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Łuczkowski M, Leszczyńska W, Wątły J, Clemens S, Krężel A. Phytochelatins Bind Zn(II) with Micro- to Picomolar Affinities without the Formation of Binuclear Complexes, Exhibiting Zinc Buffering and Muffling Rather than Storing Functions. Inorg Chem 2024; 63:10915-10931. [PMID: 38845098 PMCID: PMC11191002 DOI: 10.1021/acs.inorgchem.4c01707] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2024] [Revised: 05/24/2024] [Accepted: 05/28/2024] [Indexed: 06/18/2024]
Abstract
Phytochelatins (PCs) are poly-Cys peptides containing a repeating γ-Glu-Cys motif synthesized in plants, algae, certain fungi, and worms by PC synthase from reduced glutathione. It has been shown that an excess of toxic metal ions induces their biosynthesis and that they are responsible for the detoxification process. Little is known about their participation in essential metal binding under nontoxic, basal conditions under which PC synthase is active. This study presents spectroscopic and thermodynamic interactions with the PC2-PC5 series, mainly focusing on the relations between Zn(II) complex stability and cellular Zn(II) availability. The investigations employed mass spectrometry, UV-vis spectroscopy, potentiometry, competition assays with zinc probes, and isothermal titration calorimetry (ITC). All peptides form ZnL complexes, while ZnL2 was found only for PC2, containing two to four sulfur donors in the coordination sphere. Binuclear species typical of Cd(II)-PC complexes are not formed in the case of Zn(II). Results demonstrate that the affinity for Zn(II) increases linearly from PC2 to PC4, ranging from micro- to low-picomolar. Further elongation does not significantly increase the stability. Stability elevation is driven mainly by entropic factors related to the chelate effect and conformational restriction rather than enthalpic factors related to the increasing number of sulfur donors. The affinity of the investigated PCs falls within the range of exchangeable Zn(II) concentrations (hundreds of pM) observed in plants, supporting for the first time a role of PCs both in buffering and in muffling cytosolic Zn(II) concentrations under normal conditions, not exposed to zinc excess, where short PCs have been identified in numerous studies. Furthermore, we found that Cd(II)-PC complexes demonstrate significantly higher metal capacities due to the formation of polynuclear species, which are lacking for Zn(II), supporting the role of PCs in Cd(II) storage (detoxification) and Zn(II) buffering and muffling. Our results on phytochelatins' coordination chemistry and thermodynamics are important for zinc biology and understanding the molecular basis of cadmium toxicity, leaving room for future studies.
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Affiliation(s)
- Marek Łuczkowski
- Department
of Chemical Biology, Faculty of Biotechnology, University of Wrocław, Joliot-Curie 14a, 50-383 Wrocław, Poland
| | - Weronika Leszczyńska
- Department
of Chemical Biology, Faculty of Biotechnology, University of Wrocław, Joliot-Curie 14a, 50-383 Wrocław, Poland
| | - Joanna Wątły
- Department
of Chemical Biology, Faculty of Biotechnology, University of Wrocław, Joliot-Curie 14a, 50-383 Wrocław, Poland
| | - Stephan Clemens
- Department
of Plant Physiology, Faculty of Biology, Chemistry and Earth Sciences, University of Bayreuth, 95440 Bayreuth, Germany
| | - Artur Krężel
- Department
of Chemical Biology, Faculty of Biotechnology, University of Wrocław, Joliot-Curie 14a, 50-383 Wrocław, Poland
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2
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Hussain M, Hafeez A, Rizwan M, Rasheed R, Seleiman MF, Ashraf MA, Ali S, Farooq U, Nafees M. Pervasive influence of heavy metals on metabolic pathways is potentially relieved by hesperidin to enhance the phytoremediation efficiency of Bassia scoparia. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2024; 31:34526-34549. [PMID: 38709411 DOI: 10.1007/s11356-024-33530-4] [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: 01/16/2024] [Accepted: 04/27/2024] [Indexed: 05/07/2024]
Abstract
Hesperidin (HSP), a flavonoid, is a potent antioxidant, metal chelator, mediator of signaling pathways, and regulator of metal uptake in plants. The study examined the ameliorative effects of HSP (100 μM) on Bassia scoparia grown under excessive levels of heavy metals (zinc (500 mg kg-1), copper (400 mg kg-1), cadmium (100 mg kg-1), and chromium (100 mg kg-1)). The study clarifies the underlying mechanisms by which HSP lessens metabolic mayhem to enhance metal stress tolerance and phytoremediation efficiency of Bassia scoparia. Plants manifested diminished growth because of a drop in chlorophyll content and nutrient acquisition, along with exacerbated deterioration of cellular membranes reflected in elevated reactive oxygen species (ROS) production, lipid peroxidation, and relative membrane permeability. Besides the colossal production of cytotoxic methylglyoxal, the activity of lipoxygenase was also higher in plants under metal toxicity. Conversely, hesperidin suppressed the production of cytotoxic ROS and methylglyoxal. Hesperidin improved oxidative defense that protected membrane integrity. Hesperidin caused a more significant accumulation of osmolytes, non-protein thiols, and phytochelatins, thereby rendering metal ions non-toxic. Hydrogen sulfide and nitric oxide endogenous levels were intricately maintained higher in plants treated with HSP. Hesperidin increased metal accumulation in Bassia scoparia and thereby had the potential to promote the reclamation of metal-contaminated soils.
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Affiliation(s)
- Mazhar Hussain
- Department of Botany, Government College University Faisalabad, Faisalabad, 38000, Pakistan
| | - Arslan Hafeez
- Department of Botany, Government College University Faisalabad, Faisalabad, 38000, Pakistan
| | - Muhammad Rizwan
- Department of Environmental Sciences, Government College University Faisalabad, Faisalabad, 38000, Pakistan
| | - Rizwan Rasheed
- Department of Botany, Government College University Faisalabad, Faisalabad, 38000, Pakistan
| | - Mahmoud F Seleiman
- Department of Plant Production, College of Food and Agriculture Sciences, King Saud University, P.O. Box 2460, Riyadh, 11451, Saudi Arabia
| | - Muhammad Arslan Ashraf
- Department of Botany, Government College University Faisalabad, Faisalabad, 38000, Pakistan.
| | - Shafaqat Ali
- Department of Environmental Sciences, Government College University Faisalabad, Faisalabad, 38000, Pakistan
- Department of Biological Sciences and Technology, China Medical University, Taichung, 40402, Taiwan
| | - Umer Farooq
- Department of Botany, Government College University Faisalabad, Faisalabad, 38000, Pakistan
| | - Muhammad Nafees
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, 21023, Jiangsu, China
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Haque KS, Islam MS, Ahmed S, Rahman MZ, Hemy DH, Islam MT, Hossain MK, Uddin MR, Md Towfiqul Islam AR, Mia MY, Ismail Z, Al Bakky A, Ibrahim KA, Idris AM. WITHDRAWN: Trace metals translocation from soil to plants: Health risk assessment via consumption of vegetables in the urban sprawl of a developing country. Food Chem Toxicol 2024:114580. [PMID: 38467293 DOI: 10.1016/j.fct.2024.114580] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2023] [Revised: 03/05/2024] [Accepted: 03/06/2024] [Indexed: 03/13/2024]
Abstract
This article has been withdrawn at the request of the author(s) and/or editor. The Publisher apologizes for any inconvenience this may cause. The full Elsevier Policy on Article Withdrawal can be found at https://www.elsevier.com/about/policies/article-withdrawal.
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Affiliation(s)
- Km Shamsul Haque
- School of Agricultural Environmental and Veterinary Sciences, Charles Sturt University, Wagga, NSW, 2650, Australia
| | - Md Saiful Islam
- Department of Soil Science, Patuakhali Science and Technology University, Dumki, Patuakhali, 8602, Bangladesh
| | - Sujat Ahmed
- Environment, Center for People & Environ (CPE), Dhaka, Bangladesh
| | - Md Zillur Rahman
- Department of Agronomy and Haor Agriculture, Sylhet Agricultural University, Sylhet, 3100, Bangladesh; School of Life and Environmental Sciences, Sydney Institute of Agriculture, Faculty of Science, The 13 University of Sydney, Australia
| | - Debolina Halder Hemy
- Department of Soil Science, Patuakhali Science and Technology University, Dumki, Patuakhali, 8602, Bangladesh
| | - Md Towhidul Islam
- Department of Soil Science, Patuakhali Science and Technology University, Dumki, Patuakhali, 8602, Bangladesh
| | - Md Kamal Hossain
- Department of Soil Science, Patuakhali Science and Technology University, Dumki, Patuakhali, 8602, Bangladesh
| | - Md Rafiq Uddin
- Department of Soil Science, Patuakhali Science and Technology University, Dumki, Patuakhali, 8602, Bangladesh
| | - Abu Reza Md Towfiqul Islam
- Department of Disaster Management, Begum Bekeya University, Rangpur, 5400, Bangladesh; Department of Development Studies, Daffodil International University, Dhaka, 1216, Bangladesh
| | - Md Yousuf Mia
- Department of Disaster Management, Begum Bekeya University, Rangpur, 5400, Bangladesh
| | - Zulhilmi Ismail
- Centre for River and Coastal Engineering (CRCE), Universiti Teknologi Malaysia (UTM), 81310, Johor Bahru, Malaysia; Department of Water & Environmental Engineering, Faculty of Civil Engineering, Universiti Teknologi Malaysia (UTM), 81310, Johor, Malaysia
| | - Abdullah Al Bakky
- Agricultural wing, Bangladesh Jute Research Institute, Dhaka, 1207, Bangladesh
| | - Khalid A Ibrahim
- Department of Biology, College of Science, King Khalid University, Abha, 62529, Saudi Arabia; Center for Environment and Tourism Studies and Research, King Khalid University, Abha, 62529, Saudi Arabia
| | - Abubakr M Idris
- Department of Chemistry, College of Science, King Khalid University, Abha, 62529, Saudi Arabia
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Strenkert D, Schmollinger S, Hu Y, Hofmann C, Holbrook K, Liu HW, Purvine SO, Nicora CD, Chen S, Lipton MS, Northen TR, Clemens S, Merchant SS. Zn deficiency disrupts Cu and S homeostasis in Chlamydomonas resulting in over accumulation of Cu and Cysteine. Metallomics 2023; 15:mfad043. [PMID: 37422438 PMCID: PMC10357957 DOI: 10.1093/mtomcs/mfad043] [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: 04/12/2023] [Accepted: 07/06/2023] [Indexed: 07/10/2023]
Abstract
Growth of Chlamydomonas reinhardtii in zinc (Zn) limited medium leads to disruption of copper (Cu) homeostasis, resulting in up to 40-fold Cu over-accumulation relative to its typical Cu quota. We show that Chlamydomonas controls its Cu quota by balancing Cu import and export, which is disrupted in a Zn deficient cell, thus establishing a mechanistic connection between Cu and Zn homeostasis. Transcriptomics, proteomics and elemental profiling revealed that Zn-limited Chlamydomonas cells up-regulate a subset of genes encoding "first responder" proteins involved in sulfur (S) assimilation and consequently accumulate more intracellular S, which is incorporated into L-cysteine, γ-glutamylcysteine, and homocysteine. Most prominently, in the absence of Zn, free L-cysteine is increased ∼80-fold, corresponding to ∼2.8 × 109 molecules/cell. Interestingly, classic S-containing metal binding ligands like glutathione and phytochelatins do not increase. X-ray fluorescence microscopy showed foci of S accumulation in Zn-limited cells that co-localize with Cu, phosphorus and calcium, consistent with Cu-thiol complexes in the acidocalcisome, the site of Cu(I) accumulation. Notably, cells that have been previously starved for Cu do not accumulate S or Cys, causally connecting cysteine synthesis with Cu accumulation. We suggest that cysteine is an in vivo Cu(I) ligand, perhaps ancestral, that buffers cytosolic Cu.
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Affiliation(s)
- Daniela Strenkert
- California Institute for Quantitative Biosciences, University of California, Berkeley, CA, 94720, USA
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90095, USA
| | - Stefan Schmollinger
- California Institute for Quantitative Biosciences, University of California, Berkeley, CA, 94720, USA
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90095, USA
| | - Yuntao Hu
- Environmental Genomics and Systems Biology, Lawrence Berkeley National LaboratoryBerkeley CAUSA
| | | | - Kristen Holbrook
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90095, USA
| | - Helen W Liu
- California Institute for Quantitative Biosciences, University of California, Berkeley, CA, 94720, USA
- Department of Plant and Microbial Biology, University of California, Berkeley, CA, 94720, USA
| | - Samuel O Purvine
- Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, US Department of Energy, Richland, WA 99352, USA
| | - Carrie D Nicora
- Biological Sciences Division, Pacific Northwest National Laboratory, US Department of Energy, Richland, WA 99352, USA
| | - Si Chen
- Advanced Photon Source, Argonne National Laboratory, Lemont, IL 60439, USA
| | - Mary S Lipton
- Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, US Department of Energy, Richland, WA 99352, USA
| | - Trent R Northen
- Environmental Genomics and Systems Biology, Lawrence Berkeley National LaboratoryBerkeley CAUSA
- Joint Genome Institute, Lawrence Berkeley National Laboratory, Berkeley CAUSA
| | - Stephan Clemens
- Department of Plant Physiology, University of Bayreuth, Germany
| | - Sabeeha S Merchant
- California Institute for Quantitative Biosciences, University of California, Berkeley, CA, 94720, USA
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90095, USA
- Environmental Genomics and Systems Biology, Lawrence Berkeley National LaboratoryBerkeley CAUSA
- Department of Plant and Microbial Biology, University of California, Berkeley, CA, 94720, USA
- Department of Molecular & Cell Biology, University of California, Berkeley, CA, 94720, USA
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5
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Sun SK, Chen J, Zhao FJ. Regulatory mechanisms of sulfur metabolism affecting tolerance and accumulation of toxic trace metals and metalloids in plants. JOURNAL OF EXPERIMENTAL BOTANY 2023; 74:3286-3299. [PMID: 36861339 DOI: 10.1093/jxb/erad074] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Accepted: 02/23/2023] [Indexed: 06/08/2023]
Abstract
Soil contamination with trace metals and metalloids can cause toxicity to plants and threaten food safety and human health. Plants have evolved sophisticated mechanisms to cope with excess trace metals and metalloids in soils, including chelation and vacuolar sequestration. Sulfur-containing compounds, such as glutathione and phytochelatins, play a crucial role in their detoxification, and sulfur uptake and assimilation are regulated in response to the stress of toxic trace metals and metalloids. This review focuses on the multi-level connections between sulfur homeostasis in plants and responses to such stresses, especially those imposed by arsenic and cadmium. We consider recent progress in understanding the regulation of biosynthesis of glutathione and phytochelatins and of the sensing mechanism of sulfur homeostasis for tolerance of trace metals and metalloids in plants. We also discuss the roles of glutathione and phytochelatins in controlling the accumulation and distribution of arsenic and cadmium in plants, and possible strategies for manipulating sulfur metabolism to limit their accumulation in food crops.
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Affiliation(s)
- Sheng-Kai Sun
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, China
- Centre for Organismal Studies (COS), Heidelberg University, 69120 Heidelberg, Germany
| | - Jie Chen
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, China
| | - Fang-Jie Zhao
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, China
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6
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Strenkert D, Schmollinger S, Hu Y, Hofmann C, Holbrook K, Liu HW, Purvine SO, Nicora CD, Chen S, Lipton MS, Northen TR, Clemens S, Merchant SS. Cysteine: an ancestral Cu binding ligand in green algae? BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.15.532757. [PMID: 36993560 PMCID: PMC10055113 DOI: 10.1101/2023.03.15.532757] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/19/2023]
Abstract
Growth of Chlamydomonas reinhardtii in zinc (Zn) limited medium leads to disruption of copper (Cu) homeostasis, resulting in up to 40-fold Cu over-accumulation relative to its typical Cu quota. We show that Chlamydomonas controls its Cu quota by balancing Cu import and export, which is disrupted in a Zn deficient cell, thus establishing a mechanistic connection between Cu and Zn homeostasis. Transcriptomics, proteomics and elemental profiling revealed that Zn-limited Chlamydomonas cells up-regulate a subset of genes encoding "first responder" proteins involved in sulfur (S) assimilation and consequently accumulate more intracellular S, which is incorporated into L-cysteine, γ-glutamylcysteine and homocysteine. Most prominently, in the absence of Zn, free L-cysteine is increased ~80-fold, corresponding to ~ 2.8 × 10 9 molecules/cell. Interestingly, classic S-containing metal binding ligands like glutathione and phytochelatins do not increase. X-ray fluorescence microscopy showed foci of S accumulation in Zn-limited cells that co-localize with Cu, phosphorus and calcium, consistent with Cu-thiol complexes in the acidocalcisome, the site of Cu(I) accumulation. Notably, cells that have been previously starved for Cu do not accumulate S or Cys, causally connecting cysteine synthesis with Cu accumulation. We suggest that cysteine is an in vivo Cu(I) ligand, perhaps ancestral, that buffers cytosolic Cu.
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7
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Seregin IV, Kozhevnikova AD. Phytochelatins: Sulfur-Containing Metal(loid)-Chelating Ligands in Plants. Int J Mol Sci 2023; 24:2430. [PMID: 36768751 PMCID: PMC9917255 DOI: 10.3390/ijms24032430] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2022] [Revised: 01/20/2023] [Accepted: 01/23/2023] [Indexed: 01/28/2023] Open
Abstract
Phytochelatins (PCs) are small cysteine-rich peptides capable of binding metal(loid)s via SH-groups. Although the biosynthesis of PCs can be induced in vivo by various metal(loid)s, PCs are mainly involved in the detoxification of cadmium and arsenic (III), as well as mercury, zinc, lead, and copper ions, which have high affinities for S-containing ligands. The present review provides a comprehensive account of the recent data on PC biosynthesis, structure, and role in metal(loid) transport and sequestration in the vacuoles of plant cells. A comparative analysis of PC accumulation in hyperaccumulator plants, which accumulate metal(loid)s in their shoots, and in the excluders, which accumulate metal(loid)s in their roots, investigates the question of whether the endogenous PC concentration determines a plant's tolerance to metal(loid)s. Summarizing the available data, it can be concluded that PCs are not involved in metal(loid) hyperaccumulation machinery, though they play a key role in metal(loid) homeostasis. Unraveling the physiological role of metal(loid)-binding ligands is a fundamental problem of modern molecular biology, plant physiology, ionomics, and toxicology, and is important for the development of technologies used in phytoremediation, biofortification, and phytomining.
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Affiliation(s)
- Ilya V. Seregin
- K.A. Timiryazev Institute of Plant Physiology, Russian Academy of Sciences, Botanicheskaya St., 35, 127276 Moscow, Russia
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Uraguchi S, Ohshiro Y, Otsuka Y, Wada E, Naruse F, Sugaya K, Nagai K, Wongkaew A, Nakamura R, Takanezawa Y, Clemens S, Ohkama-Ohtsu N, Kiyono M. Phytochelatin-mediated metal detoxification pathway is crucial for an organomercurial phenylmercury tolerance in Arabidopsis. PLANT MOLECULAR BIOLOGY 2022; 109:563-577. [PMID: 34837578 DOI: 10.1007/s11103-021-01221-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Accepted: 11/16/2021] [Indexed: 06/13/2023]
Abstract
An organomercurial phenylmercury activates AtPCS1, an enzyme known for detoxification of inorganic metal(loid) ions in Arabidopsis and the induced metal-chelating peptides phytochelatins are essential for detoxification of phenylmercury. Small thiol-rich peptides phytochelatins (PCs) and their synthases (PCSs) are crucial for plants to mitigate the stress derived from various metal(loid) ions in their inorganic form including inorganic mercury [Hg(II)]. However, the possible roles of the PC/PCS system in organic mercury detoxification in plants remain elusive. We found that an organomercury phenylmercury (PheHg) induced PC synthesis in Arabidopsis thaliana plants as Hg(II), whereas methylmercury did not. The analyses of AtPCS1 mutant plants and in vitro assays using the AtPCS1-recombinant protein demonstrated that AtPCS1, the major PCS in A. thaliana, was responsible for the PheHg-responsive PC synthesis. AtPCS1 mutants cad1-3 and cad1-6, and the double mutant of PC-metal(loid) complex transporters AtABCC1 and AtABCC2 showed enhanced sensitivity to PheHg as well as to Hg(II). The hypersensitivity of cad1-3 to PheHg stress was complemented by the own-promoter-driven expression of AtPCS1-GFP. The confocal microscopy of the complementation lines showed that the AtPCS1-GFP was preferentially expressed in epidermal cells of the mature and elongation zones, and the outer-most layer of the lateral root cap cells in the meristematic zone. Moreover, in vitro PC-metal binding assay demonstrated that binding affinity between PC and PheHg was comparable to Hg(II). However, plant ionomic profiles, as well as root morphology under PheHg and Hg(II) stress, were divergent. These results suggest that PheHg phytotoxicity is different from Hg(II), but AtPCS1-mediated PC synthesis, complex formation, and vacuolar sequestration by AtABCC1 and AtABCC2 are similarly functional for both PheHg and Hg(II) detoxification in root surficial cell types.
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Affiliation(s)
- Shimpei Uraguchi
- Department of Public Health, School of Pharmacy, Kitasato University, Minato-ku, Tokyo, 108-8641, Japan.
| | - Yuka Ohshiro
- Department of Public Health, School of Pharmacy, Kitasato University, Minato-ku, Tokyo, 108-8641, Japan
| | - Yuto Otsuka
- Department of Public Health, School of Pharmacy, Kitasato University, Minato-ku, Tokyo, 108-8641, Japan
| | - Emiko Wada
- Department of Public Health, School of Pharmacy, Kitasato University, Minato-ku, Tokyo, 108-8641, Japan
| | - Fumii Naruse
- Department of Public Health, School of Pharmacy, Kitasato University, Minato-ku, Tokyo, 108-8641, Japan
| | - Kakeru Sugaya
- Department of Public Health, School of Pharmacy, Kitasato University, Minato-ku, Tokyo, 108-8641, Japan
| | - Kenichiro Nagai
- Medicinal Research Laboratories, School of Pharmacy, Kitasato University, Minato-ku, Tokyo, 108-8641, Japan
| | - Arunee Wongkaew
- United Graduate School of Agriculture, Tokyo University of Agriculture and Technology, Fuchu, Tokyo, 183-8509, Japan
- Department of Agronomy, Faculty of Agriculture, Kasetsart University, Bangkok, 10900, Thailand
| | - Ryosuke Nakamura
- Department of Public Health, School of Pharmacy, Kitasato University, Minato-ku, Tokyo, 108-8641, Japan
| | - Yasukazu Takanezawa
- Department of Public Health, School of Pharmacy, Kitasato University, Minato-ku, Tokyo, 108-8641, Japan
| | - Stephan Clemens
- Department of Plant Physiology, Bayreuth Center of Ecology and Environmental Research, University of Bayreuth, 95447, Bayreuth, Germany
| | - Naoko Ohkama-Ohtsu
- Institute of Agriculture, Tokyo University of Agriculture and Technology, Fuchu, Tokyo, 183-8509, Japan
- Institute of Global Innovation Research, Tokyo University of Agriculture and Technology, Fuchu, Tokyo, 183-8509, Japan
| | - Masako Kiyono
- Department of Public Health, School of Pharmacy, Kitasato University, Minato-ku, Tokyo, 108-8641, Japan.
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Clemens S. The cell biology of zinc. JOURNAL OF EXPERIMENTAL BOTANY 2022; 73:1688-1698. [PMID: 34727160 DOI: 10.1093/jxb/erab481] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2021] [Accepted: 10/28/2021] [Indexed: 06/13/2023]
Abstract
Nearly 10% of all plant proteins belong to the zinc (Zn) proteome. They require Zn either for catalysis or as a structural element. Most of the protein-bound Zn in eukaryotic cells is found in the cytosol. The fundamental differences between transition metal cations in the stability of their complexes with organic ligands, as described by the Irving-Williams series, necessitate buffering of cytosolic Zn (the 'free Zn' pool) in the picomolar range (i.e. ~6 orders of magnitude lower than the total cellular concentration). Various metabolites and peptides, including nicotianamine, glutathione, and phytochelatins, serve as Zn buffers. They are hypothesized to supply Zn to enzymes, transporters, or the recently identified sensor proteins. Zn2+ acquisition is mediated by ZRT/IRT-like proteins. Metal tolerance proteins transport Zn2+ into vacuoles and the endoplasmic reticulum, the major Zn storage sites. Heavy metal ATPase-dependent efflux of Zn2+ is another mechanism to control cytosolic Zn. Spatially controlled Zn2+ influx or release from intracellular stores would result in dynamic modulation of cellular Zn pools, which may directly influence protein-protein interactions or the activities of enzymes involved in signaling cascades. Possible regulatory roles of such changes, as recently elucidated in mammalian cells, are discussed.
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Affiliation(s)
- Stephan Clemens
- Department of Plant Physiology and Faculty of Life Science: Food, Nutrition and Health, University of Bayreuth, Universitätsstrasse 30, D-95447 Bayreuth, Germany
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10
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Uraguchi S, Nagai K, Naruse F, Otsuka Y, Ohshiro Y, Nakamura R, Takanezawa Y, Kiyono M. Development of affinity bead-based in vitro metal-ligand binding assay reveals dominant cadmium affinity of thiol-rich small peptides phytochelatins beyond glutathione. Metallomics 2021; 13:6445037. [PMID: 34850059 DOI: 10.1093/mtomcs/mfab068] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Accepted: 11/17/2021] [Indexed: 11/12/2022]
Abstract
For a better understanding of metal-ligand interaction and its function in cells, we developed an easy, sensitive, and high-throughput method to quantify ligand-metal(loid) binding affinity under physiological conditions by combining ligand-attached affinity beads and inductively coupled plasma-optical emission spectrometry (ICP-OES). Glutathione (GSH) and two phytochelatins (PC2 and PC3, small peptides with different numbers of free thiols) were employed as model ligands and attached to hydrophilic beads. The principle of the assay resembles that of affinity purification of proteins in biochemistry: metals binding to the ligand on the beads and the rest in the buffer are separated by a spin column and quantified by ICP-OES. The binding assay using the GSH-attached beads and various metal(loid)s suggested the different affinity of the metal-GSH interactions, in accordance with the order of the Irving-Williams series and the reported stability constants. The binding assay using PC2 or PC3-attached beads suggested positive binding between PCs and Ni(II), Cu(II), Zn(II), Cd(II), and As(III) in accordance with the number of thiols in PC2 and PC3. We then conducted the competition assay using Cd(II), Mn(II), Fe(II), Cu(II), and Zn(II), and the results suggested a better binding affinity of PC2 with Cd(II) than with the essential metals. Another competition assay using PC2 and GSH suggested a robust binding affinity between PCs and Cd(II) compared to GSH and Cd(II). These results suggested the dominance of PC-Cd complex formation in vitro, supporting the physiological importance of PCs for the detoxification of cadmium in vivo. We also discuss the potential application of the assay.
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Affiliation(s)
- Shimpei Uraguchi
- Department of Public Health, School of Pharmacy, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo 108-8641, Japan
| | - Kenichiro Nagai
- Medicinal Research Laboratories, School of Pharmacy, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo, 108-8641, Japan
| | - Fumii Naruse
- Department of Public Health, School of Pharmacy, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo 108-8641, Japan
| | - Yuto Otsuka
- Department of Public Health, School of Pharmacy, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo 108-8641, Japan
| | - Yuka Ohshiro
- Department of Public Health, School of Pharmacy, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo 108-8641, Japan
| | - Ryosuke Nakamura
- Department of Public Health, School of Pharmacy, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo 108-8641, Japan
| | - Yasukazu Takanezawa
- Department of Public Health, School of Pharmacy, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo 108-8641, Japan
| | - Masako Kiyono
- Department of Public Health, School of Pharmacy, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo 108-8641, Japan
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11
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Seregin IV, Kozhevnikova AD. Low-molecular-weight ligands in plants: role in metal homeostasis and hyperaccumulation. PHOTOSYNTHESIS RESEARCH 2021; 150:51-96. [PMID: 32653983 DOI: 10.1007/s11120-020-00768-1] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Accepted: 06/22/2020] [Indexed: 06/11/2023]
Abstract
Mineral nutrition is one of the key factors determining plant productivity. In plants, metal homeostasis is achieved through the functioning of a complex system governing metal uptake, translocation, distribution, and sequestration, leading to the maintenance of a regulated delivery of micronutrients to metal-requiring processes as well as detoxification of excess or non-essential metals. Low-molecular-weight ligands, such as nicotianamine, histidine, phytochelatins, phytosiderophores, and organic acids, play an important role in metal transport and detoxification in plants. Nicotianamine and histidine are also involved in metal hyperaccumulation, which determines the ability of some plant species to accumulate a large amount of metals in their shoots. In this review we extensively summarize and discuss the current knowledge of the main pathways for the biosynthesis of these ligands, their involvement in metal uptake, radial and long-distance transport, as well as metal influx, isolation and sequestration in plant tissues and cell compartments. It is analyzed how diverse endogenous ligand levels in plants can determine their different tolerance to metal toxic effects. This review focuses on recent advances in understanding the physiological role of these compounds in metal homeostasis, which is an essential task of modern ionomics and plant physiology. It is of key importance in studying the influence of metal deficiency or excess on various physiological processes, which is a prerequisite to the improvement of micronutrient uptake efficiency and crop productivity and to the development of a variety of applications in phytoremediation, phytomining, biofortification, and nutritional crop safety.
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Affiliation(s)
- I V Seregin
- K.A. Timiryazev Institute of Plant Physiology RAS, IPPRAS, Botanicheskaya st., 35, Moscow, Russian Federation, 127276.
| | - A D Kozhevnikova
- K.A. Timiryazev Institute of Plant Physiology RAS, IPPRAS, Botanicheskaya st., 35, Moscow, Russian Federation, 127276
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12
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Cadmium hijacks the high zinc response by binding and activating the HIZR-1 nuclear receptor. Proc Natl Acad Sci U S A 2021; 118:2022649118. [PMID: 34649987 DOI: 10.1073/pnas.2022649118] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/13/2021] [Indexed: 11/18/2022] Open
Abstract
Cadmium is an environmental pollutant and significant health hazard that is similar to the physiological metal zinc. In Caenorhabditis elegans, high zinc homeostasis is regulated by the high zinc activated nuclear receptor (HIZR-1) transcription factor. To define relationships between the responses to high zinc and cadmium, we analyzed transcription. Many genes were activated by both high zinc and cadmium, and hizr-1 was necessary for activation of a subset of these genes; in addition, many genes activated by cadmium did not require hizr-1, indicating there are at least two mechanisms of cadmium-regulated transcription. Cadmium directly bound HIZR-1, promoted nuclear accumulation of HIZR-1 in intestinal cells, and activated HIZR-1-mediated transcription via the high zinc activation (HZA) enhancer. Thus, cadmium binding promotes HIZR-1 activity, indicating that cadmium acts as a zinc mimetic to hijack the high zinc response. To elucidate the relationships between high zinc and cadmium detoxification, we analyzed genes that function in three pathways: the pcs-1/phytochelatin pathway strongly promoted cadmium resistance but not high zinc resistance, the hizr-1/HZA pathway strongly promoted high zinc resistance but not cadmium resistance, and the mek-1/sek-1/kinase signaling pathway promoted resistance to high zinc and cadmium. These studies identify resistance pathways that are specific for high zinc and cadmium, as well as a shared pathway.
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13
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Adele NC, Ngwenya BT, Heal KV, Mosselmans JFW. Role of plant growth promoting bacteria in driving speciation gradients across soil-rhizosphere-plant interfaces in zinc-contaminated soils. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2021; 279:116909. [PMID: 33744635 DOI: 10.1016/j.envpol.2021.116909] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2020] [Revised: 03/02/2021] [Accepted: 03/05/2021] [Indexed: 06/12/2023]
Abstract
Inoculation of soil or seeds with plant growth promoting bacteria ameliorates metal toxicity to plants by changing metal speciation in plant tissues but the exact location of these changes remains unknown. Knowing where the changes occur is a critical first step to establish whether metal speciation changes are driven by microbial metabolism or by plant responses. Since bacteria concentrate in the rhizosphere, we hypothesised steep changes in metal speciation across the rhizosphere. We tested this by comparing speciation of zinc (Zn) in roots of Brassica juncea plants grown in soil contaminated with 600 mg kg-1 of Zn with that of bulk and rhizospheric soil using synchrotron X-ray absorption spectroscopy (XAS). Seeds were either uninoculated or inoculated with Rhizobium leguminosarum bv. trifolii and Zn was supplied in the form of sulfide (ZnS nanoparticles) and sulfate (ZnSO4). Consistent with previous studies, Zn toxicity, as assessed by plant growth parameters, was alleviated in B. juncea inoculated with Rhizobium leguminosarum. XAS results showed that in both ZnS and ZnSO4 treatments, the most significant changes in speciation occurred between the rhizosphere and the root, and involved an increase in the proportion of organic acids and thiol complexes. In ZnS treatments, Zn phytate and Zn citrate were the dominant organic acid complexes, whilst Zn histidine also appeared in roots exposed to ZnSO4. Inoculation with bacteria was associated with the appearance of Zn cysteine and Zn formate in roots, suggesting that these two forms are driven by bacterial metabolism. In contrast, Zn complexation with phytate, citrate and histidine is attributed to plant responses, perhaps in the form of exudates, some with long range influence into the bulk soil, leading to shallower speciation gradients.
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Affiliation(s)
| | - Bryne T Ngwenya
- School of GeoSciences, University of Edinburgh, Edinburgh, UK.
| | - Kate V Heal
- School of GeoSciences, University of Edinburgh, Edinburgh, UK
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14
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Amjadi Z, Namdjoyan S, Abolhasani Soorki A. Exogenous melatonin and salicylic acid alleviates cadmium toxicity in safflower (Carthamus tinctorius L.) seedlings. ECOTOXICOLOGY (LONDON, ENGLAND) 2021; 30:387-401. [PMID: 33624206 DOI: 10.1007/s10646-021-02364-y] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 02/02/2021] [Indexed: 06/12/2023]
Abstract
The co-application of exogenous 100 µM melatonin (MT) and 100 µM salicylic acid (SA) on 21-day-old safflower seedlings grown in the presence of cadmium (Cd, 100 µM) toxicity was investigated. The application of MT, SA, or MT + SA efficiently improved toxicity symptoms and declined Cd toxicity as shown by a considerable rise in plant biomass production and chlorophyll content accompanied by decreased level of oxidative stress markers. In Cd stressed plants, the simultaneous application of MT and SA led to sharp decreases in MDA and H2O2 amounts (61.04 and 49.11%, respectively), related to plants treated with Cd alone. With respect to the control, a 41 and 48% increment in reduced glutathione (GSH) and ascorbate (ASC) content was recorded in Cd-treated seedlings. Though, with the addition of MT, SA, or MT + SA, the content of GSH and ASC increased more. The application of MT, SA, or MT + SA caused a sharp induction in phytochelatin content of the leaves of Cd-treated seedlings, while in roots, the highest PC content was recorded only in the presence of MT, which was about 1.8-fold greater than in plant treated with Cd alone. The activity of enzymes responsible for the ascorbate-glutathione cycle and glyoxalase system considerably improved by using MT, SA, or the combination of MT and SA. Our findings suggest a possible synergic interaction between MT and SA in tolerating Cd toxicity by reducing Cd uptake, improving chlorophyll biosynthesis and accelerating ascorbate-glutathione cycle as well as the modulation of glyoxalase system.
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Affiliation(s)
- Zahra Amjadi
- Department of Biology and Biochemistry, Science Faculty, Shahr-e-Qods Branch, Islamic Azad University, Tehran, Iran
| | - Shahram Namdjoyan
- Department of Biology and Biochemistry, Science Faculty, Shahr-e-Qods Branch, Islamic Azad University, Tehran, Iran.
| | - Ali Abolhasani Soorki
- ACECR-Research Institute of Applied Sciences, Shahid Beheshti University, Tehran, Iran
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15
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Majumdar S, Sachdev S, Kundu R. Salicylic acid mediated reduction in grain cadmium accumulation and amelioration of toxicity in Oryza sativa L. cv Bandana. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2020; 205:111167. [PMID: 32827967 DOI: 10.1016/j.ecoenv.2020.111167] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/12/2020] [Revised: 07/19/2020] [Accepted: 08/10/2020] [Indexed: 05/07/2023]
Abstract
Contamination of agricultural fields with Cadmium (Cd) due to several agricultural practices is increasing worldwide. The rice plants can easily take up Cd and accumulate it into different parts, including the grains, posing a threat to human health even at low concentration exposure. Several phytohormones, including Salicylic acid (SA) have been investigated since long for its alleviating properties under various biotic and abiotic stress conditions. In the present study, 100 μM SA application to ameliorate 25 μM Cd stress was studied for 72 h in hydroponics in Oryza sativa cv. Bandana seedlings. Pot experiments were done with same treatment condition and plants were grown till maturity. SA application to Cd exposed rice seedlings alleviated the stress condition, which was established by several physiological, biochemical, histochemical and gene expression analysis. SA treatment to Cd stressed seedlings showed elevated photosynthetic pigment content, on-protein thiol content and relieved the Cd induced growth inhibition considerably. It lowered the accumulation of ROS like, O2- and H2O2 with a regulated antioxidative enzymatic activity. SA application in Cd exposed rice seedlings had upregulated expression of OsHMA3 and OsPCS1 whereasOsNRAMP2 gene was downregulated. Co-application of SA and Cd led to higher yield and improved agronomic traits in comparison to only Cd exposed plants under pot experimentation. Daily intake of Cd and Carcinogenic risk were also reduced by 99.75% and 99.99% respectively in the SA treated Cd stressed plants. SA positively affected the growth and tolerance of rice seedlings to Cd stress. Hence, SA addition to Cd contaminated soil can ensure rice cultivation without posing health risk to consumers.
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Affiliation(s)
- Snehalata Majumdar
- Department of Botany, Centre of Advanced Study, University of Calcutta, 35 Ballygunge Circular Road, Kolkata, 700019, West Bengal, India
| | - Sonal Sachdev
- Division of Plant Biology, Bose Institute, P-1/12, CIT Road, Scheme VIIM, Kankurgachi, Kolkata, 700054, West Bengal, India
| | - Rita Kundu
- Department of Botany, Centre of Advanced Study, University of Calcutta, 35 Ballygunge Circular Road, Kolkata, 700019, West Bengal, India.
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16
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Nualla-Ong A, Phongdara A, Buapet P. Copper and zinc differentially affect root glutathione accumulation and phytochelatin synthase gene expression of Rhizophora mucronata seedlings: Implications for mechanisms underlying trace metal tolerance. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2020; 205:111175. [PMID: 32836161 DOI: 10.1016/j.ecoenv.2020.111175] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Revised: 08/06/2020] [Accepted: 08/11/2020] [Indexed: 06/11/2023]
Abstract
Mangroves are susceptible to contamination due to their proximity to shores and human activities. Exposure to excessive trace metals can disturb their physiological functions and may eventually lead to death. Rhizophora mucronata is a common species growing in the mangrove forests of Thailand. Previous studies have shown that seedlings of R. mucronata are tolerant of trace metal and that they accumulate a large metal content in their root tissue. However, knowledge of their tolerance mechanisms is still lacking. To elicit the role of metal detoxification and sequestration by phytochelatins (PC) in the roots of R. mucronata seedlings, the impacts of Cu and Zn exposure were assessed on 1) physiological characteristics 2) the concentration of glutathione (GSH), a precursor of PC and 3) the level of the transcripts encoding phytochelatin synthase (PCS), the key enzyme for PC biosynthesis. Seedlings of R. mucronata were exposed to Cu and Zn in a hydroponic experiment (200 mg Cu or Zn/L in 1/4× Hoagland solution containing 8‰ NaCl, single addition). We found that both trace metals were largely accumulated in the roots. Only Cu-treated seedlings showed a decrease in the photosynthetic efficiency, in line with observed toxicity symptoms (i.e. bent stems and slight wilting of leaves). Metal accumulation, however, did not induce oxidative stress in the roots as indicated by similar level of total reactive species and lipid peroxidation across treatments. The GSH content in the roots exposed to Cu was significantly reduced while no change was observed in Zn-exposed roots. Coordinated semi-quantitative PCR and RT-qPCR revealed pcs down-regulation in Cu-treated roots, whereas Zn-treated roots showed a down-regulation on day 1 and a subsequent recovery on day 5. Failure of detoxification and sequestration of excess Cu due to GSH limitation and down-regulation of pcs may lead to the phytotoxic effects observed in Cu-treated plants. Our results suggest that both GSH and PC play an important role in trace metal tolerance in R. mucronata seedlings.
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Affiliation(s)
- Aekkaraj Nualla-Ong
- Faculty of Medical Technology, Prince of Songkla University, Thailand; Center for Genomics and Bioinformatics Research, Faculty of Science, Prince of Songkla University, Thailand
| | - Amornrat Phongdara
- Faculty of Medical Technology, Prince of Songkla University, Thailand; Center for Genomics and Bioinformatics Research, Faculty of Science, Prince of Songkla University, Thailand
| | - Pimchanok Buapet
- Plant Physiology Laboratory, Division of Biological Science, Faculty of Science, Prince of Songkla University, Thailand; Coastal Oceanography and Climate Change Research Center, Prince of Songkla University, Thailand.
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17
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Li M, Barbaro E, Bellini E, Saba A, Sanità di Toppi L, Varotto C. Ancestral function of the phytochelatin synthase C-terminal domain in inhibition of heavy metal-mediated enzyme overactivation. JOURNAL OF EXPERIMENTAL BOTANY 2020; 71:6655-6669. [PMID: 32936292 PMCID: PMC7586750 DOI: 10.1093/jxb/eraa386] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2020] [Accepted: 08/17/2020] [Indexed: 05/03/2023]
Abstract
Phytochelatin synthases (PCSs) play essential roles in detoxification of a broad range of heavy metals in plants and other organisms. Until now, however, no PCS gene from liverworts, the earliest branch of land plants and possibly the first one to acquire a PCS with a C-terminal domain, has been characterized. In this study, we isolated and functionally characterized the first PCS gene from a liverwort, Marchantia polymorpha (MpPCS). MpPCS is constitutively expressed in all organs examined, with stronger expression in thallus midrib. The gene expression is repressed by Cd2+ and Zn2+. The ability of MpPCS to increase heavy metal resistance in yeast and to complement cad1-3 (the null mutant of the Arabidopsis ortholog AtPCS1) proves its function as the only PCS from M. polymorpha. Site-directed mutagenesis of the most conserved cysteines of the C-terminus of the enzyme further uncovered that two twin-cysteine motifs repress, to different extents, enzyme activation by heavy metal exposure. These results highlight an ancestral function of the PCS elusive C-terminus as a regulatory domain inhibiting enzyme overactivation by essential and non-essential heavy metals. The latter finding may be relevant for obtaining crops with decreased root to shoot mobility of cadmium, thus preventing its accumulation in the food chain.
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Affiliation(s)
- Mingai Li
- Department of Biodiversity and Molecular Ecology, Research and Innovation Centre, Fondazione Edmund Mach, San Michele all’Adige, Trento, Italy
| | - Enrico Barbaro
- Department of Biodiversity and Molecular Ecology, Research and Innovation Centre, Fondazione Edmund Mach, San Michele all’Adige, Trento, Italy
| | - Erika Bellini
- Dipartimento di Biologia, Università di Pisa, Pisa, Italy
| | - Alessandro Saba
- Dipartimento di Patologia Chirurgica, Medica, Molecolare e dell’Area Critica, Università di Pisa, Pisa, Italy
| | | | - Claudio Varotto
- Department of Biodiversity and Molecular Ecology, Research and Innovation Centre, Fondazione Edmund Mach, San Michele all’Adige, Trento, Italy
- Correspondence: ,
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18
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Whitt L, Ricachenevsky FK, Ziegler GZ, Clemens S, Walker E, Maathuis FJM, Kear P, Baxter I. A curated list of genes that affect the plant ionome. PLANT DIRECT 2020; 4:e00272. [PMID: 33103043 PMCID: PMC7576880 DOI: 10.1002/pld3.272] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Revised: 08/26/2020] [Accepted: 08/28/2020] [Indexed: 05/07/2023]
Abstract
Understanding the mechanisms underlying plants' adaptation to their environment will require knowledge of the genes and alleles underlying elemental composition. Modern genetics is capable of quickly, and cheaply indicating which regions of DNA are associated with particular phenotypes in question, but most genes remain poorly annotated, hindering the identification of candidate genes. To help identify candidate genes underlying elemental accumulations, we have created the known ionome gene (KIG) list: a curated collection of genes experimentally shown to change uptake, accumulation, and distribution of elements. We have also created an automated computational pipeline to generate lists of KIG orthologs in other plant species using the PhytoMine database. The current version of KIG consists of 176 known genes covering 5 species, 23 elements, and their 1588 orthologs in 10 species. Analysis of the known genes demonstrated that most were identified in the model plant Arabidopsis thaliana, and that transporter coding genes and genes altering the accumulation of iron and zinc are overrepresented in the current list.
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Affiliation(s)
- Lauren Whitt
- Donald Danforth Plant Science CenterSaint LouisMOUSA
| | - Felipe Klein Ricachenevsky
- Departamento de Botânica Programa de Pós‐Graduação em Biologia Celular e MolecularUniversidade Federal do Rio Grande do SulPorto AlegreBrazil
| | | | | | | | | | | | - Ivan Baxter
- Donald Danforth Plant Science CenterSaint LouisMOUSA
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19
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Su H, Zou T, Lin R, Zheng J, Jian S, Zhang M. Characterization of a phytochelatin synthase gene from Ipomoea pes-caprae involved in cadmium tolerance and accumulation in yeast and plants. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2020; 155:743-755. [PMID: 32866789 DOI: 10.1016/j.plaphy.2020.08.012] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Revised: 08/04/2020] [Accepted: 08/04/2020] [Indexed: 05/21/2023]
Abstract
Phytochelatin synthases (PCSs) play a crucial part in heavy metal tolerance in plants via the synthesis of phytochelatins (PCs), which can chelate heavy metals (HMs) in the vacuole and decrease cell damage. Plant PCSs are commonly designated as key genes for phytoremediation. In this study, we identified a PCS gene (IpPCS1) from Ipomoea pes-caprae and investigated its role in regulating cadmium (Cd) tolerance and accumulation. The expression of a truncated IpPCS1t in yeast could complement the Cd-sensitive phenotype of the ycf1Δ mutant strain, as well as improve the Cd tolerance of the wild-type yeast strain, while promoting Cd accumulation in the yeast cells. The expression of IpPCS1 was induced in I. pes-caprae plants under Cd treatment. Compared with IpPCS1, the lack of a C-terminal in IpPCS1t did not affect its Cd tolerance, but might restrict the zinc (Zn) detoxification in yeast. The overexpression of IpPCS1t in Arabidopsis could improve the Cd tolerance slightly and had little impact on Cd accumulation in transgenic plant. Our results indicated that IpPCS1 has certain potential application value in Cd tolerance and detoxification, therefore provides a useful genetic resource for enhancing Cd tolerance and improving the Cd phytoremediation capacity of plants or organisms. In addition, our research is the first time to discover a new possible Cd activation site in the C-terminal of IpPCS1.
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Affiliation(s)
- Huaxiang Su
- Guangdong Provincial Key Laboratory of Applied Botany & Key Laboratory of South China Agricultural Plant Molecular Analysis and Genetic Improvement, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, 510650, China; College of Life Sciences, University of the Chinese Academy of Sciences, Beijing, 100039, China
| | - Tao Zou
- Guangdong Provincial Key Laboratory of Applied Botany & Key Laboratory of South China Agricultural Plant Molecular Analysis and Genetic Improvement, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, 510650, China; College of Life Sciences, University of the Chinese Academy of Sciences, Beijing, 100039, China
| | - Ruoyi Lin
- Guangdong Provincial Key Laboratory of Applied Botany & Key Laboratory of South China Agricultural Plant Molecular Analysis and Genetic Improvement, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, 510650, China; College of Life Sciences, University of the Chinese Academy of Sciences, Beijing, 100039, China
| | - Jiexuan Zheng
- Guangdong Provincial Key Laboratory of Applied Botany & Key Laboratory of South China Agricultural Plant Molecular Analysis and Genetic Improvement, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, 510650, China; College of Life Sciences, University of the Chinese Academy of Sciences, Beijing, 100039, China
| | - Shuguang Jian
- Guangdong Provincial Key Laboratory of Applied Botany & Key Laboratory of South China Agricultural Plant Molecular Analysis and Genetic Improvement, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, 510650, China; Center of Economic Botany, Core Botanical Gardens, Chinese Academy of Sciences, Guangzhou, 510650, China
| | - Mei Zhang
- Guangdong Provincial Key Laboratory of Applied Botany & Key Laboratory of South China Agricultural Plant Molecular Analysis and Genetic Improvement, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, 510650, China; Center of Economic Botany, Core Botanical Gardens, Chinese Academy of Sciences, Guangzhou, 510650, China.
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20
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Weber M, Beyene B, Nagler N, Herfert J, Schempp S, Klecker M, Clemens S. A mutation in the essential and widely conserved DAMAGED DNA BINDING1-Cullin4 ASSOCIATED FACTOR gene OZS3 causes hypersensitivity to zinc excess, cold and UV stress in Arabidopsis thaliana. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2020; 103:995-1009. [PMID: 32314481 DOI: 10.1111/tpj.14779] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2018] [Revised: 02/18/2020] [Accepted: 04/01/2020] [Indexed: 05/28/2023]
Abstract
The overly zinc sensitive Arabidopsis thaliana mutant ozs3 shows reduced growth of the primary root, which is exacerbated by an excess specifically of Zn ions. In addition, ozs3 plants display various subtle developmental phenotypes, such as longer petioles and early flowering. Also, ozs3 seedlings are completely but reversibly growth-arrested when shifted to 4°C. The causal mutation was mapped to a gene encoding a putative substrate-recognition receptor of cullin4 E3 ligases. OZS3 orthologous genes can be found in almost all eukaryotic genomes. Most species from Schizosaccharomyces pombe to Homo sapiens, and including A. thaliana, possess one ortholog. No functional data are available for these genes in any of the multicellular model systems. CRISPR-Cas9-mediated knockout demonstrated that a complete loss of OZS3 function is embryo-lethal, indicating essentiality of OZS3 and its orthologs. The OZS3 protein interacts with the adaptor protein DAMAGED DNA BINDING1 (DDB1) in the nucleus. Thus, it is indeed a member of the large yet poorly characterized family of DDB1-cullin4 associated factors in plants. Mutant phenotypes of ozs3 plants are apparently caused by the weakened DDB1-OZS3 interaction as a result of the exchange of a conserved amino acid near the conserved WDxR motif.
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Affiliation(s)
- Michael Weber
- Department of Plant Physiology, University of Bayreuth, Bayreuth, 95440, Germany
| | - Blen Beyene
- Department of Plant Physiology, University of Bayreuth, Bayreuth, 95440, Germany
| | - Nicole Nagler
- Department of Plant Physiology, University of Bayreuth, Bayreuth, 95440, Germany
| | - Jörn Herfert
- Department of Plant Physiology, University of Bayreuth, Bayreuth, 95440, Germany
| | - Stefanie Schempp
- Department of Plant Physiology, University of Bayreuth, Bayreuth, 95440, Germany
| | - Maria Klecker
- Department of Plant Physiology, University of Bayreuth, Bayreuth, 95440, Germany
| | - Stephan Clemens
- Department of Plant Physiology, University of Bayreuth, Bayreuth, 95440, Germany
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21
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Prado C, Chocobar-Ponce S, Pagano E, Prado F, Rosa M. Differential effects of Zn concentrations on Cr(VI) uptake by two Salvinia species: involvement of thiol compounds. INTERNATIONAL JOURNAL OF PHYTOREMEDIATION 2020; 23:10-17. [PMID: 32633546 DOI: 10.1080/15226514.2020.1786796] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Floating ferns of the genus Salvinia have great potential for phytoremediation of heavy metals. To date, the effect of essential metals on the accumulation and transport of toxic metals by aquatic ferns has not been suitably established. The aim of this study was to compare the ability of floating leaves of Salvinia minima and Salvinia rotundifolia species to accumulate Cr from Cr(VI solutions containing very low (0.02 mg L-1) and low (5 mg L-1) Zn concentrations. After 7-day metal-exposure period, results showed that Zn increased Cr accumulation in S. minima leaves whereas in S. rotundifolia decreased significantly. Contrarily Zn accumulation did not show great differences between species. This fact may indicate that Zn interfere Cr(VI) uptake by S. rotundifolia. Bioconcentration factor (BCF) and translocation factor (TF) were affected differently by Zn in both Salvinia species. Membrane stability index (MSI) of both Salvinia species was decreased significantly by 5 mg L-1 Zn concentration. Zn ions also increased hydrogen peroxide accumulation in fronds of Salvinia species. Total thiols (TT), non-protein thiols (NPT) and protein-bound thiols (PBT) were differentially affected by Cr(VI) and Zn ions. This study provides evidences on the involvement of different mechanisms against Cr(VI)/Zn toxicity in S. minima and S rotundifolia species.
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Affiliation(s)
- Carolina Prado
- Instituto de Bioprospección y Fisiología Vegetal (INBIOFIV), CONICET-UNT. Cátedra de Fisiología Vegetal, Facultad de Ciencias Naturales e IML, Universidad Nacional de Tucumán, Tucumán, Argentina
| | - Silvana Chocobar-Ponce
- Instituto de Bioprospección y Fisiología Vegetal (INBIOFIV), CONICET-UNT. Cátedra de Fisiología Vegetal, Facultad de Ciencias Naturales e IML, Universidad Nacional de Tucumán, Tucumán, Argentina
| | - Eduardo Pagano
- Consejo Nacional de Investigaciones Científicas y Técnicas, Instituto de Investigaciones en Biociencias Agrícolas y Ambientales (INBA), Facultad de Agronomía, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Fernando Prado
- Instituto de Bioprospección y Fisiología Vegetal (INBIOFIV), CONICET-UNT. Cátedra de Fisiología Vegetal, Facultad de Ciencias Naturales e IML, Universidad Nacional de Tucumán, Tucumán, Argentina
| | - Mariana Rosa
- Instituto de Bioprospección y Fisiología Vegetal (INBIOFIV), CONICET-UNT. Cátedra de Fisiología Vegetal, Facultad de Ciencias Naturales e IML, Universidad Nacional de Tucumán, Tucumán, Argentina
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Uraguchi S, Ohshiro Y, Otsuka Y, Tsukioka H, Yoneyama N, Sato H, Hirakawa M, Nakamura R, Takanezawa Y, Kiyono M. Selection of Agar Reagents for Medium Solidification Is a Critical Factor for Metal(loid) Sensitivity and Ionomic Profiles of Arabidopsis thaliana. FRONTIERS IN PLANT SCIENCE 2020; 11:503. [PMID: 32499794 PMCID: PMC7243937 DOI: 10.3389/fpls.2020.00503] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Accepted: 04/03/2020] [Indexed: 06/11/2023]
Abstract
For researchers in the plant metal field, the agar reagent used for the solid plate medium is a problematic factor because application of different agar types and even a different lot of the same agar type can mask the plant metal-related phenotypes and impair the reproducibility. In this study, we systematically assessed effects of different agar reagents on metal(loid) sensitivity and element accumulation of the Arabidopsis metal sensitive mutants. Three established mutants (cad1-3, cad1-6, and abcc1/2), and three different types of purified agar reagents (Type A, Type E, and Nacalai) with two independent batches for each reagent were subjected to the analyses. First, we found that element concentrations in the agar reagents largely varied among the agar types. Then the effects of agar reagents on the mutant metal(loid)-sensitivity were examined under As(III), Hg(II), Cd(II), and excess Zn(II) conditions. A significant variation of the mutant metal(loid)-sensitivity was observed among the different agar plates but the variation depended on the combination of metal(loid) stress and agar reagents. Briefly, the type-dependent variation was more evident under As(III) and Hg(II) than Cd(II) or excess Zn(II) conditions. A lot-dependent variation was also observed for Type A and Type E but not for Nacalai: hypersensitive phenotypes of cad1-3, cad1-6, and abcc1/2 under As(III) or Hg(II) treatments were diminished when different batches of the Type A or Type E agar types were used. We also found a significant variation of As and Hg accumulation in the wild-type and cad1-3. Plant As and Hg concentrations were remarkably higher and the difference between the genotypes was more evident when grown with Type A agar plates. We finally analyzed ionomic profiles in the plants exposed to As(III) stress. Agar-type specific ionomic changes in cad1-3 were more observed with the Type A plates than with the Nacalai plates. The presented results overall suggest that suitability of agar reagents for metal(loid)-related phenotyping depends on the experimental design, and an inappropriate selection of agar reagents can mask even very clear phenotypes of the established mutant like cad1-3. We also discuss perspectives on the agar problem in the plant metal study.
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García-García J, Sánchez-Thomas R, Saavedra E, Fernández-Velasco D, Romero-Romero S, Casanova-Figueroa K, Mendoza-Cózatl D, Moreno-Sánchez R. Mapping the metal-catalytic site of a zinc-activated phytochelatin synthase. ALGAL RES 2020. [DOI: 10.1016/j.algal.2020.101890] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
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Hayashi S, Tanikawa H, Kuramata M, Abe T, Ishikawa S. Domain exchange between Oryza sativa phytochelatin synthases reveals a region that determines responsiveness to arsenic and heavy metals. Biochem Biophys Res Commun 2020; 523:548-553. [PMID: 31932034 DOI: 10.1016/j.bbrc.2019.12.093] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Accepted: 12/20/2019] [Indexed: 02/07/2023]
Abstract
Phytochelatin synthases (PCSs) are activated by toxic metals/metalloids such as cadmium and arsenic and synthesize phytochelatins for detoxification of toxic elements. Rice (Oryza sativa L.) has two PCSs (OsPCS1 and OsPCS2), and we previously revealed that OsPCS1 has a higher responsiveness to arsenic than to cadmium, while OsPCS2 has a higher responsiveness to cadmium than to arsenic. Moreover, we found that the specific responsiveness of OsPCS1 to arsenic at rice nodes is a key factor in reducing arsenic in rice grains. However, the molecular characteristics of two PCSs in rice that contribute to the responsiveness to arsenic or heavy metals, including Cd, remain unclear. Here, we experimentally demonstrate that the C-terminal region in PCSs determines the responsiveness to arsenic or cadmium. We constructed chimeric proteins between OsPCS1 and OsPCS2 and performed an in vitro phytochelatin synthesis assay. A chimeric protein in which the 183 C-terminal amino acids of OsPCS2 were replaced with the 185 C-terminal amino acids of OsPCS1 showed higher responsiveness to arsenite than to cadmium, similar to OsPCS1. Contrary to expectations, mutations of cysteine residues that are unique to OsPCS1 or OsPCS2 had little influence on the responsiveness, although cysteine residues are reported to be representative of sites that interact with metals/metalloids. These results would enable the development of a breeding technology for reducing arsenic in rice grains by improving the arsenic-dependent activation of PCSs.
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Affiliation(s)
- Shimpei Hayashi
- Institute of Agrobiological Sciences, National Agriculture and Food Research Organization (NARO), Tsukuba, 305-8604, Japan
| | - Hachidai Tanikawa
- Institute for Agro-Environmental Sciences, NARO, Tsukuba, 305-8604, Japan
| | - Masato Kuramata
- Institute for Agro-Environmental Sciences, NARO, Tsukuba, 305-8604, Japan
| | - Tadashi Abe
- Institute for Agro-Environmental Sciences, NARO, Tsukuba, 305-8604, Japan
| | - Satoru Ishikawa
- Institute for Agro-Environmental Sciences, NARO, Tsukuba, 305-8604, Japan.
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25
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Clemens S. Metal ligands in micronutrient acquisition and homeostasis. PLANT, CELL & ENVIRONMENT 2019; 42:2902-2912. [PMID: 31350913 DOI: 10.1111/pce.13627] [Citation(s) in RCA: 61] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2019] [Revised: 07/22/2019] [Accepted: 07/23/2019] [Indexed: 05/09/2023]
Abstract
Acquisition and homeostasis of micronutrients such as iron (Fe) and zinc (Zn) pose specific challenges. Poor solubility and high reactivity require controlled synthesis and supply of ligands to complex these metals extracellularly and intracellularly. Cytosolic labile pools represent only a minute fraction of the total cellular content. Several low-molecular-weight ligands are known in plants, including sulfur ligands (cysteine and peptides), nitrogen/oxygen ligands (S-adenosyl-l-methionine-derived molecules and histidine), and oxygen ligands (phenolics and organic acids). Some ligands are secreted into the extracellular space and influence the phytoavailability of metal ions. A second principal function is the intracellular buffering of micronutrients as well as the facilitation of long-distance transport in xylem and phloem. Furthermore, low-molecular-weight ligands are involved in the storage of metals, predominantly in vacuoles. A detailed molecular understanding is hampered by technical limitations, in particular the difficulty to detect and quantify cellular metal-ligand complexes. More, but still too little, is known about ligand synthesis and the transport across membranes, either with or without a complexed metal. Metal ligands have an immediate impact on human well-being. Engineering metal ligand synthesis and distribution in crops has tremendous potential to improve the nutritional quality of food and to tackle major human health risks.
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Affiliation(s)
- Stephan Clemens
- Department of Plant Physiology and Bayreuth Center of Ecology and Environmental Research, University of Bayreuth, Universitätsstrasse 30, 95447, Bayreuth, Germany
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26
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Zlobin IE, Kartashov AV, Nosov AV, Fomenkov AA, Kuznetsov VV. The labile zinc pool in plant cells. FUNCTIONAL PLANT BIOLOGY : FPB 2019; 46:796-805. [PMID: 31072451 DOI: 10.1071/fp19064] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2019] [Accepted: 04/18/2019] [Indexed: 06/09/2023]
Abstract
Zinc is the most abundant and important transition metal in plants; however, the dynamic aspects of zinc homeostasis in plant cells are poorly understood. In this study we explored the pool of labile exchangeable zinc complexes in plant cells, and the potential influence of changes in intracellular zinc availability on cellular physiology. Work was performed on cultivated cell extracts of Arabidopsis thaliana (L.) Heynh. and Thellungiella salsuginea (Pall.) O.E. Schulz grown under control (3.48 µM Zn2+), 10-fold Zn excess or Zn starvation conditions. The free and labile Zn contents in the extracts were then determined by fluorimetric titration. We observed for the first time that plant cells contain micromolar concentrations of labile zinc complexes that account for a low percentage of the total zinc content. Labile zinc is mainly protein bound. Zn starvation inhibits cell proliferation and leads to the disappearance of the labile zinc pool, whereas Zn excess drastically increases the labile zinc pool. Free Zn2+ is buffered at picomolar concentrations in the intracellular milieu, and the increase in free Zn2+ concentrations to low nanomolar values clearly modulates enzyme activity by direct reversible binding. Such increases in free Zn2+ can be achieved by the substantial influx of additional zinc or by the oxidation of zinc-binding thiols. The observed features of the labile zinc pool in plant cells suggest it has a role in intracellular zinc trafficking and zinc signalling.
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Affiliation(s)
- Ilya E Zlobin
- Timiryazev Institute of Plant Physiology, Russian Academy of Sciences, 127276 Moscow, Russia; and Corresponding author.
| | - Alexander V Kartashov
- Timiryazev Institute of Plant Physiology, Russian Academy of Sciences, 127276 Moscow, Russia
| | - Alexander V Nosov
- Timiryazev Institute of Plant Physiology, Russian Academy of Sciences, 127276 Moscow, Russia
| | - Artem A Fomenkov
- Timiryazev Institute of Plant Physiology, Russian Academy of Sciences, 127276 Moscow, Russia
| | - Vladimir V Kuznetsov
- Timiryazev Institute of Plant Physiology, Russian Academy of Sciences, 127276 Moscow, Russia
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Wongkaew A, Nakamura SI, Suzui N, Yin YG, Ishii S, Kawachi N, Kojima K, Sekimoto H, Yokoyama T, Ohkama-Ohtsu N. Elevated glutathione synthesis in leaves contributes to zinc transport from roots to shoots in Arabidopsis. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2019; 283:416-423. [PMID: 31128713 DOI: 10.1016/j.plantsci.2018.11.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2018] [Revised: 10/23/2018] [Accepted: 11/10/2018] [Indexed: 06/09/2023]
Abstract
Glutathione (GSH) is a vital compound involved in several plant metabolic pathways. Our previous study indicated that foliar GSH application can increase zinc (Zn) levels in leafy vegetables. The objective of this study was to determine the mode of action of GSH as it relates to Zn transport from roots to shoots. Two types of transgenic Arabidopsis plants with genes for GSH synthesis, including StGCS-GS or AtGSH1 driven by the leaf-specific promoter of chlorophyll a/b-binding protein (pCab3) gene were generated. Both types of transgenic Arabidopsis plants showed significant increases in shoot GSH concentrations compared to the wild type (WT). Monitoring 65Zn movement by positron-emitting tracer imaging system (PETIS) analysis indicated that the 65Zn amount in the shoots of both types of transgenic Arabidopsis plants were higher than that in the WT. GSH concentration in phloem sap was increased significantly in WT with foliar applications of 10 mM GSH (WT-GSH), but not in transgenic Arabidopsis with elevated foliar GSH synthesis. Both types of transgenic Arabidopsis with elevated foliar GSH synthesis and WT-GSH exhibited increased shoot Zn concentrations and Zn translocation ratios. These results suggest that enhancement of endogenous foliar GSH synthesis and exogenous foliar GSH application affect root-to-shoot transport of Zn.
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Affiliation(s)
- Arunee Wongkaew
- United Graduate School of Agriculture, Tokyo University of Agriculture and Technology, Tokyo 183-8509, Japan
| | - Shin-Ichi Nakamura
- Department of Bioscience, Tokyo University of Agriculture, Tokyo 156-8502, Japan
| | - Nobuo Suzui
- Takasaki Advanced Radiation Research Institute, National Institutes for Quantum and Radiological Science and Technology, Gunma 370-1207, Japan
| | - Yong-Gen Yin
- Takasaki Advanced Radiation Research Institute, National Institutes for Quantum and Radiological Science and Technology, Gunma 370-1207, Japan
| | - Satomi Ishii
- Takasaki Advanced Radiation Research Institute, National Institutes for Quantum and Radiological Science and Technology, Gunma 370-1207, Japan
| | - Naoki Kawachi
- Takasaki Advanced Radiation Research Institute, National Institutes for Quantum and Radiological Science and Technology, Gunma 370-1207, Japan
| | - Katsuhiro Kojima
- Institute of Global Innovation Research, Tokyo University of Agriculture and Technology, Tokyo 183-8509, Japan
| | - Hitoshi Sekimoto
- Faculty of Agriculture, Utsunomiya University, Utsunomiya 321-8505, Japan
| | - Tadashi Yokoyama
- Institute of Agriculture, Tokyo University of Agriculture and Technology, Tokyo 183-8509, Japan
| | - Naoko Ohkama-Ohtsu
- Institute of Global Innovation Research, Tokyo University of Agriculture and Technology, Tokyo 183-8509, Japan; Institute of Agriculture, Tokyo University of Agriculture and Technology, Tokyo 183-8509, Japan.
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28
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Moustakas M, Bayçu G, Gevrek N, Moustaka J, Csatári I, Rognes SE. Spatiotemporal heterogeneity of photosystem II function during acclimation to zinc exposure and mineral nutrition changes in the hyperaccumulator Noccaea caerulescens. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2019; 26:6613-6624. [PMID: 30623337 DOI: 10.1007/s11356-019-04126-0] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/09/2018] [Accepted: 01/02/2019] [Indexed: 05/20/2023]
Abstract
We investigated changes in mineral nutrient uptake and translocation and photosystem II (PSII) functionality, in the hyperaccumulator Noccaea caerulescens after exposure to 800 μM Zn in hydroponic culture. Exposure to Zn inhibited the uptake of K, Mn, Cu, Ca, and Mg, while the uptake of Fe and Zn enhanced. Yet, Ca and Mg aboveground tissue concentrations remain unchanged while Cu increased significantly. In the present study, we provide new data on the mechanism of N. caerulescens acclimation to Zn exposure by elucidating the process of photosynthetic acclimation. A spatial heterogeneity in PSII functionality in N. caerulescens leaves exposed to Zn for 3 days was detected, while a threshold time of 4 days was needed for the activation of Zn detoxification mechanism(s) to decrease Zn toxicity and for the stomatal closure to decrease Zn supply at the severely affected leaf area. After 10-day exposure to Zn, the allocation of absorbed light energy in PSII under low light did not differ compared to control ones, while under high light, the quantum yield of non-regulated energy loss in PSII (ΦNO) was lower than the control, due to an efficient photoprotective mechanism. The chlorophyll fluorescence images of non-photochemical quenching (NPQ) and photochemical quenching (qp) clearly showed spatial and temporal heterogeneity in N. caerulescens exposure to Zn and provided further information on the particular leaf area that was most sensitive to heavy metal stress. We propose the use of chlorophyll fluorescence imaging, and in particular the redox state of the plastoquinone (PQ) pool that was found to display the highest spatiotemporal heterogeneity, as a sensitive bio-indicator to measure the environmental pressure by heavy metals on plants.
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Affiliation(s)
- Michael Moustakas
- Division of Botany, Department of Biology, Faculty of Science, Istanbul University, 34134, Istanbul, Turkey.
- Department of Botany, Aristotle University of Thessaloniki, 54124, Thessaloniki, Greece.
| | - Gülriz Bayçu
- Division of Botany, Department of Biology, Faculty of Science, Istanbul University, 34134, Istanbul, Turkey
| | - Nurbir Gevrek
- Division of Botany, Department of Biology, Faculty of Science, Istanbul University, 34134, Istanbul, Turkey
| | - Julietta Moustaka
- Department of Botany, Aristotle University of Thessaloniki, 54124, Thessaloniki, Greece
- Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, 1871, Frederiksberg C, Denmark
| | - István Csatári
- Division of Botany, Department of Biology, Faculty of Science, Istanbul University, 34134, Istanbul, Turkey
| | - Sven Erik Rognes
- Department of Biosciences, University of Oslo, 0316, Oslo, Norway
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29
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Adele NC, Ngwenya BT, Heal KV, Mosselmans JFW. Soil Bacteria Override Speciation Effects on Zinc Phytotoxicity in Zinc-Contaminated Soils. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2018; 52:3412-3421. [PMID: 29466659 DOI: 10.1021/acs.est.7b05094] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The effects of zinc (Zn) speciation on plant growth in Zn-contaminated soil in the presence of bacteria are unknown but are critical to our understanding of metal biodynamics in the rhizosphere where bacteria are abundant. A 6-week pot experiment investigated the effects of two plant growth promoting bacteria (PGPB), Rhizobium leguminosarum and Pseudomonas brassicacearum, on Zn accumulation and speciation in Brassica juncea grown in soil amended with 600 mg kg-1 elemental Zn as three Zn species: soluble ZnSO4 and nanoparticles of ZnO and ZnS. Measures of plant growth were higher across all Zn treatments inoculated with PGPB compared to uninoculated controls, but Zn species effects were not significant. Transmission electron microscopy identified dense particles in the epidermis and intracellular spaces in roots, suggesting Zn uptake in both dissolved and particulate forms. X-ray absorption near-edge structure (XANES) analysis of roots revealed differences in Zn speciation between treatments. Uninoculated plants exposed to ZnSO4 contained Zn predominantly in the form of Zn phytate (35%) and Zn polygalacturonate (30%), whereas Zn cysteine (57%) and Zn polygalacturonate (37%) dominated in roots exposed to ZnO nanoparticles. Inoculation with PGPB increased (>50%) the proportion of Zn cysteine under all Zn treatments, suggesting Zn coordination with cysteine as the predominant mechanism of Zn toxicity reduction by PGPB. Using this approach, we show, for the first time, that although speciation is important, the presence of rhizospheric bacteria completely overrides speciation effects such that most of the Zn in plant tissue exists as complexes other than the original form.
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Affiliation(s)
- Nyekachi C Adele
- School of GeoSciences , University of Edinburgh , Edinburgh , U.K
| | - Bryne T Ngwenya
- School of GeoSciences , University of Edinburgh , Edinburgh , U.K
| | - Kate V Heal
- School of GeoSciences , University of Edinburgh , Edinburgh , U.K
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30
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Uraguchi S, Sone Y, Ohta Y, Ohkama-Ohtsu N, Hofmann C, Hess N, Nakamura R, Takanezawa Y, Clemens S, Kiyono M. Identification of C-terminal Regions in Arabidopsis thaliana Phytochelatin Synthase 1 Specifically Involved in Activation by Arsenite. PLANT & CELL PHYSIOLOGY 2018; 59:500-509. [PMID: 29281059 DOI: 10.1093/pcp/pcx204] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2017] [Accepted: 12/16/2017] [Indexed: 05/16/2023]
Abstract
Phytochelatins (PCs) are major chelators of toxic elements including inorganic arsenic (As) in plant cells. Their synthesis confers tolerance and influences within-plant mobility. Previous studies had shown that various metal/metalloid ions differentially activate PC synthesis. Here we identified C-terminal parts involved in arsenite- [As(III)] dependent activation of AtPCS1, the primary Arabidopsis PC synthase. The T-DNA insertion in the AtPCS1 mutant cad1-6 causes a truncation in the C-terminal regulatory domain that differentially affects activation by cadmium (Cd) and zinc (Zn). Comparisons of cad1-6 with the AtPCS1 null mutant cad1-3 and the double mutant of tonoplast PC transporters abcc1/2 revealed As(III) hypersensitivity of cad1-6 equal to that of cad1-3. Both cad1-6 and cad1-3 showed increased As distribution to shoots compared with Col-0, whereas Zn accumulation in shoots was equally lower in cad1-6 and cad1-3. Supporting these phenotypes of cad1-6, PC accumulation in the As(III)-exposed plants were at trace level in both cad1-6 and cad1-3, suggesting that the truncated AtPCS1 of cad1-6 is defective in PCS activity in response to As(III). Analysis of a C-terminal deletion series of AtPCS1 using the PCS-deficient mutant of fission yeast suggested important regions within the C-terminal domain for As(III)-dependent PC synthesis, which were different from the regions previously suggested for Cd- or Zn-dependent activation. Interestingly, we identified a truncated variant more strongly activated than the wild-type protein. This variant could potentially be used as a tool to better restrict As mobility in plants.
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Affiliation(s)
- Shimpei Uraguchi
- Department of Public Health, School of Pharmacy, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo, 108-8641 Japan
| | - Yuka Sone
- Department of Public Health, School of Pharmacy, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo, 108-8641 Japan
| | - Yumika Ohta
- Department of Public Health, School of Pharmacy, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo, 108-8641 Japan
| | - Naoko Ohkama-Ohtsu
- Institute of Agriculture, Tokyo University of Agriculture and Technology, 3-5-8 Saiwaicho, Fuchu, Tokyo, 183-8509 Japan
| | - Christian Hofmann
- Department of Plant Physiology, University of Bayreuth, Universitätsstrasse 30, D-95440 Bayreuth, Germany
| | - Natalia Hess
- Department of Plant Physiology, University of Bayreuth, Universitätsstrasse 30, D-95440 Bayreuth, Germany
| | - Ryosuke Nakamura
- Department of Public Health, School of Pharmacy, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo, 108-8641 Japan
| | - Yasukazu Takanezawa
- Department of Public Health, School of Pharmacy, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo, 108-8641 Japan
| | - Stephan Clemens
- Department of Plant Physiology, University of Bayreuth, Universitätsstrasse 30, D-95440 Bayreuth, Germany
| | - Masako Kiyono
- Department of Public Health, School of Pharmacy, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo, 108-8641 Japan
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31
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García-García JD, Peña-Sanabria KA, Sánchez-Thomas R, Moreno-Sánchez R. Nickel accumulation by the green algae-like Euglena gracilis. JOURNAL OF HAZARDOUS MATERIALS 2018; 343:10-18. [PMID: 28938155 DOI: 10.1016/j.jhazmat.2017.09.008] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2017] [Revised: 07/11/2017] [Accepted: 09/05/2017] [Indexed: 06/07/2023]
Abstract
Nickel accumulation and nickel effects on cellular growth, respiration, photosynthesis, ascorbate peroxidase (APX) activity, and levels of thiols, histidine and phosphate-molecules were determined in Euglena gracilis. Cells incubated with 0.5-1mM NiCl2 showed impairment of O2 consumption, photosynthesis, Chl a+b content and APX activity whereas cellular integrity and viability were unaltered. Nickel accumulation was depressed by Mg2+ and Cu2+, while Ca2+, Co2+, Mn2+ and Zn2+ were innocuous. The growth half-inhibitory concentrations for Ni2+ in the culture medium supplemented with 2 or 0.2mM Mg2+ were 0.43 or 0.03mM Ni2+, respectively. Maximal nickel accumulation (1362mg nickel/Kg DW) was achieved in cells exposed to 1mM Ni2+ for 24h in the absence of Mg2+ and Cu2+; accumulated nickel was partially released after 72h. GSH polymers content increased or remained unchanged in cells exposed to 0.05-1mM Ni2+; however, GSH, cysteine, γ-glutamylcysteine, and phosphate-molecules all decreased after 72h. Histidine content increased in cells stressed with 0.05 and 0.5mM Ni2+ for 24h but not at longer times. It was concluded that E. gracilis can accumulate high nickel levels depending on the external Mg2+ and Cu2+ concentrations, in a process in which thiols, histidine and phosphate-molecules have a moderate contribution.
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Affiliation(s)
- J D García-García
- Departamento de Bioquímica, Instituto Nacional de Cardiología "Ignacio Chávez", México, D.F. 14080, México.
| | - K A Peña-Sanabria
- Departamento de Bioquímica, Instituto Nacional de Cardiología "Ignacio Chávez", México, D.F. 14080, México
| | - R Sánchez-Thomas
- Departamento de Bioquímica, Instituto Nacional de Cardiología "Ignacio Chávez", México, D.F. 14080, México
| | - R Moreno-Sánchez
- Departamento de Bioquímica, Instituto Nacional de Cardiología "Ignacio Chávez", México, D.F. 14080, México
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Itouga M, Hayatsu M, Sato M, Tsuboi Y, Kato Y, Toyooka K, Suzuki S, Nakatsuka S, Kawakami S, Kikuchi J, Sakakibara H. Protonema of the moss Funaria hygrometrica can function as a lead (Pb) adsorbent. PLoS One 2017; 12:e0189726. [PMID: 29261745 PMCID: PMC5738082 DOI: 10.1371/journal.pone.0189726] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2017] [Accepted: 11/30/2017] [Indexed: 12/18/2022] Open
Abstract
Water contamination by heavy metals from industrial activities is a serious environmental concern. To mitigate heavy metal toxicity and to recover heavy metals for recycling, biomaterials used in phytoremediation and bio-sorbent filtration have recently drawn renewed attention. The filamentous protonemal cells of the moss Funaria hygrometrica can hyperaccumulate lead (Pb) up to 74% of their dry weight when exposed to solutions containing divalent Pb. Energy-dispersive X-ray spectroscopy revealed that Pb is localized to the cell walls, endoplasmic reticulum-like membrane structures, and chloroplast thylakoids, suggesting that multiple Pb retention mechanisms are operating in living F. hygrometrica. The main Pb-accumulating compartment was the cell wall, and prepared cell-wall fractions could also adsorb Pb. Nuclear magnetic resonance analysis showed that polysaccharides composed of polygalacturonic acid and cellulose probably serve as the most effective Pb-binding components. The adsorption abilities were retained throughout a wide range of pH values, and bound Pb was not desorbed under conditions of high ionic strength. In addition, the moss is highly tolerant to Pb. These results suggest that the moss F. hygrometrica could be a useful tool for the mitigation of Pb-toxicity in wastewater.
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Affiliation(s)
- Misao Itouga
- RIKEN Center for Sustainable Resource Science, Tsurumi, Yokohama, Japan
| | - Manabu Hayatsu
- Department of Biological Sciences, Faculty of Science, and Research Institute for Integrated Science, Kanagawa University, Hiratsuka, Japan
| | - Mayuko Sato
- RIKEN Center for Sustainable Resource Science, Tsurumi, Yokohama, Japan
| | - Yuuri Tsuboi
- RIKEN Center for Sustainable Resource Science, Tsurumi, Yokohama, Japan
| | - Yukari Kato
- RIKEN Center for Sustainable Resource Science, Tsurumi, Yokohama, Japan
| | - Kiminori Toyooka
- RIKEN Center for Sustainable Resource Science, Tsurumi, Yokohama, Japan
| | - Suechika Suzuki
- Department of Biological Sciences, Faculty of Science, and Research Institute for Integrated Science, Kanagawa University, Hiratsuka, Japan
| | - Seiji Nakatsuka
- RIKEN Center for Sustainable Resource Science, Tsurumi, Yokohama, Japan.,DOWA Technology Co., Ltd., Chiyoda, Tokyo, Japan
| | | | - Jun Kikuchi
- RIKEN Center for Sustainable Resource Science, Tsurumi, Yokohama, Japan
| | - Hitoshi Sakakibara
- RIKEN Center for Sustainable Resource Science, Tsurumi, Yokohama, Japan.,Graduate School of Bioagricultural Sciences, Nagoya University, Chikusa, Nagoya, Japan
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33
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Uraguchi S, Tanaka N, Hofmann C, Abiko K, Ohkama-Ohtsu N, Weber M, Kamiya T, Sone Y, Nakamura R, Takanezawa Y, Kiyono M, Fujiwara T, Clemens S. Phytochelatin Synthase has Contrasting Effects on Cadmium and Arsenic Accumulation in Rice Grains. PLANT & CELL PHYSIOLOGY 2017; 58:1730-1742. [PMID: 29016913 PMCID: PMC5914395 DOI: 10.1093/pcp/pcx114] [Citation(s) in RCA: 58] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2017] [Accepted: 08/03/2017] [Indexed: 05/18/2023]
Abstract
Phytochelatin (PC) synthesis has been well demonstrated as a major metal tolerance mechanism in Arabidopsis thaliana, whereas its contribution to long-distance element transport especially in monocots remains elusive. Using rice as a cereal model, we examined physiological roles of Oryza sativa phytochelatin synthase 1 (OsPCS1) in the distribution and detoxification of arsenic (As) and cadmium (Cd), two toxic elements associated with major food safety concerns. First, we isolated four different transcript variants of OsPCS1 as well as one from OsPCS2. Quantitative real-time reverse transcription-PCR (RT-PCR) of each OsPCS transcript in rice seedlings suggested that expression of OsPCS1full, the longest OsPCS1 variant, was most abundant, followed by OsPCS2. Heterologous expression of OsPCS variants in PCS-deficient mutants of Schizosaccharomyces pombe and A. thaliana suggested that OsPCS1full possessed PCS activity in response to As(III) and Cd while the activity of other PCS variants was very low. To address physiological functions in toxic element tolerance and accumulation, two independent OsPCS1 mutant rice lines (a T-DNA and a Tos17 insertion line) were identified. The OsPCS1 mutants exhibited increased sensitivity to As(III) and Cd in hydroponic experiments, showing the importance of OsPCS1-dependent PC synthesis for rice As(III) and Cd tolerance. Elemental analyses of rice plants grown in soil with environmentally relevant As and Cd concentrations showed increased As accumulation and decreased Cd accumulation in grains of the T-DNA line. The Tos17 mutant also exhibited the reduced Cd accumulation phenotype. These contrasting effects on As and Cd distribution to grains suggest the existence of at least partially distinct PC-dependent pathways for As and Cd.
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Affiliation(s)
- Shimpei Uraguchi
- Department of Public Health, School of Pharmacy, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo 108-8641, Japan
- Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan
- Department of Plant Physiology, University of Bayreuth, Universitätsstrasse 30, D-95440 Bayreuth, Germany
| | - Nobuhiro Tanaka
- Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Christian Hofmann
- Department of Plant Physiology, University of Bayreuth, Universitätsstrasse 30, D-95440 Bayreuth, Germany
| | - Kaho Abiko
- Department of Public Health, School of Pharmacy, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo 108-8641, Japan
| | - Naoko Ohkama-Ohtsu
- Institute of Agricultural Science, Tokyo University of Agriculture and Technology, 3-5-8 Saiwaicho, Fuchu, Tokyo 183-8509, Japan
| | - Michael Weber
- Department of Plant Physiology, University of Bayreuth, Universitätsstrasse 30, D-95440 Bayreuth, Germany
| | - Takehiro Kamiya
- Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Yuka Sone
- Department of Public Health, School of Pharmacy, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo 108-8641, Japan
| | - Ryosuke Nakamura
- Department of Public Health, School of Pharmacy, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo 108-8641, Japan
| | - Yasukazu Takanezawa
- Department of Public Health, School of Pharmacy, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo 108-8641, Japan
| | - Masako Kiyono
- Department of Public Health, School of Pharmacy, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo 108-8641, Japan
| | - Toru Fujiwara
- Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Stephan Clemens
- Department of Plant Physiology, University of Bayreuth, Universitätsstrasse 30, D-95440 Bayreuth, Germany
- Corresponding author: E-mail, ; Fax, +49-921-552642
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Natural variation in Arabidopsis thaliana Cd responses and the detection of quantitative trait loci affecting Cd tolerance. Sci Rep 2017. [PMID: 28623252 PMCID: PMC5473843 DOI: 10.1038/s41598-017-03540-z] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Metal tolerance is often a result of metal storage or distribution. Thus, with the goal of advancing the molecular understanding of such metal homeostatic mechanisms, natural variation of metal tolerance in Arabidopsis thaliana was investigated. Substantial variation exists in tolerance of excess copper (Cu), zinc (Zn) and cadmium (Cd). Two accessions, Col-0 and Bur-0, and a recombinant inbred line (RIL) population derived from these parents were chosen for further analysis of Cd and Zn tolerance variation, which is evident at different plant ages in various experimental systems and appears to be genetically linked. Three QTLs, explaining in total nearly 50% of the variation in Cd tolerance, were mapped. The one obvious candidate gene in the mapped intervals, HMA3, is unlikely to contribute to the variation. In order to identify additional candidate genes the Cd responses of Col-0 and Bur-0 were compared at the transcriptome level. The sustained common Cd response of the two accessions was dominated by processes implicated in plant pathogen defense. Accession-specific differences suggested a more efficient activation of acclimative responses as underlying the higher Cd tolerance of Bur-0. The second hypothesis derived from the physiological characterization of the accessions is a reduced Cd accumulation in Bur-0.
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