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Qu M, Song J, Ren H, Zhao B, Zhang J, Ren B, Liu P. Differences of cadmium uptake and accumulation in roots of two maize varieties (Zea mays L.). ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2023; 30:96993-97004. [PMID: 37584802 DOI: 10.1007/s11356-023-29340-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2022] [Accepted: 08/10/2023] [Indexed: 08/17/2023]
Abstract
Different maize varieties respond differentially to cadmium (Cd) stress. As the first organ in contact with the soil, the response of the root is particularly important. However, the physiological mechanisms that determine the response are not well defined. Here, we compared the differences in Cd-induced related gene expression, ionic homeostasis, and ultrastructural changes in roots of Cd-tolerant maize variety (XR57) and Cd-sensitive maize variety (LY296), and assessed their effects on Cd uptake and accumulation. Our findings indicate that XR57 absorbed a significantly lower Cd than LY296 did, and that the expression levels of genes related to Cd uptake (ZmNRAMP5 and ZmZIP4) and efflux (ZmABCG4) in the root were consistent with the Cd absorption at the physiological levels. Compared with LY296, the lower Cd concentration in the roots of XR57 caused less interference with the ion balance. Transmission electron microscope images revealed that the roots from XR57 exposed to Cd had developed thicker cell walls than LY296. In addition, the large increase ZmABCC1 and ZmABCC2 expression levels in XR57 mediated the appearance of numerous electron-dense granules in the vacuoles present in the roots. As a result, the high Cd tolerance of XR57 is the result of a multi-level response that involves increased resistance to Cd uptake, a stronger capacity for vacuolar regionalization, and the formation of thicker cell walls. These findings may provide a theoretical basis for maize cultivation in Cd-contaminated areas.
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Affiliation(s)
- Mengxue Qu
- College of Agronomy, State Key Laboratory of Crop Biology, Shandong Agricultural University, Tai'an, 271018, Shandong, China
| | - Jie Song
- College of Agronomy, State Key Laboratory of Crop Biology, Shandong Agricultural University, Tai'an, 271018, Shandong, China
| | - Hao Ren
- College of Agronomy, State Key Laboratory of Crop Biology, Shandong Agricultural University, Tai'an, 271018, Shandong, China
| | - Bin Zhao
- College of Agronomy, State Key Laboratory of Crop Biology, Shandong Agricultural University, Tai'an, 271018, Shandong, China
| | - Jiwang Zhang
- College of Agronomy, State Key Laboratory of Crop Biology, Shandong Agricultural University, Tai'an, 271018, Shandong, China
| | - Baizhao Ren
- College of Agronomy, State Key Laboratory of Crop Biology, Shandong Agricultural University, Tai'an, 271018, Shandong, China
| | - Peng Liu
- College of Agronomy, State Key Laboratory of Crop Biology, Shandong Agricultural University, Tai'an, 271018, Shandong, China.
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Zhang J, Diao F, Hao B, Xu L, Jia B, Hou Y, Ding S, Guo W. Multiomics reveals Claroideoglomus etunicatum regulates plant hormone signal transduction, photosynthesis and La compartmentalization in maize to promote growth under La stress. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2023; 262:115128. [PMID: 37315361 DOI: 10.1016/j.ecoenv.2023.115128] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2023] [Revised: 06/07/2023] [Accepted: 06/08/2023] [Indexed: 06/16/2023]
Abstract
Rare earth elements (REEs) have been widely used in traditional and high-tech fields, and high doses of REEs are considered a risk to the ecosystem. Although the influence of arbuscular mycorrhizal fungi (AMF) in promoting host resistance to heavy metal (HM) stress has been well documented, the molecular mechanism by which AMF symbiosis enhances plant tolerance to REEs is still unclear. A pot experiment was conducted to investigate the molecular mechanism by which the AMF Claroideoglomus etunicatum promotes maize (Zea mays) seedling tolerance to lanthanum (La) stress (100 mg·kg-1 La). C. etunicatum symbiosis significantly improved maize seedling growth, P and La uptake and photosynthesis. Transcriptome, proteome, and metabolome analyses performed alone and together revealed that differentially expressed genes (DEGs) related to auxin /indole-3-acetic acid (AUX/IAA) and the DEGs and differentially expressed proteins (DEPs) related to ATP-binding cassette (ABC) transporters, natural resistance-associated macrophage proteins (Nramp6), vacuoles and vesicles were upregulated. In contrast, photosynthesis-related DEGs and DEPs were downregulated, and 1-phosphatidyl-1D-myo-inositol 3-phosphate (PI(3)P) was more abundant under C. etunicatum symbiosis. C. etunicatum symbiosis can promote plant growth by increasing P uptake, regulating plant hormone signal transduction, photosynthesis and glycerophospholipid metabolism pathways and enhancing La transport and compartmentalization in vacuoles and vesicles. The results provide new insights into the promotion of plant REE tolerance by AMF symbiosis and the possibility of utilizing AMF-maize interactions in REE phytoremediation and recycling.
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Affiliation(s)
- Jingxia Zhang
- Inner Mongolia Key Laboratory of Environmental Pollution Control and Waste Resource Recycle, Ministry of Education Collaborative Innovation Center for Grassland Ecological Security, Ministry of Education Key Laboratory of Ecology and Resource Use of the Mongolian Plateau, School of Ecology and Environment, Inner Mongolia University, Hohhot 010021, China; Inner Mongolia Key Laboratory of Environmental Chemistry, School of Chemistry and Environment, Inner Mongolia Normal University, Hohhot 010021, China
| | - Fengwei Diao
- Inner Mongolia Key Laboratory of Environmental Pollution Control and Waste Resource Recycle, Ministry of Education Collaborative Innovation Center for Grassland Ecological Security, Ministry of Education Key Laboratory of Ecology and Resource Use of the Mongolian Plateau, School of Ecology and Environment, Inner Mongolia University, Hohhot 010021, China
| | - Baihui Hao
- Inner Mongolia Key Laboratory of Environmental Pollution Control and Waste Resource Recycle, Ministry of Education Collaborative Innovation Center for Grassland Ecological Security, Ministry of Education Key Laboratory of Ecology and Resource Use of the Mongolian Plateau, School of Ecology and Environment, Inner Mongolia University, Hohhot 010021, China
| | - Lei Xu
- Service Support Center, Ecology and Environmental Department of Inner Mongolia Autonomous Region, Hohhot 010010, China
| | - Bingbing Jia
- Inner Mongolia Key Laboratory of Environmental Pollution Control and Waste Resource Recycle, Ministry of Education Collaborative Innovation Center for Grassland Ecological Security, Ministry of Education Key Laboratory of Ecology and Resource Use of the Mongolian Plateau, School of Ecology and Environment, Inner Mongolia University, Hohhot 010021, China
| | - Yazhou Hou
- Inner Mongolia Key Laboratory of Environmental Pollution Control and Waste Resource Recycle, Ministry of Education Collaborative Innovation Center for Grassland Ecological Security, Ministry of Education Key Laboratory of Ecology and Resource Use of the Mongolian Plateau, School of Ecology and Environment, Inner Mongolia University, Hohhot 010021, China
| | - Shengli Ding
- Inner Mongolia Key Laboratory of Environmental Pollution Control and Waste Resource Recycle, Ministry of Education Collaborative Innovation Center for Grassland Ecological Security, Ministry of Education Key Laboratory of Ecology and Resource Use of the Mongolian Plateau, School of Ecology and Environment, Inner Mongolia University, Hohhot 010021, China
| | - Wei Guo
- Inner Mongolia Key Laboratory of Environmental Pollution Control and Waste Resource Recycle, Ministry of Education Collaborative Innovation Center for Grassland Ecological Security, Ministry of Education Key Laboratory of Ecology and Resource Use of the Mongolian Plateau, School of Ecology and Environment, Inner Mongolia University, Hohhot 010021, China.
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Zhang Z, Wang S, Wang J, Zhang C, Liu D, Wang C, Xu F. The overexpression of LOW PHOSPHATE ROOT 1 (LPR1) negatively regulates Arabidopsis growth in response to Cadmium (Cd) stress. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2023; 196:556-566. [PMID: 36774911 DOI: 10.1016/j.plaphy.2023.02.003] [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: 11/09/2022] [Revised: 01/17/2023] [Accepted: 02/02/2023] [Indexed: 06/18/2023]
Abstract
Cadmium (Cd) is a highly toxic element that is easily absorbed by plant, and the mechanisms of the plant response to Cd toxicity are very complex. In this study, the role of LPR1 (LOW Phosphate Root 1) encoding a cell-wall-targeted ferroxidase in Cd stress was investigated. The results showed that the overexpression of LPR1 caused an average reduction of 23%-40% in the primary root lengths, 67%-73% in the fresh weights, 32%-46% in the lengths of the non-root hair zone (NRHZ) and 70%-71% in the chlorophyll contents in both LPR1-OX lines when compared with the wild type (WT), while there were no significant changes in these traits between the WT and mutant lpr1 lines under Cd stress (7.5 μmol/L CdSO4). Further investigation showed that the overexpression of LPR1 triggered reactive oxygen species (ROS) bursts and reduced the entry of available iron (Fe2+) into the cell, which induced the expression of iron-regulated transporter 1 (IRT1). The up-regulation of IRT1 contributed to the increase of Cd accumulation and growth retardation under Cd stress. Exogenous Fe and ROS scavengers down-regulated the IRT1's expression and alleviated the growth inhibition in LPR1-OX lines, indicating that LPR1-dependent ROS up-regulated IRT1, which subsequently exacerbated the Cd influx into plants. Our findings highlight a pathway of LPR1-mediated plant responding to Cd toxicity stress through the regulation of ROS and Fe homeostasis.
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Affiliation(s)
- Ziwei Zhang
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, 430070, China; Microelement Research Center, College of Resources & Environment, Huazhong Agricultural University, Wuhan, 430070, China
| | - Sheliang Wang
- Microelement Research Center, College of Resources & Environment, Huazhong Agricultural University, Wuhan, 430070, China
| | - Jun Wang
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, 430070, China; Microelement Research Center, College of Resources & Environment, Huazhong Agricultural University, Wuhan, 430070, China
| | - Cheng Zhang
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, 430070, China; Microelement Research Center, College of Resources & Environment, Huazhong Agricultural University, Wuhan, 430070, China
| | - Dong Liu
- MOE Key Laboratory of Bioinformatics, Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Chuang Wang
- Microelement Research Center, College of Resources & Environment, Huazhong Agricultural University, Wuhan, 430070, China
| | - Fangsen Xu
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, 430070, China; Microelement Research Center, College of Resources & Environment, Huazhong Agricultural University, Wuhan, 430070, China.
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Noor I, Sohail H, Sun J, Nawaz MA, Li G, Hasanuzzaman M, Liu J. Heavy metal and metalloid toxicity in horticultural plants: Tolerance mechanism and remediation strategies. CHEMOSPHERE 2022; 303:135196. [PMID: 35659937 DOI: 10.1016/j.chemosphere.2022.135196] [Citation(s) in RCA: 49] [Impact Index Per Article: 24.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2022] [Revised: 04/30/2022] [Accepted: 05/31/2022] [Indexed: 05/27/2023]
Abstract
Heavy metal/metalloids (HMs) are among the primary soil pollutants that limit crop production worldwide. Plants grown in HM contaminated soils exhibit reduced growth and development, resulting in a decrease in crop production. The exposure to HMs induces plant oxidative stress due to the formation of free radicals, which alter plant morphophysiological and biochemical mechanisms at cellular and tissue levels. When exposed to HM toxicity, plants evolve sophisticated physiological and cellular defense strategies, such as sequestration and transportation of metals, to ensure their survival. Plants also have developed efficient strategies by activating signaling pathways, which induce the expression of HM transporters. Plants either avoid the uptake of HMs from the soil or activate the detoxifying mechanism to tolerate HM stress, which involves the production of antioxidants (enzymatic and non-enzymatic) for the scavenging of reactive oxygen species. The metal-binding proteins including phytochelatins and metallothioneins also participate in metal detoxification. Furthermore, phytohormones and their signaling pathways also help to regulate cellular activities to counteract HM stress. The excessive levels of HMs in the soil can contribute to plant morpho-physiological, biochemical, and molecular alterations, which have a detrimental effect on the quality and productivity of crops. To maintain the commercial value of fruits and vegetables, various measures should be considered to remove HMs from the metal-polluted soils. Bioremediation is a promising approach that involves the use of tolerant microorganisms and plants to manage HMs pollution. The understanding of HM toxicity, signaling pathways, and tolerance mechanisms will facilitate the development of new crop varieties that help in improving phytoremediation.
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Affiliation(s)
- Iqra Noor
- Key Laboratory of Horticultural Plant Biology-Ministry of Education, College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan, 430070, PR China
| | - Hamza Sohail
- Key Laboratory of Horticultural Plant Biology-Ministry of Education, College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan, 430070, PR China
| | - Jingxian Sun
- Key Laboratory of Horticultural Plant Biology-Ministry of Education, College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan, 430070, PR China
| | - Muhammad Azher Nawaz
- Department of Horticulture, College of Agriculture, University of Sargodha, Sargodha, 40100, Pakistan
| | - Guohuai Li
- Key Laboratory of Horticultural Plant Biology-Ministry of Education, College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan, 430070, PR China
| | - Mirza Hasanuzzaman
- Department of Agronomy, Faculty of Agriculture, Sher-e-Bangla Agricultural University, Dhaka, 1207, Bangladesh.
| | - Junwei Liu
- Key Laboratory of Horticultural Plant Biology-Ministry of Education, College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan, 430070, PR China.
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Transcriptome Analysis Reveals the Stress Tolerance to and Accumulation Mechanisms of Cadmium in Paspalum vaginatum Swartz. PLANTS 2022; 11:plants11162078. [PMID: 36015382 PMCID: PMC9414793 DOI: 10.3390/plants11162078] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/28/2022] [Revised: 07/30/2022] [Accepted: 07/30/2022] [Indexed: 01/08/2023]
Abstract
Cadmium (Cd) is a non-essential heavy metal and high concentrations in plants causes toxicity of their edible parts and acts as a carcinogen to humans and animals. Paspalum vaginatum is widely cultivating as turfgrass due to its higher abiotic stress tolerance ability. However, there is no clear evidence to elucidate the mechanism for heavy metal tolerance, including Cd. In this study, an RNA sequencing technique was employed to investigate the key genes associated with Cd stress tolerance and accumulation in P. vaginatum. The results revealed that antioxidant enzyme activities catalase (CAT), peroxidase (POD), superoxide dismutase (SOD), and glutathione S-transferase GST) were significantly higher at 24 h than in other treatments. A total of 6820 (4457/2363, up-/down-regulated), 14,038 (9894/4144, up-/down-regulated) and 17,327 (7956/9371, up-/down-regulated) differentially expressed genes (DEGs) between the Cd1 vs. Cd0, Cd4 vs. Cd0, and Cd24 vs. Cd0, respectively, were identified. The GO analysis and the KEGG pathway enrichment analysis showed that DEGs participated in many significant pathways in response to Cd stress. The response to abiotic stimulus, the metal transport mechanism, glutathione metabolism, and the consistency of transcription factor activity were among the most enriched pathways. The validation of gene expression by qRT-PCR results showed that heavy metal transporters and signaling response genes were significantly enriched with increasing sampling intervals, presenting consistency to the transcriptome data. Furthermore, over-expression of PvSnRK2.7 can positively regulate Cd-tolerance in Arabidopsis. In conclusion, our results provided a novel molecular mechanism of the Cd stress tolerance of P. vaginatum and will lay the foundation for target breeding of Cd tolerance in turfgrass.
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Yu W, Deng S, Chen X, Cheng Y, Li Z, Wu J, Zhu D, Zhou J, Cao Y, Fayyaz P, Shi W, Luo Z. PcNRAMP1 Enhances Cadmium Uptake and Accumulation in Populus × canescens. Int J Mol Sci 2022; 23:ijms23147593. [PMID: 35886940 PMCID: PMC9316961 DOI: 10.3390/ijms23147593] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Revised: 07/03/2022] [Accepted: 07/06/2022] [Indexed: 12/10/2022] Open
Abstract
Poplars are proposed for the phytoremediation of heavy metal (HM) polluted soil. Characterization of genes involved in HM uptake and accumulation in poplars is crucial for improving the phytoremediation efficiency. Here, Natural Resistance-Associated Macrophage Protein 1 (NRAMP1) encoding a transporter involved in cadmium (Cd) uptake and transport was functionally characterized in Populus × canescens. Eight putative PcNRAMPs were identified in the poplar genome and most of them were primarily expressed in the roots. The expression of PcNRAMP1 was induced in Cd-exposed roots and it encoded a plasma membrane-localized protein. PcNRAMP1 showed transport activity for Cd2+ when expressed in yeast. The PcNRAMP1-overexpressed poplars enhanced net Cd2+ influxes by 39–52% in the roots and Cd accumulation by 25–29% in aerial parts compared to the wildtype (WT). However, Cd-induced biomass decreases were similar between the transgenics and WT. Further analysis displayed that the two amino acid residues of PcNRAMP1, i.e., M236 and P405, play pivotal roles in regulating its transport activity for Cd2+. These results suggest that PcNRAMP1 is a plasma membrane-localized transporter involved in Cd uptake and transporting Cd from the roots to aerial tissues, and that the conserved residues in PcNRAMP1 are essential for its Cd transport activity in poplars.
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Affiliation(s)
- Wenjian Yu
- State Key Laboratory of Tree Genetics and Breeding, Key Laboratory of Silviculture of the National Forestry and Grassland Administration, Research Institute of Forestry, Chinese Academy of Forestry, Beijing 100091, China; (W.Y.); (S.D.); (X.C.); (Y.C.); (Z.L.); (J.W.); (D.Z.); (J.Z.); (Y.C.)
| | - Shurong Deng
- State Key Laboratory of Tree Genetics and Breeding, Key Laboratory of Silviculture of the National Forestry and Grassland Administration, Research Institute of Forestry, Chinese Academy of Forestry, Beijing 100091, China; (W.Y.); (S.D.); (X.C.); (Y.C.); (Z.L.); (J.W.); (D.Z.); (J.Z.); (Y.C.)
| | - Xin Chen
- State Key Laboratory of Tree Genetics and Breeding, Key Laboratory of Silviculture of the National Forestry and Grassland Administration, Research Institute of Forestry, Chinese Academy of Forestry, Beijing 100091, China; (W.Y.); (S.D.); (X.C.); (Y.C.); (Z.L.); (J.W.); (D.Z.); (J.Z.); (Y.C.)
| | - Yao Cheng
- State Key Laboratory of Tree Genetics and Breeding, Key Laboratory of Silviculture of the National Forestry and Grassland Administration, Research Institute of Forestry, Chinese Academy of Forestry, Beijing 100091, China; (W.Y.); (S.D.); (X.C.); (Y.C.); (Z.L.); (J.W.); (D.Z.); (J.Z.); (Y.C.)
| | - Zhuorong Li
- State Key Laboratory of Tree Genetics and Breeding, Key Laboratory of Silviculture of the National Forestry and Grassland Administration, Research Institute of Forestry, Chinese Academy of Forestry, Beijing 100091, China; (W.Y.); (S.D.); (X.C.); (Y.C.); (Z.L.); (J.W.); (D.Z.); (J.Z.); (Y.C.)
| | - Jiangting Wu
- State Key Laboratory of Tree Genetics and Breeding, Key Laboratory of Silviculture of the National Forestry and Grassland Administration, Research Institute of Forestry, Chinese Academy of Forestry, Beijing 100091, China; (W.Y.); (S.D.); (X.C.); (Y.C.); (Z.L.); (J.W.); (D.Z.); (J.Z.); (Y.C.)
| | - Dongyue Zhu
- State Key Laboratory of Tree Genetics and Breeding, Key Laboratory of Silviculture of the National Forestry and Grassland Administration, Research Institute of Forestry, Chinese Academy of Forestry, Beijing 100091, China; (W.Y.); (S.D.); (X.C.); (Y.C.); (Z.L.); (J.W.); (D.Z.); (J.Z.); (Y.C.)
| | - Jing Zhou
- State Key Laboratory of Tree Genetics and Breeding, Key Laboratory of Silviculture of the National Forestry and Grassland Administration, Research Institute of Forestry, Chinese Academy of Forestry, Beijing 100091, China; (W.Y.); (S.D.); (X.C.); (Y.C.); (Z.L.); (J.W.); (D.Z.); (J.Z.); (Y.C.)
| | - Yuan Cao
- State Key Laboratory of Tree Genetics and Breeding, Key Laboratory of Silviculture of the National Forestry and Grassland Administration, Research Institute of Forestry, Chinese Academy of Forestry, Beijing 100091, China; (W.Y.); (S.D.); (X.C.); (Y.C.); (Z.L.); (J.W.); (D.Z.); (J.Z.); (Y.C.)
| | - Payam Fayyaz
- Forest, Range and Watershed Management Department, Agriculture and Natural Resources Faculty, Yasouj University, Yasuj 75919-63179, Iran;
| | - Wenguang Shi
- State Key Laboratory of Tree Genetics and Breeding, Key Laboratory of Silviculture of the National Forestry and Grassland Administration, Research Institute of Forestry, Chinese Academy of Forestry, Beijing 100091, China; (W.Y.); (S.D.); (X.C.); (Y.C.); (Z.L.); (J.W.); (D.Z.); (J.Z.); (Y.C.)
- Correspondence: (W.S.); (Z.L.)
| | - Zhibin Luo
- State Key Laboratory of Tree Genetics and Breeding, Key Laboratory of Silviculture of the National Forestry and Grassland Administration, Research Institute of Forestry, Chinese Academy of Forestry, Beijing 100091, China; (W.Y.); (S.D.); (X.C.); (Y.C.); (Z.L.); (J.W.); (D.Z.); (J.Z.); (Y.C.)
- Correspondence: (W.S.); (Z.L.)
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Neri A, Traversari S, Andreucci A, Francini A, Sebastiani L. The Role of Aquaporin Overexpression in the Modulation of Transcription of Heavy Metal Transporters under Cadmium Treatment in Poplar. PLANTS 2020; 10:plants10010054. [PMID: 33383680 PMCID: PMC7824648 DOI: 10.3390/plants10010054] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Revised: 12/10/2020] [Accepted: 12/25/2020] [Indexed: 12/25/2022]
Abstract
Populus alba ‘Villafranca’ clone is well-known for its tolerance to cadmium (Cd). To determine the mechanisms of Cd tolerance of this species, wild-type (wt) plants were compared with transgenic plants over-expressing an aquaporin (aqua1, GenBank GQ918138). Plants were maintained in hydroponic conditions with Hoagland’s solution and treated with 10 µM of Cd, renewed every 5 d. The transcription levels of heavy metal transporter genes (PaHMA2, PaNRAMP1.3, PaNRAMP2, PaNRAMP3.1, PaNRAMP3.2, PaABCC9, and PaABCC13) were analyzed at 1, 7, and 60 d of treatment. Cd application did not induce visible toxicity symptoms in wt and aqua1 plants even after 2 months of treatment confirming the high tolerance of this poplar species to Cd. Most of the analyzed genes showed in wt plants a quick response in transcription at 1 d of treatment and an adaptation at 60 d. On the contrary, a lower transcriptional response was observed in aqua1 plants in concomitance with a higher Cd concentration in medial leaves. Moreover, PaHMA2 showed at 1 d an opposite trend within organs since it was up-regulated in root and stem of wt plants and in leaves of aqua1 plants. In summary, aqua1 overexpression in poplar improved Cd translocation suggesting a lower Cd sensitivity of aqua1 plants. This different response might be due to a different transcription of PaNRAMP3 genes that were more transcribed in wt line because of the importance of this gene in Cd compartmentalization.
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Affiliation(s)
- Andrea Neri
- BioLabs, Institute of Life Sciences, Scuola Superiore Sant’Anna, Piazza Martiri della Libertà 33, 56127 Pisa, Italy; (A.N.); (S.T.); (L.S.)
| | - Silvia Traversari
- BioLabs, Institute of Life Sciences, Scuola Superiore Sant’Anna, Piazza Martiri della Libertà 33, 56127 Pisa, Italy; (A.N.); (S.T.); (L.S.)
| | - Andrea Andreucci
- Department of Biology, University of Pisa, via Luca Ghini 13, 56126 Pisa, Italy
- Correspondence: (A.A.); (A.F.)
| | - Alessandra Francini
- BioLabs, Institute of Life Sciences, Scuola Superiore Sant’Anna, Piazza Martiri della Libertà 33, 56127 Pisa, Italy; (A.N.); (S.T.); (L.S.)
- Correspondence: (A.A.); (A.F.)
| | - Luca Sebastiani
- BioLabs, Institute of Life Sciences, Scuola Superiore Sant’Anna, Piazza Martiri della Libertà 33, 56127 Pisa, Italy; (A.N.); (S.T.); (L.S.)
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Liu Y, Lu M, Tao Q, Luo J, Li J, Guo X, Liang Y, Yang X, Li T. A comparative study of root cadmium radial transport in seedlings of two wheat (Triticum aestivum L.) genotypes differing in grain cadmium accumulation. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2020; 266:115235. [PMID: 32707356 DOI: 10.1016/j.envpol.2020.115235] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Revised: 07/10/2020] [Accepted: 07/10/2020] [Indexed: 06/11/2023]
Abstract
The radial transport of cadmium (Cd) is essential for Cd influx in roots. The role of radial transport pathway on the Cd translocation from root to shoot among wheat genotypes are still poorly understood. This study explored the role of apoplastic and symplastic pathway on root Cd uptake and root-to-shoot translocation in Zhenmai 10 (ZM10, high Cd in grains) and Aikang 58 (AK58, low Cd in grains). Under Cd treatment, the deposition of Casparian strips (CSs) and suberin lamellae (SL) initiated closer to the root apex in ZM10 than that in AK58, which resulted in the lower Cd concentration in apoplastic fluid of ZM10. Simultaneously, Cd-induced expression levels of genes related to Cd uptake in roots were significantly higher in AK58 by contrast with ZM10, contributing to the symplastic Cd accumulation in AK58 root. Moreover, the addition of metabolic inhibitor CCCP noticeably decreased the Cd accumulation in root of both genotypes. Intriguingly, compared to ZM10, greater amounts of Cd were sequestrated in the cell walls and vacuoles in roots of AK58, limiting the translocation of Cd from root to shoot. Furthermore, the elevated TaHMA2 expression in ZM10 indicates that ZM10 had a higher capacity of xylem loading Cd than AK58. All of these results herein suggest that the radial transport is significant for Cd accumulation in roots, but it cannot explain the difference in root-to-shoot translocation of Cd in wheat genotypes with contrast Cd accumulation in grains.
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Affiliation(s)
- Yuankun Liu
- Ministry of Education Key Laboratory of Environmental Remediation and Ecological Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, 310058, China
| | - Min Lu
- Ministry of Education Key Laboratory of Environmental Remediation and Ecological Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, 310058, China
| | - Qi Tao
- College of Resources, Sichuan Agricultural University, Chengdu, 611130, China
| | - Jipeng Luo
- Ministry of Education Key Laboratory of Environmental Remediation and Ecological Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, 310058, China
| | - Jinxing Li
- Ministry of Education Key Laboratory of Environmental Remediation and Ecological Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, 310058, China
| | - Xinyu Guo
- Ministry of Education Key Laboratory of Environmental Remediation and Ecological Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, 310058, China
| | - Yongchao Liang
- Ministry of Education Key Laboratory of Environmental Remediation and Ecological Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, 310058, China
| | - Xiaoe Yang
- Ministry of Education Key Laboratory of Environmental Remediation and Ecological Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, 310058, China
| | - Tingqiang Li
- Ministry of Education Key Laboratory of Environmental Remediation and Ecological Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, 310058, China; National Demonstration Center for Experimental Environment and Resources Education, Zhejiang University, Hangzhou, 310058, China.
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Ji J, Shi Z, Xie T, Zhang X, Chen W, Du C, Sun J, Yue J, Zhao X, Jiang Z, Shi S. Responses of GABA shunt coupled with carbon and nitrogen metabolism in poplar under NaCl and CdCl 2 stresses. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2020; 193:110322. [PMID: 32109582 DOI: 10.1016/j.ecoenv.2020.110322] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2019] [Revised: 02/05/2020] [Accepted: 02/08/2020] [Indexed: 05/20/2023]
Abstract
The γ-aminobutyric acid (GABA) shunt is closely associated with plant tolerance; however, little is known about its mechanism. This study aimed to decipher the responses of the GABA shunt and related carbon-nitrogen metabolism in poplar seedlings (Populus alba × Populus glandulosa) treated with different NaCl and CdCl2 concentrations for 30 h. The results showed that the activities of glutamate decarboxylase (GAD) and GABA-transaminase (GABA-T) were activated, as well as α-ketoglutarate dehydrogenase (α-KGDH) and succinate dehydrogenase (SDH) activities were enhanced by NaCl and CdCl2 stresses, except for SDH under CdCl2 stress. Meanwhile, the expression levels of GADs, GABA-Ts SDHs, succinyl-CoA ligases (SCSs), and succinic acid aldehyde dehydrogenases (SSADHs) were also increased. Notably, significant increases in the key components of GABA shunt, Glu and GABA, were observed under both stresses. Soluble sugars and free amino acids were enhanced, whereas citrate, malate and succinate were almost inhibited by both NaCl and CdCl2 stresses except that citrate was not changed or just increased by 50-mM NaCl stress. Thus, these results suggested that the carbon-nitrogen balance could be altered by activating the GABA shunt when main TCA-cycle intermediates were inhibited under NaCl and CdCl2 stresses. This study can enhance the understanding about the functions of the GABA shunt in woody plants under abiotic stresses and may be applied to the genetic improvement of trees for phytoremediation.
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Affiliation(s)
- Jing Ji
- State Key Laboratory of Tree Genetics and Breeding, Key Laboratory of Tree Breeding and Cultivation of State Forestry and Grassland Administration, Research Institute of Forestry, Chinese Academy of Forestry, 1958 Box, Beijing, 100091, China
| | - Zheng Shi
- Research Institute of Forest Ecology, Environment and Protection, Key Laboratory of Forest Ecology and Environment of State Forestry and Grassland Administration, Chinese Academy of Forestry, 1958 Box, Beijing, 100091, China
| | - Tiantian Xie
- State Key Laboratory of Tree Genetics and Breeding, Key Laboratory of Tree Breeding and Cultivation of State Forestry and Grassland Administration, Research Institute of Forestry, Chinese Academy of Forestry, 1958 Box, Beijing, 100091, China
| | - Xiaoman Zhang
- College of Landscape Architecture and Tourism, Hebei Agricultural University, No. 289 Lingyusi Street, Baoding, 071001, Hebei, China
| | - Wei Chen
- State Key Laboratory of Tree Genetics and Breeding, Key Laboratory of Tree Breeding and Cultivation of State Forestry and Grassland Administration, Research Institute of Forestry, Chinese Academy of Forestry, 1958 Box, Beijing, 100091, China
| | - Changjian Du
- State Key Laboratory of Tree Genetics and Breeding, Key Laboratory of Tree Breeding and Cultivation of State Forestry and Grassland Administration, Research Institute of Forestry, Chinese Academy of Forestry, 1958 Box, Beijing, 100091, China
| | - Jiacheng Sun
- State Key Laboratory of Tree Genetics and Breeding, Key Laboratory of Tree Breeding and Cultivation of State Forestry and Grassland Administration, Research Institute of Forestry, Chinese Academy of Forestry, 1958 Box, Beijing, 100091, China
| | - Jianyun Yue
- State Key Laboratory of Tree Genetics and Breeding, Key Laboratory of Tree Breeding and Cultivation of State Forestry and Grassland Administration, Research Institute of Forestry, Chinese Academy of Forestry, 1958 Box, Beijing, 100091, China
| | - Xiulian Zhao
- State Key Laboratory of Tree Genetics and Breeding, Key Laboratory of Tree Breeding and Cultivation of State Forestry and Grassland Administration, Research Institute of Forestry, Chinese Academy of Forestry, 1958 Box, Beijing, 100091, China
| | - Zeping Jiang
- Research Institute of Forest Ecology, Environment and Protection, Key Laboratory of Forest Ecology and Environment of State Forestry and Grassland Administration, Chinese Academy of Forestry, 1958 Box, Beijing, 100091, China
| | - Shengqing Shi
- State Key Laboratory of Tree Genetics and Breeding, Key Laboratory of Tree Breeding and Cultivation of State Forestry and Grassland Administration, Research Institute of Forestry, Chinese Academy of Forestry, 1958 Box, Beijing, 100091, China.
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Vannucchi F, Francini A, Pierattini EC, Raffaelli A, Sebastiani L. Populus alba dioctyl phthalate uptake from contaminated water. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2019; 26:25564-25572. [PMID: 31267403 DOI: 10.1007/s11356-019-05829-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/18/2019] [Accepted: 06/24/2019] [Indexed: 06/09/2023]
Abstract
Phthalates are micro-pollutants of great concern due to their negative effects on ecosystem functioning and human health. Thanks to its capability in uptake and accumulation of organic pollutants, Populus alba L. "Villafranca" clone could be a good candidate for reducing the impacts derived by the persistence of such compounds in the environment. We investigated plant response and uptake of dioctyl phthalate (DOP) by poplar, grown in hydroponics condition, for 21 days with 0, 40, and 400 μg L-1 of d4-DOP. Treated plants, after 21 days of 400 μg L-1 d4-DOP, showed an increase in root dry biomass (+ 29%) at the expense of aerial parts (- 8%) compared with control. The root development could be sustained by the increase of Mg uptake by poplar. LC-MS/MS analysis demonstrated the uptake and accumulation in roots of d4-DOP starting from day one (3.5 ± 3.29 and 7.1 ± 3.28 in 40 and 400 μg L-1 d4-DOP respectively), despite volatilization of d4-DOP was observed from nutritive solution. The chemical interaction between d4-DOP and Zn occurred in roots of plants treated with the high d4-DOP concentration, without limiting the Zn concentration in leaves. Results confirm the high tolerance of "Villafranca" clone to xenobiotic and suggest the poplar capability in d4-DOP uptake and accumulation at root level.
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Affiliation(s)
- Francesca Vannucchi
- Institute of Life Science, Scuola Superiore Sant'Anna, Piazza Martiri della Libertà 33, I-56127, Pisa, Italy
| | - Alessandra Francini
- Institute of Life Science, Scuola Superiore Sant'Anna, Piazza Martiri della Libertà 33, I-56127, Pisa, Italy.
| | - Erika C Pierattini
- Institute of Life Science, Scuola Superiore Sant'Anna, Piazza Martiri della Libertà 33, I-56127, Pisa, Italy
| | - Andrea Raffaelli
- CNR-Istituto di Fisiologia Clinica, Via Moruzzi 1, I-56124, Pisa, Italy
| | - Luca Sebastiani
- Institute of Life Science, Scuola Superiore Sant'Anna, Piazza Martiri della Libertà 33, I-56127, Pisa, Italy
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11
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Wu J, Mock HP, Giehl RFH, Pitann B, Mühling KH. Silicon decreases cadmium concentrations by modulating root endodermal suberin development in wheat plants. JOURNAL OF HAZARDOUS MATERIALS 2019; 364:581-590. [PMID: 30388642 DOI: 10.1016/j.jhazmat.2018.10.052] [Citation(s) in RCA: 77] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2018] [Revised: 10/16/2018] [Accepted: 10/18/2018] [Indexed: 05/10/2023]
Abstract
Silicon (Si) can alleviate cadmium (Cd) toxicity in many plants, but mechanisms underlying this beneficial effect are still lacking. In this study, the roles of Si in time-dependent apoplastic and symplastic Cd absorption by roots of wheat plants were investigated. Results showed that, during short-term Cd exposure, the symplastic pathway of Cd in roots was not significantly affected by Si. Cell wall properties and cell wall-bound Cd regarding the apoplastic pathway were unaffected by Si either. Nevertheless, Cd concentrations in the apoplastic fluid of roots were decreased by Si. The reason could be that Si delayed endodermal suberization of roots resulting in promoted apoplastic Cd translocation to shoots, thus decreasing Cd in the apoplastic fluid of roots after short-term Cd stress. By contrast, after long-term Cd stress, cell wall properties and the expression of genes related to Cd influx and transport were unaffected. Intriguingly, Si up-regulated the expression of the Cd efflux-related gene TaTM20 and repressed apoplastic Cd translocation to shoots, which might contribute to decrease of Cd after long-term Cd exposure. Taken together, these results indicate that Si-dependent decrease in root Cd concentrations during short-term Cd exposure helps plants to mitigate Cd toxicity in the long-term.
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Affiliation(s)
- Jiawen Wu
- College of Life Sciences, Yan'an University, Yan'an, Shaanxi, 716000, China; Shaanxi Key Laboratory of Chinese Jujube, Yan'an University, Yan'an, Shaanxi, 716000, China; Institute of Plant Nutrition and Soil Science, Kiel University, Hermann-Rodewald-Str. 2, 24118, Kiel, Germany.
| | - Hans-Peter Mock
- Department of Physiology and Cell Biology, Leibniz Institute of Plant Genetics and Crop Plant Research, 06466, Gatersleben, Germany
| | - Ricardo F H Giehl
- Department of Physiology and Cell Biology, Leibniz Institute of Plant Genetics and Crop Plant Research, 06466, Gatersleben, Germany
| | - Britta Pitann
- Institute of Plant Nutrition and Soil Science, Kiel University, Hermann-Rodewald-Str. 2, 24118, Kiel, Germany
| | - Karl Hermann Mühling
- Institute of Plant Nutrition and Soil Science, Kiel University, Hermann-Rodewald-Str. 2, 24118, Kiel, Germany.
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12
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Fan W, Guo Q, Liu C, Liu X, Zhang M, Long D, Xiang Z, Zhao A. Two mulberry phytochelatin synthase genes confer zinc/cadmium tolerance and accumulation in transgenic Arabidopsis and tobacco. Gene 2018; 645:95-104. [PMID: 29277319 DOI: 10.1016/j.gene.2017.12.042] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2016] [Revised: 11/29/2017] [Accepted: 12/20/2017] [Indexed: 11/18/2022]
Abstract
Phytochelatin synthase (PCS) is an enzyme involved in the synthesis of phytochelatins, cysteine-rich peptides which play a key role in heavy metal (HM) detoxification of plants. Mulberry (Morus L.), one of the most ecologically and economically important tree genera, has the potential to remediate HM-contaminated soils. However, genes involved in HM detoxification in Morus, such as the PCS genes, have not been identified and characterized. In this study, we identified two Morus notabilis PCS genes based on a genome-wide analysis of the Morus genome database. Full-length MnPCS1 and MnPCS2 cDNAs were 1509 and 1491bp long, respectively. Quantitative real-time polymerase chain reaction (qRT-PCR) analysis revealed that, under 200μM Zn2+ or either 30 or 100μM Cd2+ stress, the relative expression of each of the two MaPCSs (from Morus alba) was induced in root, stem and leaf tissues within 24h of exposure to the metals, with Cd2+ inducing expression more strongly than did Zn2+. Based on the analysis of total root length and fresh weight of seedlings, overexpression of MnPCS1 and MnPCS2 in Arabidopsis and tobacco enhanced Zn2+/Cd2+ tolerance in most transgenic individuals. The results of transgenic Arabidopsis lines overexpressing MnPCS1and MnPCS2 suggest that MnPCS1 play a more important role in Cd detoxification than MnPCS2. Zn2+/Cd2+ concentrations in both shoots and roots of the transgenic Arabidopsis seedlings were higher than in wild type (WT) seedlings at two Zn2+/Cd2+ concentrations. In addition, there was a positive correlation between Zn accumulation and the expression level of MnPCS1 or MnPCS2. Our results indicated that the Morus PCS1 and PCS2 genes play important roles in HM stress tolerance and accumulation, providing a useful genetic resource for enhancing tolerance to HMs and for increasing the HM phytoremediation potential of these plants.
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Affiliation(s)
- Wei Fan
- State Key Laboratory of Silkworm Genome Biology, Key Laboratory of Sericultural Biology and Genetic Breeding, Ministry of Agriculture, Southwest University, Chongqing 400716, China
| | - Qing Guo
- State Key Laboratory of Silkworm Genome Biology, Key Laboratory of Sericultural Biology and Genetic Breeding, Ministry of Agriculture, Southwest University, Chongqing 400716, China
| | - ChangYing Liu
- State Key Laboratory of Silkworm Genome Biology, Key Laboratory of Sericultural Biology and Genetic Breeding, Ministry of Agriculture, Southwest University, Chongqing 400716, China
| | - Xueqin Liu
- State Key Laboratory of Silkworm Genome Biology, Key Laboratory of Sericultural Biology and Genetic Breeding, Ministry of Agriculture, Southwest University, Chongqing 400716, China
| | - Meng Zhang
- State Key Laboratory of Silkworm Genome Biology, Key Laboratory of Sericultural Biology and Genetic Breeding, Ministry of Agriculture, Southwest University, Chongqing 400716, China
| | - Dingpei Long
- State Key Laboratory of Silkworm Genome Biology, Key Laboratory of Sericultural Biology and Genetic Breeding, Ministry of Agriculture, Southwest University, Chongqing 400716, China
| | - Zhonghuai Xiang
- State Key Laboratory of Silkworm Genome Biology, Key Laboratory of Sericultural Biology and Genetic Breeding, Ministry of Agriculture, Southwest University, Chongqing 400716, China
| | - Aichun Zhao
- State Key Laboratory of Silkworm Genome Biology, Key Laboratory of Sericultural Biology and Genetic Breeding, Ministry of Agriculture, Southwest University, Chongqing 400716, China.
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13
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Fan W, Liu C, Cao B, Qin M, Long D, Xiang Z, Zhao A. Genome-Wide Identification and Characterization of Four Gene Families Putatively Involved in Cadmium Uptake, Translocation and Sequestration in Mulberry. FRONTIERS IN PLANT SCIENCE 2018; 9:879. [PMID: 30008726 PMCID: PMC6034156 DOI: 10.3389/fpls.2018.00879] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2018] [Accepted: 06/06/2018] [Indexed: 05/14/2023]
Abstract
The zinc-regulated transporters, iron-regulated transporter-like proteins (ZIPs), the natural resistance and macrophage proteins (NRAMP), the heavy metal ATPases (HMAs) and the metal tolerance or transporter proteins (MTPs) families are involved in cadmium (Cd) uptake, translocation and sequestration in plants. Mulberry (Morus L.), one of the most ecologically and economically important (as a food plant for silkworm production) genera of perennial trees, exhibits excellent potential for remediating Cd-contaminated soils. However, there is no detailed information about the genes involved in Cd2+ transport in mulberry. In this study, we identified 31 genes based on a genome-wide analysis of the Morus notabilis genome database. According to bioinformatics analysis, the four transporter gene families in Morus were distributed in each group of the phylogenetic tree, and the gene exon/intron structure and protein motif structure were similar among members of the same group. Subcellular localization software predicted that these transporters were mainly distributed in the plasma membrane and the vacuolar membrane, with members of the same group exhibiting similar subcellular locations. Most of the gene promoters contained abiotic stress-related cis-elements. The expression patterns of these genes in different organs were determined, and the patterns identified, allowing the categorization of these genes into four groups. Under low or high-Cd2+ concentrations (30 μM or 100 μM, respectively), the transcriptional regulation of the 31 genes in root, stem and leaf tissues of M. alba seedlings differed with regard to tissue and time of peak expression. Heterologous expression of MaNRAMP1, MaHMA3, MaZIP4, and MaIRT1 in Saccharomyces cerevisiae increased the sensitivity of yeast to Cd, suggested that these transporters had Cd transport activity. Subcellular localization experiment showed that the four transporters were localized to the plasma membrane of yeast and tobacco. These results provide the basis for further understanding of the Cd tolerance mechanism in Morus, which can be exploited in Cd phytoremediation.
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Zeng L, Zhu T, Gao Y, Wang Y, Ning C, Björn LO, Chen D, Li S. Effects of Ca addition on the uptake, translocation, and distribution of Cd in Arabidopsis thaliana. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2017; 139:228-237. [PMID: 28152404 DOI: 10.1016/j.ecoenv.2017.01.023] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2016] [Revised: 01/12/2017] [Accepted: 01/13/2017] [Indexed: 05/07/2023]
Abstract
Cadmium (Cd) pollution poses a risk to human health for its accumulation in soil and crops, but this can be alleviated by calcium (Ca) addition. However, its mechanism remains unclear yet. In this study, Arabidopsis thaliana was used to explore the alleviating effects of Ca on Cd toxicity and its specific function during uptake, upward-translocation, and distribution of Cd. Supplementing plants with 5mM CaCl2 alleviated the intoxication symptoms caused by 50μM CdCl2, such as smaller leaves, early bolting and root browning. Ca addition decreased uptake of Cd, possibly by reducing the physical adsorption of Cd since the root cell membrane was well maintained and lignin deposition was decreased as well, and by decreasing symplastic Cd transport. Expression of the genes involved (AtZIP2 and AtZIP4) was also decreased. In addition, Ca accumulated in the plant shoot to help facilitating the upward-translocation of Cd, with evidence of higher translocation factor and expression of genes that were involved in Ca transport (AtPCR1) and Cd xylem loading (AtHMA2 and AtHMA4). Dithizone-staining of Cd in leaves showed that in Cd+Ca-treated plants, Ca addition initially protected the leaf stomata by preventing Cd from entering guard cells, but with prolonged Cd treatment facilitated the Cd accumulation around trichomes and maybe its excretion. We conclude that Ca promotes the upward-translocation of Cd and changes its distribution in leaves. The results may have relevance for bioremediation.
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Affiliation(s)
- Lihua Zeng
- Key Laboratory of Ecology and Environmental Science in Guangdong Higher Education, School of Life Science, South China Normal University, Guangzhou 510631, China
| | - Ting Zhu
- Key Laboratory of Ecology and Environmental Science in Guangdong Higher Education, School of Life Science, South China Normal University, Guangzhou 510631, China
| | - Ya Gao
- Key Laboratory of Ecology and Environmental Science in Guangdong Higher Education, School of Life Science, South China Normal University, Guangzhou 510631, China
| | - Yutao Wang
- Key Laboratory of Ecology and Environmental Science in Guangdong Higher Education, School of Life Science, South China Normal University, Guangzhou 510631, China
| | - Chanjuan Ning
- Key Laboratory of Ecology and Environmental Science in Guangdong Higher Education, School of Life Science, South China Normal University, Guangzhou 510631, China
| | - Lars Olof Björn
- Key Laboratory of Ecology and Environmental Science in Guangdong Higher Education, School of Life Science, South China Normal University, Guangzhou 510631, China; Department of Biology, Molecular Cell Biology, Lund University, Lund 22467, Sweden
| | - Da Chen
- Cooperative Wildlife Research Laboratory and Department of Zoology, Southern Illinois University Carbondale, Carbondale, IL 62901, USA
| | - Shaoshan Li
- Key Laboratory of Ecology and Environmental Science in Guangdong Higher Education, School of Life Science, South China Normal University, Guangzhou 510631, China.
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