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Ferrari M, Marieschi M, Cozza R, Torelli A. Phytochelatin Synthase: An In Silico Comparative Analysis in Cyanobacteria and Eukaryotic Microalgae. PLANTS (BASEL, SWITZERLAND) 2024; 13:2165. [PMID: 39124283 PMCID: PMC11314372 DOI: 10.3390/plants13152165] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2024] [Revised: 07/09/2024] [Accepted: 08/01/2024] [Indexed: 08/12/2024]
Abstract
Phytochelatins (PCs) are small cysteine-rich peptides involved in metal detoxification, not genetically encoded but enzymatically synthesized by phytochelatin synthases (PCSs) starting from glutathione. The constitutive PCS expression even in the absence of metal contamination, the wide phylogenetic distribution and the similarity between PCSs and the papain-type cysteine protease catalytic domain suggest a wide range of functions for PCSs. These proteins, widely studied in land plants, have not been fully analyzed in algae and cyanobacteria, although these organisms are the first to cope with heavy-metal stress in aquatic environments and can be exploited for phytoremediation. To fill this gap, we compared the features of the PCS proteins of different cyanobacterial and algal taxa by phylogenetic linkage. The analyzed sequences fall into two main, already known groups of PCS-like proteins. Contrary to previous assumptions, they are not classed as prokaryotic and eukaryotic sequences, but rather as sequences characterized by the alternative presence of asparagine and aspartic/glutamic acid residues in proximity of the catalytic cysteine. The presence of these enzymes with peculiar features suggests differences in their post-translational regulation related to cell/environmental requirements or different cell functions rather than to differences due to their belonging to different phylogenetic taxa.
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Affiliation(s)
- Michele Ferrari
- Department of Biology, Ecology and Earth Science, University of Calabria, Arcavacata di Rende, 87036 Cosenza, Italy; (M.F.); (R.C.)
| | - Matteo Marieschi
- Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Viale delle Scienze 11/A, 43124 Parma, Italy;
| | - Radiana Cozza
- Department of Biology, Ecology and Earth Science, University of Calabria, Arcavacata di Rende, 87036 Cosenza, Italy; (M.F.); (R.C.)
| | - Anna Torelli
- Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Viale delle Scienze 11/A, 43124 Parma, Italy;
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Emamverdian A, Ding Y, Hasanuzzaman M, Barker J, Liu G, Li Y, Mokhberdoran F. Insight into the biochemical and physiological mechanisms of nanoparticles-induced arsenic tolerance in bamboo. FRONTIERS IN PLANT SCIENCE 2023; 14:1121886. [PMID: 37063222 PMCID: PMC10102603 DOI: 10.3389/fpls.2023.1121886] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Accepted: 03/09/2023] [Indexed: 06/19/2023]
Abstract
INTRODUCTION Arsenic (As) contamination in soil, sediments, and water poses a significant threat to the growth of bamboo plants. However, nanoparticles with high metal absorbance capacity can play a key role in the reduction of heavy metals toxicity in plants as well as maintaining their growth under toxicity. METHODS Hence, an in vitro experiment was conducted to determine the influence of three types of nanoparticles: 150 µM silicon nanoparticles (SiO2 NPs), 150 µM titanium nanoparticles (TiO2 NPs), and 150 µM zinc oxide nanoparticles (ZnO NPs) on As (150 µM and 250 µM) tolerance enhancement of a one-year-old bamboo species (Pleioblastus pygmaeus). RESULTS AND DISCUSSION The results showed that while As at 150 µM and 250 µM significantly disrupted the plant growth by excessive generation of reactive oxygen species (ROS) components, and inducing cell membrane peroxidation, the addition of NPs increased both enzymatic and non-enzymatic antioxidant activities, upregulated glyoxalase defense system, and improved gas exchange parameters and photosynthetic pigments content, leading to the enhanced plant shoot and root dry weight. These were achieved by lowering levels of ROS, electrolyte leakage (EL), malondialdehyde (MDA), hydrogen peroxide (H2O2) and the superoxide radical ( O 2 • - ), as well as decreasing As accumulation in the plant organs. Thus, it might be concluded that ZnO NPs, SiO2NPs, and TiO2NPS alone or in combination can significantly increase the bamboo plant tolerance to As toxicity via key mechanisms, including induction of various antioxidants and glyoxalase defense systems, scavenging of ROS and methylglyoxal (MG), increasing phytochelatins production, reduction of As accumulation and translocation, and improving photosynthetic pigments under As toxicity. Additionally, the results showed that the combined application of 150 µM ZnO NPs, SiO2 NPs, and TiO2 NPs had the greatest effect on enhancing the plant tolerance to As at 150 µM and 250 µM.
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Affiliation(s)
- Abolghassem Emamverdian
- Co-Innovation Center for Sustainable Forestry in Southern China, Nanjing Forestry University, Nanjing, China
- Bamboo Research Institute, Nanjing Forestry University, Nanjing, China
| | - Yulong Ding
- Co-Innovation Center for Sustainable Forestry in Southern China, Nanjing Forestry University, Nanjing, China
- Bamboo Research Institute, Nanjing Forestry University, Nanjing, China
| | - Mirza Hasanuzzaman
- Department of Agronomy, Faculty of Agriculture, Sher-e-Bangla Agricultural University, Dhaka, Bangladesh
| | - James Barker
- School of Life Sciences, Pharmacy and Chemistry, Kingston University, Kingston-upon-Thames, United Kingdom
| | - Guohua Liu
- Co-Innovation Center for Sustainable Forestry in Southern China, Nanjing Forestry University, Nanjing, China
- Bamboo Research Institute, Nanjing Forestry University, Nanjing, China
| | - Yang Li
- Department of Mathematical Sciences, Florida Atlantic University, Boca Raton, FL, United States
| | - Farzad Mokhberdoran
- Co-Innovation Center for Sustainable Forestry in Southern China, Nanjing Forestry University, Nanjing, China
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Khanna K, Kohli SK, Ohri P, Bhardwaj R, Ahmad P. Agroecotoxicological Aspect of Cd in Soil–Plant System: Uptake, Translocation and Amelioration Strategies. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2022; 29:30908-30934. [PMID: 0 DOI: 10.1007/s11356-021-18232-5] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Accepted: 12/16/2021] [Indexed: 05/27/2023]
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Deckers J, Hendrix S, Prinsen E, Vangronsveld J, Cuypers A. Glutathione Is Required for the Early Alert Response and Subsequent Acclimation in Cadmium-Exposed Arabidopsis thaliana Plants. Antioxidants (Basel) 2021; 11:6. [PMID: 35052510 PMCID: PMC8773091 DOI: 10.3390/antiox11010006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Revised: 12/13/2021] [Accepted: 12/14/2021] [Indexed: 11/16/2022] Open
Abstract
Pollution by cadmium (Cd) is a worldwide problem, posing risks to human health and impacting crop yield and quality. Cadmium-induced phytotoxicity arises from an imbalance between antioxidants and pro-oxidants in favour of the latter. The Cd-induced depletion of the major antioxidant glutathione (GSH) strongly contributes to this imbalance. Rather than being merely an adverse effect of Cd exposure, the rapid depletion of root GSH levels was proposed to serve as an alert response. This alarm phase is crucial for an optimal stress response, which defines acclimation later on. To obtain a better understanding on the importance of GSH in the course of these responses and how these are defined by the rapid GSH depletion, analyses were performed in the GSH-deficient cadmium-sensitive 2-1 (cad2-1) mutant. Cadmium-induced root and leaf responses related to oxidative challenge, hydrogen peroxide (H2O2), GSH, ethylene, and 1-aminocyclopropane-1-carboxylic acid (ACC) were compared between wild-type (WT) and mutant Arabidopsis thaliana plants. Although the cad2-1 mutant has significantly lower GSH levels, root GSH depletion still occurred, suggesting that the chelating capacity of GSH is prioritised over its antioxidative function. We demonstrated that responses related to GSH metabolism and ACC production were accelerated in mutant roots and that stress persisted due to suboptimal acclimation. In general, the redox imbalance in cad2-1 mutant plants and the lack of proper transient ethylene signalling contributed to this suboptimal acclimation, resulting in a more pronounced Cd effect.
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Affiliation(s)
- Jana Deckers
- Centre for Environmental Sciences, Hasselt University, Agoralaan Building D, 3590 Diepenbeek, Belgium; (J.D.); (S.H.); (J.V.)
| | - Sophie Hendrix
- Centre for Environmental Sciences, Hasselt University, Agoralaan Building D, 3590 Diepenbeek, Belgium; (J.D.); (S.H.); (J.V.)
- Institute of Crop Science and Resource Conservation (INRES), University of Bonn, 53113 Bonn, Germany
| | - Els Prinsen
- Department of Biology, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerpen, Belgium;
| | - Jaco Vangronsveld
- Centre for Environmental Sciences, Hasselt University, Agoralaan Building D, 3590 Diepenbeek, Belgium; (J.D.); (S.H.); (J.V.)
| | - Ann Cuypers
- Centre for Environmental Sciences, Hasselt University, Agoralaan Building D, 3590 Diepenbeek, Belgium; (J.D.); (S.H.); (J.V.)
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Wu X, Tian H, Li L, Guan C, Zhang Z. Higher Cd-accumulating oilseed rape has stronger Cd tolerance due to stronger Cd fixation in pectin and hemicellulose and higher Cd chelation. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2021; 285:117218. [PMID: 33933876 DOI: 10.1016/j.envpol.2021.117218] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2021] [Revised: 04/19/2021] [Accepted: 04/20/2021] [Indexed: 06/12/2023]
Abstract
Oilseed rape (Brassica napus) has potential as a hyperaccumulator in the phytoremediation of cadmium (Cd)-contaminated soils. Oilseed rape varieties with higher Cd accumulation ability and Cd tolerance are ideal candidates for the hyperaccumulation of excess Cd. To explore the physiological and molecular mechanisms underlying Cd tolerance and high Cd accumulation in oilseed rape leaves, we examined two genotypes, "BN067" (Cd-sensitive with lower Cd accumulation in leaves) and "BN06" (Cd-tolerant with higher Cd accumulation in leaves). We characterized the physiological morphology, structure, subcellular distribution of Cd, cell wall components, cell chelates, and the transcriptional levels of the related genes. Greater Cd accumulation was observed in the cell walls and vacuoles of Cd-tolerant leaves, reducing Cd toxicity to the lamellar structure of the chloroplast thylakoid and leaf stomata. Higher expression of PMEs genes and lower expression of pectin methylesterase inhibitors (PMEI) genes improved pectin methylesterase (PME) activity in leaves of Cd-tolerant genotype. Stronger demethylation of pectin along with higher pectin and hemicellulose levels induced by lower pectinase and hemicellulose activities in the leaves of the Cd-tolerant genotype, resulting in higher Cd retention in the cell walls. Under Cd toxicity, higher Cd sequestration within the vacuoles of Cd-tolerant leaves was closely related to greater accumulation of Cd chelates with stronger biosynthesis in protoplasts. The results highlight the importance of using hyperaccumulation by plants to remediate our environment, and also provide a theoretical basis for the development of Cd-tolerant varieties.
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Affiliation(s)
- Xiuwen Wu
- College of Resources and Environmental Sciences, Qingdao Agricultural University, Qingdao, China.
| | - Hui Tian
- College of Resources and Environmental Sciences, Qingdao Agricultural University, Qingdao, China; Southern Regional Collaborative Innovation Center for Grain and Oil Crops in China, College of Resources and Environmental Sciences, Hunan Agricultural University, Changsha, China
| | - Li Li
- Southern Regional Collaborative Innovation Center for Grain and Oil Crops in China, College of Resources and Environmental Sciences, Hunan Agricultural University, Changsha, China
| | - Chunyun Guan
- National Center of Oilseed Crops Improvement, Hunan Branch, Changsha, China
| | - Zhenhua Zhang
- Southern Regional Collaborative Innovation Center for Grain and Oil Crops in China, College of Resources and Environmental Sciences, Hunan Agricultural University, Changsha, China.
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Lu M, Yu S, Lian J, Wang Q, He Z, Feng Y, Yang X. Physiological and metabolomics responses of two wheat (Triticum aestivum L.) genotypes differing in grain cadmium accumulation. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 769:145345. [PMID: 33736242 DOI: 10.1016/j.scitotenv.2021.145345] [Citation(s) in RCA: 41] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2020] [Revised: 01/12/2021] [Accepted: 01/17/2021] [Indexed: 05/12/2023]
Abstract
To reduce cadmium (Cd) pollution of food chains, screening and breeding of low-Cd-accumulating genotypes have received increasing attention. However, the mechanisms involving Cd tolerance and accumulation are not fully understood. Here, we investigated the physiological responses and metabolomics profiling on two wheat (Triticum aestivum L.) genotypes, a low-Cd-accumulating genotype in grains (Aikang58, AK58) and a high-Cd-accumulating genotype in grains (Zhenmai10, ZM10), in hydroponic culture treated without/with Cd for 7 days. The results showed that AK58 was a Cd tolerant genotype with higher capacity of antioxidant systems in root. In addition, the concentrations of Cd bound to root cell walls were higher in AK58 than ZM10, of which pectin and hemicellulose played important roles in Cd binding. Moreover, subcellular distribution manifested that Cd sequestrated in the vacuoles was another tolerance mechanism in AK58. Simultaneously, metabolomics profiling showed that, in AK58, phenylalanine metabolism, alanine, aspartate and glutamate metabolism, isoquinoline alkaloid biosynthesis, arginine and proline metabolism, arginine biosynthesis and glyoxylate and dicarboxylate metabolism are highly related to antioxidant defense system, cell wall biosynthesis and metabolisms of phytochelatins together with other organic ligands, playing crucial roles in Cd tolerance and Cd fixation mechanisms in roots. These novel findings should be useful for molecular assisted screening and breeding of low Cd-accumulating genotypes for wheat crop.
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Affiliation(s)
- Min Lu
- Key Laboratory of Environmental Remediation and Ecosystem Health, Ministry of Education (MOE), College of Environmental and Resources Sciences, Zhejiang University, Hangzhou 310058, PR China
| | - Song Yu
- Key Laboratory of Environmental Remediation and Ecosystem Health, Ministry of Education (MOE), College of Environmental and Resources Sciences, Zhejiang University, Hangzhou 310058, PR China
| | - Jiapan Lian
- Key Laboratory of Environmental Remediation and Ecosystem Health, Ministry of Education (MOE), College of Environmental and Resources Sciences, Zhejiang University, Hangzhou 310058, PR China
| | - Qiong Wang
- Key Laboratory of Environmental Remediation and Ecosystem Health, Ministry of Education (MOE), College of Environmental and Resources Sciences, Zhejiang University, Hangzhou 310058, PR China
| | - Zhenli He
- University of Florida, Institute of Food and Agricultural Sciences, Department of Soil and Water Sciences, Indian River Research and Education Center, Fort Pierce, FL 34945, United States
| | - Ying Feng
- Key Laboratory of Environmental Remediation and Ecosystem Health, Ministry of Education (MOE), College of Environmental and Resources Sciences, Zhejiang University, Hangzhou 310058, PR China
| | - Xiaoe Yang
- Key Laboratory of Environmental Remediation and Ecosystem Health, Ministry of Education (MOE), College of Environmental and Resources Sciences, Zhejiang University, Hangzhou 310058, PR China.
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Zhu T, Li L, Duan Q, Liu X, Chen M. Progress in our understanding of plant responses to the stress of heavy metal cadmium. PLANT SIGNALING & BEHAVIOR 2021; 16:1836884. [PMID: 33084518 PMCID: PMC7781755 DOI: 10.1080/15592324.2020.1836884] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2020] [Revised: 10/09/2020] [Accepted: 10/11/2020] [Indexed: 05/30/2023]
Abstract
Heavy metal pollution is a major environmental stress affecting plant growth and development. The heavy metal cadmium inhibits various physiological processes in plants, including seed germination and seedling growth, photosynthesis, and antioxidation. Extensive research has been conducted on the toxic effects of Cd2+ on plants and the mechanisms of Cd2+ tolerance. Here, we review recent advancements in our understanding of the absorption, transport, and accumulation of Cd2+ in plants and the mechanisms of Cd2+ tolerance.
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Affiliation(s)
- Tingting Zhu
- Shandong Provincial Key Laboratory of Plant Stress Research, College of Life Science, Shandong Normal University, Shandong, PR China
| | - Lingyu Li
- Shandong Provincial Key Laboratory of Plant Stress Research, College of Life Science, Shandong Normal University, Shandong, PR China
| | - Qixin Duan
- Shandong Provincial Key Laboratory of Plant Stress Research, College of Life Science, Shandong Normal University, Shandong, PR China
| | - Xiuling Liu
- Shandong Provincial Key Laboratory of Plant Stress Research, College of Life Science, Shandong Normal University, Shandong, PR China
| | - Min Chen
- Shandong Provincial Key Laboratory of Plant Stress Research, College of Life Science, Shandong Normal University, Shandong, PR China
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9
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Zhang ZH, Zhou T, Tang TJ, Song HX, Guan CY, Huang JY, Hua YP. A multiomics approach reveals the pivotal role of subcellular reallocation in determining rapeseed resistance to cadmium toxicity. JOURNAL OF EXPERIMENTAL BOTANY 2019; 70:5437-5455. [PMID: 31232451 PMCID: PMC6793439 DOI: 10.1093/jxb/erz295] [Citation(s) in RCA: 59] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2018] [Accepted: 06/13/2019] [Indexed: 05/04/2023]
Abstract
Oilseed rape (Brassica napus) has great potential for phytoremediation of cadmium (Cd)-polluted soils due to its large plant biomass production and strong metal accumulation. Enhanced plant Cd resistance (PCR) is a crucial prerequisite for phytoremediation through hyper-accumulation of excess Cd. However, the complexity of the allotetraploid genome of rapeseed hinders our understanding of PCR. To explore rapeseed Cd-resistance mechanisms, we examined two genotypes, 'ZS11' (Cd-resistant) and 'W10' (Cd-sensitive), that exhibit contrasting PCR while having similar tissue Cd concentrations, and characterized their different fingerprints in terms of plant morphophysiology (electron microscopy), ion abundance (inductively coupled plasma mass spectrometry), DNA variation (whole-genome resequencing), transcriptomics (high-throughput mRNA sequencing), and metabolomics (ultra-high performance liquid chromatography-mass spectrometry). Fine isolation of cell components combined with ionomics revealed that more Cd accumulated in the shoot vacuoles and root pectins of the resistant genotype than in the sensitive one. Genome and transcriptome sequencing identified numerous DNA variants and differentially expressed genes involved in pectin modification, ion binding, and compartmentalization. Transcriptomics-assisted gene co-expression networks characterized BnaCn.ABCC3 and BnaA8.PME3 as the central members involved in the determination of rapeseed PCR. High-resolution metabolic profiles revealed greater accumulation of shoot Cd chelates, and stronger biosynthesis and higher demethylation of root pectins in the resistant genotype than in the sensitive one. Our comprehensive examination using a multiomics approach has greatly improved our understanding of the role of subcellular reallocation of Cd in the determination of PCR.
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Affiliation(s)
- Zhen-Hua Zhang
- Southern Regional Collaborative Innovation Center for Grain and Oil Crops in China, College of Resources and Environmental Sciences, Hunan Agricultural University, Changsha, China
| | - Ting Zhou
- Southern Regional Collaborative Innovation Center for Grain and Oil Crops in China, College of Resources and Environmental Sciences, Hunan Agricultural University, Changsha, China
| | - Tian-Jiao Tang
- Southern Regional Collaborative Innovation Center for Grain and Oil Crops in China, College of Resources and Environmental Sciences, Hunan Agricultural University, Changsha, China
| | - Hai-Xing Song
- Southern Regional Collaborative Innovation Center for Grain and Oil Crops in China, College of Resources and Environmental Sciences, Hunan Agricultural University, Changsha, China
| | - Chun-Yun Guan
- National Center of Oilseed Crop Improvement, Hunan Branch, Changsha, China
| | - Jin-Yong Huang
- School of Agricultural Sciences, Zhengzhou University, Zhengzhou, China
| | - Ying-Peng Hua
- Southern Regional Collaborative Innovation Center for Grain and Oil Crops in China, College of Resources and Environmental Sciences, Hunan Agricultural University, Changsha, China
- Correspondence:
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Zhang D, Tang D, Yamamoto T, Kato Y, Horiuchi S, Ogawa S, Yoshimura E, Suzuki M. Improving biosynthesis of Au Pd core-shell nanoparticles through Escherichia coli with the assistance of phytochelatin for catalytic enhanced chemiluminescence and benzyl alcohol oxidation. J Inorg Biochem 2019; 199:110795. [DOI: 10.1016/j.jinorgbio.2019.110795] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2019] [Revised: 07/25/2019] [Accepted: 07/31/2019] [Indexed: 01/13/2023]
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Enhanced biosynthesis of CdS nanoparticles through Arabidopsis thaliana phytochelatin synthase-modified Escherichia coli with fluorescence effect in detection of pyrogallol and gallic acid. Talanta 2019; 195:447-455. [DOI: 10.1016/j.talanta.2018.11.092] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2018] [Revised: 11/23/2018] [Accepted: 11/24/2018] [Indexed: 12/13/2022]
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Shahid M, Niazi NK, Khalid S, Murtaza B, Bibi I, Rashid MI. A critical review of selenium biogeochemical behavior in soil-plant system with an inference to human health. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2018; 234:915-934. [PMID: 29253832 DOI: 10.1016/j.envpol.2017.12.019] [Citation(s) in RCA: 217] [Impact Index Per Article: 36.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2017] [Revised: 11/22/2017] [Accepted: 12/06/2017] [Indexed: 05/06/2023]
Abstract
Selenium (Se) is an essential trace element for humans and animals, although controversial for different plant species. There exists a narrow line between essential, beneficial and toxic levels of Se to living organisms which greatly varies with Se speciation, as well as the type of living organisms. Therefore, it is crucial to monitor its solid- and solution-phase speciation, exposure levels and pathways to living organisms. Consumption of Se-laced food (cereals, vegetables, legumes and pulses) is the prime source of Se exposure to humans. Thus, it is imperative to assess the biogeochemical behavior of Se in soil-plant system with respect to applied levels and speciation, which ultimately affect Se status in humans. Based on available relevant literature, this review traces a plausible link among (i) Se levels, sources, speciation, bioavailability, and effect of soil chemical properties on selenium bioavailability/speciation in soil; (ii) role of different protein transporters in soil-root-shoot transfer of Se; and (iii) speciation, metabolism, phytotoxicity and detoxification of Se inside plants. The toxic and beneficial effects of Se to plants have been discussed with respect to speciation and toxic/deficient concentration of Se. We highlight the significance of various enzymatic (catalase, peroxidase, superoxide dismutase, ascorbate peroxidase, glutathione peroxidase) and non-enzymatic (phytochelatins and glutathione) antioxidants which help combat Se-induced overproduction of reactive oxygen species (ROS). The review also delineates Se accumulation in edible plant parts from soils containing low or high Se levels; elucidates associated health disorders or risks due to the consumption of Se-deficient or Se-rich foods; discusses the potential role of Se in different human disorders/diseases.
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Affiliation(s)
- Muhammad Shahid
- Department of Environmental Sciences, COMSATS Institute of Information Technology, Vehari 61100, Pakistan.
| | - Nabeel Khan Niazi
- Institute of Soil and Environmental Sciences, University of Agriculture Faisalabad, Faisalabad 38040, Pakistan; MARUM and Department of Geosciences, University of Bremen, Bremen, D-28359, Germany; Southern Cross GeoScience, Southern Cross University, Lismore 2480, NSW, Australia.
| | - Sana Khalid
- Department of Environmental Sciences, COMSATS Institute of Information Technology, Vehari 61100, Pakistan
| | - Behzad Murtaza
- Department of Environmental Sciences, COMSATS Institute of Information Technology, Vehari 61100, Pakistan
| | - Irshad Bibi
- Institute of Soil and Environmental Sciences, University of Agriculture Faisalabad, Faisalabad 38040, Pakistan; Southern Cross GeoScience, Southern Cross University, Lismore 2480, NSW, Australia
| | - Muhammad Imtiaz Rashid
- Department of Environmental Sciences, COMSATS Institute of Information Technology, Vehari 61100, Pakistan; Center of Excellence in Environmental Studies, King Abdulaziz University, Jeddah 21589, Saudi Arabia
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Nourimand M, Todd CD. Allantoin contributes to the stress response in cadmium-treated Arabidopsis roots. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2017; 119:103-109. [PMID: 28858669 DOI: 10.1016/j.plaphy.2017.08.012] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2017] [Revised: 08/15/2017] [Accepted: 08/16/2017] [Indexed: 05/21/2023]
Abstract
Ureides are nitrogen-rich compounds, derived from purine catabolism. A dual role for ureides, and for allantoin in particular, in both nitrogen recycling and the abiotic stress response has been recently identified. Previous work on the effect of allantoin on cadmium (Cd)-exposed Arabidopsis revealed that high concentration of allantoin in allantoinase-negative mutant (aln-3) leaves alleviates Cd toxicity via inducing antioxidant mechanisms in these plants. In the present study, we evaluate whether allantoin has a similar protective role in roots. Both wild type and aln-3 roots contain higher amounts of internal Cd compared to leaves. Likewise, aln-3 roots are more resistant to Cd, reflected in fresh and dry weight, and stimulated antioxidant enzyme activity, including superoxide dismutase (SOD) and catalase (CAT), resulting in lower reactive oxygen species concentration. In contrast with wild-type leaves, high levels of Cd in Col-0 roots reduces transcript abundance of uricase, leading to a significant decline in allantoin level of treated roots at 1000 and 1500 μM CdCl2. This metabolite change is also accompanied by decreasing the activity of antioxidant enzymes (SOD and CAT). Additionally, contrary to wild-type leaves, root genotype has a significant effect on CAT activity under Cd treatment, suggesting the possible different sources of damage and oxidative stress response in these two tissues.
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Affiliation(s)
- Maryam Nourimand
- Department of Biology, University of Saskatchewan, Saskatoon, S7N 5E2, Canada
| | - Christopher D Todd
- Department of Biology, University of Saskatchewan, Saskatoon, S7N 5E2, Canada.
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Shahid M, Dumat C, Khalid S, Niazi NK, Antunes PMC. Cadmium Bioavailability, Uptake, Toxicity and Detoxification in Soil-Plant System. REVIEWS OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY 2017; 241:73-137. [PMID: 27300014 DOI: 10.1007/398_2016_8] [Citation(s) in RCA: 80] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
This review summarizes the findings of the most recent studies, published from 2000 to 2016, which focus on the biogeochemical behavior of Cd in soil-plant systems and its impact on the ecosystem. For animals and people not subjected to a Cd-contaminated environment, consumption of Cd contaminated food (vegetables, cereals, pulses and legumes) is the main source of Cd exposure. As Cd does not have any known biological function, and can further cause serious deleterious effects both in plants and mammalian consumers, cycling of Cd within the soil-plant system is of high global relevance.The main source of Cd in soil is that which originates as emissions from various industrial processes. Within soil, Cd occurs in various chemical forms which differ greatly with respect to their lability and phytoavailability. Cadmium has a high phytoaccumulation index because of its low adsorption coefficient and high soil-plant mobility and thereby may enter the food chain. Plant uptake of Cd is believed to occur mainly via roots by specific and non-specific transporters of essential nutrients, as no Cd-specific transporter has yet been identified. Within plants, Cd causes phytotoxicity by decreasing nutrient uptake, inhibiting photosynthesis, plant growth and respiration, inducing lipid peroxidation and altering the antioxidant system and functioning of membranes. Plants tackle Cd toxicity via different defense strategies such as decreased Cd uptake or sequestration into vacuoles. In addition, various antioxidants combat Cd-induced overproduction of ROS. Other mechanisms involve the induction of phytochelatins, glutathione and salicylic acid.
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Affiliation(s)
- Muhammad Shahid
- Department of Environmental Sciences, COMSATS Institute of Information Technology, Vehari, 61100, Pakistan.
| | - Camille Dumat
- Centre d'Etude et de Recherche Travail Organisation Pouvoir (CERTOP), UMR5044, Université J. Jaurès-Toulouse II, 5 Allée Antonio Machado, 31058, Toulouse Cedex 9, France
| | - Sana Khalid
- Department of Environmental Sciences, COMSATS Institute of Information Technology, Vehari, 61100, Pakistan
| | - Nabeel Khan Niazi
- Institute of Soil and Environmental Sciences, University of Agriculture Faisalabad, Faisalabad, 38040, Pakistan
- Southern Cross GeoScience, Southern Cross University, Lismore, 2480, NSW, Australia
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15
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Aborode FA, Raab A, Voigt M, Costa LM, Krupp EM, Feldmann J. The importance of glutathione and phytochelatins on the selenite and arsenate detoxification in Arabidopsis thaliana. J Environ Sci (China) 2016; 49:150-161. [PMID: 28007170 DOI: 10.1016/j.jes.2016.08.009] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2016] [Revised: 08/08/2016] [Accepted: 08/13/2016] [Indexed: 05/24/2023]
Abstract
We investigated the role of glutathione (GSH) and phytochelatins (PCs) on the detoxification of selenite using Arabidopsis thaliana. The wild-type (WT) of Arabidopsis thaliana and its mutants (glutathione deficient Cad 2-1 and phytochelatins deficient Cad 1-3) were separately exposed to varying concentrations of selenite and arsenate and jointly to both toxicants to determine their sensitivities. The results of the study revealed that, the mutants were about 20-fold more sensitive to arsenate than the WT, an indication that the GSH and PCs affect arsenate detoxification. On the contrary, the WT and both mutants showed a similar level of sensitivity to selenite, an indication that the GSH and PCs do not significantly affect selenite detoxification. However, the WT is about 8 times more sensitive to selenite than to arsenate, and the mutants were more resistant to selenite than arsenate by a factor of 2. This could not be explained by the accumulation of both elements in roots and shoots in exposure experiments. The co-exposure of the WT indicates a synergistic effect with regards to toxicity since selenite did not induce PCs but arsenic and selenium compete in their PC binding as revealed by speciation analysis of the root extracts using HPLC-ICP-MS/ESI-MS. In the absence of PCs an antagonistic effect has been detected which might suggest indirectly that the formation of Se glutathione complex prevent the formation of detrimental selenopeptides. This study, therefore, revealed that PC and GSH have only a subordinate role in the detoxification of selenite.
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Affiliation(s)
- Fatai Adigun Aborode
- Trace Element Speciation Laboratory, Department of Chemistry, University of Aberdeen, Aberdeen AB24 3UE, Scotland, UK.
| | - Andrea Raab
- Trace Element Speciation Laboratory, Department of Chemistry, University of Aberdeen, Aberdeen AB24 3UE, Scotland, UK
| | - Matthias Voigt
- Trace Element Speciation Laboratory, Department of Chemistry, University of Aberdeen, Aberdeen AB24 3UE, Scotland, UK
| | - Leticia Malta Costa
- Trace Element Speciation Laboratory, Department of Chemistry, University of Aberdeen, Aberdeen AB24 3UE, Scotland, UK; Departamento de Química, Universidade Federal de Minas Gerais, Belo Horizonte, MG CEP: 31270-901, Brazil
| | - Eva M Krupp
- Trace Element Speciation Laboratory, Department of Chemistry, University of Aberdeen, Aberdeen AB24 3UE, Scotland, UK
| | - Joerg Feldmann
- Trace Element Speciation Laboratory, Department of Chemistry, University of Aberdeen, Aberdeen AB24 3UE, Scotland, UK.
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16
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Jozefczak M, Keunen E, Schat H, Bliek M, Hernández LE, Carleer R, Remans T, Bohler S, Vangronsveld J, Cuypers A. Differential response of Arabidopsis leaves and roots to cadmium: glutathione-related chelating capacity vs antioxidant capacity. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2014; 83:1-9. [PMID: 25049163 DOI: 10.1016/j.plaphy.2014.07.001] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2014] [Accepted: 07/01/2014] [Indexed: 05/18/2023]
Abstract
This study aims to uncover the spatiotemporal involvement of glutathione (GSH) in two major mechanisms of cadmium (Cd)-induced detoxification (i.e. chelation and antioxidative defence). A kinetic study was conducted on hydroponically grown Arabidopsis thaliana (L. Heyhn) to gain insight into the early events after exposure to Cd. Cadmium detoxification was investigated at different levels, including gene transcripts, enzyme activities and metabolite content. Data indicate a time-dependent response both within roots and between plant organs. Early on in roots, GSH was preferentially allocated to phytochelatin (PC) synthesis destined for Cd chelation. This led to decreased GSH levels, without alternative pathways activated to complement GSH's antioxidative functions. After one day however, multiple antioxidative pathways increased including superoxide dismutase (SOD), ascorbate (AsA) and catalase (CAT) to ensure efficient neutralization of Cd-induced reactive oxygen species (ROS). As a consequence of Cd retention and detoxification in roots, a delayed response occurred in leaves. Together with high leaf thiol contents and possibly signalling responses from the roots, the leaves were protected, allowing them sufficient time to activate their defence mechanisms.
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Affiliation(s)
- Marijke Jozefczak
- Hasselt University, Centre for Environmental Sciences, Agoralaan Building D, B-3590 Diepenbeek, Belgium.
| | - Els Keunen
- Hasselt University, Centre for Environmental Sciences, Agoralaan Building D, B-3590 Diepenbeek, Belgium.
| | - Henk Schat
- Free University of Amsterdam, Institute of Molecular and Cellular Biology, De Boelelaan 1085, NL-1081 HV Amsterdam, The Netherlands.
| | - Mattijs Bliek
- Free University of Amsterdam, Institute of Molecular and Cellular Biology, De Boelelaan 1085, NL-1081 HV Amsterdam, The Netherlands.
| | - Luis E Hernández
- Universidad Autónoma de Madrid, Laboratorio de Fisiología Vegetal, Departamento de Biología, Campus de Cantoblanco, 28049 Madrid, Spain.
| | - Robert Carleer
- Hasselt University, Centre for Environmental Sciences, Agoralaan Building D, B-3590 Diepenbeek, Belgium.
| | - Tony Remans
- Hasselt University, Centre for Environmental Sciences, Agoralaan Building D, B-3590 Diepenbeek, Belgium.
| | - Sacha Bohler
- Hasselt University, Centre for Environmental Sciences, Agoralaan Building D, B-3590 Diepenbeek, Belgium.
| | - Jaco Vangronsveld
- Hasselt University, Centre for Environmental Sciences, Agoralaan Building D, B-3590 Diepenbeek, Belgium.
| | - Ann Cuypers
- Hasselt University, Centre for Environmental Sciences, Agoralaan Building D, B-3590 Diepenbeek, Belgium.
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17
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Zhou J, Wang Z, Huang Z, Lu C, Han Z, Zhang J, Jiang H, Ge C, Yang J. Expression of sulfur uptake assimilation-related genes in response to cadmium, bensulfuron-methyl and their co-contamination in rice roots. J Environ Sci (China) 2014; 26:650-661. [PMID: 25079279 DOI: 10.1016/s1001-0742(13)60446-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2013] [Revised: 06/14/2013] [Accepted: 06/25/2013] [Indexed: 06/03/2023]
Abstract
The responses of sulfur (S) uptake assimilation-related genes' expression in roots of two rice cultivars to cadmium (Cd), bensulfuron-methyl (BSM) and their co-contamination (Cd+BSM) were investigated by gene-chip microarray analysis and quantitative real-time PCR (QRT-PCR) technology. Treatments of Cd and Cd+BSM induced expression of sulfate transporter and permease genes, and promoted sulfate uptake in rice roots. Cd+BSM could alleviate Cd toxicity to cv. Fengmeizhan seedlings, probably due to Cd+BSM promoting greater S absorption by seedlings. Cd and Cd+BSM induced expression of sulfate assimilation-related genes, and thus activated the sulfur assimilation pathway. Cd and Cd+BSM induced expression of phytochelatin synthase and metallothionein genes, and induced expression of glutathione S-transferases (GSTs), glutathione synthase (GS) and S-containing antioxidation enzyme genes, which detoxified Cd(2+). It is suggested that (to cope with the toxicity of Cd, BSM and their co-contamination) the S uptake and assimilation pathway was activated in rice roots by increased expression of related genes, thus enhancing the supply of organic S for synthesis of Cd or BSM resistance-related substances.
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Affiliation(s)
- Jian Zhou
- College of Bioscience and Biotechnology, Yangzhou University, Yangzhou 225009, China
| | - Zegang Wang
- College of Bioscience and Biotechnology, Yangzhou University, Yangzhou 225009, China.
| | - Zhiwei Huang
- College of Bioscience and Biotechnology, Yangzhou University, Yangzhou 225009, China
| | - Chao Lu
- Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Zhuo Han
- College of Bioscience and Biotechnology, Yangzhou University, Yangzhou 225009, China
| | - Jianfeng Zhang
- Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Huimin Jiang
- Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Cailin Ge
- College of Bioscience and Biotechnology, Yangzhou University, Yangzhou 225009, China.
| | - Juncheng Yang
- Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing 100081, China.
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18
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García-García JD, Girard L, Hernández G, Saavedra E, Pardo JP, Rodríguez-Zavala JS, Encalada R, Reyes-Prieto A, Mendoza-Cózatl DG, Moreno-Sánchez R. Zn-bis-glutathionate is the best co-substrate of the monomeric phytochelatin synthase from the photosynthetic heavy metal-hyperaccumulator Euglena gracilis. Metallomics 2014; 6:604-16. [PMID: 24464102 DOI: 10.1039/c3mt00313b] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The phytochelatin synthase from photosynthetic Euglena gracilis (EgPCS) was analyzed at the transcriptional, kinetic, functional, and phylogenetic levels. Recombinant EgPCS was a monomeric enzyme able to synthesize, in the presence of Zn(2+) or Cd(2+), phytochelatin2-phytochelatin4 (PC2-PC4) using GSH or S-methyl-GS (S-methyl-glutathione), but not γ-glutamylcysteine or PC2 as a substrate. Kinetic analysis of EgPCS firmly established a two-substrate reaction mechanism for PC2 synthesis with Km values of 14-22 mM for GSH and 1.6-2.5 μM for metal-bis-glutathionate (Me-GS2). EgPCS showed the highest Vmax and catalytic efficiency with Zn-(GS)2, and was inactivated by peroxides. The EgPCS N-terminal domain showed high similarity to that of other PCSases, in which the typical catalytic core (Cys-70, His-179 and Asp-197) was identified. In contrast, the C-terminal domain showed no similarity to other PCSases. An EgPCS mutant comprising only the N-terminal 235 amino acid residues was inactive, suggesting that the C-terminal domain is essential for activity/stability. EgPCS transcription in Euglena cells was not modified by Cd(2+), whereas its heterologous expression in ycf-1 yeast cells provided resistance to Cd(2+) stress. Phylogenetic analysis of the N-terminal domain showed that EgPCS is distant from plants and other photosynthetic organisms, suggesting that it evolved independently. Although EgPCS showed typical features of PCSases (constitutive expression; conserved N-terminal domain; kinetic mechanism), it also exhibited distinct characteristics such as preference for Zn-(GS)2 over Cd-(GS)2 as a co-substrate, a monomeric structure, and ability to solely synthesize short-chain PCs, which may be involved in conferring enhanced heavy-metal resistance.
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Affiliation(s)
- Jorge D García-García
- Departamento de Bioquímica, Instituto Nacional de Cardiología, Juan Badiano No. 1, Sección XVI, Tlalpan, México D.F. 14080, México.
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19
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Shahid M, Pourrut B, Dumat C, Nadeem M, Aslam M, Pinelli E. Heavy-metal-induced reactive oxygen species: phytotoxicity and physicochemical changes in plants. REVIEWS OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY 2014; 232:1-44. [PMID: 24984833 DOI: 10.1007/978-3-319-06746-9_1] [Citation(s) in RCA: 91] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
As a result of the industrial revolution, anthropogenic activities have enhanced there distribution of many toxic heavy metals from the earth's crust to different environmental compartments. Environmental pollution by toxic heavy metals is increasing worldwide, and poses a rising threat to both the environment and to human health.Plants are exposed to heavy metals from various sources: mining and refining of ores, fertilizer and pesticide applications, battery chemicals, disposal of solid wastes(including sewage sludge), irrigation with wastewater, vehicular exhaust emissions and adjacent industrial activity.Heavy metals induce various morphological, physiological, and biochemical dysfunctions in plants, either directly or indirectly, and cause various damaging effects. The most frequently documented and earliest consequence of heavy metal toxicity in plants cells is the overproduction of ROS. Unlike redox-active metals such as iron and copper, heavy metals (e.g, Pb, Cd, Ni, AI, Mn and Zn) cannot generate ROS directly by participating in biological redox reactions such as Haber Weiss/Fenton reactions. However, these metals induce ROS generation via different indirect mechanisms, such as stimulating the activity of NADPH oxidases, displacing essential cations from specific binding sites of enzymes and inhibiting enzymatic activities from their affinity for -SH groups on the enzyme.Under normal conditions, ROS play several essential roles in regulating the expression of different genes. Reactive oxygen species control numerous processes like the cell cycle, plant growth, abiotic stress responses, systemic signalling, programmed cell death, pathogen defence and development. Enhanced generation of these species from heavy metal toxicity deteriorates the intrinsic antioxidant defense system of cells, and causes oxidative stress. Cells with oxidative stress display various chemical,biological and physiological toxic symptoms as a result of the interaction between ROS and biomolecules. Heavy-metal-induced ROS cause lipid peroxidation, membrane dismantling and damage to DNA, protein and carbohydrates. Plants have very well-organized defense systems, consisting of enzymatic and non-enzymatic antioxidation processes. The primary defense mechanism for heavy metal detoxification is the reduced absorption of these metals into plants or their sequestration in root cells.Secondary heavy metal tolerance mechanisms include activation of antioxidant enzymes and the binding of heavy metals by phytochelatins, glutathione and amino acids. These defense systems work in combination to manage the cascades of oxidative stress and to defend plant cells from the toxic effects of ROS.In this review, we summarized the biochemiCal processes involved in the over production of ROS as an aftermath to heavy metal exposure. We also described the ROS scavenging process that is associated with the antioxidant defense machinery.Despite considerable progress in understanding the biochemistry of ROS overproduction and scavenging, we still lack in-depth studies on the parameters associated with heavy metal exclusion and tolerance capacity of plants. For example, data about the role of glutathione-glutaredoxin-thioredoxin system in ROS detoxification in plant cells are scarce. Moreover, how ROS mediate glutathionylation (redox signalling)is still not completely understood. Similarly, induction of glutathione and phytochelatins under oxidative stress is very well reported, but it is still unexplained that some studied compounds are not involved in the detoxification mechanisms. Moreover,although the role of metal transporters and gene expression is well established for a few metals and plants, much more research is needed. Eventually, when results for more metals and plants are available, the mechanism of the biochemical and genetic basis of heavy metal detoxification in plants will be better understood. Moreover, by using recently developed genetic and biotechnological tools it may be possible to produce plants that have traits desirable for imparting heavy metal tolerance.
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Affiliation(s)
- Muhammad Shahid
- Department of Environmental Sciences, COMSATS Institute of Information Technology, Vehari, 61100, Pakistan
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20
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Chia JC, Yang CC, Sui YT, Lin SY, Juang RH. Tentative identification of the second substrate binding site in Arabidopsis phytochelatin synthase. PLoS One 2013; 8:e82675. [PMID: 24340051 PMCID: PMC3855540 DOI: 10.1371/journal.pone.0082675] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2013] [Accepted: 10/26/2013] [Indexed: 01/18/2023] Open
Abstract
Phytochelatin synthase (PCS) uses the substrates glutathione (GSH, γGlu-Cys-Gly) and a cadmium (Cd)-bound GSH (Cd∙GS2) to produce the shortest phytochelatin product (PC2, (γGlu-Cys)2-Gly) through a ping-pong mechanism. The binding of the 2 substrates to the active site, particularly the second substrate binding site, is not well-understood. In this study, we generated a structural model of the catalytic domain of Arabidopsis AtPCS1 (residues 12-218) by using the crystal structure of the γGlu-Cys acyl-enzyme complex of the PCS of the cyanobacterium Nostoc (NsPCS) as a template. The modeled AtPCS1 revealed a cavity in proximity to the first substrate binding site, consisting of 3 loops containing several conserved amino acids including Arg152, Lys185, and Tyr55. Substitutions of these amino acids (R152K, K185R, or double mutation) resulted in the abrogation of enzyme activity, indicating that the arrangement of these 2 positive charges is crucial for the binding of the second substrate. Recombinant AtPCS1s with mutations at Tyr55 showed lower catalytic activities because of reduced affinity (3-fold for Y55W) for the Cd∙GS2, further suggesting the role of the cation-π interaction in recognition of the second substrate. Our study results indicate the mechanism for second substrate recognition in PCS. The integrated catalytic mechanism of PCS is further discussed.
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Affiliation(s)
- Ju-Chen Chia
- Department of Biochemical Science and Technology, College of Life Science, National Taiwan University, Taipei, Taiwan
| | - Chien-Chih Yang
- Department of Biochemical Science and Technology, College of Life Science, National Taiwan University, Taipei, Taiwan
| | - Yu-Ting Sui
- Department of Biochemical Science and Technology, College of Life Science, National Taiwan University, Taipei, Taiwan
| | - Shin-Yu Lin
- Department of Biochemical Science and Technology, College of Life Science, National Taiwan University, Taipei, Taiwan
| | - Rong-Huay Juang
- Department of Biochemical Science and Technology, College of Life Science, National Taiwan University, Taipei, Taiwan
- * E-mail:
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21
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Rigouin C, Vermeire JJ, Nylin E, Williams DL. Characterization of the phytochelatin synthase from the human parasitic nematode Ancylostoma ceylanicum. Mol Biochem Parasitol 2013; 191:1-6. [PMID: 23916800 PMCID: PMC3823645 DOI: 10.1016/j.molbiopara.2013.07.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2013] [Revised: 07/18/2013] [Accepted: 07/19/2013] [Indexed: 11/21/2022]
Abstract
Hookworm disease is a debilitating worm infection that affects hundreds of millions of people. Despite the existence of anthelmintic drugs, reports have testified of a decrease in efficacy of these drugs. Therefore, it is imperative to find new drugs and drug targets for hookworm disease treatment. In this study we identify the gene encoding the phytochelatin synthase in the human hookworm, Ancylostoma ceylanicum (AcePCS). Phytochelatin synthase catalyzes the production of metal chelating peptides, the phytochelatins, from glutathione (GSH). In plants, algae, and fungi phytochelatin production is important for metal tolerance and detoxification. Phytochelatin synthase proteins also function in the elimination of xenobiotics by processing GSH S-conjugates. We found that in vitro AcePCS could both synthesize phytochelatins and hydrolyze a GSH S-conjugate. Interestingly, the enzyme works through a thiol-dependent and, notably, metal-independent mechanism for both transpeptidase (phytochelatin synthesis) and peptidase (hydrolysis of GSH S-conjugates) activities. AcePCS mRNAs are expressed in vivo throughout the life cycle of A. ceylanicum. Mature adult male hookworms isolated from the small intestines of their hosts displayed significantly enhanced expression of AcePCS with transcript levels 5-fold greater than other developmental forms. Although the role of AcePCS in A. ceylanicum biology has yet to be fully investigated the results reported here provide encouraging evidence of the potential that this enzyme holds as a target for new chemotherapeutic intervention.
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Affiliation(s)
- Coraline Rigouin
- Department of Immunology/Microbiology, Rush University Medical Center, 1735 West Harrison Street, Chicago, IL 60612, United States
| | - Jon J. Vermeire
- Program in International Child Health and Department of Pediatrics, Yale University School of Medicine, New Haven, CT, United States
| | - Elyse Nylin
- Department of Immunology/Microbiology, Rush University Medical Center, 1735 West Harrison Street, Chicago, IL 60612, United States
| | - David L. Williams
- Department of Immunology/Microbiology, Rush University Medical Center, 1735 West Harrison Street, Chicago, IL 60612, United States
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22
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Matsuura H, Yamamoto Y, Muraoka M, Akaishi K, Hori Y, Uemura K, Tsuji N, Harada K, Hirata K, Bamba T, Miyasaka H, Kuroda K, Ueda M. Development of surface-engineered yeast cells displaying phytochelatin synthase and their application to cadmium biosensors by the combined use of pyrene-excimer fluorescence. Biotechnol Prog 2013; 29:1197-202. [PMID: 23926095 DOI: 10.1002/btpr.1789] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2013] [Revised: 06/27/2013] [Indexed: 11/09/2022]
Abstract
The development of simple, portable, inexpensive, and rapid analytical methods for detecting and monitoring toxic heavy metals are important for the safety and security of humans and their environment. Herein, we describe the application of phytochelatin (PC) synthase, which plays a critical role in heavy metal responses in higher plants and green algae, in a novel fluorescent sensing platform for cadmium (Cd). We first created surface-engineered yeast cells on which the PC synthase from Arabidopsis (AtPCS1) was displayed with retention of enzymatic activity. The general concept for the sensor is based on the Cd level-dependent synthesis of PC2 from glutathiones by AtPCS1-displaying yeast cells, followed by simple discriminative detection of PC2 via sensing of excimer fluorescence of thiol-labeling pyrene probes. The intensity of excimer fluorescence increased in the presence of Cd up to 1.0 μM in an approximately dose-dependent manner. This novel biosensor achieved a detection limit of as low as 0.2 μM (22.5 μg/L) for Cd. Although its use may be limited by the fact that Cu and Pb can induce cross-reaction, the proposed simple biosensor holds promise as a method useful for cost-effective screening of Cd contamination in environmental and food samples. The AtPCS1-displaying yeast cells also might be attractive tools for dissection of the catalytic mechanisms of PCS.
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Affiliation(s)
- Hideyuki Matsuura
- Graduate School of Pharmaceutical Sciences, Osaka University, Osaka, 565-0871, Japan
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23
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Gupton-Campolongo T, Damasceno LM, Hay AG, Ahner BA. Characterization of a High Affinity Phytochelatin Synthase from The Cd-Utilizing Marine Diatom Thalassiosira pseudonana. JOURNAL OF PHYCOLOGY 2013; 49:32-40. [PMID: 27008386 DOI: 10.1111/jpy.12022] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/21/2012] [Accepted: 08/06/2012] [Indexed: 06/05/2023]
Abstract
Phytochelatin synthase (PC synthase) is the enzyme that catalyzes the production of phytochelatins, peptides of the structure (γ-Glu-Cys)n -Gly, where n = 2-11, from the sulfhydryl-containing tripeptide glutathione, in response to elevated metal exposure. Biochemical utilization of Cd in the marine diatom Thalassiosira weissfloggi, as well as unusually high ratios of PC to Cd in some Thalassiosira species including T. pseudonana Hasle et Heimdal, motivated the characterization of T. pseudonana PC synthase 1 (TpPCS1). This enzyme is the product of one of three genes in the T. pseudonana genome predicted to encode for a PC synthase based on its homology to canonical PC synthases previously examined. TpPCS1 was cloned, expressed in Escherichia coli and purified under both aerobic and anaerobic conditions. TpPCS1 exhibits several characteristics that set it distinctly apart from the well-studied PC synthase, Arabidopsis thaliana PCS1 (AtPCS1). It is extremely sensitive to oxidation, which suppresses activity, and it is readily inhibited by the addition of Cd in the absence of thiolate ligands. TpPCS1 also has significantly greater affinity for one of its key substrates, the bis-glutathionato-Cd complex. TpPCS1 kinetics is best described by a ternary complex model, as opposed to the ping-pong model used to describe AtPCS1 kinetics. The findings indicate that although the function of TpPCS1 is synonymous to that of AtPCS1, its divergent biochemistry suggests adaptation of this enzyme to the distinct trace metal chemistry of the marine environment and the unique physiological needs of T. pseudonana.
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Affiliation(s)
- Tiffany Gupton-Campolongo
- Department of Biological and Environmental Engineering, Cornell University, Ithaca, New York, 14853, USA
| | | | - Anthony G Hay
- Department of Microbiology, Cornell University, Ithaca, New York, 14853, USA
| | - Beth A Ahner
- Department of Biological and Environmental Engineering, Cornell University, Ithaca, New York, 14853, USA
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24
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Rigouin C, Nylin E, Cogswell AA, Schaumlöffel D, Dobritzsch D, Williams DL. Towards an understanding of the function of the phytochelatin synthase of Schistosoma mansoni. PLoS Negl Trop Dis 2013; 7:e2037. [PMID: 23383357 PMCID: PMC3561135 DOI: 10.1371/journal.pntd.0002037] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2012] [Accepted: 12/13/2012] [Indexed: 11/19/2022] Open
Abstract
Phytochelatin synthase (PCS) is a protease-like enzyme that catalyzes the production of metal chelating peptides, the phytochelatins, from glutathione (GSH). In plants, algae, and fungi phytochelatin production is important for metal tolerance and detoxification. PCS proteins also function in xenobiotic metabolism by processing GSH S-conjugates. The aim of the present study is to elucidate the role of PCS in the parasitic worm Schistosoma mansoni. Recombinant S. mansoni PCS proteins expressed in bacteria could both synthesize phytochelatins and hydrolyze various GSH S-conjugates. We found that both the N-truncated protein and the N- and C-terminal truncated form of the enzyme (corresponding to only the catalytic domain) work through a thiol-dependant and, notably, metal-independent mechanism for both transpeptidase (phytochelatin synthesis) and peptidase (hydrolysis of GSH S-conjugates) activities. PCS transcript abundance was increased by metals and xenobiotics in cultured adult worms. In addition, these treatments were found to increase transcript abundance of other enzymes involved in GSH metabolism. Highest levels of PCS transcripts were identified in the esophageal gland of adult worms. Taken together, these results suggest that S. mansoni PCS participates in both metal homoeostasis and xenobiotic metabolism rather than metal detoxification as previously suggested and that the enzyme may be part of a global stress response in the worm. Because humans do not have PCS, this enzyme is of particular interest as a drug target for schistosomiasis. Schistosomiasis is a chronic, debilitating disease that affects hundreds of millions of people. The treatment of schistosomiasis relies solely on monotherapy with praziquantel and there is concern that drug-resistant parasites will evolve. Therefore, it is imperative to identify new drugs for schistosomiasis treatment. In this study our goal was to characterize the function of the phytochelatin synthase of Schistosoma mansoni, previously suggested as a candidate for drug targeting to control schistosomiasis. Phytochelatin synthase catalyzes the production of metal chelating peptides, the phytochelatins, from glutathione (GSH). In plants, algae, and fungi phytochelatin production is important for metal tolerance and detoxification. PCS proteins also function in the elimination of xenobiotics by processing GSH S-conjugates. We found that SmPCS expressed in bacteria could both synthesize phytochelatins and hydrolyze various GSH S-conjugates. We found the enzyme works through a thiol-dependant and, notably, metal-independent mechanism for both transpeptidase (phytochelatin synthesis) and peptidase (hydrolysis of GSH S-conjugates) activities. The expression of the PCS gene in adult schistosome worms was increased by exposure to a number of metals and xenobiotics. In addition, these treatments were found to increase the expression of other enzymes involved in GSH metabolism. Highest levels of PCS transcripts were localized in the esophageal gland of adult worms. Taken together, these results suggest that S. mansoni PCS participates in both metal homoeostasis and xenobiotic metabolism rather than metal detoxification as previously suggested and that it may be part of a global stress response in the worm.
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Affiliation(s)
- Coraline Rigouin
- Department of Immunology/Microbiology, Rush University Medical Center, Chicago, Illinois, United States of America
| | - Elyse Nylin
- Department of Immunology/Microbiology, Rush University Medical Center, Chicago, Illinois, United States of America
| | - Alexis A. Cogswell
- Department of Immunology/Microbiology, Rush University Medical Center, Chicago, Illinois, United States of America
| | - Dirk Schaumlöffel
- Université de Pau et des Pays de l'Adour/CNRS UMR 5254, Laboratoire de Chimie Analytique Bio-Inorganique et Environnement/IPREM, Hélioparc, Pau, France
| | - Dirk Dobritzsch
- Martin-Luther-Universität Halle-Wittenberg, Institut für Biochemie und Biotechnologie, Abteilung Pflanzenbiochemie, Halle, Saale, Germany
| | - David L. Williams
- Department of Immunology/Microbiology, Rush University Medical Center, Chicago, Illinois, United States of America
- * E-mail:
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Ogawa S, Yoshimura E. Comparison of methanol and acetonitrile eluents for the quantitation of chelators specific to soft-metal ions by HPLC. J Chromatogr B Analyt Technol Biomed Life Sci 2012; 909:34-6. [PMID: 23153641 DOI: 10.1016/j.jchromb.2012.10.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2012] [Revised: 09/29/2012] [Accepted: 10/01/2012] [Indexed: 10/27/2022]
Abstract
HPLC eluent systems employing acetonitrile and methanol were evaluated for the quantitation of glutathione (GSH) and phytochelatin (PC(n)), a family of peptides implicated in heavy-metal detoxification in higher plants. The detection system is based on the dequenching of copper(I)-bathocuproine disulfonate and is specific for soft-metal chelators. Although both elution systems yielded comparable analytical performance for each PC(n), the acetonitrile system had a lower sensitivity for GSH and a steadily increasing baseline. The inferior properties of the acetonitrile system may be due to complex formation between acetonitrile and Cu(I) ions. Both methods were applied to measure peptide levels in the primitive red alga Cyanidioschyzon merolae. Coefficients of variation (CVs) were less than 5%, except for GSH and PC(4) determinations in the acetonitrile system, in cases when CV values were found to be 8.8% and 6.3%, respectively. Recoveries were greater than 96%, except for GSH determination in the acetonitrile system, with a recovery of 84.4%; however, the concentration measured in the acetonitrile system did not differ from that measured in the methanol system at a significance level of 0.05.
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Affiliation(s)
- Shinya Ogawa
- Department of Applied Biological Chemistry, The University of Tokyo, Yayoi, Bunkyo, Tokyo 113-8657, Japan
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Jozefczak M, Remans T, Vangronsveld J, Cuypers A. Glutathione is a key player in metal-induced oxidative stress defenses. Int J Mol Sci 2012; 13:3145-3175. [PMID: 22489146 PMCID: PMC3317707 DOI: 10.3390/ijms13033145] [Citation(s) in RCA: 442] [Impact Index Per Article: 36.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2011] [Revised: 02/10/2012] [Accepted: 02/23/2012] [Indexed: 01/15/2023] Open
Abstract
Since the industrial revolution, the production, and consequently the emission of metals, has increased exponentially, overwhelming the natural cycles of metals in many ecosystems. Metals display a diverse array of physico-chemical properties such as essential versus non-essential and redox-active versus non-redox-active. In general, all metals can lead to toxicity and oxidative stress when taken up in excessive amounts, imposing a serious threat to the environment and human health. In order to cope with different kinds of metals, plants possess defense strategies in which glutathione (GSH; γ-glu-cys-gly) plays a central role as chelating agent, antioxidant and signaling component. Therefore, this review highlights the role of GSH in: (1) metal homeostasis; (2) antioxidative defense; and (3) signal transduction under metal stress. The diverse functions of GSH originate from the sulfhydryl group in cysteine, enabling GSH to chelate metals and participate in redox cycling.
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Affiliation(s)
- Marijke Jozefczak
- Centre for Environmental Sciences, Hasselt University, Agoralaan Building D, 3590 Diepenbeek, Belgium; E-Mails: (M.J.); (T.R.); (J.V.)
| | - Tony Remans
- Centre for Environmental Sciences, Hasselt University, Agoralaan Building D, 3590 Diepenbeek, Belgium; E-Mails: (M.J.); (T.R.); (J.V.)
| | - Jaco Vangronsveld
- Centre for Environmental Sciences, Hasselt University, Agoralaan Building D, 3590 Diepenbeek, Belgium; E-Mails: (M.J.); (T.R.); (J.V.)
| | - Ann Cuypers
- Centre for Environmental Sciences, Hasselt University, Agoralaan Building D, 3590 Diepenbeek, Belgium; E-Mails: (M.J.); (T.R.); (J.V.)
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Biochemical and Functional Responses of Arabidopsis thaliana Exposed to Cadmium, Copper and Zinc. THE PLANT FAMILY BRASSICACEAE 2012. [DOI: 10.1007/978-94-007-3913-0_9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/06/2022]
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