMID: 18775974 PMCID: PMC2577254 DOI: 10.1104/pp.108.118810] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2008] [Accepted: 08/30/2008] [Indexed: 05/18/2023]
Abstract
The Arabidopsis (Arabidopsis thaliana) cation calcium exchangers (CCXs) were recently identified as a subfamily of cation transporters; however, no plant CCXs have been functionally characterized. Here, we show that Arabidopsis AtCCX3 (At3g14070) and AtCCX4 (At1g54115) can suppress yeast mutants defective in Na(+), K(+), and Mn(2+) transport. We also report high-capacity uptake of (86)Rb(+) in tonoplast-enriched vesicles from yeast expressing AtCCX3. Cation competition studies showed inhibition of (86)Rb(+) uptake in AtCCX3 cells by excess Na(+), K(+), and Mn(2+). Functional epitope-tagged AtCCX3 fusion proteins were localized to endomembranes in plants and yeast. In Arabidopsis, AtCCX3 is primarily expressed in flowers, while AtCCX4 is expressed throughout the plant. Quantitative polymerase chain reaction showed that expression of AtCCX3 increased in plants treated with NaCl, KCl, and MnCl(2). Insertional mutant lines of AtCCX3 and AtCCX4 displayed no apparent growth defects; however, overexpression of AtCCX3 caused increased Na(+) accumulation and increased (86)Rb(+) transport. Uptake of (86)Rb(+) increased in tonoplast-enriched membranes isolated from Arabidopsis lines expressing CCX3 driven by the cauliflower mosaic virus 35S promoter. Overexpression of AtCCX3 in tobacco (Nicotiana tabacum) produced lesions in the leaves, stunted growth, and resulted in the accumulation of higher levels of numerous cations. In summary, these findings suggest that AtCCX3 is an endomembrane-localized H(+)-dependent K(+) transporter with apparent Na(+) and Mn(2+) transport properties distinct from those of previously characterized plant transporters.
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Affiliation(s)
- Jay Morris
- Vegetable and Fruit Improvement Center, Texas A&M University, College Station, Texas 77845, USA
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41
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Advances of calcium signals involved in plant anti-drought. C R Biol 2008; 331:587-96. [DOI: 10.1016/j.crvi.2008.03.012] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2008] [Revised: 03/31/2008] [Accepted: 03/31/2008] [Indexed: 01/23/2023]
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42
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Topology mapping of the vacuolar Vcx1p Ca2+/H+ exchanger from Saccharomyces cerevisiae. Biochem J 2008; 414:133-41. [DOI: 10.1042/bj20080364] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Saccharomyces cerevisiae uses vacuolar storage to dynamically control the cytoplasmic calcium concentration. Vcx1p, a Ca2+/H+ antiporter and a member of the CAX (Ca2+/anion exchanger) family of exchangers, is one of the proteins that sequesters calcium into the vacuole. Although the biological importance of Vcx1p is clear, the molecular mechanism by which Vcx1p and its family members mediate Ca2+/H+ exchange activity remains poorly understood. To provide a basic structural framework for understanding functional studies of the CAX proteins, we have mapped Vcx1p's topology using three biochemical assays: C-terminal reporter localization, glycosylation mapping and proteolysis. We have found that the protein has an odd number of TM (transmembrane) domains and that its termini are located on opposite sides of the membrane, with the N-terminus in the cytoplasm. Our results indicate that loops 1, 3, 7 and 9 are luminal, while loops 6 and 8 are cytosolic. Our experimentally-based topology model for Vcx1p is in agreement with models derived from topology algorithms and with biochemical data reported by other groups. In addition, our studies suggest that the calcium domain, a nine-residue domain found to be critical for function in CAX proteins from plants, is not essential to Vcx1p activity.
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43
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Song WY, Zhang ZB, Shao HB, Guo XL, Cao HX, Zhao HB, Fu ZY, Hu XJ. Relationship between calcium decoding elements and plant abiotic-stress resistance. Int J Biol Sci 2008; 4:116-25. [PMID: 18463716 PMCID: PMC2359902 DOI: 10.7150/ijbs.4.116] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2008] [Accepted: 04/25/2008] [Indexed: 01/08/2023] Open
Abstract
Serving as an important second messenger, calcium ion has unique properties and universal ability to transmit diverse signals that trigger primary physiological actions in cells in response to hormones, pathogens, light, gravity, and stress factors. Being a second messenger of paramount significance, calcium is required at almost all stages of plant growth and development, playing a fundamental role in regulating polar growth of cells and tissues and participating in plant adaptation to various stress factors. Many researches showed that calcium signals decoding elements are involved in ABA-induced stomatal closure and plant adaptation to drought, cold, salt and other abiotic stresses. Calcium channel proteins like AtTPC1 and TaTPC1 can regulate stomatal closure. Recently some new studies show that Ca(2+) is dissolved in water in the apoplast and transported primarily from root to shoot through the transpiration stream. The oscillating amplitudes of [Ca(2+)](o) and [Ca(2+)](i) are controlled by soil Ca(2+) concentrations and transpiration rates. Because leaf water use efficiency (WUE) is determined by stomatal closure and transpiration rate, so there may be a close relationship between Ca(2+) transporters and stomatal closure as well as WUE, which needs to be studied. The selection of varieties with better drought resistance and high WUE plays an increasing role in bio-watersaving in arid and semi-arid areas on the globe. The current paper reviews the relationship between calcium signals decoding elements and plant drought resistance as well as other abiotic stresses for further study.
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Affiliation(s)
- Wei-Yi Song
- Center for Agricultural Resources Research, Institute of Genetic &Developmental Biology, Chinese Academy of Sciences, Shijiazhuang, 050021, China
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44
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Hong-Bo S, Li-Ye C, Ming-An S. Calcium as a versatile plant signal transducer under soil water stress. Bioessays 2008; 30:634-41. [DOI: 10.1002/bies.20770] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
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45
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Cagnac O, Leterrier M, Yeager M, Blumwald E. Identification and Characterization of Vnx1p, a Novel Type of Vacuolar Monovalent Cation/H+ Antiporter of Saccharomyces cerevisiae. J Biol Chem 2007; 282:24284-93. [PMID: 17588950 DOI: 10.1074/jbc.m703116200] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
We identified and characterized Vnx1p, a novel vacuolar monovalent cation/H+ antiporter encoded by the open reading frame YNL321w from Saccharomyces cerevisiae. Despite the homology of Vnx1p with other members of the CAX (calcium exchanger) family of transporters, Vnx1p is unable to mediate Ca2+ transport but is a low affinity Na+/H+ and K+/H+ anti-porter with a Km of 22.4 and 82.2 mm for Na+ and K+, respectively. Sequence analyses of Vnx1p revealed the absence of key amino acids shown to be essential for Ca2+/H+ exchange. vnx1Delta cells displayed growth inhibition when grown in the presence of hygromycin B or NaCl. Vnx1p activity was found in the vacuoles and shown to be dependent on the electrochemical potential gradient of H+ generated by the action of the V-type H+-ATPase. The presence of Vnx1p at the vacuolar membrane was further confirmed with cells expressing a VNX1::GFP chimeric gene. Similar to Nhx1p, the prevacuolar compartment-bound Na+/H+ antiporter, the vacuole-bound Vnx1p appears to play roles in the regulation of ion homeostasis and cellular pH.
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Affiliation(s)
- Olivier Cagnac
- Department of Plant Sciences, University of California, Davis, California 95616, USA
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46
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Shigaki T, Rees I, Nakhleh L, Hirschi KD. Identification of three distinct phylogenetic groups of CAX cation/proton antiporters. J Mol Evol 2006; 63:815-25. [PMID: 17086450 DOI: 10.1007/s00239-006-0048-4] [Citation(s) in RCA: 110] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2006] [Accepted: 07/21/2006] [Indexed: 11/26/2022]
Abstract
Ca(2+)/cation antiporter (CaCA) proteins are integral membrane proteins that transport Ca(2+) or other cations using the H(+) or Na(+) gradient generated by primary transporters. The CAX (for CAtion eXchanger) family is one of the five families that make up the CaCA superfamily. CAX genes have been found in bacteria, Dictyostelium, fungi, plants, and lower vertebrates, but only a small number of CAXs have been functionally characterized. In this study, we explored the diversity of CAXs and their phylogenetic relationships. The results demonstrate that there are three major types of CAXs: type I (CAXs similar to Arabidopsis thaliana CAX1, found in plants, fungi, and bacteria), type II (CAXs with a long N-terminus hydrophilic region, found in fungi, Dictyostelium, and lower vertebrates), and type III (CAXs similar to Escherichia coli ChaA, found in bacteria). Some CAXs were found to have secondary structures that are different from the canonical six transmembrane (TM) domains-acidic motif-five TM domain structure. Our phylogenetic tree indicated no evidence to support the cyanobacterial origin of plant CAXs or the classification of Arabidopsis exchangers CAX7 to CAX11. For the first time, these results clearly define the CAX exchanger family and its subtypes in phylogenetic terms. The surprising diversity of CAXs demonstrates their potential range of biochemical properties and physiologic relevance.
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Affiliation(s)
- T Shigaki
- Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Room 9016, CNRC, 1100 Bates Street, Houston, TX 77030, USA.
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47
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Shigaki T, Hirschi KD. Diverse functions and molecular properties emerging for CAX cation/H+ exchangers in plants. PLANT BIOLOGY (STUTTGART, GERMANY) 2006; 8:419-29. [PMID: 16906482 DOI: 10.1055/s-2006-923950] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Steep concentration gradients of many ions are actively maintained, with lower concentrations typically located in the cytosol, and higher concentrations in organelles and outside the cell. The vacuole is an important storage organelle for many ions. The concentration gradient of cations is established across the plant tonoplast, in part, by high-capacity cation/H+ (CAX) exchange activity. While plants may not be green yeast, analysis of CAX regulation and substrate specificity has been greatly aided by utilizing yeast as an experimental tool. The basic CAX biology in ARABIDOPSIS has immediate relevance toward understanding the functional interplay between diverse transport processes. The long-range applied goals are to identify novel transporters and express them in crop plants in order to "mine" nutrients out of the soil and into plants. In doing so, this could boost the levels of essential nutrients in plants.
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Affiliation(s)
- T Shigaki
- USDA/ARS Children's Nutrition Research Center, Baylor College of Medicine, 1100 Bates St., Houston, TX 77030, USA.
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48
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Diatloff E, Forde BG, Roberts SK. Expression and transport characterisation of the wheat low-affinity cation transporter (LCT1) in the methylotrophic yeast Pichia pastoris. Biochem Biophys Res Commun 2006; 344:807-13. [PMID: 16631619 DOI: 10.1016/j.bbrc.2006.03.212] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2006] [Accepted: 03/31/2006] [Indexed: 10/24/2022]
Abstract
The low-affinity cation transporter (LCT1) from wheat (Triticum aestivum) was expressed in the methylotrophic yeast Pichia pastoris and its transport characteristics studied employing Ca(45) and Cd(109). A clone (LCT1#3) with the highest uptake of 14pmol of Ca/10(6)cells/10min when exposed to 100microM Ca(45) was chosen for further Ca(45) and Cd(109) transport characteristics. We report for the first time a K(m) for Ca by LCT1 of 0.43+/-0.15mM Ca activity which confirms LCT1 to be a low affinity transporter. Interestingly, the expression of LCT1 in Pichia resulted in reduced Cd(109) uptake compared to wild type cells, when cells were exposed to >or=60microM Cd. This is the first report of the ability of a heterologously expressed transporter to reduce the activity of endogenous transporter proteins to transport Cd. To our knowledge, this is the first demonstration of functional expression of a plant ion transporter using P. pastoris.
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Affiliation(s)
- Eugene Diatloff
- Department of Biological Sciences, Lancaster Environment Centre, Lancaster University, Lancaster LA1 4YQ, UK.
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49
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Kamiya T, Akahori T, Ashikari M, Maeshima M. Expression of the vacuolar Ca2+/H+ exchanger, OsCAX1a, in rice: cell and age specificity of expression, and enhancement by Ca2+. PLANT & CELL PHYSIOLOGY 2006; 47:96-106. [PMID: 16275657 DOI: 10.1093/pcp/pci227] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Calcium is an essential macronutrient for plants and functions in signal transduction. Regulation of the cytosolic calcium concentration is required for normal cell growth. In calcium homeostasis in plant cells, Ca(2+)/H(+) exchangers are involved in Ca(2+) compartmentalization into intracellular compartments. Here, we examine the intracellular localization of a rice Ca(2+)/H(+) exchanger, OsCAX1a, fused to a green fluorescent protein and transiently expressed in onion epidermis and rice protoplasts. Green fluorescence was observed in the vacuolar membrane. After sucrose gradient centrifugation of the homogenate of rice plants, OsCAX1a was detected in the same fraction as the vacuolar membrane aquaporin gamma-TIP. We then quantified the mRNA and protein of OsCAX1a in plants grown with metal ions. OsCAX1a mRNA was induced in roots by high concentrations of Ca(2+). The protein level in shoots was also increased in the presence of high concentrations of Ca(2+). Furthermore, transgenic rice plants transformed with the OsCAX1a promoter fused to beta-glucuronidase showed reporter expression in vascular bundles, stomata, trichomes, steles, flowers, embryos and aleurone layers. In the case of stomata and trichomes, transcription of OsCAX1a was particularly high in aged organs. These results suggest that OsCAX1a transports Ca(2+) into vacuoles and is involved in Ca(2+) homeostasis in cells that suffer from high concentrations of Ca(2+).
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Affiliation(s)
- Takehiro Kamiya
- Laboratory of Cell Dynamics, Graduate School of Bioagricultural Sciences, Nagoya University, Japan
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50
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Kamiya T, Akahori T, Maeshima M. Expression profile of the genes for rice cation/H+ exchanger family and functional analysis in yeast. PLANT & CELL PHYSIOLOGY 2005; 46:1735-40. [PMID: 16043430 DOI: 10.1093/pcp/pci173] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
We identified five cation/H(+) exchangers (CAX) from rice, and phylogenetically divided them into two clusters. Gene expression and absolute amounts of mRNA in different organs were analyzed by real-time PCR. OsCAX1a showed high expression in almost all organs. OsCAX1b and OsCAX1c were detected in a limited number of organs and their expression levels were very low. The mRNA levels of OsCAX2 and OsCAX3 varied with the organ. OsCAXs were heterologously expressed in yeast to characterize the ion transport activity. All exchangers, except for OsCAX2, conferred tolerance to calcium. OsCAX1a and OsCAX3 conferred tolerance to manganese. The diversity of expression sites and substrates suggest the broad range function of CAX.
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Affiliation(s)
- Takehiro Kamiya
- Laboratory of Cell Dynamics, Graduate School of Bioagricultural Sciences, Nagoya University, Furocho, Chikusa-ku, Japan
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