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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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Salbitani G, Maresca V, Cianciullo P, Bossa R, Carfagna S, Basile A. Non-Protein Thiol Compounds and Antioxidant Responses Involved in Bryophyte Heavy-Metal Tolerance. Int J Mol Sci 2023; 24:ijms24065302. [PMID: 36982378 PMCID: PMC10049163 DOI: 10.3390/ijms24065302] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2023] [Revised: 02/23/2023] [Accepted: 03/04/2023] [Indexed: 03/12/2023] Open
Abstract
Heavy-metal pollution represents a problem which has been widely discussed in recent years. The biological effects of heavy metals have been studied in both animals and plants, ranging from oxidative stress to genotoxicity. Plants, above all metal-tolerant species, have evolved a wide spectrum of strategies to counteract exposure to toxic metal concentrations. Among these strategies, the chelation and vacuolar sequestration of heavy metals are, after cell-wall immobilization, the first line of defence that prevent heavy metals from interacting with cell components. Furthermore, bryophytes activate a series of antioxidant non-enzymatic and enzymatic responses to counteract the effects of heavy metal in the cellular compartments. In this review, the role of non-protein thiol compounds and antioxidant molecules in bryophytes will be discussed.
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Zhao J, Xie R, Lin J, Xu L, Gao X, Lin X, Tian S, Lu L. SaMT3 in Sedum alfredii drives Cd detoxification by chelation and ROS-scavenging via Cys residues. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2022; 315:120410. [PMID: 36240968 DOI: 10.1016/j.envpol.2022.120410] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2022] [Revised: 10/03/2022] [Accepted: 10/06/2022] [Indexed: 06/16/2023]
Abstract
Metallothioneins (MTs), a group of cysteine-rich proteins, are effective chelators of cadmium (Cd) and play a key role in plant Cd detoxification. However, little is known about the role of single cysteine (Cys) residues in the MTs involved in the adaptation of plants to Cd stress, especially, in hyperaccumulators. In the present study, we functionally characterised SaMT3 in S. alfredii, a Cd/Zn hyperaccumulator native to China. Our results showed that the C- and N- terminal regions of SaMT3 had differential functional natures in S. alfredii and determined its Cd hypertolerance and detoxification. Two CXC motifs within the C-terminal region were revealed to play a crucial role in Cd sensing and binding, whereas the four Cys-residues within the N-terminal region were involved in scavenging reactive oxygen species (ROS). An S. alfredii transgenic system based on callus transformation was developed to further investigate the in-planta gene function. The SaMT3-overexpressing transgenic plant roots were more tolerant to Cd than those of wild-type plants. Knockout of SaMT3 resulted in significantly decreased Cd concentrations and increased ROS levels after exposure to Cd stress. We demonstrated the SaMT3-mediated adaptation strategy in S. alfredii, which uses metal chelation and ROS scavenging in response to Cd stress. Our results further reveal the molecular mechanisms underlying Cd detoxification in hyperaccumulating plants, as well as the relation between Cys-related motifs and the metal binding properties of MTs. This research provides valuable insights into the functions of SaMT3 in S. alfredii, and improves our understanding of Cd hyperaccumulation in plants.
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Affiliation(s)
- Jianqi Zhao
- MOE Key Laboratory of Environment Remediation and Ecological Health, College of Environmental & Resource Science, Zhejiang University, Hangzhou, 310058, China; Zhejiang Provincial Key Laboratory of Subtropic Soil and Plant Nutrition, Zhejiang University, Hangzhou, 310058, China.
| | - Ruohan Xie
- School of Agriculture, Sun Yat-Sen University, Guangzhou, 510275, China.
| | - Jiayu Lin
- MOE Key Laboratory of Environment Remediation and Ecological Health, College of Environmental & Resource Science, Zhejiang University, Hangzhou, 310058, China; Zhejiang Provincial Key Laboratory of Subtropic Soil and Plant Nutrition, Zhejiang University, Hangzhou, 310058, China.
| | - Lingling Xu
- MOE Key Laboratory of Environment Remediation and Ecological Health, College of Environmental & Resource Science, Zhejiang University, Hangzhou, 310058, China; Zhejiang Provincial Key Laboratory of Subtropic Soil and Plant Nutrition, Zhejiang University, Hangzhou, 310058, China.
| | - Xiaoyu Gao
- MOE Key Laboratory of Environment Remediation and Ecological Health, College of Environmental & Resource Science, Zhejiang University, Hangzhou, 310058, China; College of Environmental Science and Engineering, Tongji University, Shanghai, 200092, China.
| | - Xianyong Lin
- MOE Key Laboratory of Environment Remediation and Ecological Health, College of Environmental & Resource Science, Zhejiang University, Hangzhou, 310058, China; Zhejiang Provincial Key Laboratory of Subtropic Soil and Plant Nutrition, Zhejiang University, Hangzhou, 310058, China.
| | - Shengke Tian
- MOE Key Laboratory of Environment Remediation and Ecological Health, College of Environmental & Resource Science, Zhejiang University, Hangzhou, 310058, China; Zhejiang Provincial Key Laboratory of Subtropic Soil and Plant Nutrition, Zhejiang University, Hangzhou, 310058, China.
| | - Lingli Lu
- MOE Key Laboratory of Environment Remediation and Ecological Health, College of Environmental & Resource Science, Zhejiang University, Hangzhou, 310058, China; Zhejiang Provincial Key Laboratory of Subtropic Soil and Plant Nutrition, Zhejiang University, Hangzhou, 310058, China.
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The Response of Thiols to Cadmium Stress in Spinach ( Spinacia Oleracea L.). TOXICS 2022; 10:toxics10080429. [PMID: 36006108 PMCID: PMC9415539 DOI: 10.3390/toxics10080429] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/09/2022] [Revised: 07/25/2022] [Accepted: 07/27/2022] [Indexed: 02/04/2023]
Abstract
The aim of this study is to examine the thiol species for the high cadmium (Cd) tolerance of spinach and provide information for the improvement of soil utilization. The spinach was cultured in aqueous solution with concentrations of Cd ranging from 1 to 9 mg/L. The time responses of glutathione (GSH) and phytochelatins (PCs, PC2-PC4) in the tissues of spinach were monitored via HPLC−MS/MS, and the concentrations of Cd in the roots, shoots and leaves were detected by ICP−OES. Data were analyzed via one-way ANOVA and Spearman correlation to assess the relationships among the types of thiols and the changes between types of thiols and Cd. As Cd stress increased, Cd concentrations in tissues also increased. The total thiol contents responded to Cd stresses with correlations r ranging from 0.394 (root), 0.520 (shoot) to 0.771 (leaf) (p < 0.01). GSH and PC3 were dominant on most of the days under Cd stress. The correlation r between improvements in GSH and increments of Cd concentration in roots was −0.808 (p < 0.01), and r between changes in PC3 and changes in Cd concentrations in leaves was −0.503 (p < 0.01). No correlation can be found between GSH and the subtypes of PCs in shoots, but strong positive correlations within the subtypes of PCs. Thiols can be produced in different tissues of spinach, while the shoots are only a transport tissue for GSH.
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Navazas A, Mesa V, Thijs S, Fuente-Maqueda F, Vangronsveld J, Peláez AI, Cuypers A, González A. Bacterial inoculant-assisted phytoremediation affects trace element uptake and metabolite content in Salix atrocinerea. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 820:153088. [PMID: 35063508 DOI: 10.1016/j.scitotenv.2022.153088] [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: 08/24/2021] [Revised: 12/23/2021] [Accepted: 01/09/2022] [Indexed: 06/14/2023]
Abstract
Natural plant-associated microorganisms are of critical importance to plant growth and survival in field conditions under toxic concentrations of trace elements (TE) and these plant-microbial processes can be harnessed to enhance phytoremediation. The total bacterial diversity from grey willow (Salix atrocinerea) on a brownfield heavily-polluted with lead (Pb) and arsenic (As) was studied through pyrosequencing. Culturable bacteria were isolated and in vitro tested for plant growth-promotion (PGP) traits, arsenic (As) tolerance and impact on As speciation. Two of the most promising bacterial strains - the root endophyte Pantoea sp. AV62 and the rhizospheric strain Rhodococcus erythropolis AV96 - were inoculated in field to S. atrocinerea. This bioaugmentation resulted in higher As and Pb concentrations in both, roots and leaves of bacterial-inoculated plants as compared to non-inoculated plants. In consequence, bacterial bioaugmentation also affected parameters related to plant growth, oxidative stress, the levels of phytochelatins and phenylpropanoids, together with the differential expression of genes related to these tolerance mechanisms to TE in leaves. This study extends our understanding about plant-bacterial interactions and provides a solid basis for further bioaugmentation studies aiming to improve TE phytoremediation efficiency and predictability in the field.
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Affiliation(s)
- Alejandro Navazas
- Department of Organisms and Systems Biology, Area of Plant Physiology, University of Oviedo, Catedrático Rodrigo Uría s/n, 33006 Oviedo, Spain; Centre for Environmental Sciences, Hasselt University, Agoralaan Building D, B-3590 Diepenbeek, Belgium
| | - Victoria Mesa
- Faculty of Pharmacy, Université de Paris, UMR-S1139, F-75006 Paris, France
| | - Sofie Thijs
- Centre for Environmental Sciences, Hasselt University, Agoralaan Building D, B-3590 Diepenbeek, Belgium
| | | | - Jaco Vangronsveld
- Centre for Environmental Sciences, Hasselt University, Agoralaan Building D, B-3590 Diepenbeek, Belgium; Department of Plant Physiology and Biophysics, Institute of Biological Sciences, Faculty of Biology and Biotechnology, Maria Curie-Skłodowska University, Lublin, Poland
| | - Ana I Peláez
- Area of Microbiology, Department of Functional Biology and Environmental Biogeochemistry and Raw Materials Group, University of Oviedo, Oviedo, Spain; University Institute of Biotechnology of Asturias (IUBA), University of Oviedo, Oviedo, Spain
| | - Ann Cuypers
- Centre for Environmental Sciences, Hasselt University, Agoralaan Building D, B-3590 Diepenbeek, Belgium
| | - Aida González
- Department of Organisms and Systems Biology, Area of Plant Physiology, University of Oviedo, Catedrático Rodrigo Uría s/n, 33006 Oviedo, Spain.
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Tools for In Vitro Propagation/Synchronization of the Liverwort Marchantia polymorpha and Application of a Validated HPLC-ESI-MS-MS Method for Glutathione and Phytochelatin Analysis. STRESSES 2022. [DOI: 10.3390/stresses2010010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Bryophytes, due to their poikilohydric nature and peculiar traits, are useful and versatile organisms for studies on metal accumulation and detoxification in plants. Among bryophytes, the liverwort Marchantia polymorpha is an excellent candidate as a model organism, having a key role in plant evolutionary history. In particular, M. polymorpha axenic cultivation of gametophytes offers several advantages, such as fast growth, easy propagation and high efficiency of crossing. Thus, the main purpose of this work was to promote and validate experimental procedures useful in the establishment of a standardized set-up of M. polymorpha gametophytes, as well as to study cadmium detoxification processes in terms of thiol-peptide production, detection and characterisation by HPLC-mass spectrometry. The results show how variations in the composition of the Murashige and Skoog medium impact the growth rate or development of this liverwort, and what levels of glutathione and phytochelatins are produced by gametophytes to counteract cadmium stress.
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Navazas A, Thijs S, Feito I, Vangronsveld J, Peláez AI, Cuypers A, González A. Arsenate-reducing bacteria affect As accumulation and tolerance in Salix atrocinerea. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 769:144648. [PMID: 33736260 DOI: 10.1016/j.scitotenv.2020.144648] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Revised: 12/18/2020] [Accepted: 12/18/2020] [Indexed: 06/12/2023]
Abstract
Arsenic (As)-reducing bacteria are able to influence As-speciation and, in this way, change As bio-availability. In consequence, this has an impact on As uptake by plants growing on polluted soil and on the effectiveness of the phytoremediation process. To be able to efficiently utilize these bacteria for As-phytoremediation in the field, a better understanding of the plant-bacterial interactions involved in As-tolerance or toxicity is needed. In this work, seedlings of a clone of Salix atrocinerea derived from a specimen naturally growing on an As-polluted brownfield were grown under gnotobiotic conditions exposed to As, and in the presence or absence of two of its field-associated and in vitro characterized plant growth-promoting (PGP) bacteria. The inoculation with Pantoea sp., induced a moderate reduction of AsV to AsIII in the exposure medium that, together with a coordinated plant response of As uptake, chelation and sequestration, increased As accumulation in roots; which is reflected into a higher phytostabilization. However, inoculation with Rhodococcus erythropolis due to a higher disproportionate reduction of AsV to AsIII in the medium caused less As accumulation in roots that non-bioaugmented plants and despite the lower As content, the concentrations of AsIII present in the medium and the damage suffered in roots and leaves, indicated that As tolerance mechanisms (such as prevention of AsIII uptake and efflux) did not occur in time to avoid physical disturbance and plants growth reduction. Interestingly, by two different metabolic pathways -coordinated by different key transporters mediating As uptake, tolerance, distribution and vacuolar accumulation at the roots- both bacteria limited As accumulation in Salix shoots. Our results provide for the first time a detailed insight in the plant-bacterial responses and physiological changes contributing to As tolerance in S. atrocinerea, that will facilitate the design of effective strategies for exploitation of plant-associated microorganisms for phytoremediation.
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Affiliation(s)
- Alejandro Navazas
- Department of Organisms and Systems Biology, Area of Plant Physiology-IUBA, University of Oviedo, Catedrático Rodrigo Uría s/n, 33006 Oviedo, Spain; Centre for Environmental Sciences, Hasselt University, Agoralaan Building D, 3590 Diepenbeek, Belgium
| | - Sofie Thijs
- Centre for Environmental Sciences, Hasselt University, Agoralaan Building D, 3590 Diepenbeek, Belgium
| | - Isabel Feito
- Agri-Food Research and Development Service, Forestry Program, La Mata s/n, 33825 Grado, Spain
| | - Jaco Vangronsveld
- Centre for Environmental Sciences, Hasselt University, Agoralaan Building D, 3590 Diepenbeek, Belgium; Department of Plant Physiology, Faculty of Biology and Biotechnology, Maria Curie-Skłodowska University, Lublin, Poland
| | - Ana I Peláez
- Department of Functional Biology - Area of Microbiology-IUBA, University of Oviedo, Oviedo, Spain
| | - Ann Cuypers
- Centre for Environmental Sciences, Hasselt University, Agoralaan Building D, 3590 Diepenbeek, Belgium
| | - Aida González
- Department of Organisms and Systems Biology, Area of Plant Physiology-IUBA, University of Oviedo, Catedrático Rodrigo Uría s/n, 33006 Oviedo, Spain.
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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: 17] [Impact Index Per Article: 4.3] [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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Reconstitution of polythioamide antibiotic backbone formation reveals unusual thiotemplated assembly strategy. Proc Natl Acad Sci U S A 2020; 117:8850-8858. [PMID: 32265283 PMCID: PMC7183216 DOI: 10.1073/pnas.1918759117] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Nonribosomal peptides (NRPs) are a vast class of natural products and an important source of therapeutics. Typically, these secondary metabolites are assembled by NRP synthetases (NRPSs) that function on substrates covalently linked to the enzyme by a thioester, in a process known as thiotemplated biosynthesis. Although NRPS-independent assembly pathways are known, all are nonthiotemplated. Here we report an NRPS-independent yet thiotemplated pathway for NRP biosynthesis and demonstrate that members of the ATP-grasp and cysteine protease families form the β-peptide backbone of an antibiotic. Armed with this knowledge, we provide genomic evidence that this noncanonical assembly pathway is widespread in bacteria. Our results will inspire future genome mining efforts for the discovery of potential therapeutics that otherwise would be overlooked. Closthioamide (CTA) is a rare example of a thioamide-containing nonribosomal peptide and is one of only a handful of secondary metabolites described from obligately anaerobic bacteria. Although the biosynthetic gene cluster responsible for CTA production and the thioamide synthetase that catalyzes sulfur incorporation were recently discovered, the logic for peptide backbone assembly has remained a mystery. Here, through the use of in vitro biochemical assays, we demonstrate that the amide backbone of CTA is assembled in an unusual thiotemplated pathway involving the cooperation of a transacylating member of the papain-like cysteine protease family and an iteratively acting ATP-grasp protein. Using the ATP-grasp protein as a bioinformatic handle, we identified hundreds of such thiotemplated yet nonribosomal peptide synthetase (NRPS)-independent biosynthetic gene clusters across diverse bacterial phyla. The data presented herein not only clarify the pathway for the biosynthesis of CTA, but also provide a foundation for the discovery of additional secondary metabolites produced by noncanonical biosynthetic pathways.
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Hématy K, Lim M, Cherk C, Piślewska-Bednarek M, Sanchez-Rodriguez C, Stein M, Fuchs R, Klapprodt C, Lipka V, Molina A, Grill E, Schulze-Lefert P, Bednarek P, Somerville S. Moonlighting Function of Phytochelatin Synthase1 in Extracellular Defense against Fungal Pathogens. PLANT PHYSIOLOGY 2020; 182:1920-1932. [PMID: 31992602 PMCID: PMC7140922 DOI: 10.1104/pp.19.01393] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2019] [Accepted: 01/06/2020] [Indexed: 05/04/2023]
Abstract
Phytochelatin synthase (PCS) is a key component of heavy metal detoxification in plants. PCS catalyzes both the synthesis of the peptide phytochelatin from glutathione and the degradation of glutathione conjugates via peptidase activity. Here, we describe a role for PCS in disease resistance against plant pathogenic fungi. The pen4 mutant, which is allelic to cadmium insensitive1 (cad1/pcs1) mutants, was recovered from a screen for Arabidopsis mutants with reduced resistance to the nonadapted barley fungal pathogen Blumeria graminis f. sp. hordei PCS1, which is found in the cytoplasm of cells of healthy plants, translocates upon pathogen attack and colocalizes with the PEN2 myrosinase on the surface of immobilized mitochondria. pcs1 and pen2 mutant plants exhibit similar metabolic defects in the accumulation of pathogen-inducible indole glucosinolate-derived compounds, suggesting that PEN2 and PCS1 act in the same metabolic pathway. The function of PCS1 in this pathway is independent of phytochelatin synthesis and deglycination of glutathione conjugates, as catalytic-site mutants of PCS1 are still functional in indole glucosinolate metabolism. In uncovering a peptidase-independent function for PCS1, we reveal this enzyme to be a moonlighting protein important for plant responses to both biotic and abiotic stresses.
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Affiliation(s)
- Kian Hématy
- Carnegie Institution for Science, Department of Plant Biology, Stanford, California 94350
- Energy Biosciences Institute, University of California at Berkeley, Berkeley, California 94720
| | - Melisa Lim
- Carnegie Institution for Science, Department of Plant Biology, Stanford, California 94350
- Energy Biosciences Institute, University of California at Berkeley, Berkeley, California 94720
| | - Candice Cherk
- Energy Biosciences Institute, University of California at Berkeley, Berkeley, California 94720
| | - Mariola Piślewska-Bednarek
- Department of Plant Microbe Interactions, Max Planck Institute for Plant Breeding Research, D-50829 Köln, Germany
- Institute of Bioorganic Chemistry, Polish Academy of Sciences, 61-704 Poznań, Poland
| | - Clara Sanchez-Rodriguez
- Centro de Biotecnología y Genómica de Plantas, Universidad Politécnica de Madrid-Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), Campus de Montegancedo-UPM, E-28223-Pozuelo de Alarcón (Madrid), Spain
| | - Monica Stein
- Carnegie Institution for Science, Department of Plant Biology, Stanford, California 94350
| | - Rene Fuchs
- University of Goettingen, Schwann-Schleiden Research Center for Molecular Cell Biology, Albrecht-von-Haller-Institute for Plant Sciences, Department of Plant Cell BiologyD-37077 Goettingen, Germany
| | - Christine Klapprodt
- University of Goettingen, Schwann-Schleiden Research Center for Molecular Cell Biology, Albrecht-von-Haller-Institute for Plant Sciences, Department of Plant Cell BiologyD-37077 Goettingen, Germany
| | - Volker Lipka
- University of Goettingen, Schwann-Schleiden Research Center for Molecular Cell Biology, Albrecht-von-Haller-Institute for Plant Sciences, Department of Plant Cell BiologyD-37077 Goettingen, Germany
| | - Antonio Molina
- Centro de Biotecnología y Genómica de Plantas, Universidad Politécnica de Madrid-Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), Campus de Montegancedo-UPM, E-28223-Pozuelo de Alarcón (Madrid), Spain
- Departamento de Biotecnología-Biología Vegetal, Escuela Técnica Superior de Ingeniería Agronómica, Alimentaria y de Biosistemas, E-28020-Madrid, Spain
| | - Erwin Grill
- Lehrstuhl für Botanik, Technische Universtät München, D-85350 Freising, Germany
| | - Paul Schulze-Lefert
- Department of Plant Microbe Interactions, Max Planck Institute for Plant Breeding Research, D-50829 Köln, Germany
| | - Paweł Bednarek
- Department of Plant Microbe Interactions, Max Planck Institute for Plant Breeding Research, D-50829 Köln, Germany
- Institute of Bioorganic Chemistry, Polish Academy of Sciences, 61-704 Poznań, Poland
| | - Shauna Somerville
- Carnegie Institution for Science, Department of Plant Biology, Stanford, California 94350
- Energy Biosciences Institute, University of California at Berkeley, Berkeley, California 94720
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Navazas A, Hendrix S, Cuypers A, González A. Integrative response of arsenic uptake, speciation and detoxification by Salix atrocinerea. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 689:422-433. [PMID: 31279189 DOI: 10.1016/j.scitotenv.2019.06.279] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2019] [Revised: 06/17/2019] [Accepted: 06/18/2019] [Indexed: 06/09/2023]
Abstract
Despite arsenic (As) being very toxic with deleterious effects on metabolism, it can be tolerated and accumulated by some plants. General genetic mechanisms responsible for As tolerance in plants, including Salix species, have been described in transcriptomic analysis, but further experimental verification of the significance of particular transcripts is needed. In this study, a Salix atrocinerea clone, able to thrive in an As-contaminated brownfield, was grown hydroponically in controlled conditions under an As concentration similar to the bioavailable fraction of the contaminated area (18 mg kg-1) for 30 days. At different time points, i.e. short-term and long-term exposure, biometric data, As accumulation, phytochelatin synthesis, non-protein thiol production and expression of target genes related to these processes were studied. Results showed that S. atrocinerea presents a great tolerance to As and accumulates up to 2400 mg As kg-1 dry weight in roots and 25 mg As kg-1 dry weight in leaves. Roots reduce As V to As III rapidly, with As III being the predominant form of As accumulated in root tissues, whereas in the leaves it is As V. After 1 d of As exposure, roots and leaves show de novo synthesis and an increase in non-protein thiols as compared to the control. Integrating these data on As accumulation in the plant and its speciation, non-protein thiol production and the kinetic gene expression of related target genes, a fundamental role is highlighted for these processes in As accumulation and tolerance in S. atrocinerea. As such, this study offers new insights in the plant tolerance mechanisms to As, which provides important knowledge for future application of high-biomass willow plants in phytoremediation of As-polluted soils.
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Affiliation(s)
- Alejandro Navazas
- Centre for Environmental Sciences, Hasselt University, Agoralaan Building D, B-3590 Diepenbeek, Belgium; Department of Organisms and Systems Biology, Area of Plant Physiology, University of Oviedo, Catedrático Rodrigo Uría s/n, 33006 Oviedo, Spain.
| | - Sophie Hendrix
- Centre for Environmental Sciences, Hasselt University, Agoralaan Building D, B-3590 Diepenbeek, Belgium.
| | - Ann Cuypers
- Centre for Environmental Sciences, Hasselt University, Agoralaan Building D, B-3590 Diepenbeek, Belgium.
| | - Aida González
- Department of Organisms and Systems Biology, Area of Plant Physiology, University of Oviedo, Catedrático Rodrigo Uría s/n, 33006 Oviedo, Spain; Institute of Biotechnology of Asturias, Spain.
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12
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Raab A, Feldmann J. Biological sulphur-containing compounds – Analytical challenges. Anal Chim Acta 2019; 1079:20-29. [DOI: 10.1016/j.aca.2019.05.064] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2019] [Revised: 05/25/2019] [Accepted: 05/27/2019] [Indexed: 01/19/2023]
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13
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Li M, Stragliati L, Bellini E, Ricci A, Saba A, Sanità di Toppi L, Varotto C. Evolution and functional differentiation of recently diverged phytochelatin synthase genes from Arundo donax L. JOURNAL OF EXPERIMENTAL BOTANY 2019; 70:5391-5405. [PMID: 31145784 PMCID: PMC6793451 DOI: 10.1093/jxb/erz266] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2018] [Accepted: 05/24/2019] [Indexed: 05/15/2023]
Abstract
Phytochelatin synthases (PCSs) play pivotal roles in the detoxification of heavy metals and metalloids in plants; however, little information on the evolution of recently duplicated PCS genes in plant species is available. Here we characterize the evolution and functional differentiation of three PCS genes from the giant reed (Arundo donax L.), a biomass/bioenergy crop with remarkable resistance to cadmium and other heavy metals. Phylogenetic reconstruction with PCS genes from fully sequenced monocotyledonous genomes indicated that the three A. donax PCSs, namely AdPCS1-3, form a monophyletic clade. The AdPCS1-3 genes were expressed at low levels in many A. donax organs and displayed different levels of cadmium-responsive expression in roots. Overexpression of AdPCS1-3 in Arabidopsis thaliana and yeast reproduced the phenotype of functional PCS genes. Mass spectrometry analyses confirmed that AdPCS1-3 are all functional enzymes, but with significant differences in the amount of the phytochelatins synthesized. Moreover, heterogeneous evolutionary rates characterized the AdPCS1-3 genes, indicative of relaxed natural selection. These results highlight the elevated functional differentiation of A. donax PCS genes from both a transcriptional and an enzymatic point of view, providing evidence of the high evolvability of PCS genes and of plant responsiveness to heavy metal stress.
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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 (TN) , Italy
| | - Luca Stragliati
- Dipartimento di Scienze Chimiche, della Vita e della Sostenibilità Ambientale, Università degli studi di Parma, Parco Area delle Scienze, Parma, Italy
| | - Erika Bellini
- Dipartimento di Biologia, Università di Pisa, Pisa, Italy
| | - Ada Ricci
- Dipartimento di Scienze Chimiche, della Vita e della Sostenibilità Ambientale, Università degli studi di Parma, Parco Area delle Scienze, Parma, 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 (TN) , Italy
- Correspondence: or
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Puente-Sánchez F, Díaz S, Penacho V, Aguilera A, Olsson S. Basis of genetic adaptation to heavy metal stress in the acidophilic green alga Chlamydomonas acidophila. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2018; 200:62-72. [PMID: 29727772 DOI: 10.1016/j.aquatox.2018.04.020] [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: 02/11/2018] [Revised: 04/24/2018] [Accepted: 04/25/2018] [Indexed: 05/26/2023]
Abstract
To better understand heavy metal tolerance in Chlamydomonas acidophila, an extremophilic green alga, we assembled its transcriptome and measured transcriptomic expression before and after Cd exposure in this and the neutrophilic model microalga Chlamydomonas reinhardtii. Genes possibly related to heavy metal tolerance and detoxification were identified and analyzed as potential key innovations that enable this species to live in an extremely acid habitat with high levels of heavy metals. In addition we provide a data set of single orthologous genes from eight green algal species as a valuable resource for comparative studies including eukaryotic extremophiles. Our results based on differential gene expression, detection of unique genes and analyses of codon usage all indicate that there are important genetic differences in C. acidophila compared to C. reinhardtii. Several efflux family proteins were identified as candidate key genes for adaptation to acid environments. This study suggests for the first time that exposure to cadmium strongly increases transposon expression in green algae, and that oil biosynthesis genes are induced in Chlamydomonas under heavy metal stress. Finally, the comparison of the transcriptomes of several acidophilic and non-acidophilic algae showed that the Chlamydomonas genus is polyphyletic and that acidophilic algae have distinctive aminoacid usage patterns.
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MESH Headings
- Actins/genetics
- Actins/metabolism
- Adaptation, Physiological/drug effects
- Cadmium/metabolism
- Cadmium/toxicity
- Carboxylic Ester Hydrolases/classification
- Carboxylic Ester Hydrolases/genetics
- Chlamydomonas/classification
- Chlamydomonas/drug effects
- Chlamydomonas/metabolism
- Dioxygenases/classification
- Dioxygenases/genetics
- Drug Tolerance/genetics
- Metals, Heavy/metabolism
- Metals, Heavy/toxicity
- Phylogeny
- Plant Proteins/classification
- Plant Proteins/genetics
- RNA, Plant/chemistry
- RNA, Plant/isolation & purification
- RNA, Plant/metabolism
- RNA, Ribosomal, 18S/genetics
- RNA, Ribosomal, 18S/metabolism
- Sequence Analysis, RNA
- Transcriptome/drug effects
- Water Pollutants, Chemical/chemistry
- Water Pollutants, Chemical/metabolism
- Water Pollutants, Chemical/toxicity
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Affiliation(s)
- Fernando Puente-Sánchez
- Systems Biology Program, Centro Nacional de Biotecnología (CNB-CSIC), Calle Darwin 3, 28049, Madrid, Spain
| | - Silvia Díaz
- Department of Physiology, Genetics and Microbiology, Complutense University of Madrid (UCM), Calle José Antonio Novais 12, 28040 Madrid, Spain
| | - Vanessa Penacho
- Bioarray, S.L. Parque Científico y Empresarial de la UMH, Edificio Quorum III, Avenida de la Universidad s/n, 03202 Elche, Alicante, Spain
| | - Angeles Aguilera
- Centro de Astrobiología (CSIC-INTA), Carretera de Ajalvir Km 4, 28850 Torrejón de Ardoz, Madrid, Spain
| | - Sanna Olsson
- INIA Forest Research Centre (INIA-CIFOR), Department Forest Ecology and Genetics, Carretera de la Coruña km 7.5, 28040 Madrid, Spain; Department Agricultural Sciences, P.O. Box 27, 00014 University of Helsinki, Finland.
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15
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Fontanini D, Andreucci A, Ruffini Castiglione M, Basile A, Sorbo S, Petraglia A, Degola F, Bellini E, Bruno L, Varotto C, Sanità di Toppi L. The phytochelatin synthase from Nitella mucronata (Charophyta) plays a role in the homeostatic control of iron(II)/(III). PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2018; 127:88-96. [PMID: 29554573 DOI: 10.1016/j.plaphy.2018.03.014] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2018] [Revised: 03/10/2018] [Accepted: 03/12/2018] [Indexed: 06/08/2023]
Abstract
Although some charophytes (sister group to land plants) have been shown to synthesize phytochelatins (PCs) in response to cadmium (Cd), the functional characterization of their phytochelatin synthase (PCS) is still completely lacking. To investigate the metal response and the presence of PCS in charophytes, we focused on the species Nitella mucronata. A 40 kDa immunoreactive PCS band was revealed in mono-dimensional western blot by using a polyclonal antibody against Arabidopsis thaliana PCS1. In two-dimensional western blot, the putative PCS showed various spots with acidic isoelectric points, presumably originated by post-translational modifications. Given the PCS constitutive expression in N. mucronata, we tested its possible involvement in the homeostasis of metallic micronutrients, using physiological concentrations of iron (Fe) and zinc (Zn), and verified its role in the detoxification of a non-essential metal, such as Cd. Neither in vivo nor in vitro exposure to Zn resulted in PCS activation and PC significant biosynthesis, while Fe(II)/(III) and Cd were able to activate the PCS in vitro, as well as to induce PC accumulation in vivo. While Cd toxicity was evident from electron microscopy observations, the normal morphology of cells and organelles following Fe treatments was preserved. The overall results support a function of PCS and PCs in managing Fe homeostasis in the carophyte N. mucronata.
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Affiliation(s)
| | | | | | - Adriana Basile
- Department of Biology, University of Naples "Federico II", Naples, Italy
| | - Sergio Sorbo
- CeSMA, Microscopy Section, University of Naples "Federico II", Naples, Italy
| | - Alessandro Petraglia
- Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Parma, Italy
| | - Francesca Degola
- Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Parma, Italy
| | - Erika Bellini
- Department of Biology, University of Pisa, Pisa, Italy; Department of Biology, University of Rome "Tor Vergata", Rome, Italy
| | - Laura Bruno
- Department of Biology, University of Rome "Tor Vergata", Rome, Italy
| | - Claudio Varotto
- Department of Biodiversity and Molecular Ecology, "Edmund Mach" Foundation, S. Michele all'Adige (TN), Italy
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16
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Zayneb C, Imen RH, Walid K, Grubb CD, Bassem K, Franck V, Hafedh M, Amine E. The phytochelatin synthase gene in date palm (Phoenix dactylifera L.): Phylogeny, evolution and expression. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2017; 140:7-17. [PMID: 28231507 DOI: 10.1016/j.ecoenv.2017.02.020] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2016] [Revised: 02/11/2017] [Accepted: 02/13/2017] [Indexed: 06/06/2023]
Abstract
We studied date palm phytochelatin synthase type I (PdPCS1), which catalyzes the cytosolic synthesis of phytochelatins (PCs), a heavy metal binding protein, in plant cells. The gene encoding PdPCS1 (Pdpcs) consists of 8 exons and 7 introns and encodes a protein of 528 amino acids. PCs gene history was studied using Notung phylogeny. During evolution, gene loss from several lineages was predicted including Proteobacteria, Bilateria and Brassicaceae. In addition, eleven gene duplication events appeared toward interior nodes of the reconciled tree and four gene duplication events appeared toward the external nodes. These latter sequences belong to species with a second copy of PCs suggesting that this gene evolved through subfunctionalization. Pdpcs1 gene expression was measured in seedling hypocotyls exposed to Cd, Cu and Cr using quantitative real-time polymerase chain reaction (qPCR). A Pdpcs1 overexpression was evidenced in P. dactylifera seedlings exposed to metals suggesting that 1-the Pdpcs1 gene is functional, 2-there is an implication of the enzyme in metal detoxification mechanisms. Additionally, the structure of PdPCS1 was predicted using its homologue from Nostoc (cyanobacterium, NsPCS) as a template in Discovery studio and PyMol software. These analyses allowed us to identify the phytochelatin synthase type I enzyme in date palm (PdPCS1) via recognition of key consensus amino acids involved in the catalytic mechanism, and to propose a hypothetical binding and catalytic site for an additional substrate binding cavity.
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Affiliation(s)
- Chaâbene Zayneb
- Laboratory of Plant Biotechnology, Faculty of Sciences, University of Sfax, BP 1171, 3000 Sfax, Tunisia; Laboratoire de Génie Civil et géo-Environnement, Université de Lille 1, F-59655 Villeneuve d'Ascq, France
| | - Rekik Hakim Imen
- Laboratory of Plant Biotechnology, Faculty of Sciences, University of Sfax, BP 1171, 3000 Sfax, Tunisia
| | - Kriaa Walid
- Laboratory of Plant Biotechnology, Faculty of Sciences, University of Sfax, BP 1171, 3000 Sfax, Tunisia
| | - C Douglas Grubb
- Biorecycling Operations Research Laboratory, Des Moines, IA, USA
| | - Khemakhem Bassem
- Laboratory of Plant Biotechnology, Faculty of Sciences, University of Sfax, BP 1171, 3000 Sfax, Tunisia
| | - Vandenbulcke Franck
- Laboratoire de Génie Civil et géo-Environnement, Université de Lille 1, F-59655 Villeneuve d'Ascq, France
| | - Mejdoub Hafedh
- Laboratory of Plant Biotechnology, Faculty of Sciences, University of Sfax, BP 1171, 3000 Sfax, Tunisia
| | - Elleuch Amine
- Laboratory of Plant Biotechnology, Faculty of Sciences, University of Sfax, BP 1171, 3000 Sfax, Tunisia.
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17
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Ferri A, Lancilli C, Maghrebi M, Lucchini G, Sacchi GA, Nocito FF. The Sulfate Supply Maximizing Arabidopsis Shoot Growth Is Higher under Long- than Short-Term Exposure to Cadmium. FRONTIERS IN PLANT SCIENCE 2017; 8:854. [PMID: 28588602 PMCID: PMC5439006 DOI: 10.3389/fpls.2017.00854] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Accepted: 05/08/2017] [Indexed: 05/23/2023]
Abstract
The processes involved in cadmium detoxification in plants deeply affect sulfate uptake and thiol homeostasis and generate increases in the plant nutritional request for sulfur. Here, we present an analysis of the dependence of Arabidopsis growth on the concentration of sulfate in the growing medium with the aim of providing evidence on how plants optimize growth at a given sulfate availability. Results revealed that short-term (72 h) exposure to a broad range of Cd concentrations (0.1, 1, and 10 μM) inhibited plant growth but did not produce any significant effects on the growth pattern of both shoots and roots in relation to the external sulfate. Conversely, long-term (22 days) exposure to 0.1 μM Cd significantly changed the pattern of fresh weight accumulation of the shoots in relation to the external sulfate, without affecting that of the roots, although their growth was severely inhibited by Cd. Moreover, under long-term exposure to Cd, increasing the sulfate external concentration up to the critical value progressively reduced the inhibitory effects exerted by Cd on shoot growth, indicating the existence of sulfate-dependent adaptive responses protecting the shoot tissues against Cd injury. Transcriptional induction of the high-affinity sulfate transporter genes (SULTR1; 1 and SULTR1; 2) involved in sulfate uptake by roots was a common adaptive response to both short- and long-term exposure to Cd. Such a response was closely related to the total amount of non-protein thiols accumulated by a single plant under short-term exposure to Cd, but did not showed any clear relation with thiols under long-term exposure to Cd. In this last condition, Cd exposure did not change the level of non-protein thiols per plant and thus did not alter the nutritional need for sulfur. In conclusion, our results indicate that long term-exposure to Cd, although it induces sulfate uptake, decreases the capacity of the Arabidopsis roots to efficiently absorb the sulfate ions available in the growing medium making the adaptive response of SULTR1; 1 and SULTR1; 2 "per se" not enough to optimize the growth at sulfate external concentrations lower than the critical value.
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Affiliation(s)
- Alessandro Ferri
- Dipartimento di Scienze Agrarie e Ambientali – Produzione, Territorio, Agroenergia, Università degli Studi di MilanoMilano, Italy
| | - Clarissa Lancilli
- Dipartimento di Scienze Agrarie e Ambientali – Produzione, Territorio, Agroenergia, Università degli Studi di MilanoMilano, Italy
- Istituto d’Istruzione Superiore di CodognoCodogno, Italy
| | - Moez Maghrebi
- Dipartimento di Scienze Agrarie e Ambientali – Produzione, Territorio, Agroenergia, Università degli Studi di MilanoMilano, Italy
| | - Giorgio Lucchini
- Dipartimento di Scienze Agrarie e Ambientali – Produzione, Territorio, Agroenergia, Università degli Studi di MilanoMilano, Italy
| | - Gian Attilio Sacchi
- Dipartimento di Scienze Agrarie e Ambientali – Produzione, Territorio, Agroenergia, Università degli Studi di MilanoMilano, Italy
| | - Fabio F. Nocito
- Dipartimento di Scienze Agrarie e Ambientali – Produzione, Territorio, Agroenergia, Università degli Studi di MilanoMilano, Italy
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18
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Olsson S, Penacho V, Puente-Sánchez F, Díaz S, Gonzalez-Pastor JE, Aguilera A. Horizontal Gene Transfer of Phytochelatin Synthases from Bacteria to Extremophilic Green Algae. MICROBIAL ECOLOGY 2017; 73:50-60. [PMID: 27592346 DOI: 10.1007/s00248-016-0848-z] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2015] [Accepted: 08/25/2016] [Indexed: 06/06/2023]
Abstract
Transcriptomic sequencing together with bioinformatic analyses and an automated annotation process led us to identify novel phytochelatin synthase (PCS) genes from two extremophilic green algae (Chlamydomonas acidophila and Dunaliella acidophila). These genes are of intermediate length compared to known PCS genes from eukaryotes and PCS-like genes from prokaryotes. A detailed phylogenetic analysis gives new insight into the complicated evolutionary history of PCS genes and provides evidence for multiple horizontal gene transfer events from bacteria to eukaryotes within the gene family. A separate subgroup containing PCS-like genes within the PCS gene family is not supported since the PCS genes are monophyletic only when the PCS-like genes are included. The presence and functionality of the novel genes in the organisms were verified by genomic sequencing and qRT-PCR. Furthermore, the novel PCS gene in Chlamydomonas acidophila showed very strong induction by cadmium. Cloning and expression of the gene in Escherichia coli clearly improves its cadmium resistance. The gene in Dunaliella was not induced, most likely due to gene duplication.
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Affiliation(s)
- Sanna Olsson
- Department of Agricultural Sciences, University of Helsinki, P.O. Box 27, 00014, Helsinki, Finland.
- Centro de Astrobiología (CSIC-INTA), Carretera de Ajalvir Km 4, Torrejón de Ardoz, 28850, Madrid, Spain.
| | - Vanessa Penacho
- Centro de Astrobiología (CSIC-INTA), Carretera de Ajalvir Km 4, Torrejón de Ardoz, 28850, Madrid, Spain
- Bioarray, S.L., Parque Científico y Empresarial de la UMH. Edificio Quorum III, Avenida de la Universidad s/n, 03202, Elche, Alicante, Spain
| | - Fernando Puente-Sánchez
- Centro de Astrobiología (CSIC-INTA), Carretera de Ajalvir Km 4, Torrejón de Ardoz, 28850, Madrid, Spain
| | - Silvia Díaz
- Departamento de Microbiología-III, Facultad de Biología, Universidad Complutense (UCM), Madrid, Spain
| | | | - Angeles Aguilera
- Centro de Astrobiología (CSIC-INTA), Carretera de Ajalvir Km 4, Torrejón de Ardoz, 28850, Madrid, Spain
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19
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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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20
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Essig YJ, Webb SM, Stürzenbaum SR. Deletion of Phytochelatin Synthase Modulates the Metal Accumulation Pattern of Cadmium Exposed C. elegans. Int J Mol Sci 2016; 17:257. [PMID: 26907254 PMCID: PMC4783986 DOI: 10.3390/ijms17020257] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2016] [Revised: 02/04/2016] [Accepted: 02/14/2016] [Indexed: 01/28/2023] Open
Abstract
Environmental metal pollution is a growing health risk to flora and fauna. It is therefore important to fully elucidate metal detoxification pathways. Phytochelatin synthase (PCS), an enzyme involved in the biosynthesis of phytochelatins (PCs), plays an important role in cadmium detoxification. The PCS and PCs are however not restricted to plants, but are also present in some lower metazoans. The model nematode Caenorhabditis elegans, for example, contains a fully functional phytochelatin synthase and phytochelatin pathway. By means of a transgenic nematode strain expressing a pcs-1 promoter-tagged GFP (pcs-1::GFP) and a pcs-1 specific qPCR assay, further evidence is presented that the expression of the C. elegans phytochelatin synthase gene (pcs-1) is transcriptionally non-responsive to a chronic (48 h) insult of high levels of zinc (500 μM) or acute (3 h) exposures to high levels of cadmium (300 μM). However, the accumulation of cadmium, but not zinc, is dependent on the pcs-1 status of the nematode. Synchrotron based X-ray fluorescence imaging uncovered that the cadmium body burden increased significantly in the pcs-1(tm1748) knockout allele. Taken together, this suggests that whilst the transcription of pcs-1 may not be mediated by an exposure zinc or cadmium, it is nevertheless an integral part of the cadmium detoxification pathway in C. elegans.
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Affiliation(s)
- Yona J Essig
- Analytical and Environmental Sciences Division, Faculty of Life Sciences & Medicine, King's College London, London SE1 9NH, UK.
- Medical Research Council-Public Health England (MRC-PHE) Centre for Environment & Health, King's College London, London SE1 9NH, UK.
| | - Samuel M Webb
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025, USA.
| | - Stephen R Stürzenbaum
- Analytical and Environmental Sciences Division, Faculty of Life Sciences & Medicine, King's College London, London SE1 9NH, UK.
- Medical Research Council-Public Health England (MRC-PHE) Centre for Environment & Health, King's College London, London SE1 9NH, UK.
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21
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Lavoie M, Raven JA, Jones OAH, Qian H. Energy cost of intracellular metal and metalloid detoxification in wild-type eukaryotic phytoplankton. Metallomics 2016; 8:1097-1109. [DOI: 10.1039/c6mt00049e] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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22
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Kühnlenz T, Westphal L, Schmidt H, Scheel D, Clemens S. Expression of Caenorhabditis elegans PCS in the AtPCS1-deficient Arabidopsis thaliana cad1-3 mutant separates the metal tolerance and non-host resistance functions of phytochelatin synthases. PLANT, CELL & ENVIRONMENT 2015; 38:2239-47. [PMID: 25764348 DOI: 10.1111/pce.12534] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2015] [Revised: 02/19/2015] [Accepted: 03/06/2015] [Indexed: 05/22/2023]
Abstract
Phytochelatin synthases (PCS) play key roles in plant metal tolerance. They synthesize small metal-binding peptides, phytochelatins, under conditions of metal excess. Respective mutants are strongly cadmium and arsenic hypersensitive. However, their ubiquitous presence and constitutive expression had long suggested a more general function of PCS besides metal detoxification. Indeed, phytochelatin synthase1 from Arabidopsis thaliana (AtPCS1) was later implicated in non-host resistance. The two different physiological functions may be attributable to the two distinct catalytic activities demonstrated for AtPCS1, that is the dipeptidyl transfer onto an acceptor molecule in phytochelatin synthesis, and the proteolytic deglycylation of glutathione conjugates. In order to test this hypothesis and to possibly separate the two biological roles, we expressed a phylogenetically distant PCS from Caenorhabditis elegans in an AtPCS1 mutant. We confirmed the involvement of AtPCS1 in non-host resistance by showing that plants lacking the functional gene develop a strong cell death phenotype when inoculated with the potato pathogen Phytophthora infestans. Furthermore, we found that the C. elegans gene rescues phytochelatin synthesis and cadmium tolerance, but not the defect in non-host resistance. This strongly suggests that the second enzymatic function of AtPCS1, which remains to be defined in detail, is underlying the plant immunity function.
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Affiliation(s)
- Tanja Kühnlenz
- Department of Plant Physiology, University of Bayreuth, Universitätsstrasse 30, Bayreuth, 95440, Germany
| | - Lore Westphal
- Department of Stress and Developmental Biology, Leibniz Institute of Plant Biochemistry, Weinberg 3, Halle, 06120, Germany
| | - Holger Schmidt
- Department of Plant Physiology, University of Bayreuth, Universitätsstrasse 30, Bayreuth, 95440, Germany
| | - Dierk Scheel
- Department of Stress and Developmental Biology, Leibniz Institute of Plant Biochemistry, Weinberg 3, Halle, 06120, Germany
| | - Stephan Clemens
- Department of Plant Physiology, University of Bayreuth, Universitätsstrasse 30, Bayreuth, 95440, Germany
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Cheng MC, Ko K, Chang WL, Kuo WC, Chen GH, Lin TP. Increased glutathione contributes to stress tolerance and global translational changes in Arabidopsis. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2015; 83:926-939. [PMID: 26213235 DOI: 10.1111/tpj.12940] [Citation(s) in RCA: 83] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/03/2015] [Revised: 06/19/2015] [Accepted: 07/09/2015] [Indexed: 05/18/2023]
Abstract
Although glutathione is well known for its reactive oxygen species (ROS) scavenging function and plays a protective role in biotic stress, its regulatory function in abiotic stress still remains to be elucidated. Our previous study showed that exogenously applied reduced glutathione (GSH) could improve abiotic stress tolerance in Arabidopsis. Here, we report that endogenously increased GSH also conferred tolerance to drought and salt stress in Arabidopsis. Moreover, both exogenous and endogenous GSH delayed senescence and flowering time. Polysomal profiling results showed that global translation was enhanced after GSH treatment and by the induced increase of GSH level by salt stress. By performing transcriptomic analyses of steady-state and polysome-bound mRNAs in GSH-treated plants, we reveal that GSH has a substantial impact on translation. Translational changes induced by GSH treatment target numerous hormones and stress signaling molecules, which might contribute to the enhanced stress tolerance in GSH-treated plants. Our translatome analysis also revealed that abscisic acid (ABA), auxin and jasmonic acid (JA) biosynthesis, as well as signaling genes, were activated during GSH treatment, which has not been reported in previously published transcriptomic data. Together, our data suggest that the increased glutathione level results in stress tolerance and global translational changes.
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Affiliation(s)
- Mei-Chun Cheng
- Institute of Plant Biology, National Taiwan University, 1 Roosevelt Road, Section 4, Taipei, 10617, Taiwan
| | - Ko Ko
- Institute of Plant Biology, National Taiwan University, 1 Roosevelt Road, Section 4, Taipei, 10617, Taiwan
| | - Wan-Ling Chang
- Institute of Plant Biology, National Taiwan University, 1 Roosevelt Road, Section 4, Taipei, 10617, Taiwan
| | - Wen-Chieh Kuo
- Institute of Plant Biology, National Taiwan University, 1 Roosevelt Road, Section 4, Taipei, 10617, Taiwan
| | - Guan-Hong Chen
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, 11529, Taiwan
| | - Tsan-Piao Lin
- Institute of Plant Biology, National Taiwan University, 1 Roosevelt Road, Section 4, Taipei, 10617, Taiwan
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24
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Cahoon RE, Lutke WK, Cameron JC, Chen S, Lee SG, Rivard RS, Rea PA, Jez JM. Adaptive Engineering of Phytochelatin-based Heavy Metal Tolerance. J Biol Chem 2015; 290:17321-30. [PMID: 26018077 DOI: 10.1074/jbc.m115.652123] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2015] [Indexed: 11/06/2022] Open
Abstract
Metabolic engineering approaches are increasingly employed for environmental applications. Because phytochelatins (PC) protect plants from heavy metal toxicity, strategies directed at manipulating the biosynthesis of these peptides hold promise for the remediation of soils and groundwaters contaminated with heavy metals. Directed evolution of Arabidopsis thaliana phytochelatin synthase (AtPCS1) yields mutants that confer levels of cadmium tolerance and accumulation greater than expression of the wild-type enzyme in Saccharomyces cerevisiae, Arabidopsis, or Brassica juncea. Surprisingly, the AtPCS1 mutants that enhance cadmium tolerance and accumulation are catalytically less efficient than wild-type enzyme. Metabolite analyses indicate that transformation with AtPCS1, but not with the mutant variants, decreases the levels of the PC precursors, glutathione and γ-glutamylcysteine, upon exposure to cadmium. Selection of AtPCS1 variants with diminished catalytic activity alleviates depletion of these metabolites, which maintains redox homeostasis while supporting PC synthesis during cadmium exposure. These results emphasize the importance of metabolic context for pathway engineering and broaden the range of tools available for environmental remediation.
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Affiliation(s)
- Rebecca E Cahoon
- From the Department of Biology, Washington University, St. Louis, Missouri 63130, the Donald Danforth Plant Science Center, St. Louis, Missouri 63132
| | - W Kevin Lutke
- the Donald Danforth Plant Science Center, St. Louis, Missouri 63132
| | - Jeffrey C Cameron
- From the Department of Biology, Washington University, St. Louis, Missouri 63130
| | - Sixue Chen
- the Donald Danforth Plant Science Center, St. Louis, Missouri 63132, the Department of Biology, Genetics Institute, University of Florida, Gainesville, Florida 32610, and
| | - Soon Goo Lee
- From the Department of Biology, Washington University, St. Louis, Missouri 63130
| | - Rebecca S Rivard
- the Donald Danforth Plant Science Center, St. Louis, Missouri 63132
| | - Philip A Rea
- the Department of Biology, University of Pennsylvania, Philadelphia, Pennsylvania 19104
| | - Joseph M Jez
- From the Department of Biology, Washington University, St. Louis, Missouri 63130, the Donald Danforth Plant Science Center, St. Louis, Missouri 63132, the Department of Biology, University of Pennsylvania, Philadelphia, Pennsylvania 19104
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25
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Transcriptional response to copper excess and identification of genes involved in heavy metal tolerance in the extremophilic microalga Chlamydomonas acidophila. Extremophiles 2015; 19:657-72. [DOI: 10.1007/s00792-015-0746-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2014] [Accepted: 03/23/2015] [Indexed: 01/05/2023]
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26
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Bernard F, Brulle F, Dumez S, Lemiere S, Platel A, Nesslany F, Cuny D, Deram A, Vandenbulcke F. Antioxidant responses of Annelids, Brassicaceae and Fabaceae to pollutants: a review. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2015; 114:273-303. [PMID: 24951273 DOI: 10.1016/j.ecoenv.2014.04.024] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2013] [Revised: 04/15/2014] [Accepted: 04/20/2014] [Indexed: 06/03/2023]
Abstract
Pollutants, such as Metal Trace Elements (MTEs) and organic compounds (polycyclic aromatic hydrocarbons, pesticides), can impact DNA structure of living organisms and thus generate damage. For instance, cadmium is a well-known genotoxic and mechanisms explaining its clastogenicity are mainly indirect: inhibition of DNA repair mechanisms and/or induction of Reactive Oxygen Species (ROS). Animal or vegetal cells use antioxidant defense systems to protect themselves against ROS produced during oxidative stress. Because tolerance of organisms depends, at least partially, on their ability to cope with ROS, the mechanisms of production and management of ROS were investigated a lot in Ecotoxicology as markers of biotic and abiotic stress. This was mainly done through the measurement of enzyme activities The present Review focuses on 3 test species living in close contact with soil that are often used in soil ecotoxicology: the worm Eisenia fetida, and two plant species, Trifolium repens (white clover) and Brassica oleracea (cabbage). E. fetida is a soil-dwelling organism commonly used for biomonitoring. T. repens is a symbiotic plant species which forms root nodule with soil bacteria, while B. oleracea is a non-symbiotic plant. In literature, some oxidative stress enzyme activities have already been measured in those species but such analyses do not allow distinction between individual enzyme involvements in oxidative stress. Gene expression studies would allow this distinction at the transcriptomic level. A literature review and a data search in molecular database were carried out on the basis of keywords in Scopus, in PubMed and in Genbank™ for each species. Molecular data regarding E. fetida were already available in databases, but a lack of data regarding oxidative stress related genes was observed for T. repens and B. oleracea. By exploiting the conservation observed between species and using molecular biology techniques, we partially cloned missing candidates involved in oxidative stress and in metal detoxification in E. fetida, T. repens and B. oleracea.
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Affiliation(s)
- F Bernard
- Université Lille Nord de France, F-59000 Lille, France; Laboratoire de Génie Civil et géo-Environnement EA4515 - Université Lille Nord de France - Lille 1, Ecologie Numérique et Ecotoxicologie, F-59655 Villeneuve d'Ascq, France; Laboratoire des Sciences Végétales et Fongiques - Université de Lille 2, EA4483, F-59006 Lille Cedex, France
| | - F Brulle
- Université Lille Nord de France, F-59000 Lille, France; Laboratoire des Sciences Végétales et Fongiques - Université de Lille 2, EA4483, F-59006 Lille Cedex, France
| | - S Dumez
- Université Lille Nord de France, F-59000 Lille, France; Laboratoire des Sciences Végétales et Fongiques - Université de Lille 2, EA4483, F-59006 Lille Cedex, France
| | - S Lemiere
- Université Lille Nord de France, F-59000 Lille, France; Laboratoire de Génie Civil et géo-Environnement EA4515 - Université Lille Nord de France - Lille 1, Ecologie Numérique et Ecotoxicologie, F-59655 Villeneuve d'Ascq, France
| | - A Platel
- Université Lille Nord de France, F-59000 Lille, France; Laboratoire de Toxicologie - Institut Pasteur de Lille, EA 4483, F-59800 Lille, France
| | - F Nesslany
- Université Lille Nord de France, F-59000 Lille, France; Laboratoire de Toxicologie - Institut Pasteur de Lille, EA 4483, F-59800 Lille, France
| | - D Cuny
- Université Lille Nord de France, F-59000 Lille, France; Laboratoire des Sciences Végétales et Fongiques - Université de Lille 2, EA4483, F-59006 Lille Cedex, France
| | - A Deram
- Université Lille Nord de France, F-59000 Lille, France; Laboratoire des Sciences Végétales et Fongiques - Université de Lille 2, EA4483, F-59006 Lille Cedex, France; Faculté de Management de la Santé (ILIS) - Université de Lille 2, EA4483, F-59120 Loos, France
| | - F Vandenbulcke
- Université Lille Nord de France, F-59000 Lille, France; Laboratoire de Génie Civil et géo-Environnement EA4515 - Université Lille Nord de France - Lille 1, Ecologie Numérique et Ecotoxicologie, F-59655 Villeneuve d'Ascq, France.
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Girdhar M, Sharma NR, Rehman H, Kumar A, Mohan A. Comparative assessment for hyperaccumulatory and phytoremediation capability of three wild weeds. 3 Biotech 2014; 4:579-589. [PMID: 28324308 PMCID: PMC4235884 DOI: 10.1007/s13205-014-0194-0] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2013] [Accepted: 01/03/2014] [Indexed: 11/10/2022] Open
Abstract
The composition and the organization of soil are changing rapidly by the diverged mankind activities, leading to the contamination of environment. Several methods are employed to clean up the environment from these kinds of contaminants, but most of them are costly and ineffective to yield optimum results. Phytoremediation is a natural green technology, which is eco-friendly for the removal of toxic metals from the polluted environment. Phytoremediation is a cost-effective technique through which the cleanup of contaminated soil laced with heavy metals is performed by wild weeds and small herbal plants. The phytoremediation technique provides a promising tool for hyperaccumulation of heavy metals; arsenic, lead, mercury, copper, chromium, and nickel, etc., by the wild weeds and that has been discussed here in detail in case of Cannabissativa, Solanum nigrum and Rorippa globosa. In general, weeds that have the intrinsic capacity to accumulate metals into their shoots and roots, have the ability to form phytochelates and formation of stable compound with ions. This behavior of accumulation along with chelate and stable compound formation is utilized as a tool for phytoremediation activity.
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Affiliation(s)
- Madhuri Girdhar
- Department of Biotechnology, Lovely Professional University, Chehru, Phagwara, India
| | - Neeta Raj Sharma
- Department of Biotechnology, Lovely Professional University, Chehru, Phagwara, India
| | - Hasibur Rehman
- Department of Biology, Faculty of Sciences, University of Tabuk, Tabuk, Saudi Arabia
| | - Anupam Kumar
- Department of Biotechnology, Lovely Professional University, Chehru, Phagwara, India
| | - Anand Mohan
- Department of Biotechnology, Lovely Professional University, Chehru, Phagwara, India.
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28
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Kühnlenz T, Schmidt H, Uraguchi S, Clemens S. Arabidopsis thaliana phytochelatin synthase 2 is constitutively active in vivo and can rescue the growth defect of the PCS1-deficient cad1-3 mutant on Cd-contaminated soil. JOURNAL OF EXPERIMENTAL BOTANY 2014; 65:4241-53. [PMID: 24821959 PMCID: PMC4112630 DOI: 10.1093/jxb/eru195] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Phytochelatins play a key role in the detoxification of metals in plants and many other eukaryotes. Their formation is catalysed by phytochelatin synthases (PCS) in the presence of metal excess. It appears to be common among higher plants to possess two PCS genes, even though in Arabidopsis thaliana only AtPCS1 has been demonstrated to confer metal tolerance. Employing a highly sensitive quantification method based on ultraperformance electrospray ionization quadrupole time-of-flight mass spectrometry, we detected AtPCS2-dependent phytochelatin formation. Overexpression of AtPCS2 resulted in constitutive phytochelatin accumulation, i.e. in the absence of metal excess, both in planta and in a heterologous system. This indicates distinct enzymatic differences between AtPCS1 and AtPCS2. Furthermore, AtPCS2 was able to partially rescue the Cd hypersensitivity of the AtPCS1-deficient cad1-3 mutant in a liquid seedling assay, and, more importantly, when plants were grown on soil spiked with Cd to a level that is close to what can be found in agricultural soils. No rescue was found in vertical-plate assays, the most commonly used method to assess metal tolerance. Constitutive AtPCS2-dependent phytochelatin synthesis suggests a physiological role of AtPCS2 other than metal detoxification. The differences observed between wild-type plants and cad1-3 on Cd soil demonstrated: (i) the essentiality of phytochelatin synthesis for tolerating levels of Cd contamination that can naturally be encountered by plants outside of metal-rich habitats, and (ii) a contribution to Cd accumulation under these conditions.
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Affiliation(s)
- Tanja Kühnlenz
- Department of Plant Physiology, University of Bayreuth, Universitätsstrasse 30, 95447 Bayreuth, Germany
| | - Holger Schmidt
- Department of Plant Physiology, University of Bayreuth, Universitätsstrasse 30, 95447 Bayreuth, Germany
| | - Shimpei Uraguchi
- Department of Plant Physiology, University of Bayreuth, Universitätsstrasse 30, 95447 Bayreuth, Germany
| | - Stephan Clemens
- Department of Plant Physiology, University of Bayreuth, Universitätsstrasse 30, 95447 Bayreuth, Germany
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29
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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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30
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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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31
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Liebeke M, Garcia-Perez I, Anderson CJ, Lawlor AJ, Bennett MH, Morris CA, Kille P, Svendsen C, Spurgeon DJ, Bundy JG. Earthworms produce phytochelatins in response to arsenic. PLoS One 2013; 8:e81271. [PMID: 24278409 PMCID: PMC3838358 DOI: 10.1371/journal.pone.0081271] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2013] [Accepted: 10/10/2013] [Indexed: 12/13/2022] Open
Abstract
Phytochelatins are small cysteine-rich non-ribosomal peptides that chelate soft metal and metalloid ions, such as cadmium and arsenic. They are widely produced by plants and microbes; phytochelatin synthase genes are also present in animal species from several different phyla, but there is still little known about whether these genes are functional in animals, and if so, whether they are metal-responsive. We analysed phytochelatin production by direct chemical analysis in Lumbricus rubellus earthworms exposed to arsenic for a 28 day period, and found that arsenic clearly induced phytochelatin production in a dose-dependent manner. It was necessary to measure the phytochelatin metabolite concentrations directly, as there was no upregulation of phytochelatin synthase gene expression after 28 days: phytochelatin synthesis appears not to be transcriptionally regulated in animals. A further untargetted metabolomic analysis also found changes in metabolites associated with the transsulfuration pathway, which channels sulfur flux from methionine for phytochelatin synthesis. There was no evidence of biological transformation of arsenic (e.g. into methylated species) as a result of laboratory arsenic exposure. Finally, we compared wild populations of earthworms sampled from the field, and found that both arsenic-contaminated and cadmium-contaminated mine site worms had elevated phytochelatin concentrations.
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Affiliation(s)
- Manuel Liebeke
- Department of Surgery and Cancer, Imperial College London, London, United Kingdom
| | - Isabel Garcia-Perez
- Department of Surgery and Cancer, Imperial College London, London, United Kingdom
| | - Craig J. Anderson
- Centre for Ecology and Hydrology, Wallingford, United Kingdom
- School of Biosciences, University of Cardiff, Cardiff, United Kingdom
| | - Alan J. Lawlor
- Centre for Ecology and Hydrology, Lancaster, United Kingdom
| | - Mark H. Bennett
- Department of Life Sciences, Imperial College London, London, United Kingdom
| | - Ceri A. Morris
- School of Biosciences, University of Cardiff, Cardiff, United Kingdom
| | - Peter Kille
- School of Biosciences, University of Cardiff, Cardiff, United Kingdom
| | - Claus Svendsen
- Centre for Ecology and Hydrology, Wallingford, United Kingdom
| | | | - Jacob G. Bundy
- Department of Surgery and Cancer, Imperial College London, London, United Kingdom
- * E-mail:
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32
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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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Li YW, Gong ZH, Mu Y, Zhang YX, Qiao ZJ, Zhang LP, Jin ZP, Li H, Pei YX. An Arabidopsis mutant atcsr-2 exhibits high cadmium stress sensitivity involved in the restriction of H2S emission. J Zhejiang Univ Sci B 2013; 13:1006-14. [PMID: 23225856 DOI: 10.1631/jzus.b1200089] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The gene AtCSR encodes peptidyl-prolyl cis/trans isomerases (PPIases) that accelerate energetically unfavorable cis/trans isomerization of the peptide bond preceding proline production. In our studies, we found that AtCSR was associated with cadmium (Cd)-sensitive response in Arabidopsis. Our results show that AtCSR expression was triggered by Cd-stress in wild type Arabidopsis. The expression of some genes responsible for Cd(2+) transportation into vacuoles was induced, and the expression of the iron-regulated transporter 1 (IRT1) related to Cd(2+) absorption from the environment was not induced in wild type with Cd(2+) treatment. The expression of Cd-transportation related genes was not in response to Cd-stress, whereas IRT expression increased dramatically in atcsr-2 with Cd(2+) treatment. The expression of glutathione 1 (GSH1) was consistent with GSH being much lower in atcsr-2 in comparison with the wild type with Cd(2+) treatment. Additionally, malondialdehyde (MDA), hydrogen peroxide, and Cd(2+) contents, and activities of some antioxidative enzymes, differed between the wild type and atcsr-2. Hydrogen sulfide (H(2)S) has been confirmed as the third gas-transmitter over recent years. The findings revealed that the expression pattern of H(2)S-releasing related genes and that of Cd-induced chelation and transportation genes matched well in the wild type and atcsr-2, and H(2)S could regulate the expression of the Cd-induced genes and alleviate Cd-triggered toxicity. Finally, one possible suggestion was given: down-regulation of atcsr-2, depending on H(2)S gas-transmitter not only weakened Cd(2+) chelation, but also reduced Cd(2+) transportation into vacuoles, as well as enhancing the Cd(2+) assimilation, thus rendering atcsr-2 mutant sensitive to Cd-stress.
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Affiliation(s)
- Ya-wei Li
- School of Life Science, Shanxi University, Taiyuan 030006, China
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Synthetic phytochelatins complement a phytochelatin-deficient Arabidopsis mutant and enhance the accumulation of heavy metal(loid)s. Biochem Biophys Res Commun 2013; 434:664-9. [DOI: 10.1016/j.bbrc.2013.03.138] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2013] [Accepted: 03/29/2013] [Indexed: 12/14/2022]
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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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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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Shukla D, Kesari R, Mishra S, Dwivedi S, Tripathi RD, Nath P, Trivedi PK. Expression of phytochelatin synthase from aquatic macrophyte Ceratophyllum demersum L. enhances cadmium and arsenic accumulation in tobacco. PLANT CELL REPORTS 2012; 31:1687-99. [PMID: 22614255 DOI: 10.1007/s00299-012-1283-3] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2012] [Revised: 04/27/2012] [Accepted: 05/03/2012] [Indexed: 05/22/2023]
Abstract
UNLABELLED Phytochelatin synthase (PCS), the key enzyme involved in heavy metal detoxification and accumulation has been used from various sources to develop transgenic plants for the purpose of phytoremediation. However, some of the earlier studies provided contradictory results. Most of the PCS genes were isolated from plants that are not potential metal accumulators. In this study, we have isolated PCS gene from Ceratophyllum demersum cv. L. (CdPCS1), a submerged rootless aquatic macrophyte, which is considered as potential accumulator of heavy metals. The CdPCS1 cDNA of 1,757 bp encodes a polypeptide of 501 amino acid residues and differs from other known PCS with respect to the presence of a number of cysteine residues known for their interaction with heavy metals. Complementation of cad1-3 mutant of Arabidopsis deficient in PC (phytochelatin) biosynthesis by CdPCS1 suggests its role in the synthesis of PCs. Transgenic tobacco plants expressing CdPCS1 showed several-fold increased PC content and precursor non-protein thiols with enhanced accumulation of cadmium (Cd) and arsenic (As) without significant decrease in plant growth. We conclude that CdPCS1 encodes functional PCS and may be part of metal detoxification mechanism of the heavy metal accumulating plant C. demersum. KEY MESSAGE Heterologous expression of PCS gene from C. demersum complements Arabidopsis cad1-3 mutant and leads to enhanced accumulation of Cd and As in transgenic tobacco.
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Affiliation(s)
- Devesh Shukla
- CSIR-National Botanical Research Institute, Rana Pratap Marg, Lucknow, 226 001, India
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Abstract
Of the mechanisms known to protect vascular plants and some algae, fungi and invertebrates from the toxic effects of non-essential heavy metals such as As, Cd or Hg, one of the most sophisticated is the enzyme-catalyzed synthesis of phytochelatins (PCs). PCs, (γ-Glu-Cys)(n) Gly polymers, which serve as high-affinity, thiol-rich cellular chelators and contribute to the detoxification of heavy metal ions, are derived from glutathione (GSH; γ-Glu-Cys-Gly) and related thiols in a reaction catalyzed by phytochelatin synthases (PC synthases, EC 2.3.2.15). Using the enzyme from Arabidopsis thaliana (AtPCS1) as a model, the reasoning and experiments behind the conclusion that PC synthases are novel papain-like Cys protease superfamily members are presented. The status of S-substituted GSH derivatives as generic PC synthase substrates and the sufficiency of the N-terminal domain of the enzyme from eukaryotic and its half-size equivalents from prokaryotic sources, for net PC synthesis and deglycylation of GSH and its derivatives, respectively, are emphasized. The question of the common need or needs met by PC synthases and their homologs is discussed. Of the schemes proposed to account for the combined protease and peptide polymerase capabilities of the eukaryotic enzymes vs the limited protease capabilities of the prokaryotic enzymes, two that will be considered are the storage and homeostasis of essential heavy metals in eukaryotes and the metabolism of S-substituted GSH derivatives in both eukaryotes and prokaryotes.
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Affiliation(s)
- Philip A Rea
- Carolyn Hoff Lynch Biology Laboratory, Plant Science Institute, Department of Biology, University of Pennsylvania, Philadelphia, PA 19104, USA.
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Shanmugam V, Tsednee M, Yeh KC. ZINC TOLERANCE INDUCED BY IRON 1 reveals the importance of glutathione in the cross-homeostasis between zinc and iron in Arabidopsis thaliana. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2012; 69:1006-17. [PMID: 22066515 DOI: 10.1111/j.1365-313x.2011.04850.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Zinc is an essential micronutrient for plants, but it is toxic in excess concentrations. In Arabidopsis, additional iron (Fe) can increase Zn tolerance. We isolated a mutant, zinc tolerance induced by iron 1, designated zir1, with a defect in Fe-mediated Zn tolerance. Using map-based cloning and genetic complementation, we identified that zir1 has a mutation of glutamate to lysine at position 385 on γ-glutamylcysteine synthetase (GSH1), the enzyme involved in glutathione biosynthesis. The zir1 mutant contains only 15% of the wild-type glutathione level. Blocking glutathione biosynthesis in wild-type plants by a specific inhibitor of GSH1, buthionine sulfoximine, resulted in loss of Fe-mediated Zn tolerance, which provides further evidence that glutathione plays an essential role in Fe-mediated Zn tolerance. Two glutathione-deficient mutant alleles of GSH1, pad2-1 and cad2-1, which contain 22% and 39%, respectively, of the wild-type glutathione level, revealed that a minimal glutathione level between 22 and 39% of the wild-type level is required for Fe-mediated Zn tolerance. Under excess Zn and Fe, the recovery of shoot Fe contents in pad2-1 and cad2-1 was lower than that of the wild type. However, the phytochelatin-deficient mutant cad1-3 showed normal Fe-mediated Zn tolerance. These results indicate a specific role of glutathione in Fe-mediated Zn tolerance. The induced accumulation of glutathione in response to excess Zn and Fe suggests that glutathione plays a specific role in Fe-mediated Zn tolerance in Arabidopsis. We conclude that glutathione is required for the cross-homeostasis between Zn and Fe in Arabidopsis.
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Affiliation(s)
- Varanavasiappan Shanmugam
- Molecular and Biological Agricultural Sciences, Taiwan International Graduate Program, National Chung-Hsing University and Academia Sinica, Taipei, Taiwan
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Noctor G, Mhamdi A, Chaouch S, Han Y, Neukermans J, Marquez-Garcia B, Queval G, Foyer CH. Glutathione in plants: an integrated overview. PLANT, CELL & ENVIRONMENT 2012; 35:454-84. [PMID: 21777251 DOI: 10.1111/j.1365-3040.2011.02400.x] [Citation(s) in RCA: 791] [Impact Index Per Article: 65.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Plants cannot survive without glutathione (γ-glutamylcysteinylglycine) or γ-glutamylcysteine-containing homologues. The reasons why this small molecule is indispensable are not fully understood, but it can be inferred that glutathione has functions in plant development that cannot be performed by other thiols or antioxidants. The known functions of glutathione include roles in biosynthetic pathways, detoxification, antioxidant biochemistry and redox homeostasis. Glutathione can interact in multiple ways with proteins through thiol-disulphide exchange and related processes. Its strategic position between oxidants such as reactive oxygen species and cellular reductants makes the glutathione system perfectly configured for signalling functions. Recent years have witnessed considerable progress in understanding glutathione synthesis, degradation and transport, particularly in relation to cellular redox homeostasis and related signalling under optimal and stress conditions. Here we outline the key recent advances and discuss how alterations in glutathione status, such as those observed during stress, may participate in signal transduction cascades. The discussion highlights some of the issues surrounding the regulation of glutathione contents, the control of glutathione redox potential, and how the functions of glutathione and other thiols are integrated to fine-tune photorespiratory and respiratory metabolism and to modulate phytohormone signalling pathways through appropriate modification of sensitive protein cysteine residues.
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Affiliation(s)
- Graham Noctor
- Institut de Biologie des Plantes, UMR CNRS 8618, Université de Paris sud 11, Orsay cedex, France.
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Bianucci E, Sobrino-Plata J, Carpena-Ruiz RO, Del Carmen Tordable M, Fabra A, Hernández LE, Castro S. Contribution of phytochelatins to cadmium tolerance in peanut plants. Metallomics 2012; 4:1119-24. [PMID: 22986748 DOI: 10.1039/c2mt20146a] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Affiliation(s)
- Eliana Bianucci
- Departamento de Ciencias Naturales, Facultad de Ciencias Exactas, Físico-Químicas y Naturales, Universidad Nacional de Río Cuarto, Ruta 36 Km 601, 5800 Río Cuarto, Córdoba, Argentina
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Huang HH, Rigouin C, Williams DL. The redox biology of schistosome parasites and applications for drug development. Curr Pharm Des 2012; 18:3595-3611. [PMID: 22607149 PMCID: PMC3638776] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2012] [Accepted: 03/09/2012] [Indexed: 05/31/2023]
Abstract
Schistosomiasis caused by Schistosoma spp. is a serious public health concern, especially in sub-Saharan Africa. Praziquantel is the only drug currently administrated to treat this disease. However, praziquantel-resistant parasites have been identified in endemic areas and can be generated in the laboratory. Therefore, it is essential to find new therapeutics. Antioxidants are appealing drug targets. In order to survive in their hosts, schistosomes are challenged by reactive oxygen species from intrinsic and extrinsic sources. Schistosome antioxidant enzymes have been identified as essential proteins and novel drug targets and inhibition of the antioxidant response can lead to parasite death. Because the organization of the redox network in schistosomes is significantly different from that in humans, new drugs are being developed targeting schistosome antioxidants. In this paper the redox biology of schistosomes is discussed and their potential use as drug targets is reviewed. It is hoped that compounds targeting parasite antioxidant responses will become clinically relevant drugs in the near future.
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Affiliation(s)
| | | | - David L. Williams
- Correspondence should be addressed to: Dr. David L. Williams, Department of Microbiology and Immunology, Rush University Medical Center, Chicago, IL 60612-3824 . Phone: (312) 942-1375; Fax: (312) 942-2808
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Ravilious GE, Jez JM. Structural biology of plant sulfur metabolism: From assimilation to biosynthesis. Nat Prod Rep 2012; 29:1138-52. [DOI: 10.1039/c2np20009k] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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45
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Brulle F, Lemière S, Waterlot C, Douay F, Vandenbulcke F. Gene expression analysis of 4 biomarker candidates in Eisenia fetida exposed to an environmental metallic trace elements gradient: a microcosm study. THE SCIENCE OF THE TOTAL ENVIRONMENT 2011; 409:5470-5482. [PMID: 21937088 DOI: 10.1016/j.scitotenv.2011.08.040] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2011] [Revised: 08/17/2011] [Accepted: 08/20/2011] [Indexed: 05/31/2023]
Abstract
Past activities of 2 smelters (Metaleurop Nord and Nyrstar) led to the accumulation of high amounts of Metal Trace Elements (TEs) in top soils of the Noyelles-Godault/Auby area, Northern France. Earthworms were exposed to polluted soils collected in this area to study and better understand the physiological changes, the mechanisms of acclimation, and detoxification resulting from TE exposure. Previously we have cloned and transcriptionally characterized potential biomarkers from immune cells of the ecotoxicologically important earthworm species Eisenia fetida exposed in vivo to TE-spiked standard soils. In the present study, analysis of expression kinetics of four candidate indicator genes (Cadmium-metallothionein, coactosin like protein, phytochelatin synthase and lysenin) was performed in E. fetida after microcosm exposures to natural soils exhibiting an environmental cadmium (Cd) gradient in a kinetic manner. TE body burdens were also measured. This microcosm study provided insights into: (1) the ability of the 4 tested genes to serve as expression biomarkers, (2) detoxification processes through the expression analysis of selected genes, and (3) influence of land uses on the response of potential biomarkers (gene expression or TE uptake).
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Affiliation(s)
- Franck Brulle
- University Lille Nord de France, F-59000 Lille, France
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Abstract
It has long been understood that many of the same manipulations that increase longevity in Caenorhabditis elegans also increase resistance to various acute stressors, and vice-versa; moreover these findings hold in more complex organisms as well. Nevertheless, the mechanistic relationship between these phenotypes remains unclear, and in many cases the overlap between stress resistance and longevity is inexact. Here we review the known connections between stress resistance and longevity, discuss instances in which these connections are absent, and summarize the theoretical explanations that have been posited for these phenomena.
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Affiliation(s)
- Katherine I. Zhou
- Department of Molecular, Cellular and Developmental Biology, PO Box 208103, Yale University, New Haven, CT 06520
| | - Zachary Pincus
- Department of Molecular, Cellular and Developmental Biology, PO Box 208103, Yale University, New Haven, CT 06520
| | - Frank J. Slack
- Department of Molecular, Cellular and Developmental Biology, PO Box 208103, Yale University, New Haven, CT 06520
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Nocito FF, Lancilli C, Dendena B, Lucchini G, Sacchi GA. Cadmium retention in rice roots is influenced by cadmium availability, chelation and translocation. PLANT, CELL & ENVIRONMENT 2011; 34:994-1008. [PMID: 21388416 DOI: 10.1111/j.1365-3040.2011.02299.x] [Citation(s) in RCA: 122] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Analysis of rice plants exposed to a broad range of relatively low and environmentally realistic Cd concentrations showed that the root capacity to retain Cd ions rose from 49 to 79%, corresponding to increases in the external Cd²+ concentration in the 0.01-1 µM range. Fractioning of Cd ions retained by roots revealed that different events along the metal sequestration pathway (i.e. chelation by thiols, vacuolar compartmentalization, adsorption) contributed to Cd immobilization in the roots. However, large amounts of Cd ions (around 24% of the total amount) predictable as potentially mobile were still found in all conditions, while the amount of Cd ions loaded in the xylem seemed to have already reached saturation at 0.1 µM Cd²+, suggesting that Cd translocation may also play an indirect role in determining Cd root retention, especially at the highest external concentrations. In silico search and preliminary analyses in yeast suggest OsHMA2 as a good candidate for the control of Cd xylem loading in rice. Taken as a whole, data indicate Cd chelation, compartmentalization, adsorption and translocation processes as components of a complex 'firewall system' which acts in limiting Cd translocation from the root to the shoot and which reaches different equilibrium positions depending on Cd external concentration.
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Affiliation(s)
- Fabio Francesco Nocito
- Dipartimento di Produzione Vegetale, Università degli Studi di Milano, 20133 Milan, Italy
| | - Clarissa Lancilli
- Dipartimento di Produzione Vegetale, Università degli Studi di Milano, 20133 Milan, Italy
| | - Bianca Dendena
- Dipartimento di Produzione Vegetale, Università degli Studi di Milano, 20133 Milan, Italy
| | - Giorgio Lucchini
- Dipartimento di Produzione Vegetale, Università degli Studi di Milano, 20133 Milan, Italy
| | - Gian Attilio Sacchi
- Dipartimento di Produzione Vegetale, Università degli Studi di Milano, 20133 Milan, Italy
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Ray D, Williams DL. Characterization of the phytochelatin synthase of Schistosoma mansoni. PLoS Negl Trop Dis 2011; 5:e1168. [PMID: 21629724 PMCID: PMC3101182 DOI: 10.1371/journal.pntd.0001168] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2010] [Accepted: 03/28/2011] [Indexed: 02/07/2023] Open
Abstract
Treatment for schistosomiasis, which is responsible for more than 280,000 deaths annually, depends exclusively on the use of praziquantel. Millions of people are treated annually with praziquantel and drug resistant parasites are likely to evolve. In order to identify novel drug targets the Schistosoma mansoni sequence databases were queried for proteins involved in glutathione metabolism. One potential target identified was phytochelatin synthase (PCS). Phytochelatins are oligopeptides synthesized enzymatically from glutathione by PCS that sequester toxic heavy metals in many organisms. However, humans do not have a PCS gene and do not synthesize phytochelatins. In this study we have characterized the PCS of S. mansoni (SmPCS). The conserved catalytic triad of cysteine-histidine-aspartate found in PCS proteins and cysteine proteases is also found in SmPCS, as are several cysteine residues thought to be involved in heavy metal binding and enzyme activation. The SmPCS open reading frame is considerably extended at both the N- and C-termini compared to PCS from other organisms. Multiple PCS transcripts are produced from the single encoded gene by alternative splicing, resulting in both mitochondrial and cytoplasmic protein variants. Expression of SmPCS in yeast increased cadmium tolerance from less than 50 µM to more than 1,000 µM. We confirmed the function of SmPCS by identifying PCs in yeast cell extracts using HPLC-mass spectrometry. SmPCS was found to be expressed in all mammalian stages of worm development investigated. Increases in SmPCS expression were seen in ex vivo worms cultured in the presence of iron, copper, cadmium, or zinc. Collectively, these results indicate that SmPCS plays an important role in schistosome response to heavy metals and that PCS is a potential drug target for schistosomiasis treatment. This is the first characterization of a PCS from a parasitic organism. 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 a unique gene of Schistosoma mansoni that may be a candidate for drug targeting to control schistosomiasis. This gene, phytochelatin synthase (PCS), is a single copy gene in S. mansoni but is absent from humans. Our results confirm that schistosome PCS produces phytochelatins that are capable of scavenging and detoxifying heavy metals. The expression of the PCS gene in ex vivo adult schistosome worms was increased by exposure to a number of heavy metals. These results indicate that S. mansoni PCS regulates the availability of metal ions that the worm may be exposed to, either as co-factors in metalloenzymes or as excess metals encountered in the blood stream of their mammalian host. Collectively, these results have important implications for drug development for the control of schistosomiasis. Since other helminth parasites have PCS, drug development targeting this enzyme may have wide applications in the control of multiple neglected diseases.
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Affiliation(s)
- Debalina Ray
- Department of Biological Sciences, Illinois State University, Normal, Illinois, United States of America
- Department of Immunology/Microbiology, Rush University Medical Center, Chicago, Illinois, United States of America
| | - David L. Williams
- Department of Biological Sciences, Illinois State University, Normal, Illinois, United States of America
- Department of Immunology/Microbiology, Rush University Medical Center, Chicago, Illinois, United States of America
- * E-mail:
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Noctor G, Queval G, Mhamdi A, Chaouch S, Foyer CH. Glutathione. THE ARABIDOPSIS BOOK 2011; 9:e0142. [PMID: 22303267 PMCID: PMC3267239 DOI: 10.1199/tab.0142] [Citation(s) in RCA: 133] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Glutathione is a simple sulfur compound composed of three amino acids and the major non-protein thiol in many organisms, including plants. The functions of glutathione are manifold but notably include redox-homeostatic buffering. Glutathione status is modulated by oxidants as well as by nutritional and other factors, and can influence protein structure and activity through changes in thiol-disulfide balance. For these reasons, glutathione is a transducer that integrates environmental information into the cellular network. While the mechanistic details of this function remain to be fully elucidated, accumulating evidence points to important roles for glutathione and glutathione-dependent proteins in phytohormone signaling and in defense against biotic stress. Work in Arabidopsis is beginning to identify the processes that govern glutathione status and that link it to signaling pathways. As well as providing an overview of the components that regulate glutathione homeostasis (synthesis, degradation, transport, and redox turnover), the present discussion considers the roles of this metabolite in physiological processes such as light signaling, cell death, and defense against microbial pathogen and herbivores.
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Affiliation(s)
- Graham Noctor
- Institut de Biologie des Plantes, UMR CNRS 8618, Université de Paris sud 11, 91405 Orsay cedex, France
| | - Guillaume Queval
- Institut de Biologie des Plantes, UMR CNRS 8618, Université de Paris sud 11, 91405 Orsay cedex, France
- Present address: Department of Plant Systems Biology, Flanders Institute for Biotechnology and Department of Plant Biotechnologyand Genetics, Gent University, 9052 Gent, Belgium
| | - Amna Mhamdi
- Institut de Biologie des Plantes, UMR CNRS 8618, Université de Paris sud 11, 91405 Orsay cedex, France
| | - Sejir Chaouch
- Institut de Biologie des Plantes, UMR CNRS 8618, Université de Paris sud 11, 91405 Orsay cedex, France
| | - Christine H. Foyer
- Centre for Plant Sciences, Faculty of Biology, University of Leeds, Leeds, LS2 9JT, UK
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Noctor G, Queval G, Mhamdi A, Chaouch S, Foyer CH. Glutathione. THE ARABIDOPSIS BOOK 2011. [PMID: 22303267 DOI: 10.1199/tab0142] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
Glutathione is a simple sulfur compound composed of three amino acids and the major non-protein thiol in many organisms, including plants. The functions of glutathione are manifold but notably include redox-homeostatic buffering. Glutathione status is modulated by oxidants as well as by nutritional and other factors, and can influence protein structure and activity through changes in thiol-disulfide balance. For these reasons, glutathione is a transducer that integrates environmental information into the cellular network. While the mechanistic details of this function remain to be fully elucidated, accumulating evidence points to important roles for glutathione and glutathione-dependent proteins in phytohormone signaling and in defense against biotic stress. Work in Arabidopsis is beginning to identify the processes that govern glutathione status and that link it to signaling pathways. As well as providing an overview of the components that regulate glutathione homeostasis (synthesis, degradation, transport, and redox turnover), the present discussion considers the roles of this metabolite in physiological processes such as light signaling, cell death, and defense against microbial pathogen and herbivores.
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