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Dharni JS, Shi Y, Zhang C, Petersen C, Walia H, Staswick P. Growth and transcriptional response of wheat and rice to the tertiary amine BMVE. FRONTIERS IN PLANT SCIENCE 2024; 14:1273620. [PMID: 38269141 PMCID: PMC10806070 DOI: 10.3389/fpls.2023.1273620] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/06/2023] [Accepted: 12/04/2023] [Indexed: 01/26/2024]
Abstract
Introduction Seed vigor is largely a product of sound seed development, maturation processes, genetics, and storage conditions. It is a crucial factor impacting plant growth and crop yield and is negatively affected by unfavorable environmental conditions, which can include drought and heat as well as cold wet conditions. The latter leads to slow germination and increased seedling susceptibility to pathogens. Prior research has shown that a class of plant growth regulators called substituted tertiary amines (STAs) can enhance seed germination, seedling growth, and crop productivity. However, inconsistent benefits have limited STA adoption on a commercial scale. Methods We developed a novel seed treatment protocol to evaluate the efficacy of 2-(N-methyl benzyl aminoethyl)-3-methyl butanoate (BMVE), which has shown promise as a crop seed treatment in field trials. Transcriptomic analysis of rice seedlings 24 h after BMVE treatment was done to identify the molecular basis for the improved seedling growth. The impact of BMVE on seed development was also evaluated by spraying rice panicles shortly after flower fertilization and subsequently monitoring the impact on seed traits. Results BMVE treatment of seeds 24 h after imbibition consistently improved wheat and rice seedling shoot and root growth in lab conditions. Treated wheat seedlings grown to maturity in a greenhouse also resulted in higher biomass than controls, though only under drought conditions. Treated seedlings had increased levels of transcripts involved in reactive oxygen species scavenging and auxin and gibberellic acid signaling. Conversely, several genes associated with increased reactive oxygen species/ROS load, abiotic stress responses, and germination hindering processes were reduced. BMVE spray increased both fresh and mature seed weights relative to the control for plants exposed to 96 h of heat stress. BMVE treatment during seed development also benefited germination and seedling growth in the next generation, under both ambient and heat stress conditions. Discussion The optimized experimental conditions we developed provide convincing evidence that BMVE does indeed have efficacy in plant growth enhancement. The results advance our understanding of how STAs work at the molecular level and provide insights for their practical application to improve crop growth.
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Affiliation(s)
- Jaspinder Singh Dharni
- Department of Agronomy and Horticulture, University of Nebraska, Lincoln, NE, United States
| | - Yu Shi
- School of Biological Sciences, University of Nebraska, Lincoln, NE, United States
| | - Chi Zhang
- School of Biological Sciences, University of Nebraska, Lincoln, NE, United States
| | | | - Harkamal Walia
- Department of Agronomy and Horticulture, University of Nebraska, Lincoln, NE, United States
| | - Paul Staswick
- Department of Agronomy and Horticulture, University of Nebraska, Lincoln, NE, United States
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Konieczna W, Mierek-Adamska A, Chojnacka N, Antoszewski M, Szydłowska-Czerniak A, Dąbrowska GB. Characterization of the Metallothionein Gene Family in Avena sativa L. and the Gene Expression during Seed Germination and Heavy Metal Stress. Antioxidants (Basel) 2023; 12:1865. [PMID: 37891944 PMCID: PMC10603854 DOI: 10.3390/antiox12101865] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2023] [Revised: 10/10/2023] [Accepted: 10/11/2023] [Indexed: 10/29/2023] Open
Abstract
Metallothioneins (MTs) are a family of small proteins rich in cysteine residues. The sulfhydryl group of metallothioneins can bind to metal ions, maintaining metal homeostasis and protecting the cells from damage caused by toxic heavy metals. Moreover, MTs can function as reactive oxygen species scavengers since cysteine thiols undergo reversible and irreversible oxidation. Here, we identified 21 metallothionein genes (AsMTs) in the oat (Avena sativa L.) genome, which were divided into four types depending on the amino acid sequences of putative proteins encoded by identified genes. Analysis of promoter sequences showed that MTs might respond to a variety of stimuli, including biotic and abiotic stresses and phytohormones. The results of qRT-PCR showed that all four types of AsMTs are differentially expressed during the first 48 hours of seed germination. Moreover, stress induced by the application of zinc, cadmium, and a mixture of zinc and cadmium affects the expression of oat MTs variously depending on the MT type, indicating that AsMT1-4 fulfil different roles in plant cells.
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Affiliation(s)
- Wiktoria Konieczna
- Department of Genetics, Faculty of Biological and Veterinary Sciences, Nicolaus Copernicus University in Toruń, Lwowska 1, 87-100 Toruń, Poland; (W.K.); (M.A.)
- Centre for Modern Interdisciplinary Technologies, Nicolaus Copernicus University in Toruń, Wileńska 4, 87-100 Toruń, Poland
| | - Agnieszka Mierek-Adamska
- Department of Genetics, Faculty of Biological and Veterinary Sciences, Nicolaus Copernicus University in Toruń, Lwowska 1, 87-100 Toruń, Poland; (W.K.); (M.A.)
- Centre for Modern Interdisciplinary Technologies, Nicolaus Copernicus University in Toruń, Wileńska 4, 87-100 Toruń, Poland
| | - Natalia Chojnacka
- Department of Genetics, Faculty of Biological and Veterinary Sciences, Nicolaus Copernicus University in Toruń, Lwowska 1, 87-100 Toruń, Poland; (W.K.); (M.A.)
- Centre for Modern Interdisciplinary Technologies, Nicolaus Copernicus University in Toruń, Wileńska 4, 87-100 Toruń, Poland
| | - Marcel Antoszewski
- Department of Genetics, Faculty of Biological and Veterinary Sciences, Nicolaus Copernicus University in Toruń, Lwowska 1, 87-100 Toruń, Poland; (W.K.); (M.A.)
- Centre for Modern Interdisciplinary Technologies, Nicolaus Copernicus University in Toruń, Wileńska 4, 87-100 Toruń, Poland
| | - Aleksandra Szydłowska-Czerniak
- Department of Analytical Chemistry and Applied Spectroscopy, Faculty of Chemistry, Nicolaus Copernicus University in Toruń, Gagarina 7, 87-100 Toruń, Poland;
| | - Grażyna B. Dąbrowska
- Department of Genetics, Faculty of Biological and Veterinary Sciences, Nicolaus Copernicus University in Toruń, Lwowska 1, 87-100 Toruń, Poland; (W.K.); (M.A.)
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Yan K, Ablimit M, Liu S, Liu Z, Wang Y. A novel metallothionein gene HcMT from halophyte shrub Halostachys caspica respond to cadmium and sodium stress. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2023; 201:107763. [PMID: 37301187 DOI: 10.1016/j.plaphy.2023.107763] [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: 02/17/2023] [Revised: 04/23/2023] [Accepted: 05/12/2023] [Indexed: 06/12/2023]
Abstract
Cadmium (Cd) and sodium (Na) are two of the most phytotoxic metallic elements causing environmental and agricultural problems. Metallothioneins (MTs) play an important role in the adaptation to abiotic stress. We previously isolated a novel type 2 MT gene from Halostachys caspica (H. caspica), named HcMT, which responded to metal and salt stress. To understand the regulatory mechanisms controlling HcMT expression, we cloned the HcMT promoter and characterized its tissue-specific and spatiotemporal expression patterns. β-Glucuronidase (GUS) activity analysis showed that the HcMT promoter was responsive to CdCl2, CuSO4, ZnSO4 and NaCl stress. Therefore, we further investigated the function of HcMT under abiotic stress in yeast and Arabidopsis thaliana (Arabidopsis). In CdCl2, CuSO4 or ZnSO4 stress, HcMT significantly enhanced the metal ions tolerance and accumulation in yeast through function as a metal chelator. Moreover, the HcMT protein also protected yeast cells from NaCl, PEG and hydrogen peroxide (H2O2) toxicity with less effectiveness. However, transgenic Arabidopsis carrying HcMT gene only displayed tolerance to CdCl2 and NaCl, accompanying by higher content of Cd2+ or Na+ and lower H2O2, compared to wild-type (WT) plants. Next, we demonstrated that the recombinant HcMT protein has the ability to bind Cd2+ and the potential of scavenging ROS (reactive oxygen species) in vitro. This result further confirmed that the role of HcMT to influence plants to CdCl2 and NaCl stress may bind metal ions and scavenge ROS. Overall, we described the biological functions of HcMT and developed a metal- and salt-inducible promoter system for using in genetic engineering.
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Affiliation(s)
- Kexin Yan
- Xinjiang Key Laboratory of Biological Resources and Genetic Engineering, College of Life Science and Technology, Xinjiang University, Urumqi, 830017, China.
| | - Mehriban Ablimit
- Xinjiang Key Laboratory of Biological Resources and Genetic Engineering, College of Life Science and Technology, Xinjiang University, Urumqi, 830017, China.
| | - Sai Liu
- Xinjiang Key Laboratory of Biological Resources and Genetic Engineering, College of Life Science and Technology, Xinjiang University, Urumqi, 830017, China.
| | - Zhongyuan Liu
- School of Chemical Engineering, Sichuan University of Science and Engineering, Sichuan, 643000, China.
| | - Yan Wang
- Xinjiang Key Laboratory of Biological Resources and Genetic Engineering, College of Life Science and Technology, Xinjiang University, Urumqi, 830017, China.
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Gao C, Gao K, Yang H, Ju T, Zhu J, Tang Z, Zhao L, Chen Q. Genome-wide analysis of metallothionein gene family in maize to reveal its role in development and stress resistance to heavy metal. Biol Res 2022; 55:1. [PMID: 35012672 PMCID: PMC8751047 DOI: 10.1186/s40659-021-00368-w] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2021] [Accepted: 12/22/2021] [Indexed: 01/11/2023] Open
Abstract
BACKGROUND Maize (Zea mays L.) is a widely cultivated cereal and has been used as an optimum heavy metal phytoremediation crop. Metallothionein (MT) proteins are small, cysteine-rich, proteins that play important roles in plant growth and development, and the regulation of stress response to heavy metals. However, the MT genes for maize have not been fully analyzed so far. METHODS The putative ZmMT genes were identified by HMMER.The heat map of ZmMT genes spatial expression analysis was generated by using R with the log2 (FPKM + 1).The expression profiles of ZmMT genes under three kinds of heavy metal stresses were quantified by using qRT-PCR. The metallothionein proteins was aligned using MAFFT and phylogenetic analysis were constructed by ClustalX 2.1. The protein theoretical molecular weight and pI, subcellular localization, TFs binding sites, were predicted using ProtParam, PSORT, PlantTFDB, respectively. RESULTS A total of 9 ZmMT genes were identified in the whole genome of maize. The results showed that eight of the nine ZmMT proteins contained one highly conserved metallothio_2 domain, while ZmMT4 contained a Metallothio_PEC domain. All the ZmMT proteins could be classified into three major groups and located on five chromosomes. The ZmMT promoters contain a large number of hormone regulatory elements and hormone-related transcription factor binding sites. The ZmMT genes exhibited spatiotemporal specific expression patterns in 23 tissues of maize development stages and showed the different expression patterns in response to Cu, Cd, and Pb heavy metal stresses. CONCLUSIONS We identified the 9 ZmMT genes, and explored their conserved motif, tissue expression patterns, evolutionary relationship. The expression profiles of ZmMT genes under three kinds of heavy metal stresses (Cu, Cd, Pb) were analyzed. In summary, the expression of ZmMTs have poteintial to be regulated by hormones. The specific expression of ZmMTs in different tissues of maize and the response to different heavy metal stresses are revealed that the role of MT in plant growth and development, and stress resistance to heavy metals.
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Affiliation(s)
- Canhong Gao
- School of Agronomy, Anhui Agricultural University, Anhui province, Hefei, 230036 People’s Republic of China
| | - Kun Gao
- School of Agronomy, Anhui Agricultural University, Anhui province, Hefei, 230036 People’s Republic of China
| | - Huixian Yang
- School of Agronomy, Anhui Agricultural University, Anhui province, Hefei, 230036 People’s Republic of China
| | - Tangdan Ju
- School of Agronomy, Anhui Agricultural University, Anhui province, Hefei, 230036 People’s Republic of China
| | - Jingyi Zhu
- School of Agronomy, Anhui Agricultural University, Anhui province, Hefei, 230036 People’s Republic of China
| | - Zailin Tang
- School of Agronomy, Anhui Agricultural University, Anhui province, Hefei, 230036 People’s Republic of China
| | - Liangxia Zhao
- School of Agronomy, Anhui Agricultural University, Anhui province, Hefei, 230036 People’s Republic of China
| | - Qingquan Chen
- School of Agronomy, Anhui Agricultural University, Anhui province, Hefei, 230036 People’s Republic of China
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Rono JK, Le Wang L, Wu XC, Cao HW, Zhao YN, Khan IU, Yang ZM. Identification of a new function of metallothionein-like gene OsMT1e for cadmium detoxification and potential phytoremediation. CHEMOSPHERE 2021; 265:129136. [PMID: 33276998 DOI: 10.1016/j.chemosphere.2020.129136] [Citation(s) in RCA: 42] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Revised: 11/07/2020] [Accepted: 11/25/2020] [Indexed: 05/27/2023]
Abstract
Cadmium (Cd) is a biologically non-essential and toxic heavy metal leaking to the environment via natural emission or anthropogenic activities, thereby contaminating crops and threatening human health. Metallothioneins (MTs) are a group of metal-binding proteins playing critical roles in metal allocation and homeostasis. In this study, we identified a novel function of OsMT1e from rice plants. OsMT1e was dominantly expressed in roots at all developmental stages and, to less extent, expressed in leaves at vegetative and seed filling stages. OsMT1e was mainly targeted to the nucleus and substantially induced by Cd exposure. Expression of OsMT1e in a yeast Cd-sensitive strain ycf1 conferred cellular tolerance to Cd, even though the ycf1 + OsMT1e cells accumulated more Cd than the control cells (ycf1 + pYES2). Both transgenic rice overexpressing (OX) and repressing OsMT1e by RNA interference (RNAi) were developed. Phenotypic analysis revealed that OsMT1e overexpression enhanced the rice growth concerning the increased shoot or root elongation, dry weight and chlorophyll contents, whereas the RNAi lines displayed a sensitive growth phenotype compared to wild-type. Assessment with 0.5, 2 and 10 μM Cd for two weeks revealed that the RNAi lines accumulated less Cd, while the OX lines had an increased Cd accumulation in root and shoot tissues. The contrasting Cd accumulation phenotypes between the OX and RNAi lines were further confirmed by a long-term study with 0.5 μM Cd for one month. Overall, the study unveiled a new function of OsMT1e in rice, which can be potentially used for engineering genotypes for phytoremediation or minimizing Cd in rice crops.
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Affiliation(s)
- Justice Kipkorir Rono
- Department of Biochemistry and Molecular Biology, College of Life Sciences, Nanjing Agricultural University, Nanjing, 210095, China
| | - Le Le Wang
- Department of Biochemistry and Molecular Biology, College of Life Sciences, Nanjing Agricultural University, Nanjing, 210095, China
| | - Xue Chun Wu
- Department of Biochemistry and Molecular Biology, College of Life Sciences, Nanjing Agricultural University, Nanjing, 210095, China
| | - Hong Wei Cao
- Department of Biochemistry and Molecular Biology, College of Life Sciences, Nanjing Agricultural University, Nanjing, 210095, China
| | - Ya Ning Zhao
- Department of Biochemistry and Molecular Biology, College of Life Sciences, Nanjing Agricultural University, Nanjing, 210095, China
| | - Irfan Ullah Khan
- Department of Biochemistry and Molecular Biology, College of Life Sciences, Nanjing Agricultural University, Nanjing, 210095, China
| | - Zhi Min Yang
- Department of Biochemistry and Molecular Biology, College of Life Sciences, Nanjing Agricultural University, Nanjing, 210095, China.
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Babaei-Bondarti Z, Shahpiri A. A metallothionein type 2 from Avicennia marina binds to iron and mediates hydrogen peroxide balance by activation of enzyme catalase. PHYTOCHEMISTRY 2020; 176:112396. [PMID: 32353553 DOI: 10.1016/j.phytochem.2020.112396] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/02/2019] [Revised: 04/20/2020] [Accepted: 04/21/2020] [Indexed: 06/11/2023]
Abstract
Metallothioneins (MTs) are low molecular weight, cysteine-rich, metal-binding proteins that are important for essential metal homeostasis, protection against oxidative stress, and buffering against toxic heavy metals. In this work the gene encoding an MT type 2 from Avicennia marina (Forssk.) Vierh. (AmMT2) was cloned into pET41a and transformed into the Escherichia coli strain Rosetta (DE3). Following the induction with isopropyl β-D-1-thiogalactopyranoside, AmMT2 was expressed as glutathione-S-transferase (GST)-tagged fusion protein. The accumulation of Zn2+, Cu2+, Fe2+, Ni2+ and Cd2+ for strain R-AmMT2 was 4, 8, 5.4, 2 and 1.6 fold of control strain suggesting the role of AmMT2 in accumulation of metals. Particularly the strain R-AmMT2 was able to accumulate 30.7 mg per g dry weight. The cells expressing AmMT2 was more tolerant to hydrogen peroxide and had higher catalase (CAT) activity. To understand the mechanistic action of AmMT2 hydrogen peroxide tolerance, the activity of CAT in the E. coli protein extract was assayed after addition of pure Fe2+/GST-AmMT complex and Apo/GST-AmMT2 in vitro. Whereas, the activity of CAT did not change by the addition of Apo/GST-AmMT2, the activity of CAT significantly increased after addition of Fe2+/GST-AmMT2. These results show that AmMT2 activates CAT through Fe2+ transfer which subsequently causes the oxidative stress tolerance.
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Affiliation(s)
- Zahra Babaei-Bondarti
- Department of Biotechnology, College of Agriculture, Isfahan University of Technology, Isfahan, 84156-83111, Iran
| | - Azar Shahpiri
- Department of Biotechnology, College of Agriculture, Isfahan University of Technology, Isfahan, 84156-83111, Iran.
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Wang Y, Li N, Chen T, Gong Y. Generation and characterization of expressed sequence tags (ESTs) from coralloid root cDNA library of Cycas debaoensis. PLANT DIVERSITY 2018; 40:245-252. [PMID: 30740571 PMCID: PMC6224666 DOI: 10.1016/j.pld.2018.09.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/09/2018] [Revised: 08/31/2018] [Accepted: 09/03/2018] [Indexed: 06/09/2023]
Abstract
A normalized full-length cDNA library was constructed from the coralloid roots of Cycas debaoensis by the DSN (duplex-specific nuclease) normalization method combined with the SMART (Switching Mechanism At 5' end of the RNA Transcript) technique. The titer of the original cDNA library was about 1.5 × 106 cfu·mL-1 and the average insertion size was about 1 kb with a high recombination rate (97%). The 5011 high-quality expressed sequence tags (ESTs) were obtained from 5393 randomly picked cDNA clones. Clustering and assembly of ESTs resulted in 2984 unique sequences, consisting of 618 contigs and 2366 singlets. EST sequence annotation revealed that 2333 and 1901 unigenes were functionally annotated in the NCBI non-redundant database and Swiss-Prot protein database, respectively. Functional analysis demonstrated that 1495 (50.1%) unigenes were associated with 4082 Gene Ontology (GO) terms. A total of 847 unigenes were grouped into 22 Cluster of Orthologous Groups (COG) functional categories. Based on the EST dataset, 22 ESTs that encoded putative receptor-like protein kinase (RLK) genes were screened. Furthermore, a total of 94 simple sequence repeats (SSRs) were discovered, of which 20 loci were successfully amplified in C. debaoensis. This study is the first EST analysis for the coralloid roots of C. debaoensis and provides a valuable genomic resource for novel gene discovery, gene expression and comparative genomics, conservation and management studies as well as applications in C. debaoensis and related cycad species.
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Affiliation(s)
- Yunhua Wang
- Shenzhen Key Laboratory of Southern Subtropical Plant Diversity, Fairylake Botanical Garden, Shenzhen & Chinese Academy of Sciences, Shenzhen, 518004, Guangdong, China
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Mierek-Adamska A, Dąbrowska GB, Blindauer CA. The type 4 metallothionein from Brassica napus seeds folds in a metal-dependent fashion and favours zinc over other metals. Metallomics 2018; 10:1430-1443. [DOI: 10.1039/c8mt00161h] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Rapeseed MT4 only folds properly in the presence of Zn2+ and thus may serve as a selectivity filter for metal accumulation in plant embryos.
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Affiliation(s)
- Agnieszka Mierek-Adamska
- Department of Genetics
- Faculty of Biology and Environmental Protection
- Nicolaus Copernicus University
- 87-100 Toruń
- Poland
| | - Grażyna B. Dąbrowska
- Department of Genetics
- Faculty of Biology and Environmental Protection
- Nicolaus Copernicus University
- 87-100 Toruń
- Poland
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Isolation, molecular characterization and functional analysis of OeMT2, an olive metallothionein with a bioremediation potential. Mol Genet Genomics 2014; 290:187-99. [PMID: 25204791 DOI: 10.1007/s00438-014-0908-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2014] [Accepted: 08/23/2014] [Indexed: 10/24/2022]
Abstract
Metallothioneins are essential in plants for metal detoxification in addition to their other roles in plant life cycle. This study reports the characterization of an olive (Olea europaea L. cv. Ayvalik) metallothionein with respect to molecular and functional properties. A cDNA encoding a type 2 metallothionein from olive was isolated from a leaf cDNA library, characterized and named OeMT2 after its molecular and functional properties. OeMT2 was expressed in Escherichia coli, and a single protein band was confirmed by protein gel blot analysis. Metal tolerance ability of bacterial cells expressing OeMT2 was determined against 0.2 mM CdCl2, 0.4 mM CdCl2 and 1 mM CuSO4 in the growth medium. Metal ion contents of bacterial cells expressing OeMT2 were measured by ICP. Metal tolerance assays and ICP measurements suggested that OeMT2 effectively binds Cu and Cd. Molecular analysis of OeMT2 revealed two introns, three exons, a short 3' UTR and a long 5' UTR. Comparing the genomic sequences from 14 olive cultivars revealed OeMT2 had both intron and exon polymorphisms dividing the cultivars into three groups. Real-time PCR analysis demonstrated that OeMT2 expresses more or less the same amounts in all tissues of the olive tree examined. The genomic copy number of OeMT2 was also determined employing real-time PCR which suggested a single copy gene in the olive genome while three other MT2 members were determined from the draft olive genome sequences of Ayvalik cultivar and that of wild olive. This is the first report on molecular and functional characterization of an olive metallothionein and shows that OeMT2 expressed in E. coli has the capability of effectively binding toxic heavy metals. This may suggest that OeMT2 plays an important role in metal homeostasis in addition to a good potential for environmental and industrial usage.
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Nezhad RM, Shahpiri A, Mirlohi A. Discrimination between two rice metallothionein isoforms belonging to type 1 and type 4 in metal-binding ability. Biotechnol Appl Biochem 2014; 60:275-82. [PMID: 23782215 DOI: 10.1002/bab.1078] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2012] [Accepted: 12/12/2012] [Indexed: 10/26/2022]
Abstract
Metallothioneins (MTs) are a superfamily of low-molecular-weight, cysteine (Cys)-rich proteins that are believed to play important roles in protection against metal toxicity and oxidative stress. Plants have several MT isoforms, which are classified into four types based on the arrangement of Cys residues. In this study, two rice (Oryza sativa) MT isoforms, OsMTI-1b and OsMTII-1a from type 1 and type 4, respectively, were heterologously expressed in Escherichia coli as carboxy-terminal extensions of glutathione-S-transferase (GST). Transformed cells expressing GST-OsMTI-1b showed increased tolerance to Ni(2+) , Cd(2+) , and Zn(2+) and accumulated more metal ions compared with cells expressing GST alone. However, heterologous expression of GST-OsMTII-1a had no significant effects on metal tolerance or ion accumulation. The UV absorption spectra and competitive reactions of in vitro Cd-incubated proteins with 5-5'-dithiobis(2-nitrobenzoic) acid revealed that GST-OsMTI-1b, but not GST-OsMTII-1a, is able to form Cd-thiolate clusters. Furthermore, heterologous expression of both GST-OsMTI-1b and GST-OsMTII-1a conferred H2 O2 tolerance to E. coli cells. Taken together, the results presented here show that two different rice MT isoforms belonging to type 1 and type 4 differ in Ni(2+) , Cd(2+) , and Zn(2+) binding abilities, but they may have overlapping function in protection of cells against oxidative stress.
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Affiliation(s)
- Rezvan Mohammadi Nezhad
- Department of Agricultural Biotechnology, College of Agriculture, Isfahan University of Technology, Isfahan, Iran
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Mudalkar S, Golla R, Sengupta D, Ghatty S, Reddy AR. Molecular cloning and characterisation of metallothionein type 2a gene from Jatropha curcas L., a promising biofuel plant. Mol Biol Rep 2013; 41:113-24. [DOI: 10.1007/s11033-013-2843-5] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2012] [Accepted: 10/26/2013] [Indexed: 11/28/2022]
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Mann IK, Wegrzyn JL, Rajora OP. Generation, functional annotation and comparative analysis of black spruce (Picea mariana) ESTs: an important conifer genomic resource. BMC Genomics 2013; 14:702. [PMID: 24119028 PMCID: PMC4007752 DOI: 10.1186/1471-2164-14-702] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2013] [Accepted: 10/08/2013] [Indexed: 12/01/2022] Open
Abstract
Background EST (expressed sequence tag) sequences and their annotation provide a highly valuable resource for gene discovery, genome sequence annotation, and other genomics studies that can be applied in genetics, breeding and conservation programs for non-model organisms. Conifers are long-lived plants that are ecologically and economically important globally, and have a large genome size. Black spruce (Picea mariana), is a transcontinental species of the North American boreal and temperate forests. However, there are limited transcriptomic and genomic resources for this species. The primary objective of our study was to develop a black spruce transcriptomic resource to facilitate on-going functional genomics projects related to growth and adaptation to climate change. Results We conducted bidirectional sequencing of cDNA clones from a standard cDNA library constructed from black spruce needle tissues. We obtained 4,594 high quality (2,455 5' end and 2,139 3' end) sequence reads, with an average read-length of 532 bp. Clustering and assembly of ESTs resulted in 2,731 unique sequences, consisting of 2,234 singletons and 497 contigs. Approximately two-thirds (63%) of unique sequences were functionally annotated. Genes involved in 36 molecular functions and 90 biological processes were discovered, including 24 putative transcription factors and 232 genes involved in photosynthesis. Most abundantly expressed transcripts were associated with photosynthesis, growth factors, stress and disease response, and transcription factors. A total of 216 full-length genes were identified. About 18% (493) of the transcripts were novel, representing an important addition to the Genbank EST database (dbEST). Fifty-seven di-, tri-, tetra- and penta-nucleotide simple sequence repeats were identified. Conclusions We have developed the first high quality EST resource for black spruce and identified 493 novel transcripts, which may be species-specific related to life history and ecological traits. We have also identified full-length genes and microsatellite-containing ESTs. Based on EST sequence similarities, black spruce showed close evolutionary relationships with congeneric Picea glauca and Picea sitchensis compared to other Pinaceae members and angiosperms. The EST sequences reported here provide an important resource for genome annotation, functional and comparative genomics, molecular breeding, conservation and management studies and applications in black spruce and related conifer species.
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Affiliation(s)
- Ishminder K Mann
- Forest Genetics and Biotechnology Group, Department of Biology, Life Sciences Centre, Dalhousie University, 1355 Oxford Street, Halifax, NS B3H 4J1, Canada.
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Heterologous expression and metal-binding characterization of a type 1 metallothionein isoform (OsMTI-1b) from rice (Oryza sativa). Protein J 2013; 32:131-7. [PMID: 23385446 DOI: 10.1007/s10930-013-9469-2] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Metallothioneins (MTs) are ubiquitous, low molecular mass and cysteine-rich proteins that play important roles in maintaining intracellular metal homeostasis, eliminating metal toxification and protecting the cells against oxidative damages. MTs are able to bind metal ions through the thiol groups of their cysteine residues. Plants have several MT isoforms which are classified into four types based on the arrangement of cysteine residues. In the present study, a rice (Oryza sativa) gene encoding type 1 MT isoform, OsMTI-1b, was inserted in vector pET41a and overexpressed in Escherichia coli as carboxy-terminal extensions of glutathione-S-transferase (GST). The recombinant protein GST-OsMTI-1b was purified using affinity chromatography and its ability to bind with Ni(2+), Cd(2+), Zn(2+) and Cu(2+) ions was analyzed. The results demonstrated that this isoform has ability to bind Ni(2+), Cd(2+) and Zn(2+) ions in vitro, whereas it has no substantial ability to bind Cu(2+) ions. From competitive reaction with 5,5'-dithiobis(2-nitrobenzoic acid), DTNB, the affinity of metal ions for recombinant form of GST-OsMTI-1b was as follows: Ni(2+)/Cd(2+) > Zn(2+) > Cu(2+).
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Kim YO, Jung S, Kim K, Bae HJ. Role of pCeMT, a putative metallothionein from Colocasia esculenta, in response to metal stress. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2013; 64:25-32. [PMID: 23344478 DOI: 10.1016/j.plaphy.2012.12.009] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/2012] [Accepted: 12/03/2012] [Indexed: 05/11/2023]
Abstract
Metallothioneins (MTs) play a major role in metal homeostasis and/or detoxification in plants. In this study, a novel gene, pCeMT, was isolated from Colocasia esculenta and characterized. Our results indicate that Escherichia coli cells expressing pCeMT exhibited enhanced Cd, Cu, and Zn tolerance and accumulation compared with control cells. Furthermore, pCeMT-overexpressing tobacco seedlings displayed better growth under Cd, Cu, and Zn stresses and accumulated more Cd and Zn compared with the wild type. Interestingly, transgenic tobacco displayed markedly decreased hydrogen peroxide (H(2)O(2)) and lipid peroxidation levels under Cd, Cu, and Zn treatments. These results suggest that pCeMT could play an important role in the protection of plant cells from oxidative stress by reactive oxygen species (ROS) scavenging and in the detoxification of free metals by metal binding, leading to improved plant metal tolerance.
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Affiliation(s)
- Yeon-Ok Kim
- Bio-energy Research Institute, Chonnam National University, Gwangju 500-757, Republic of Korea
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15
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Cozza R, Bruno L, Bitonti MB. Expression pattern of a type-2 metallothionein gene in a wild population of the psammophyte Silene nicaeensis. PROTOPLASMA 2013; 250:381-389. [PMID: 22688806 DOI: 10.1007/s00709-012-0425-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2012] [Accepted: 05/25/2012] [Indexed: 06/01/2023]
Abstract
Silene nicaeensis is a wild Mediterranean grass often restricted to sandy sea shore and exhibiting an excellent tolerance to drought and salinity. Within Silene genus, several heavy metal-tolerant ecotypes have been identified, but information on molecular basis of such metal tolerance is still limited. Conceivably, salt-tolerant plants may represent a powerful tool for the remediation of heavy metal contaminated sites in saline environment. Here, a gene encoding a metallothionein protein was isolated from S. nicaeensis. Sequence analysis identified the motifs characteristic of type II metallothionein and designated as SnMT2. SnMT2 expression was investigated in plants collected from two sites differing in Metal Pollution Index (MPI). SnMT2 expression by polymerase chain reaction-based semi-quantitative transcript analysis showed a high accumulation in the leaves; in situ hybridization showed a steady localization of SnMT2 mRNA in the vascular bundle and in proliferating tissues. Moreover, an increase of SnMT2 was observed in the root of plants collected from area with higher MPI. The putative role of SnMT2 in metal tolerance is discussed.
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Affiliation(s)
- Radiana Cozza
- Department of Ecology, University of Calabria, 87030 Arcavacata di Rende (CS), Italy.
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16
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Leszczyszyn OI, Imam HT, Blindauer CA. Diversity and distribution of plant metallothioneins: a review of structure, properties and functions. Metallomics 2013; 5:1146-69. [DOI: 10.1039/c3mt00072a] [Citation(s) in RCA: 133] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
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17
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Garg B, Puranik S, Tuteja N, Prasad M. Abiotic stress-responsive expression of wali1 and wali5 genes from wheat. PLANT SIGNALING & BEHAVIOR 2012; 7:1393-1396. [PMID: 22918504 PMCID: PMC3548855 DOI: 10.4161/psb.21885] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Two cDNA clones, encoding Aluminum-responsive wali1 and wali5, were identified in dehydration stress-specific cDNA library from wheat. Their sequence variations and structural dissimilarities indicated them to be non-homologous genes. Expression of both genes was induced by various abiotic stresses as well as in response to plant hormones and oxidative molecules. Further, they were expressed differentially in shoot and root tissues of wheat seedlings, their transcripts being specifically abundant in roots. Previously characterized as being only Aluminum treatment induced, this report proposes them as novel candidates for stress-responsive studies.
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Affiliation(s)
- Bharti Garg
- International Centre for Genetic Engineering and Biotechnology; Aruna Asaf Ali Marg; New Delhi, India
| | - Swati Puranik
- National Institute of Plant Genome Research; Aruna Asaf Ali Marg; New Delhi, India
| | - Narendra Tuteja
- International Centre for Genetic Engineering and Biotechnology; Aruna Asaf Ali Marg; New Delhi, India
| | - Manoj Prasad
- National Institute of Plant Genome Research; Aruna Asaf Ali Marg; New Delhi, India
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18
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Gautam N, Verma PK, Verma S, Tripathi RD, Trivedi PK, Adhikari B, Chakrabarty D. Genome-wide identification of rice class I metallothionein gene: tissue expression patterns and induction in response to heavy metal stress. Funct Integr Genomics 2012; 12:635-47. [PMID: 23053198 DOI: 10.1007/s10142-012-0297-9] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2012] [Revised: 09/03/2012] [Accepted: 09/24/2012] [Indexed: 01/11/2023]
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19
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Kumar G, Kushwaha HR, Panjabi-Sabharwal V, Kumari S, Joshi R, Karan R, Mittal S, Pareek SLS, Pareek A. Clustered metallothionein genes are co-regulated in rice and ectopic expression of OsMT1e-P confers multiple abiotic stress tolerance in tobacco via ROS scavenging. BMC PLANT BIOLOGY 2012; 12:107. [PMID: 22780875 PMCID: PMC3491035 DOI: 10.1186/1471-2229-12-107] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2012] [Accepted: 06/25/2012] [Indexed: 05/04/2023]
Abstract
BACKGROUND Metallothioneins (MT) are low molecular weight, cysteine rich metal binding proteins, found across genera and species, but their function(s) in abiotic stress tolerance are not well documented. RESULTS We have characterized a rice MT gene, OsMT1e-P, isolated from a subtractive library generated from a stressed salinity tolerant rice genotype, Pokkali. Bioinformatics analysis of the rice genome sequence revealed that this gene belongs to a multigenic family, which consists of 13 genes with 15 protein products. OsMT1e-P is located on chromosome XI, away from the majority of other type I genes that are clustered on chromosome XII. Various members of this MT gene cluster showed a tight co-regulation pattern under several abiotic stresses. Sequence analysis revealed the presence of conserved cysteine residues in OsMT1e-P protein. Salinity stress was found to regulate the transcript abundance of OsMT1e-P in a developmental and organ specific manner. Using transgenic approach, we found a positive correlation between ectopic expression of OsMT1e-P and stress tolerance. Our experiments further suggest ROS scavenging to be the possible mechanism for multiple stress tolerance conferred by OsMT1e-P. CONCLUSION We present an overview of MTs, describing their gene structure, genome localization and expression patterns under salinity and development in rice. We have found that ectopic expression of OsMT1e-P enhances tolerance towards multiple abiotic stresses in transgenic tobacco and the resultant plants could survive and set viable seeds under saline conditions. Taken together, the experiments presented here have indicated that ectopic expression of OsMT1e-P protects against oxidative stress primarily through efficient scavenging of reactive oxygen species.
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Affiliation(s)
- Gautam Kumar
- Stress Physiology and Molecular Biology Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi, 110067, India
| | - Hemant Ritturaj Kushwaha
- Stress Physiology and Molecular Biology Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi, 110067, India
| | - Vaishali Panjabi-Sabharwal
- Stress Physiology and Molecular Biology Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi, 110067, India
| | - Sumita Kumari
- Stress Physiology and Molecular Biology Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi, 110067, India
| | - Rohit Joshi
- Stress Physiology and Molecular Biology Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi, 110067, India
| | - Ratna Karan
- Stress Physiology and Molecular Biology Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi, 110067, India
| | - Shweta Mittal
- Stress Physiology and Molecular Biology Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi, 110067, India
| | - Sneh L Singla Pareek
- Plant Molecular Biology, International Centre for Genetic Engineering and Biotechnology, New Delhi, 110067, India
| | - Ashwani Pareek
- Stress Physiology and Molecular Biology Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi, 110067, India
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Hegelund JN, Schiller M, Kichey T, Hansen TH, Pedas P, Husted S, Schjoerring JK. Barley metallothioneins: MT3 and MT4 are localized in the grain aleurone layer and show differential zinc binding. PLANT PHYSIOLOGY 2012; 159:1125-37. [PMID: 22582132 PMCID: PMC3387699 DOI: 10.1104/pp.112.197798] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2012] [Accepted: 05/09/2012] [Indexed: 05/20/2023]
Abstract
Metallothioneins (MTs) are low-molecular-weight, cysteine-rich proteins believed to play a role in cytosolic zinc (Zn) and copper (Cu) homeostasis. However, evidence for the functional properties of MTs has been hampered by methodological problems in the isolation and characterization of the proteins. Here, we document that barley (Hordeum vulgare) MT3 and MT4 proteins exist in planta and that they differ in tissue localization as well as in metal coordination chemistry. Combined transcriptional and histological analyses showed temporal and spatial correlations between transcript levels and protein abundance during grain development. MT3 was present in tissues of both maternal and filial origin throughout grain filling. In contrast, MT4 was confined to the embryo and aleurone layer, where it appeared during tissue specialization and remained until maturity. Using state-of-the-art speciation analysis by size-exclusion chromatography inductively coupled plasma mass spectrometry and electrospray ionization time-of-flight mass spectrometry on recombinant MT3 and MT4, their specificity and capacity for metal ion binding were quantified, showing a strong preferential Zn binding relative to Cu and cadmium (Cd) in MT4, which was not the case for MT3. When complementary DNAs from barley MTs were expressed in Cu- or Cd-sensitive yeast mutants, MT3 provided a much stronger complementation than did MT4. We conclude that MT3 may play a housekeeping role in metal homeostasis, while MT4 may function in Zn storage in developing and mature grains. The localization of MT4 and its discrimination against Cd make it an ideal candidate for future biofortification strategies directed toward increasing food and feed Zn concentrations.
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Affiliation(s)
- Josefine Nymark Hegelund
- Plant and Soil Science Section, Department of Plant and Environmental Sciences, Faculty of Science, University of Copenhagen, DK–1871 Frederiksberg, Denmark (J.N.H., M.S., T.H.H., P.P., S.H., J.K.S.); and
- Unité Ecologie et Dynamique des Systèmes Anthropisés, Université de Picardie Jules Verne, 80039 Amiens cedex, France (T.K.)
| | - Michaela Schiller
- Plant and Soil Science Section, Department of Plant and Environmental Sciences, Faculty of Science, University of Copenhagen, DK–1871 Frederiksberg, Denmark (J.N.H., M.S., T.H.H., P.P., S.H., J.K.S.); and
- Unité Ecologie et Dynamique des Systèmes Anthropisés, Université de Picardie Jules Verne, 80039 Amiens cedex, France (T.K.)
| | - Thomas Kichey
- Plant and Soil Science Section, Department of Plant and Environmental Sciences, Faculty of Science, University of Copenhagen, DK–1871 Frederiksberg, Denmark (J.N.H., M.S., T.H.H., P.P., S.H., J.K.S.); and
- Unité Ecologie et Dynamique des Systèmes Anthropisés, Université de Picardie Jules Verne, 80039 Amiens cedex, France (T.K.)
| | - Thomas Hesselhøj Hansen
- Plant and Soil Science Section, Department of Plant and Environmental Sciences, Faculty of Science, University of Copenhagen, DK–1871 Frederiksberg, Denmark (J.N.H., M.S., T.H.H., P.P., S.H., J.K.S.); and
- Unité Ecologie et Dynamique des Systèmes Anthropisés, Université de Picardie Jules Verne, 80039 Amiens cedex, France (T.K.)
| | - Pai Pedas
- Plant and Soil Science Section, Department of Plant and Environmental Sciences, Faculty of Science, University of Copenhagen, DK–1871 Frederiksberg, Denmark (J.N.H., M.S., T.H.H., P.P., S.H., J.K.S.); and
- Unité Ecologie et Dynamique des Systèmes Anthropisés, Université de Picardie Jules Verne, 80039 Amiens cedex, France (T.K.)
| | - Søren Husted
- Plant and Soil Science Section, Department of Plant and Environmental Sciences, Faculty of Science, University of Copenhagen, DK–1871 Frederiksberg, Denmark (J.N.H., M.S., T.H.H., P.P., S.H., J.K.S.); and
- Unité Ecologie et Dynamique des Systèmes Anthropisés, Université de Picardie Jules Verne, 80039 Amiens cedex, France (T.K.)
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21
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Chaturvedi AK, Mishra A, Tiwari V, Jha B. Cloning and transcript analysis of type 2 metallothionein gene (SbMT-2) from extreme halophyte Salicornia brachiata and its heterologous expression in E. coli. Gene 2012; 499:280-7. [DOI: 10.1016/j.gene.2012.03.001] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2012] [Revised: 03/01/2012] [Accepted: 03/01/2012] [Indexed: 11/16/2022]
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22
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Singh RK, Anandhan S, Singh S, Patade VY, Ahmed Z, Pande V. Metallothionein-like gene from Cicer microphyllum is regulated by multiple abiotic stresses. PROTOPLASMA 2011; 248:839-47. [PMID: 21161305 DOI: 10.1007/s00709-010-0249-y] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2010] [Accepted: 11/24/2010] [Indexed: 05/23/2023]
Abstract
Cicer microphyllum, a wild relative of cultivated chickpea, is a high altitude cold desert-adapted species distributed in western and trans-Himalayas. A complementary DNA (cDNA) encoding metallothionein-like protein has been identified from a cold-induced subtraction cDNA library from C. microphyllum. The sequence of the cloned metallothionein gene from C. microphyllum (GQ900702) contains 240-bp-long open reading frame and encodes predicted 79-amino acid protein of 7.9 kDa. Sequence analysis identified the motifs characteristic of type II metallothionein and designated as CmMet-2. Southern hybridization confirms a single copy of the CmMet-2 gene in C. microphyllum genome. In situ hybridization indicated spatial transcript regulation of CmMet-2 in root and aerial parts and also confirmed through real-time PCR-based quantitative transcript analysis. The data revealed a significantly low level of transcript in the aerial parts than the roots. Quantitative analysis using real-time PCR assay revealed induction of transcript in all parts of plants in response to cold stress at 4°C. The transcript abundance was found to increase exponentially with time course from 6 to 24 h after exposure. Further, regulation of transcript accumulation in response to abscisic acid application, polyethylene glycol (100 μM)-induced osmotic stress, or ZnSO(4) (1 μM) foliar spray indicated by Northern hybridization suggests the involvement of CmMet-2 in multiple stress response.
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Affiliation(s)
- Rupesh K Singh
- Molecular Biology and Genetic Engineering, Defence Institute of Bio Energy Research, Goraparao, Haldwani, Nainital, 263139, Uttarakhand, India
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23
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Ye JL, Zhu AD, Tao NG, Xu Q, Xu J, Deng XX. Comprehensive analysis of expressed sequence tags from the pulp of the red mutant 'Cara Cara' navel orange (Citrus sinensis Osbeck). JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2010; 52:856-867. [PMID: 20883438 DOI: 10.1111/j.1744-7909.2010.00952.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Expressed sequence tag (EST) analysis of the pulp of the red-fleshed mutant 'Cara Cara' navel orange provided a starting point for gene discovery and transcriptome survey during citrus fruit maturation. Interpretation of the EST datasets revealed that the mutant pulp transcriptome held a high section of stress responses related genes, such as the type III metallothionein-like gene (6.0%), heat shock protein (2.8%), Cu/Zn superoxide dismutase (0.8%), late embryogenesis abundant protein 5 (0.8%), etc. 133 transcripts were detected to be differentially expressed between the red mutant and its orange-color wild genotype 'Washington' via digital expression analysis. Among them, genes involved in metabolism, defense/stress and signal transduction were statistical overrepresented. Fifteen transcription factors, composed of NAM, ATAF, and CUC transcription factor (NAC); myeloblastosis (MYB); myelocytomatosis (MYC); basic helix-loop-helix (bHLH); basic leucine zipper (bZIP) domain members, were also included. The data reflected the distinct expression profile and the unique regulatory module associated with these two genotypes. Eight differently expressed genes analyzed in digital were validated by quantitative real-time polymerase chain reaction. For structural polymorphism, both simple sequence repeats and single nucleotide polymorphisms (SNP) loci were surveyed; dinucleotide presentation revealed a bias toward AG/GA/TC/CT repeats (52.5%), against GC/CG repeats (0%). SNPs analysis found that transitions (73%) outnumbered transversions (27%). Seventeen potential cultivar-specific and 387 heterozygous SNP loci were detected from 'Cara Cara' and 'Washington' EST pool.
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Affiliation(s)
- Jun-Li Ye
- National Center of Citrus Breeding, Huazhong Agricultural University, Wuhan, China
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24
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Dong CJ, Wang Y, Yu SS, Liu JY. Characterization of a novel rice metallothionein gene promoter: its tissue specificity and heavy metal responsiveness. JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2010; 52:914-924. [PMID: 20883443 DOI: 10.1111/j.1744-7909.2010.00966.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
The rice (Oryza sativa L.) metallothionein gene OsMT-I-4b has previously been identified as a type I MT gene. To elucidate the regulatory mechanism involved in its tissue specificity and abiotic induction, we isolated a 1 730 bp fragment of the OsMT-I-4b promoter region. Histochemical β-glucuronidase (GUS) staining indicated a precise spacial and temporal expression pattern in transgenic Arabidopsis. Higher GUS activity was detected in the roots and the buds of flower stigmas, and relatively lower GUS staining in the shoots was restricted to the trichomes and hydathodes of leaves. No activity was observed in the stems and seeds. Additionally, in the root of transgenic plants, the promoter activity was highly upregulated by various environmental signals, such as abscisic acid, drought, dark, and heavy metals including Cu²(+) , Zn²(+) , Pb²(+) and Al³(+) . Slight induction was observed in transgenic seedlings under salinity stress, or when treated with Co²(+) and Cd²(+) . Promoter analysis of 5'-deletions revealed that the region -583/-1 was sufficient to drive strong GUS expression in the roots but not in the shoots. Furthermore, deletion analysis indicated important promoter regions containing different metal-responsive cis-elements that were responsible for responding to different heavy metals. Collectively, these findings provided important insight into the transcriptional regulation mechanisms of the OsMT-I-4b promoter, and the results also gave us some implications for the potential application of this promoter in plant genetic engineering.
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Omidvar V, Abdullah SNA, Izadfard A, Ho CL, Mahmood M. The oil palm metallothionein promoter contains a novel AGTTAGG motif conferring its fruit-specific expression and is inducible by abiotic factors. PLANTA 2010; 232:925-936. [PMID: 20635097 DOI: 10.1007/s00425-010-1220-z] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2010] [Accepted: 06/30/2010] [Indexed: 05/29/2023]
Abstract
The 1,053-bp promoter of the oil palm metallothionein gene (so-called MSP1) and its 5' deletions were fused to the GUS reporter gene, and analysed in transiently transformed oil palm tissues. The full length promoter showed sevenfold higher activity in the mesocarp than in leaves and 1.5-fold more activity than the CaMV35S promoter in the mesocarp. The 1,053-bp region containing the 5' untranslated region (UTR) gave the highest activity in the mesocarp, while the 148-bp region was required for minimal promoter activity. Two positive regulatory regions were identified at nucleotides (nt) -953 to -619 and -420 to -256 regions. Fine-tune deletion of the -619 to -420 nt region led to the identification of a 21-bp negative regulatory sequence in the -598 to -577 nt region, which is involved in mesocarp-specific expression. Gel mobility shift assay revealed a strong interaction of the leaf nuclear extract with the 21-bp region. An AGTTAGG core-sequence within this region was identified as a novel negative regulatory element controlling fruit-specificity of the MSP1 promoter. Abscisic acid (ABA) and copper (Cu(2+)) induced the activity of the promoter and its 5' deletions more effectively than methyl jasmonate (MeJa) and ethylene. In the mesocarp, the full length promoter showed stronger inducibility in response to ABA and Cu(2+) than its 5' deletions, while in leaves, the -420 nt fragment was the most inducible by ABA and Cu(2+). These results suggest that the MSP1 promoter and its regulatory regions are potentially useful for engineering fruit-specific and inducible gene expression in oil palm.
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Affiliation(s)
- Vahid Omidvar
- Department of Agriculture Technology, Faculty of Agriculture, University Putra Malaysia (UPM), Serdang, Selangor, Malaysia
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26
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Huang GY, Wang YS. Expression and characterization analysis of type 2 metallothionein from grey mangrove species (Avicennia marina) in response to metal stress. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2010; 99:86-92. [PMID: 20435357 DOI: 10.1016/j.aquatox.2010.04.004] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2010] [Revised: 03/17/2010] [Accepted: 04/02/2010] [Indexed: 05/28/2023]
Abstract
Metallothioneins (MTs) are a family of low-molecular-weight cysteine-rich proteins and are thought to play possible roles in metal metabolism or detoxification. To evaluate the roles of metallothioneins in metal homeostasis or tolerance in Avicennia marina, a real-time quantitative PCR protocol was developed to directly evaluate the expression of AmMT2 mRNA, when A. marina seedlings were exposed to different concentrations of zinc (Zn), copper (Cu) or lead (Pb) for 3 and 7d. Real-time quantitative PCR results indicated that the regulation of AmMT2 mRNA expression by Zn, Cu and Pb was strongly dependent on concentration and time of exposure. A significant increase in the transcripts of AmMT2 gene was also found in response to Zn, Cu and Pb, at least under some experimental conditions. When AmMT2 was overexpressed in Escherichia coli BL21 as a carboxy-terminal extension of glutathione-S-transferase (GST), the transgenic bacteria showed an increased tolerance to Zn, Cu, Pb and Cd exposure as compared to control strains. Moreover, GST-AmMT2 was purified from E. coli cells grown in the presence of 400 microM Zn, Cu, Pb or Cd. The purified GST-AmMT2 fusion protein could bind higher levels of all four metals than GST alone. Taken together, these data support the hypothesis that AmMT2 may be involved in processes of metal homeostasis or tolerance in A. marina.
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Affiliation(s)
- Guo-Yong Huang
- Key Laboratory of Tropical Marine Environmental Dynamics, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, China. huang
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27
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Nikolić DB, Samardzić JT, Bratić AM, Radin IP, Gavrilović SP, Rausch T, Maksimović VR. Buckwheat (Fagopyrum esculentum Moench) FeMT3 gene in heavy metal stress: protective role of the protein and inducibility of the promoter region under Cu(2+) and Cd(2+) treatments. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2010; 58:3488-94. [PMID: 20187605 DOI: 10.1021/jf904483a] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
The protective role in vivo of buckwheat metallothionein type 3 (FeMT3) during metal stress and the responsiveness of its promoter to metal ions were examined. Increased tolerance to heavy metals of FeMT3 producing Escherichia coli and cup1(Delta) yeast cells was detected. The defensive ability of buckwheat MT3 during Cd and Cu stresses was also demonstrated in Nicotiana debneyii leaves transiently expressing FeMT3. In contrast to phytochelatins, the cytoplasmatic localization of FeMT3 was not altered under heavy metal stress. Functional analysis of the corresponding promoter region revealed extremely high inducibility upon Cu(2+) and Cd(2+) treatments. The confirmed defense ability of FeMT3 protein in vivo and the great responsiveness of its promoter during heavy metal exposure make this gene a suitable candidate for biotechnological applications.
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Affiliation(s)
- Dragana B Nikolić
- Laboratory for Plant Molecular Biology, Institute of Molecular Genetics and Genetic Engineering, University of Belgrade, Vojvode Stepe 444a, Belgrade, Serbia.
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28
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Balestrazzi A, Botti S, Zelasco S, Biondi S, Franchin C, Calligari P, Racchi M, Turchi A, Lingua G, Berta G, Carbonera D. Expression of the PsMTA1 gene in white poplar engineered with the MAT system is associated with heavy metal tolerance and protection against 8-hydroxy-2'-deoxyguanosine mediated-DNA damage. PLANT CELL REPORTS 2009; 28:1179-92. [PMID: 19506883 DOI: 10.1007/s00299-009-0719-x] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2009] [Revised: 05/13/2009] [Accepted: 05/13/2009] [Indexed: 05/27/2023]
Abstract
Marker-free transgenic white poplar (Populus alba L., cv 'Villafranca') plants, expressing the PsMT (A1) gene from Pisum sativum for a metallothionein-like protein, were produced by Agrobacterium tumefaciens-mediated transformation. The 35SCaMV-PsMT (A1)-NosT cassette was inserted into the ipt-type vector pMAT22. The occurrence of the abnormal ipt-shooty phenotype allowed the visual selection of transformants, while the yeast site-specific recombination R/RS system was responsible for the excision of the undesired vector sequences with the consequent recovery of normal marker-free transgenic plants. Molecular analyses confirmed the presence of the 35SCaMV-PsMT (A1)-NosT cassette and transgene expression. Five selected lines were further characterized, revealing the ability to withstand heavy metal toxicity. They survived 0.1 mM CuCl(2), a concentration which strongly affected the nontransgenic plants. Moreover, root development was only slightly affected by the ectopic expression of the transgene. Reactive oxygen species were accumulated to a lower extent in leaf tissues of multi-auto-transformation (MAT)-PsMT(A1) plants exposed to copper and zinc, compared to control plants. Tolerance to photo-oxidative stress induced by paraquat was another distinctive feature of the MAT-PsMT(A1) lines. Finally, low levels of DNA damage were detected by quantifying the amounts of 8-hydroxy-2'-deoxyguanosine in leaf tissues of the transgenic plants exposed to copper.
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Affiliation(s)
- Alma Balestrazzi
- Dipartimento di Genetica e Microbiologia, Università di Pavia, Pavia, Italy
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Guo B, Chen X, Hong Y, Liang X, Dang P, Brenneman T, Holbrook C, Culbreath A. Analysis of Gene Expression Profiles in Leaf Tissues of Cultivated Peanuts and Development of EST-SSR Markers and Gene Discovery. INTERNATIONAL JOURNAL OF PLANT GENOMICS 2009; 2009:715605. [PMID: 19584933 PMCID: PMC2703745 DOI: 10.1155/2009/715605] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2008] [Accepted: 04/10/2009] [Indexed: 05/20/2023]
Abstract
Peanut is vulnerable to a range of foliar diseases such as spotted wilt caused by Tomato spotted wilt virus (TSWV), early (Cercospora arachidicola) and late (Cercosporidium personatum) leaf spots, southern stem rot (Sclerotium rolfsii), and sclerotinia blight (Sclerotinia minor). In this study, we report the generation of 17,376 peanut expressed sequence tags (ESTs) from leaf tissues of a peanut cultivar (Tifrunner, resistant to TSWV and leaf spots) and a breeding line (GT-C20, susceptible to TSWV and leaf spots). After trimming vector and discarding low quality sequences, a total of 14,432 high-quality ESTs were selected for further analysis and deposition to GenBank. Sequence clustering resulted in 6,888 unique ESTs composed of 1,703 tentative consensus (TCs) sequences and 5185 singletons. A large number of ESTs (5717) representing genes of unknown functions were also identified. Among the unique sequences, there were 856 EST-SSRs identified. A total of 290 new EST-based SSR markers were developed and examined for amplification and polymorphism in cultivated peanut and wild species. Resequencing information of selected amplified alleles revealed that allelic diversity could be attributed mainly to differences in repeat type and length in the SSR regions. In addition, a few additional INDEL mutations and substitutions were observed in the regions flanking the microsatellite regions. In addition, some defense-related transcripts were also identified, such as putative oxalate oxidase (EU024476) and NBS-LRR domains. EST data in this study have provided a new source of information for gene discovery and development of SSR markers in cultivated peanut. A total of 16931 ESTs have been deposited to the NCBI GenBank database with accession numbers ES751523 to ES768453.
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Affiliation(s)
- Baozhu Guo
- Crop Protection and Management Research Unit, USDA-ARS, Tifton, GA 31793, USA
| | - Xiaoping Chen
- Department of Plant Pathology, University of Georgia, Tifton, GA 31793, USA
- Crops Research Institute, Guangdong Academy of Agricultural Sciences, Guangzhou, 51064 China
| | - Yanbin Hong
- Crops Research Institute, Guangdong Academy of Agricultural Sciences, Guangzhou, 51064 China
| | - Xuanqiang Liang
- Crops Research Institute, Guangdong Academy of Agricultural Sciences, Guangzhou, 51064 China
| | - Phat Dang
- National Peanut Research Laboratory, USDA-ARS, Dawson, GA 31742, USA
| | - Tim Brenneman
- Department of Plant Pathology, University of Georgia, Tifton, GA 31793, USA
| | - Corley Holbrook
- Crop Genetics and Breeding Research Unit, USDA-ARS, Tifton, GA 31793, USA
| | - Albert Culbreath
- Department of Plant Pathology, University of Georgia, Tifton, GA 31793, USA
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Bratić AM, Majić DB, Samardzić JT, Maksimović VR. Functional analysis of the buckwheat metallothionein promoter: tissue specificity pattern and up-regulation under complex stress stimuli. JOURNAL OF PLANT PHYSIOLOGY 2009; 166:996-1000. [PMID: 19185389 DOI: 10.1016/j.jplph.2008.12.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2008] [Revised: 12/04/2008] [Accepted: 12/05/2008] [Indexed: 05/27/2023]
Abstract
To shed light on expression regulation of the metallothionein gene from buckwheat (FeMT3), functional promoter analysis was performed with a complete 5' regulatory region and two deletion variants, employing stably transformed tobacco plants. Histochemical GUS assay of transgenic tobacco lines showed the strongest signals in vascular elements of leaves and in pollen grains, while somewhat weaker staining was observed in the roots of mature plants. This tissue specificity pattern implies a possible function of buckwheat MT3 in those tissues. Quantitative GUS assay showed strong up-regulation of all three promoter constructs (proportional to the length of the regulatory region) in leaves submerged in liquid MS medium containing sucrose, after a prolonged time period. This represented a complex stress situation composed of several synergistically related stress stimuli. These findings suggest complex transcriptional regulation of FeMT3, requiring interactions among a number of different factors.
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Affiliation(s)
- Ana M Bratić
- Department of Plant Molecular Biology, Institute of Molecular Genetics and Genetic Engineering, University of Belgrade, Vojvode Stepe 444a, P.O. Box 23, Belgrade 11010, Serbia
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31
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Yang Z, Wu Y, Li Y, Ling HQ, Chu C. OsMT1a, a type 1 metallothionein, plays the pivotal role in zinc homeostasis and drought tolerance in rice. PLANT MOLECULAR BIOLOGY 2009; 70:219-29. [PMID: 19229638 DOI: 10.1007/s11103-009-9466-1] [Citation(s) in RCA: 124] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/13/2008] [Accepted: 02/01/2009] [Indexed: 05/08/2023]
Abstract
Metallothioneins (MTs) are small, cysteine-rich, metal-binding proteins that may be involved in metal homeostasis and detoxification in both plants and animals. OsMT1a, encoding a type 1 metallothionein, was isolated via suppression subtractive hybridization from Brazilian upland rice (Oryza sativa L. cv. Iapar 9). Expression analysis revealed that OsMT1a predominantly expressed in the roots, and was induced by dehydration. Interestingly, the OsMT1a expression was also induced specifically by Zn(2+) treatment. Both transgenic plants and yeasts harboring OsMT1a accumulated more Zn(2+) than wild type controls, suggesting OsMT1a is most likely to be involved in zinc homeostasis. Transgenic rice plants overexpressing OsMT1a demonstrated enhanced tolerance to drought. The examination of antioxidant enzyme activities demonstrated that catalase (CAT), peroxidase (POD) and ascorbate peroxidase (APX) were significantly elevated in transgenic plants. Furthermore, the transcripts of several Zn(2+)-induced CCCH zinc finger transcription factors accumulated in OsMT1a transgenic plants, suggesting that OsMT1a not only participates directly in ROS scavenging pathway but also regulates expression of the zinc finger transcription factors via the alteration of Zn(2+) homeostasis, which leads to improved plant stress tolerance.
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Affiliation(s)
- Zhao Yang
- State Key Laboratory of Plant Genomics and National Centre for Plant Gene Research (Beijing), Institute of Genetics and Developmental Biology, The Chinese Academy of Sciences, 100101, Beijing, China
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Ren Y, Zhao J. Functional analysis of the rice metallothionein gene OsMT2b promoter in transgenic Arabidopsis plants and rice germinated embryos. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2009; 176:528-538. [PMID: 26493143 DOI: 10.1016/j.plantsci.2009.01.010] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/08/2008] [Revised: 01/17/2009] [Accepted: 01/19/2009] [Indexed: 06/05/2023]
Abstract
In this paper, the promoter of a type 2 metallothionein gene OsMT2b was cloned in indica rice Jiayu948 and its function was analyzed in transgenic Arabidopsis plant and rice germinated embryo aided by a GUS reporter gene. The result shows that the full promoter drives GUS expression predominantly in the vascular tissues of Arabidopsis, and the expression undergoes a unimodal pattern during the development, with peaking in the mature tissues in leaves and floral organs. Further promoter deletion analysis in Arabidopsis displays different function regions that are crucial for regulating gene expression: the -212/-21 region for keeping the minimal promoter activity and the expression in the initiation site of lateral root; the -924/-213 region for the expression in vegetative and reproductive organs; the -1227/-925 region for confining high expression in silique; and the -1502/-1228 and -1227/-925 regions for the balanceable control of high expression in embryo. And by using a transient expression system in rice germinated embryo, the similar promoter region-based regulation was observed. In addition, from studying the promoter activities under different stress conditions such as ABA, GA, ZT, PEG, cold, hot, NaCl, Cu, Zn and wounding, it is proposed that environmental stresses may regulate OsMT2b expression through the promoter cis-acing elements.
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Affiliation(s)
- Yujun Ren
- Key Laboratory of the Ministry of Education for Plant Developmental Biology, College of Life Sciences, Wuhan University, Wuhan, China
| | - Jie Zhao
- Key Laboratory of the Ministry of Education for Plant Developmental Biology, College of Life Sciences, Wuhan University, Wuhan, China.
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Memon AR, Schröder P. Implications of metal accumulation mechanisms to phytoremediation. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2009; 16:162-75. [PMID: 19067014 DOI: 10.1007/s11356-008-0079-z] [Citation(s) in RCA: 124] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2008] [Accepted: 11/11/2008] [Indexed: 05/23/2023]
Abstract
BACKGROUND, AIM, AND SCOPE Trace elements (heavy metals and metalloids) are important environmental pollutants, and many of them are toxic even at very low concentrations. Pollution of the biosphere with trace elements has accelerated dramatically since the Industrial Revolution. Primary sources are the burning of fossil fuels, mining and smelting of metalliferous ores, municipal wastes, agrochemicals, and sewage. In addition, natural mineral deposits containing particularly large quantities of heavy metals are found in many regions. These areas often support characteristic plant species thriving in metal-enriched environments. Whereas many species avoid the uptake of heavy metals from these soils, some of them can accumulate significantly high concentrations of toxic metals, to levels which by far exceed the soil levels. The natural phenomenon of heavy metal tolerance has enhanced the interest of plant ecologists, plant physiologists, and plant biologists to investigate the physiology and genetics of metal tolerance in specialized hyperaccumulator plants such as Arabidopsis halleri and Thlaspi caerulescens. In this review, we describe recent advances in understanding the genetic and molecular basis of metal tolerance in plants with special reference to transcriptomics of heavy metal accumulator plants and the identification of functional genes implied in tolerance and detoxification. RESULTS Plants are susceptible to heavy metal toxicity and respond to avoid detrimental effects in a variety of different ways. The toxic dose depends on the type of ion, ion concentration, plant species, and stage of plant growth. Tolerance to metals is based on multiple mechanisms such as cell wall binding, active transport of ions into the vacuole, and formation of complexes with organic acids or peptides. One of the most important mechanisms for metal detoxification in plants appears to be chelation of metals by low-molecular-weight proteins such as metallothioneins and peptide ligands, the phytochelatins. For example, glutathione (GSH), a precursor of phytochelatin synthesis, plays a key role not only in metal detoxification but also in protecting plant cells from other environmental stresses including intrinsic oxidative stress reactions. In the last decade, tremendous developments in molecular biology and success of genomics have highly encouraged studies in molecular genetics, mainly transcriptomics, to identify functional genes implied in metal tolerance in plants, largely belonging to the metal homeostasis network. DISCUSSION Analyzing the genetics of metal accumulation in these accumulator plants has been greatly enhanced through the wealth of tools and the resources developed for the study of the model plant Arabidopsis thaliana such as transcript profiling platforms, protein and metabolite profiling, tools depending on RNA interference (RNAi), and collections of insertion line mutants. To understand the genetics of metal accumulation and adaptation, the vast arsenal of resources developed in A. thaliana could be extended to one of its closest relatives that display the highest level of adaptation to high metal environments such as A. halleri and T. caerulescens. CONCLUSIONS This review paper deals with the mechanisms of heavy metal accumulation and tolerance in plants. Detailed information has been provided for metal transporters, metal chelation, and oxidative stress in metal-tolerant plants. Advances in phytoremediation technologies and the importance of metal accumulator plants and strategies for exploring these immense and valuable genetic and biological resources for phytoremediation are discussed. RECOMMENDATIONS AND PERSPECTIVES A number of species within the Brassicaceae family have been identified as metal accumulators. To understand fully the genetics of metal accumulation, the vast genetic resources developed in A. thaliana must be extended to other metal accumulator species that display traits absent in this model species. A. thaliana microarray chips could be used to identify differentially expressed genes in metal accumulator plants in Brassicaceae. The integration of resources obtained from model and wild species of the Brassicaceae family will be of utmost importance, bringing most of the diverse fields of plant biology together such as functional genomics, population genetics, phylogenetics, and ecology. Further development of phytoremediation requires an integrated multidisciplinary research effort that combines plant biology, genetic engineering, soil chemistry, soil microbiology, as well as agricultural and environmental engineering.
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Affiliation(s)
- Abdul R Memon
- TUBITAK, Marmara Research Center, Institute for Genetic Engineering and Biotechnology, P.O. Box 21, 41470, Gebze, Kocaeli, Turkey.
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Heavy metal and abiotic stress inducible metallothionein isoforms from Prosopis juliflora (SW) D.C. show differences in binding to heavy metals in vitro. Mol Genet Genomics 2008; 281:99-108. [PMID: 19015881 DOI: 10.1007/s00438-008-0398-2] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2008] [Accepted: 10/22/2008] [Indexed: 10/21/2022]
Abstract
Prosopis juliflora is a tree species that grows well in heavy metal laden industrial sites and accumulates heavy metals. To understand the possible contribution of metallothioneins (MTs) in heavy metal accumulation in P. juliflora, we isolated and compared the metal binding ability of three different types of MTs (PjMT1-3). Glutathione S-transferase fusions of PjMTs (GSTMT1-3) were purified from Escherichia coli cells grown in the presence of 0.3 mM cadmium, copper or zinc. Analysis of metal bound fusion proteins using atomic absorption spectrometry showed that PjMT1 bound higher levels of all three heavy metals as compared to PjMT2 and PjMT3. A comparative analysis of the genomic regions (including promoter for all three PjMTs) is also presented. All three PjMTs are induced by H(2)O(2) and ABA applications. PjMT1 and PjMT2 are induced by copper and zinc respectively while PjMT3 is induced by copper, zinc and cadmium. Variation in induction of PjMTs in response to metal exposure and their differential binding to metals suggests that each MT has a specific role in P. juliflora. Of the three MTs analyzed, PjMT1 shows maximum heavy metal sequestration and is thus a potential candidate for use in heavy metal phytoremediation.
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Quan XQ, Wang ZL, Zhang H, Bi YP. Cloning and characterization of TsMT3, a type 3 metallothionein gene from salt cress (Thellungiella salsuginea). ACTA ACUST UNITED AC 2008; 19:340-6. [PMID: 17852348 DOI: 10.1080/10425170701606201] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
A full-length type 3 plant metallothionein cDNA was isolated from 200 mM NaCl stressed shoots of the salt cress (Thellungiella salsuginea). The 447 bp TsMT3 cDNA sequence has a 207 bp open reading frame (ORF) and encodes a deduced 69 residue peptide of molecular weight 7.52 kDa. Southern blot analysis indicates that, there is only one copy of TsMT3 in the T. salsuginea genome. The accumulation of TsMT3 mRNA is enhanced by the stress imposed by PEG6000, 200 mM NaCl, 50 microM ABA, 4 degrees C, 40 microM CuSO(4) or 25 microM CdCl2. The expression vector pET28-TsMT3 was heterologously expressed in Escherichia coli to define the contribution of TsMT3 to heavy metal tolerance. In the presence of 2 mM CuSO4, 0.3 mM Pb(NO3)2 or 0.4 mM CdCl2, TsMT3 expressing cells exhibited enhanced metal tolerance and accumulated more metal than the controls. We believe that TsMT3 is probably involved in the processes of metal homeostasis, tolerance, and reactive oxygen species (ROS) scavenging.
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Affiliation(s)
- Xian Q Quan
- College of Life Sciences, Shandong Normal University, Shandong Jinan, PR China
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Expression patterns of the rice class I metallothionein gene family in response to lead stress in rice seedlings and functional complementation of its members in lead-sensitive yeast cells. ACTA ACUST UNITED AC 2007. [DOI: 10.1007/s11434-007-0335-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Yang Q, Wang Y, Zhang J, Shi W, Qian C, Peng X. Identification of aluminum-responsive proteins in rice roots by a proteomic approach: cysteine synthase as a key player in Al response. Proteomics 2007; 7:737-49. [PMID: 17295357 DOI: 10.1002/pmic.200600703] [Citation(s) in RCA: 99] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Aluminum (Al) toxicity is a serious limitation to worldwide crop production. Rice is one of the most Al-tolerant crops and also serves as an important monocot model plant. This study aims to identify Al-responsive proteins in rice, based on evidence that Al resistance is an inducible process. Two Al treatment systems were applied in the study: Al3+-containing simple Ca solution culture and Al3+-containing complete nutrient solution culture. Proteins prepared from rice roots were separated by 2-DE. The 2-DE patterns were compared and the differentially expressed proteins were identified by MS. A total of 17 Al-responsive proteins were identified, with 12 of those being up-regulated and 5 down-regulated. Among the up-regulated proteins are copper/zinc superoxide dismutase (Cu-Zn SOD), GST, and S-adenosylmethionine synthetase 2, which are the consistently known Al-induced enzymes previously detected at the transcriptional level in other plants. More importantly, a number of other identified proteins including cysteine synthase (CS), 1-aminocyclopropane-1-carboxylate oxidase, G protein beta subunit-like protein, abscisic acid- and stress-induced protein, putative Avr9/Cf-9 rapidly elicited protein 141, and a 33 kDa secretory protein are novel Al-induced proteins. Most of these proteins are functionally associated with signaling transduction, antioxidation, and detoxification. CS, as consistently detected in both Al stress systems, was further validated by Western blot and CS activity assays. Moreover, the metabolic products of CS catalysis, i.e. both the total glutathione pool and reduced glutathione, were also significantly increased in response to Al stress. Taken together, our results suggest that antioxidation and detoxification ultimately related to sulfur metabolism, particularly to CS, may play a functional role in Al adaptation for rice.
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Affiliation(s)
- Qiaosong Yang
- Laboratory of Molecular Plant Physiology, College of Life Sciences, South China Agricultural University, Guangzhou, China
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Castiglione S, Franchin C, Fossati T, Lingua G, Torrigiani P, Biondi S. High zinc concentrations reduce rooting capacity and alter metallothionein gene expression in white poplar (Populus alba L. cv. Villafranca). CHEMOSPHERE 2007; 67:1117-26. [PMID: 17223164 DOI: 10.1016/j.chemosphere.2006.11.039] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2006] [Revised: 11/13/2006] [Accepted: 11/14/2006] [Indexed: 05/13/2023]
Abstract
Poplar is a good candidate for phytoremediation purposes because of its rapid growth, extensive root system, and ease of propagation and transformation; however its tolerance to heavy metals has not been fully investigated yet. In the present work, an in vitro model system with shoot cultures was used to investigate the tolerance to high concentrations of zinc (Zn) of a commercial clone (Villafranca) of Populus alba. Based on chlorophyll content (leaf chlorosis) and the rate of adventitious root formation from shoot cuttings as parameters of damage, 0.5-4mM zinc concentrations were all toxic albeit to different extents. Northern blot and reverse transcriptase (RT)-PCR analyses were used to examine the expression profiles of types 1, 2 and 3 PaMT genes in stems, leaves and roots of plants exposed to Zn treatments. In leaves, MT1 and MT3 mRNA levels were enhanced by Zn, while MT2 transcripts were not affected. The PaMT expression profiles were differentially affected by Zn in an organ-specific manner, and the relationship with Zn concentration and exposure time was rarely linear. The developmental and molecular data reveal that the in vitro model is a sensitive and reliable system to study heavy metal stress responses.
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Gorantla M, Babu PR, Lachagari VBR, Reddy AMM, Wusirika R, Bennetzen JL, Reddy AR. Identification of stress-responsive genes in an indica rice (Oryza sativa L.) using ESTs generated from drought-stressed seedlings. JOURNAL OF EXPERIMENTAL BOTANY 2007; 58:253-65. [PMID: 17132712 DOI: 10.1093/jxb/erl213] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
The impacts of drought on plant growth and development limit cereal crop production worldwide. Rice (Oryza sativa) productivity and production is severely affected due to recurrent droughts in almost all agroecological zones. With the advent of molecular and genomic technologies, emphasis is now placed on understanding the mechanisms of genetic control of the drought-stress response. In order to identify genes associated with water-stress response in rice, ESTs generated from a normalized cDNA library, constructed from drought-stressed leaf tissue of an indica cultivar, Nagina 22 were used. Analysis of 7794 cDNA sequences led to the identification of 5815 rice ESTs. Of these, 334 exhibited no significant sequence homology with any rice ESTs or full-length cDNAs in public databases, indicating that these transcripts are enriched during drought stress. Analysis of these 5815 ESTs led to the identification of 1677 unique sequences. To characterize this drought transcriptome further and to identify candidate genes associated with the drought-stress response, the rice data were compared with those for abiotic stress-induced sequences obtained from expression profiling studies in Arabidopsis, barley, maize, and rice. This comparative analysis identified 589 putative stress-responsive genes (SRGs) that are shared by these diverse plant species. Further, the identified leaf SRGs were compared to expression profiles for a drought-stressed rice panicle library to identify common sequences. Significantly, 125 genes were found to be expressed under drought stress in both tissues. The functional classification of these 125 genes showed that a majority of them are associated with cellular metabolism, signal transduction, and transcriptional regulation.
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Affiliation(s)
- Markandeya Gorantla
- Department of Plant Sciences, School of Life Sciences, University of Hyderabad, Hyderabad-500046, AP, India
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Lü S, Gu H, Yuan X, Wang X, Wu AM, Qu L, Liu JY. The GUS reporter-aided analysis of the promoter activities of a rice metallothionein gene reveals different regulatory regions responsible for tissue-specific and inducible expression in transgenic Arabidopsis. Transgenic Res 2006; 16:177-91. [PMID: 17146614 DOI: 10.1007/s11248-006-9035-1] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2006] [Accepted: 08/21/2006] [Indexed: 10/23/2022]
Abstract
To gain a better understanding of the regulatory mechanism of plant metallothionein (MT) genes, a chimeric expression unit consisting of the beta-glucuronidase (gusA) reporter gene under the control of a 1,324 bp fragment of the rice MT (ricMT) promoter was introduced into Arabidopsis via Agrobacterium tumefaciens. The strongest histochemical staining for GUS activity was observed in the cotyledons and hypocotyls of the transgenic seedlings and in the stigma, filaments and anthers of young and mature flowers, and especially in the wounded tissues of transgenic plants. In contrast, a relatively low level of reporter gene expression was seen in the young roots of transgenic seedlings and no GUS activity was detected in the stems, seeds and leaves, but GUS activity was observed in cotyledons and the first two true leaves. Promoter analysis of 5' deletions further identified several important regions responsible for organ-specific expression including roots, flowers and wound induction, light and ABA, Cu and Zn responses. These findings demonstrate that a 1,324 bp fragment of the rice MT promoter performs a complicated transcriptional regulation with clearly functional regions in a model plant, and provide an important insight into the transcriptional regulation mechanisms that operate the temporal- and spatial-specific expression and stress responses of the rice MT gene. These results suggest that the ricMT promoter and its functional regions are potentially useful in genetic engineering of plants to express the desired genes whose products are preferentially needed in roots, flowers and wound induction.
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Affiliation(s)
- Shiyou Lü
- Laboratory of Molecular Biology and Protein Science Laboratory of the Ministry of Education, Department of Biological Sciences and Biotechnology, Tsinghua University, Beijing, 100084, China
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Zhou G, Xu Y, Li J, Yang L, Liu JY. Molecular analyses of the metallothionein gene family in rice (Oryza sativa L.). BMB Rep 2006; 39:595-606. [PMID: 17002881 DOI: 10.5483/bmbrep.2006.39.5.595] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Metallothioneins are a group of low molecular mass and cysteine-rich metal-binding proteins, ubiquitously found in most living organisms. They play an important role in maintaining intracellular metal homeostasis, eliminating metal toxification and protecting against intracellular oxidative damages. Analysis of complete rice genome sequences revealed eleven genes encoding putative metallothionein (OsMT), indicating that OsMTs constitute a small gene family in rice. Expression profiling revealed that each member of the OsMT gene family differs not only in sequence but also in their tissue expression patterns, suggesting that these isoforms may have different functions they perform in specific tissues. On the basis of OsMT structural and phylogenetic analysis, the OsMT family was classified as two classes and class I was subdivided into four types. Additionally, in this paper we also present a complete overview of this family, describing the gene structure, genome localization, upstream regulatory element, and exon/intron organization of each member in order to provide valuable insight into this OsMT gene family.
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Affiliation(s)
- Gongke Zhou
- Laboratory of Molecular Biology and Protein Science Laboratory of the Ministry of Education, Department of Biological Sciences and Biotechnology, Tsinghua University, Beijing 100084, China
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Dauch AL, Jabaji-Hare SH. Metallothionein and bZIP Transcription Factor Genes from Velvetleaf and Their Differential Expression Following Colletotrichum coccodes Infection. PHYTOPATHOLOGY 2006; 96:1116-1123. [PMID: 18943500 DOI: 10.1094/phyto-96-1116] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
ABSTRACT Colletotrichum coccodes is a biocontrol agent of velvetleaf (Abutilon theophrasti), a noxious weed of corn and soybean. Metallothioneins (MTs) and basic region/leucine zipper motif (bZIP) are heavy-metal-binding proteins and transcription factors, respectively, that have been related to several plant processes, including the responses of plants to pathogen attack. Previous investigation of the determinants involved in the velvet-leaf-C. coccodes interaction had shed light on particular plant and fungal genes expressed in this pathosystem. Here, we report on the temporal expression patterns of two distinct types (2 and 3) of MT and bZIP transcription factor genes in velvetleaf leaves following infection with C. coccodes using quantitative reverse-transcription polymerase chain reaction. Gene expression ratios were significantly upregulated 1 day after infection (DAI), a time at which velvetleaf leaves appeared symptomless. At 2 DAI, bZIP and type 3 MT expression ratios dropped to levels significantly lower than those estimated for noninfected plants. Necrotic symptoms appeared 5 DAI and increased with time, during which gene expression levels were maintained either below or at levels observed in the control. These findings indicate that C. coccodes altered the expression of type 2 and 3 MT and bZIP genes. In addition, this is the first report on induction of a type 3 MT in plants in response to a pathogen attack.
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Cho SH, Hoang QT, Kim YY, Shin HY, Ok SH, Bae JM, Shin JS. Proteome analysis of gametophores identified a metallothionein involved in various abiotic stress responses in Physcomitrella patens. PLANT CELL REPORTS 2006; 25:475-88. [PMID: 16397781 DOI: 10.1007/s00299-005-0079-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2005] [Revised: 10/04/2005] [Accepted: 10/10/2005] [Indexed: 05/06/2023]
Abstract
Physcomitrella patens is a model plant for studying gene function using a knockout strategy. To establish a proteome database for P. patens, we resolved over 1,500 soluble proteins from gametophore and protonema tissues by two-dimensional electrophoresis (2-DE) and obtained peptide mass fingerprints (PMFs) by matrix-assisted laser desorption/ionization-time of flight-mass spectrometry (MALDI-TOF-MS). Using expressed sequence tags (ESTs), we were able to predict the identities of 90 protein spots. Most of these were related to energy or primary metabolism. Comparative proteome analysis was used to identify proteins specific for each of the tissue types. One of these was a metallothionein type-2 (PpMT2) protein that was highly upregulated in gametophore tissue. PpMT2 was induced in both the gametophore and protonema following culture on solid media and in response to various abiotic stresses such as copper, cadmium, cold, indole-3-acetic acid, and ethylene. We suggest that PpMT2 is not only involved in metal binding and detoxification, but also in many biological aspects as a metal messenger or a protein with additional functions.
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Affiliation(s)
- Sung Hyun Cho
- School of Life Sciences and Biotechnology, Korea University, Seoul, 136-701 Korea
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