1
|
Ur Rahman S, Qin A, Zain M, Mushtaq Z, Mehmood F, Riaz L, Naveed S, Ansari MJ, Saeed M, Ahmad I, Shehzad M. Pb uptake, accumulation, and translocation in plants: Plant physiological, biochemical, and molecular response: A review. Heliyon 2024; 10:e27724. [PMID: 38500979 PMCID: PMC10945279 DOI: 10.1016/j.heliyon.2024.e27724] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2023] [Revised: 02/17/2024] [Accepted: 03/06/2024] [Indexed: 03/20/2024] Open
Abstract
Lead (Pb) is a highly toxic contaminant that is ubiquitously present in the ecosystem and poses severe environmental issues, including hazards to soil-plant systems. This review focuses on the uptake, accumulation, and translocation of Pb metallic ions and their toxicological effects on plant morpho-physiological and biochemical attributes. We highlight that the uptake of Pb metal is controlled by cation exchange capacity, pH, size of soil particles, root nature, and other physio-chemical limitations. Pb toxicity obstructs seed germination, root/shoot length, plant growth, and final crop-yield. Pb disrupts the nutrient uptake through roots, alters plasma membrane permeability, and disturbs chloroplast ultrastructure that triggers changes in respiration as well as transpiration activities, creates the reactive oxygen species (ROS), and activates some enzymatic and non-enzymatic antioxidants. Pb also impairs photosynthesis, disrupts water balance and mineral nutrients, changes hormonal status, and alters membrane structure and permeability. This review provides consolidated information concentrating on the current studies associated with Pb-induced oxidative stress and toxic conditions in various plants, highlighting the roles of different antioxidants in plants mitigating Pb-stress. Additionally, we discussed detoxification and tolerance responses in plants by regulating different gene expressions, protein, and glutathione metabolisms to resist Pb-induced phytotoxicity. Overall, various approaches to tackle Pb toxicity have been addressed; the phytoremediation techniques and biochar amendments are economical and eco-friendly remedies for improving Pb-contaminated soils.
Collapse
Affiliation(s)
- Shafeeq Ur Rahman
- Water Science and Environmental Engineering Research Center, College of Chemical and Environmental Engineering, Shenzhen University, Shenzhen, 518060, China
| | - Anzhen Qin
- Institute of Farmland Irrigation, Chinese Academy of Agricultural Sciences/Key Laboratory of Crop Water Use and Regulation, Ministry of Agriculture and Rural Affairs, Xinxiang, 453002, China
| | - Muhammad Zain
- Key Laboratory of Crop Genetics and Physiology of Jiangsu Province, Key Laboratory of Crop Cultivation and Physiology of Jiangsu Province, College of Agriculture, Yangzhou University, Yangzhou, 225009, China
| | - Zain Mushtaq
- Department of Soil Science, Faculty of Agricultural Sciences, University of the Punjab, Lahore, Pakistan
| | - Faisal Mehmood
- Department of Land and Water Management, Faculty of Agricultural Engineering, Sindh Agriculture University, Tandojam, 70060, Pakistan
| | - Luqman Riaz
- Department of Environmental Sciences, Kohsar University Murree, 47150, Punjab, Pakistan
| | - Sadiq Naveed
- Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, China
| | - Mohammad Javed Ansari
- Department of Botany, Hindu College Moradabad (Mahatma Jyotiba Phule Rohilkhand University Bareilly), 244001, India
| | - Mohd Saeed
- Department of Biology, College of Science, University of Hail, Hail, P.O. Box 2240, Saudi Arabia
| | - Irfan Ahmad
- Department of Clinical Laboratory Sciences, College of Applied Medical Sciences, King Khalid University, Abha, Saudi Arabia
| | - Muhammad Shehzad
- State Key Laboratory of Cotton Biology, Institute of Cotton Research, Chinese Academy of Agricultural Sciences, Anyang, Henan, China
| |
Collapse
|
2
|
Sun X, Tang Z, Zheng G, Du H, Li P. Effects of different cellular and subcellular characteristics on the atmospheric Pb uptake, distribution and morphology in Tillandsia usneoides leaves. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2024; 207:108400. [PMID: 38295526 DOI: 10.1016/j.plaphy.2024.108400] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2024] [Accepted: 01/24/2024] [Indexed: 02/02/2024]
Abstract
Lead (Pb) is a widespread highly toxic and persistent environmental pollutant. Plant leaves play a key role in accumulating atmospheric Pb, but its distribution in different cells and subcellular structures and the factors affecting it have been little studied. Here, Tillandsia usneoides, an indicator plant for atmospheric heavy metals, was treated with an aerosol generation device to analyze Pb contents in different cells (three types of cells in leaf surface scales, epidermal cells, mesophyll cells, vascular bundle cells), subcellular structures (cell wall, cell membrane, vacuoles, and organelles) and cell wall components (pectin, hemicellulose 1 and 2, and cellulose). Results show the different cells of T. usneoides leaves play distinct roles in the process of Pb retention. The outermost wing cells are structures that capture external pollutants, while mesophyll cells, as the aggregation site after material transport, ring cells, disc cells, epidermal cells, and vascular cells are material transporters. Pb was only detected in the cell wall and pectin, indicating the cell wall was the dominant subcellular structure for Pb retention, while pectin was the main component affecting Pb retention. FTIR analysis of cell wall components indicated the esterified carboxyl (CO) functional group in pectin may function in absorbing Pb. Pb entered leaf cells mainly in the form of low toxicity and activity to enhance its resistance.
Collapse
Affiliation(s)
- Xingyue Sun
- School of Resources and Environment, Qingdao Agricultural University, Qingdao, 266109, Shandong, China; Center of Molecular Ecophysiology (CMEP), College of Resources and Environment, Southwest University, Chongqing, 400715, China
| | - Zhen Tang
- School of Resources and Environment, Qingdao Agricultural University, Qingdao, 266109, Shandong, China
| | - Guiling Zheng
- School of Resources and Environment, Qingdao Agricultural University, Qingdao, 266109, Shandong, China
| | - Hongxia Du
- Chongqing Key Laboratory of Bio-resource for Bioenergy, College of Resources and Environment, Southwest University, Chongqing, 400715, China
| | - Peng Li
- School of Resources and Environment, Qingdao Agricultural University, Qingdao, 266109, Shandong, China.
| |
Collapse
|
3
|
Li F, Deng Y, Liu Y, Mai C, Xu Y, Wu J, Zheng X, Liang C, Wang J. Arabidopsis transcription factor WRKY45 confers cadmium tolerance via activating PCS1 and PCS2 expression. JOURNAL OF HAZARDOUS MATERIALS 2023; 460:132496. [PMID: 37703737 DOI: 10.1016/j.jhazmat.2023.132496] [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: 06/29/2023] [Revised: 08/29/2023] [Accepted: 09/04/2023] [Indexed: 09/15/2023]
Abstract
Cadmium (Cd) has long been recognized as toxic pollutant to crops worldwide. The biosynthesis of glutathione-dependent phytochelatin (PC) plays crucial roles in the detoxification of Cd in plants. However, its regulatory mechanism remains elusive. Here, we revealed that Arabidopsis transcription factor WRKY45 confers Cd tolerance via promoting the expression of PC synthesis-related genes PCS1 and PCS2, respectively. Firstly, we found that Cd stress induces the transcript levels of WRKY45 and its protein abundance. Accordingly, in contrast to wild type Col-0, the increased sensitivity to Cd is observed in wrky45 mutant, while overexpressing WRKY45 plants are more tolerant to Cd. Secondly, quantitative real-time PCR revealed that the expression of AtPCS1 and AtPCS2 is stimulated in overexpressing WRKY45 plants, but decreased in wrky45 mutant. Thirdly, WRKY45 promotes the expression of PCS1 and PCS2, electrophoresis mobility shift assay analysis uncovered that WRKY45 directly binds to the W-box cis-element of PCS2 promoter. Lastly, the overexpression of WRKY45 in Col-0 leads to more accumulation of PCs in Arabidopsis, and the overexpression of PCS1 or PCS2 in wrky45 mutant plants rescues the phenotypes induced by Cd stress. In conclusion, our results show that AtWRKY45 positively regulates Cd tolerance in Arabidopsis via activating PCS1 and PCS2 expression.
Collapse
Affiliation(s)
- Fangjian Li
- Root Biology Center, South China Agricultural University, Guangzhou 510642, China; College of Natural Resources and Environment, South China Agricultural University, Guangzhou 510642, China
| | - Yaru Deng
- Root Biology Center, South China Agricultural University, Guangzhou 510642, China; College of Natural Resources and Environment, South China Agricultural University, Guangzhou 510642, China
| | - Yan Liu
- Root Biology Center, South China Agricultural University, Guangzhou 510642, China; College of Natural Resources and Environment, South China Agricultural University, Guangzhou 510642, China
| | - Cuishan Mai
- Root Biology Center, South China Agricultural University, Guangzhou 510642, China; College of Natural Resources and Environment, South China Agricultural University, Guangzhou 510642, China
| | - Yun Xu
- College of Natural Resources and Environment, South China Agricultural University, Guangzhou 510642, China
| | - Jiarui Wu
- College of Natural Resources and Environment, South China Agricultural University, Guangzhou 510642, China
| | - Xinni Zheng
- College of Natural Resources and Environment, South China Agricultural University, Guangzhou 510642, China
| | - Cuiyue Liang
- Root Biology Center, South China Agricultural University, Guangzhou 510642, China; College of Natural Resources and Environment, South China Agricultural University, Guangzhou 510642, China; State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, South China Agricultural University, Guangzhou 510642, China
| | - Jinxiang Wang
- Root Biology Center, South China Agricultural University, Guangzhou 510642, China; College of Natural Resources and Environment, South China Agricultural University, Guangzhou 510642, China; Key Laboratory of Agricultural and Rural pollution Control and Environmental Safety in Guangdong Province, Guangzhou 510642, China.
| |
Collapse
|
4
|
Guo H, Tang Y, Li Y, Tian H, Zhang T, Li Y, Liu L, He B, Hu L, Jiang G. Endocytosis-Mediated Transport of Pb in Rat Blood Cells. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:8514-8523. [PMID: 37252706 DOI: 10.1021/acs.est.3c02182] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Blood is an important reservoir for Pb storage in living organisms, and the storage of Pb in blood cells inhibits its discharge from blood. However, the mechanism and molecular targets of Pb entry and exit from blood cells have not been elucidated, which is the major barrier to reducing blood Pb levels in normal human beings. In this study, we explored the effect of Pb-binding proteins on blood Pb levels in rats at environmentally relevant concentrations (0.32 μg/g) by identifying the functions of Pb-binding proteins and validating them with inhibitors. The results showed that Pb-binding proteins in blood cells were mainly related to phagocytosis, while in plasma, they were mainly involved in the regulation of endopeptidase activity. Meanwhile, at the normal population Pb levels, endocytosis inhibitors, endopeptidase activity inhibitors, and coadministration of both can reduce the level of Pb in MEL (mouse erythroleukemia cells) cells by up to 50, 40, and 50%, respectively, while in rat blood, the reduction can reach up to 26, 13, and 32%, respectively. Collectively, these findings reveal that endocytosis increases blood Pb levels and provides a possible molecular target for Pb excretion at ambient concentrations.
Collapse
Affiliation(s)
- Hua Guo
- School of Environment, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Hangzhou 310024, China
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Yinyin Tang
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Yu Li
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Haozhong Tian
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Tingting Zhang
- School of Environment, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Hangzhou 310024, China
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Yingying Li
- School of Environment, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Hangzhou 310024, China
| | - Lihong Liu
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Bin He
- School of Environment, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Hangzhou 310024, China
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Ligang Hu
- School of Environment, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Hangzhou 310024, China
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
- School of Environment and Health, Jianghan University, Wuhan 430056, China
| | - Guibin Jiang
- School of Environment, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Hangzhou 310024, China
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| |
Collapse
|
5
|
Sun SK, Chen J, Zhao FJ. Regulatory mechanisms of sulfur metabolism affecting tolerance and accumulation of toxic trace metals and metalloids in plants. JOURNAL OF EXPERIMENTAL BOTANY 2023; 74:3286-3299. [PMID: 36861339 DOI: 10.1093/jxb/erad074] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Accepted: 02/23/2023] [Indexed: 06/08/2023]
Abstract
Soil contamination with trace metals and metalloids can cause toxicity to plants and threaten food safety and human health. Plants have evolved sophisticated mechanisms to cope with excess trace metals and metalloids in soils, including chelation and vacuolar sequestration. Sulfur-containing compounds, such as glutathione and phytochelatins, play a crucial role in their detoxification, and sulfur uptake and assimilation are regulated in response to the stress of toxic trace metals and metalloids. This review focuses on the multi-level connections between sulfur homeostasis in plants and responses to such stresses, especially those imposed by arsenic and cadmium. We consider recent progress in understanding the regulation of biosynthesis of glutathione and phytochelatins and of the sensing mechanism of sulfur homeostasis for tolerance of trace metals and metalloids in plants. We also discuss the roles of glutathione and phytochelatins in controlling the accumulation and distribution of arsenic and cadmium in plants, and possible strategies for manipulating sulfur metabolism to limit their accumulation in food crops.
Collapse
Affiliation(s)
- Sheng-Kai Sun
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, China
- Centre for Organismal Studies (COS), Heidelberg University, 69120 Heidelberg, Germany
| | - Jie Chen
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, China
| | - Fang-Jie Zhao
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, China
| |
Collapse
|
6
|
Liu X, Ju Y, Mandzhieva S, Pinskii D, Minkina T, Rajput VD, Roane T, Huang S, Li Y, Ma LQ, Clemens S, Rensing C. Sporadic Pb accumulation by plants: Influence of soil biogeochemistry, microbial community and physiological mechanisms. JOURNAL OF HAZARDOUS MATERIALS 2023; 444:130391. [PMID: 36410245 DOI: 10.1016/j.jhazmat.2022.130391] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/01/2022] [Revised: 10/23/2022] [Accepted: 11/10/2022] [Indexed: 06/16/2023]
Abstract
Recent results revealed that considerable Pb accumulation in plants is possible under specific soil conditions that make Pb phytoavailable. In this review, the sources and transformations of Pb in soils, the interaction of Pb with bacteria and specifically the microbiota in the soil, factors and mechanisms of Pb uptake, translocation and accumulation in plants and Pb toxicity in living organisms are comprehensively elaborated. Specific adsorption and post-adsorption transformations of Pb in soil are the main mechanisms affecting the mobility, bioavailability, and toxicity of Pb. The adsorption ability of Pb largely depends on the composition and properties of soils and environmental conditions. Microbial impact on Pb mobility in soil and bioavailability as well as bacterial resistance to Pb are considered. Specific mechanisms conferring Pb-resistance, including Pb-efflux, siderophores, and EPS, have been identified. Pathways of Pb entry into plants as well as mechanisms of in planta Pb transport are poorly understood. Available evidence suggests the involvement of Ca transporters, organic acids and the phytochelatin pathway in Pb transport, mobility and detoxification, respectively.
Collapse
Affiliation(s)
- Xue Liu
- Institute of Environmental Remediation and Human Health, College of Ecology and Environment, Southwest Forestry University, Kunming 650224, China
| | - Yongwang Ju
- Institute of Environmental Remediation and Human Health, College of Ecology and Environment, Southwest Forestry University, Kunming 650224, China
| | - Saglara Mandzhieva
- Southern Federal University, 105, Bolshaya Sadovaya Street, Rostov-on-Don 344006, Russia
| | - David Pinskii
- Institute of Physicochemical and Biological Problems of Soil Science, Russian Academy of Sciences, Pushchino 142290, Russia
| | - Tatiana Minkina
- Southern Federal University, 105, Bolshaya Sadovaya Street, Rostov-on-Don 344006, Russia
| | - Vishnu D Rajput
- Southern Federal University, 105, Bolshaya Sadovaya Street, Rostov-on-Don 344006, Russia
| | - Timberley Roane
- Department of Integrative Biology, University of Colorado Denver, Denver, CO 80217-3364, USA
| | - Shuangqin Huang
- Institute of Environmental Microbiology, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Yuanping Li
- Institute of Environmental Microbiology, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Lena Q Ma
- Institute of Soil and Water Resources and Environmental Science, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China
| | - Stephan Clemens
- Department of Plant Physiology, University of Bayreuth, 95440 Bayreuth, Germany.
| | - Christopher Rensing
- Institute of Environmental Remediation and Human Health, College of Ecology and Environment, Southwest Forestry University, Kunming 650224, China; Institute of Environmental Microbiology, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou, China.
| |
Collapse
|
7
|
Tang Z, Wang HQ, Chen J, Chang JD, Zhao FJ. Molecular mechanisms underlying the toxicity and detoxification of trace metals and metalloids in plants. JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2023; 65:570-593. [PMID: 36546407 DOI: 10.1111/jipb.13440] [Citation(s) in RCA: 28] [Impact Index Per Article: 28.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Accepted: 12/21/2022] [Indexed: 06/17/2023]
Abstract
Plants take up a wide range of trace metals/metalloids (hereinafter referred to as trace metals) from the soil, some of which are essential but become toxic at high concentrations (e.g., Cu, Zn, Ni, Co), while others are non-essential and toxic even at relatively low concentrations (e.g., As, Cd, Cr, Pb, and Hg). Soil contamination of trace metals is an increasing problem worldwide due to intensifying human activities. Trace metal contamination can cause toxicity and growth inhibition in plants, as well as accumulation in the edible parts to levels that threatens food safety and human health. Understanding the mechanisms of trace metal toxicity and how plants respond to trace metal stress is important for improving plant growth and food safety in contaminated soils. The accumulation of excess trace metals in plants can cause oxidative stress, genotoxicity, programmed cell death, and disturbance in multiple physiological processes. Plants have evolved various strategies to detoxify trace metals through cell-wall binding, complexation, vacuolar sequestration, efflux, and translocation. Multiple signal transduction pathways and regulatory responses are involved in plants challenged with trace metal stresses. In this review, we discuss the recent progress in understanding the molecular mechanisms involved in trace metal toxicity, detoxification, and regulation, as well as strategies to enhance plant resistance to trace metal stresses and reduce toxic metal accumulation in food crops.
Collapse
Affiliation(s)
- Zhong Tang
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, 210095, China
| | - Han-Qing Wang
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, 210095, China
| | - Jie Chen
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, 210095, China
| | - Jia-Dong Chang
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, 210095, China
| | - Fang-Jie Zhao
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, 210095, China
| |
Collapse
|
8
|
Seregin IV, Kozhevnikova AD. Phytochelatins: Sulfur-Containing Metal(loid)-Chelating Ligands in Plants. Int J Mol Sci 2023; 24:2430. [PMID: 36768751 PMCID: PMC9917255 DOI: 10.3390/ijms24032430] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2022] [Revised: 01/20/2023] [Accepted: 01/23/2023] [Indexed: 01/28/2023] Open
Abstract
Phytochelatins (PCs) are small cysteine-rich peptides capable of binding metal(loid)s via SH-groups. Although the biosynthesis of PCs can be induced in vivo by various metal(loid)s, PCs are mainly involved in the detoxification of cadmium and arsenic (III), as well as mercury, zinc, lead, and copper ions, which have high affinities for S-containing ligands. The present review provides a comprehensive account of the recent data on PC biosynthesis, structure, and role in metal(loid) transport and sequestration in the vacuoles of plant cells. A comparative analysis of PC accumulation in hyperaccumulator plants, which accumulate metal(loid)s in their shoots, and in the excluders, which accumulate metal(loid)s in their roots, investigates the question of whether the endogenous PC concentration determines a plant's tolerance to metal(loid)s. Summarizing the available data, it can be concluded that PCs are not involved in metal(loid) hyperaccumulation machinery, though they play a key role in metal(loid) homeostasis. Unraveling the physiological role of metal(loid)-binding ligands is a fundamental problem of modern molecular biology, plant physiology, ionomics, and toxicology, and is important for the development of technologies used in phytoremediation, biofortification, and phytomining.
Collapse
Affiliation(s)
- Ilya V. Seregin
- K.A. Timiryazev Institute of Plant Physiology, Russian Academy of Sciences, Botanicheskaya St., 35, 127276 Moscow, Russia
| | | |
Collapse
|
9
|
Chang JD, Gao W, Wang P, Zhao FJ. OsNRAMP5 Is a Major Transporter for Lead Uptake in Rice. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:17481-17490. [PMID: 36418022 DOI: 10.1021/acs.est.2c06384] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Lead (Pb) is one of the most toxic metals affecting human health globally. Food is an important source of chronic Pb exposure in humans. How Pb is taken up by rice, a staple food for over half of the global population, remains unknown. In the present study, we investigated the role of OsNRAMP5, a member of the NRAMP (Natural Resistance-Associated Macrophage Protein) transporter family, in Pb uptake by rice roots. Heterologous expression of OsNRAMP5 in yeast increased Pb uptake and sensitivity toward Pb. Knockout of OsNRAMP5 in rice by CRISPR/Cas9 gene editing resulted in significant decreases in root uptake of Pb and accumulation in rice shoots. The maximum influx velocity (Vmax) for Pb uptake of the knockout mutants was 70% lower than that of wild-type plants. When grown in Pb-contaminated paddy soil, OsNRAMP5 knockout mutants accumulated approximately 50 and 70% lower Pb concentrations in the grain and straw, respectively, than the wild type. OsNRAMP5 expression in rice roots was not affected by Pb exposure. These results indicate that OsNRAMP5 is a major transporter for Pb uptake in rice, in addition to its role in the uptake of manganese and cadmium. This study provides a mechanistic understanding of Pb uptake in rice plants and a potential strategy to limit Pb accumulation in rice grains.
Collapse
Affiliation(s)
- Jia-Dong Chang
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, China
| | - Weiping Gao
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, China
| | - Peng Wang
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, China
| | - Fang-Jie Zhao
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, China
| |
Collapse
|
10
|
Minling G, Dong Y, Wang S, Wang T, Bai L, Song Z. Effect of co-toxicity of lead and nanoplastics on the flavonoid biosynthetic pathway in dandelion (Taraxacum asiaticum Dahlst). PLANTA 2022; 256:94. [PMID: 36205775 DOI: 10.1007/s00425-022-04008-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2022] [Accepted: 10/02/2022] [Indexed: 06/16/2023]
Abstract
Negatively charged carboxy-polystyrene (CPS) and positively charged amino-polystyrene (NPS) could significantly inhibit the biomass and flavonoid content of dandelion roots and leaves, and the inhibitory effect of NPS was stronger than that of CPS. The increasingly serious pollution of microplastics and heavy metals is likely to affect the efficacy of flavonoids synthesized by dandelion in natural medicine fields. Therefore, we combined hydroponic experiments with computational chemistry (Gaussian and autodock analysis) to explore the mechanism by which amino-polystyrene (NPS), carboxy-polystyrene (CPS), and lead affect the flavonoid biosynthetic pathway in dandelion (Taraxacum asiaticum Dahlst). Our results show that CPS and NPS could significantly inhibit the biomass and flavonoid content of dandelion roots and leaves, and the inhibitory effect of NPS was stronger than that of CPS. Mechanistic studies showed that CPS and NPS increased the content of O2- and H2O2 in dandelion roots and leaves, causing membrane lipid peroxidation, resulting in cell damage and decreased biomass. CPS and NPS inhibited related enzymatic activities by affecting their tertiary structures, resulting in a decrease in phenolic acid, coumaroyl-CoA, and flavonoid content. Dandelion preferred to absorb positively charged NPS compared to negatively charged CPS, but CPS inhibited the uptake of Pb by dandelion more strongly than NPS. Pb promoted CPS agglomeration and increased the surface positive charge of CPS through coordination bonds and hydrogen bonds, so more CPS entered dandelion under CPS + Pb treatment than under CPS alone. Although NPS and CPS reduced the uptake of Pb by dandelion, the biomass and flavonoid contents of dandelion were lower than those of single Pb treatment because of the higher toxicity of NPS and CPS than Pb. Pb significantly increased the effect of CPS on the root biomass of dandelion compared with CPS alone by increasing the positive charge of CPS. We suggest that microplastics with different charges and lead composite pollution inhibit dandelion flavonoid biosynthesis and provide a reference for the loss of dandelion medicinal components and economic value.
Collapse
Affiliation(s)
- Gao Minling
- Department of Civil and Environmental Engineering, Shantou University, No. 243 Daxue Road, Shantou, 515063, Guangdong Province, China
| | - Youming Dong
- Department of Civil and Environmental Engineering, Shantou University, No. 243 Daxue Road, Shantou, 515063, Guangdong Province, China
| | - Shengli Wang
- School of Environmental Science and Engineering, Tiangong University, No. 399 Binshui West Road, Xiqing District, Tianjin, 300387, China
| | - Tianbo Wang
- College of Chemistry, Jilin University, Changchun, 130012, China
| | - Linsen Bai
- Department of Civil and Environmental Engineering, Shantou University, No. 243 Daxue Road, Shantou, 515063, Guangdong Province, China
| | - Zhengguo Song
- Department of Civil and Environmental Engineering, Shantou University, No. 243 Daxue Road, Shantou, 515063, Guangdong Province, China.
- Guangdong Provincial Key Laboratory of Marine Disaster Prediction and Prevention, Shantou University, Shantou, 515063, China.
| |
Collapse
|
11
|
Pischke E, Barozzi F, Colina Blanco AE, Kerl CF, Planer-Friedrich B, Clemens S. Dimethylmonothioarsenate Is Highly Toxic for Plants and Readily Translocated to Shoots. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:10072-10083. [PMID: 35759640 DOI: 10.1021/acs.est.2c01206] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Arsenic is one of the most relevant environmental pollutants and human health threats. Several arsenic species occur in soil pore waters. Recently, it was discovered that these include inorganic and organic thioarsenates. Among the latter, dimethylmonothioarsenate (DMMTA) is of particular concern because in mammalian cells, its toxicity was found to exceed even that of arsenite. We investigated DMMTA toxicity for plants in experiments with Arabidopsis thaliana and indeed observed stronger growth inhibition than with arsenite. DMMTA caused a specific, localized deformation of root epidermal cells. Toxicity mechanisms apparently differ from those of arsenite since no accumulation of reactive oxygen species was observed in DMMTA-exposed root tips. Also, there was no contribution of the phytochelatin pathway to the DMMTA detoxification as indicated by exposure experiments with respective mutants and thiol profiling. RNA-seq analysis found strong transcriptome changes dominated by stress-responsive genes. DMMTA was taken up more efficiently than the methylated oxyarsenate dimethylarsenate and highly mobile within plants as revealed by speciation analysis. Shoots showed clear indications of DMMTA toxicity such as anthocyanin accumulation and a decrease in chlorophyll and carotenoid levels. The toxicity and efficient translocation of DMMTA within plants raise important food safety issues.
Collapse
Affiliation(s)
- Erik Pischke
- Plant Physiology, Bayreuth Center for Ecology and Environmental Research (BayCEER), University of Bayreuth, D-95440 Bayreuth, Germany
| | - Fabrizio Barozzi
- Plant Physiology, Bayreuth Center for Ecology and Environmental Research (BayCEER), University of Bayreuth, D-95440 Bayreuth, Germany
| | - Andrea E Colina Blanco
- Environmental Geochemistry, Bayreuth Center for Ecology and Environmental Research (BayCEER), University of Bayreuth, D-95440 Bayreuth, Germany
| | - Carolin F Kerl
- Environmental Geochemistry, Bayreuth Center for Ecology and Environmental Research (BayCEER), University of Bayreuth, D-95440 Bayreuth, Germany
| | - Britta Planer-Friedrich
- Environmental Geochemistry, Bayreuth Center for Ecology and Environmental Research (BayCEER), University of Bayreuth, D-95440 Bayreuth, Germany
| | - Stephan Clemens
- Plant Physiology, Bayreuth Center for Ecology and Environmental Research (BayCEER), University of Bayreuth, D-95440 Bayreuth, Germany
| |
Collapse
|
12
|
Zhang H, Quintana J, Ütkür K, Adrian L, Hawer H, Mayer K, Gong X, Castanedo L, Schulten A, Janina N, Peters M, Wirtz M, Brinkmann U, Schaffrath R, Krämer U. Translational fidelity and growth of Arabidopsis require stress-sensitive diphthamide biosynthesis. Nat Commun 2022; 13:4009. [PMID: 35817801 PMCID: PMC9273596 DOI: 10.1038/s41467-022-31712-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2021] [Accepted: 06/30/2022] [Indexed: 11/09/2022] Open
Abstract
Diphthamide, a post-translationally modified histidine residue of eukaryotic TRANSLATION ELONGATION FACTOR2 (eEF2), is the human host cell-sensitizing target of diphtheria toxin. Diphthamide biosynthesis depends on the 4Fe-4S-cluster protein Dph1 catalyzing the first committed step, as well as Dph2 to Dph7, in yeast and mammals. Here we show that diphthamide modification of eEF2 is conserved in Arabidopsis thaliana and requires AtDPH1. Ribosomal -1 frameshifting-error rates are increased in Arabidopsis dph1 mutants, similar to yeast and mice. Compared to the wild type, shorter roots and smaller rosettes of dph1 mutants result from fewer formed cells. TARGET OF RAPAMYCIN (TOR) kinase activity is attenuated, and autophagy is activated, in dph1 mutants. Under abiotic stress diphthamide-unmodified eEF2 accumulates in wild-type seedlings, most strongly upon heavy metal excess, which is conserved in human cells. In summary, our results suggest that diphthamide contributes to the functionality of the translational machinery monitored by plants to regulate growth.
Collapse
Affiliation(s)
- Hongliang Zhang
- Molecular Genetics and Physiology of Plants, Faculty of Biology and Biotechnology, Ruhr University Bochum, Universitaetsstrasse 150, Box 44 ND3/30, 44801, Bochum, Germany
| | - Julia Quintana
- Molecular Genetics and Physiology of Plants, Faculty of Biology and Biotechnology, Ruhr University Bochum, Universitaetsstrasse 150, Box 44 ND3/30, 44801, Bochum, Germany
| | - Koray Ütkür
- Microbiology, Institute for Biology, University of Kassel, 34132, Kassel, Germany
| | - Lorenz Adrian
- Environmental Biotechnology, Helmholtz Centre for Environmental Research-UFZ, 04318, Leipzig, Germany.,Chair of Geobiotechnology, Technische Universität Berlin, 13355, Berlin, Germany
| | - Harmen Hawer
- Microbiology, Institute for Biology, University of Kassel, 34132, Kassel, Germany
| | - Klaus Mayer
- Roche Pharma Research & Early Development, Large Molecule Research, Roche Innovation Center Munich, 82377, Penzberg, Germany
| | - Xiaodi Gong
- Centre for Organismal Studies (COS), University of Heidelberg, 69120, Heidelberg, Germany
| | - Leonardo Castanedo
- Molecular Genetics and Physiology of Plants, Faculty of Biology and Biotechnology, Ruhr University Bochum, Universitaetsstrasse 150, Box 44 ND3/30, 44801, Bochum, Germany
| | - Anna Schulten
- Molecular Genetics and Physiology of Plants, Faculty of Biology and Biotechnology, Ruhr University Bochum, Universitaetsstrasse 150, Box 44 ND3/30, 44801, Bochum, Germany
| | - Nadežda Janina
- Molecular Genetics and Physiology of Plants, Faculty of Biology and Biotechnology, Ruhr University Bochum, Universitaetsstrasse 150, Box 44 ND3/30, 44801, Bochum, Germany
| | - Marcus Peters
- Molecular Immunology, Medical Faculty, Ruhr University Bochum, 44801, Bochum, Germany
| | - Markus Wirtz
- Centre for Organismal Studies (COS), University of Heidelberg, 69120, Heidelberg, Germany
| | - Ulrich Brinkmann
- Roche Pharma Research & Early Development, Large Molecule Research, Roche Innovation Center Munich, 82377, Penzberg, Germany
| | - Raffael Schaffrath
- Microbiology, Institute for Biology, University of Kassel, 34132, Kassel, Germany
| | - Ute Krämer
- Molecular Genetics and Physiology of Plants, Faculty of Biology and Biotechnology, Ruhr University Bochum, Universitaetsstrasse 150, Box 44 ND3/30, 44801, Bochum, Germany.
| |
Collapse
|
13
|
Uraguchi S, Ohshiro Y, Otsuka Y, Wada E, Naruse F, Sugaya K, Nagai K, Wongkaew A, Nakamura R, Takanezawa Y, Clemens S, Ohkama-Ohtsu N, Kiyono M. Phytochelatin-mediated metal detoxification pathway is crucial for an organomercurial phenylmercury tolerance in Arabidopsis. PLANT MOLECULAR BIOLOGY 2022; 109:563-577. [PMID: 34837578 DOI: 10.1007/s11103-021-01221-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Accepted: 11/16/2021] [Indexed: 06/13/2023]
Abstract
An organomercurial phenylmercury activates AtPCS1, an enzyme known for detoxification of inorganic metal(loid) ions in Arabidopsis and the induced metal-chelating peptides phytochelatins are essential for detoxification of phenylmercury. Small thiol-rich peptides phytochelatins (PCs) and their synthases (PCSs) are crucial for plants to mitigate the stress derived from various metal(loid) ions in their inorganic form including inorganic mercury [Hg(II)]. However, the possible roles of the PC/PCS system in organic mercury detoxification in plants remain elusive. We found that an organomercury phenylmercury (PheHg) induced PC synthesis in Arabidopsis thaliana plants as Hg(II), whereas methylmercury did not. The analyses of AtPCS1 mutant plants and in vitro assays using the AtPCS1-recombinant protein demonstrated that AtPCS1, the major PCS in A. thaliana, was responsible for the PheHg-responsive PC synthesis. AtPCS1 mutants cad1-3 and cad1-6, and the double mutant of PC-metal(loid) complex transporters AtABCC1 and AtABCC2 showed enhanced sensitivity to PheHg as well as to Hg(II). The hypersensitivity of cad1-3 to PheHg stress was complemented by the own-promoter-driven expression of AtPCS1-GFP. The confocal microscopy of the complementation lines showed that the AtPCS1-GFP was preferentially expressed in epidermal cells of the mature and elongation zones, and the outer-most layer of the lateral root cap cells in the meristematic zone. Moreover, in vitro PC-metal binding assay demonstrated that binding affinity between PC and PheHg was comparable to Hg(II). However, plant ionomic profiles, as well as root morphology under PheHg and Hg(II) stress, were divergent. These results suggest that PheHg phytotoxicity is different from Hg(II), but AtPCS1-mediated PC synthesis, complex formation, and vacuolar sequestration by AtABCC1 and AtABCC2 are similarly functional for both PheHg and Hg(II) detoxification in root surficial cell types.
Collapse
Affiliation(s)
- Shimpei Uraguchi
- Department of Public Health, School of Pharmacy, Kitasato University, Minato-ku, Tokyo, 108-8641, Japan.
| | - Yuka Ohshiro
- Department of Public Health, School of Pharmacy, Kitasato University, Minato-ku, Tokyo, 108-8641, Japan
| | - Yuto Otsuka
- Department of Public Health, School of Pharmacy, Kitasato University, Minato-ku, Tokyo, 108-8641, Japan
| | - Emiko Wada
- Department of Public Health, School of Pharmacy, Kitasato University, Minato-ku, Tokyo, 108-8641, Japan
| | - Fumii Naruse
- Department of Public Health, School of Pharmacy, Kitasato University, Minato-ku, Tokyo, 108-8641, Japan
| | - Kakeru Sugaya
- Department of Public Health, School of Pharmacy, Kitasato University, Minato-ku, Tokyo, 108-8641, Japan
| | - Kenichiro Nagai
- Medicinal Research Laboratories, School of Pharmacy, Kitasato University, Minato-ku, Tokyo, 108-8641, Japan
| | - Arunee Wongkaew
- United Graduate School of Agriculture, Tokyo University of Agriculture and Technology, Fuchu, Tokyo, 183-8509, Japan
- Department of Agronomy, Faculty of Agriculture, Kasetsart University, Bangkok, 10900, Thailand
| | - Ryosuke Nakamura
- Department of Public Health, School of Pharmacy, Kitasato University, Minato-ku, Tokyo, 108-8641, Japan
| | - Yasukazu Takanezawa
- Department of Public Health, School of Pharmacy, Kitasato University, Minato-ku, Tokyo, 108-8641, Japan
| | - Stephan Clemens
- Department of Plant Physiology, Bayreuth Center of Ecology and Environmental Research, University of Bayreuth, 95447, Bayreuth, Germany
| | - Naoko Ohkama-Ohtsu
- Institute of Agriculture, Tokyo University of Agriculture and Technology, Fuchu, Tokyo, 183-8509, Japan
- Institute of Global Innovation Research, Tokyo University of Agriculture and Technology, Fuchu, Tokyo, 183-8509, Japan
| | - Masako Kiyono
- Department of Public Health, School of Pharmacy, Kitasato University, Minato-ku, Tokyo, 108-8641, Japan.
| |
Collapse
|
14
|
Zhao FJ, Tang Z, Song JJ, Huang XY, Wang P. Toxic metals and metalloids: Uptake, transport, detoxification, phytoremediation, and crop improvement for safer food. MOLECULAR PLANT 2022; 15:27-44. [PMID: 34619329 DOI: 10.1016/j.molp.2021.09.016] [Citation(s) in RCA: 97] [Impact Index Per Article: 48.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/13/2021] [Revised: 09/24/2021] [Accepted: 09/29/2021] [Indexed: 05/20/2023]
Abstract
Agricultural soils are under threat of toxic metal/metalloid contamination from anthropogenic activities, leading to excessive accumulation of arsenic (As), cadmium (Cd), lead (Pb), and mercury (Hg) in food crops that poses significant risks to human health. Understanding how these toxic metals and their methylated species are taken up, translocated, and detoxified is prerequisite to developing strategies to limit their accumulation for safer food. Toxic metals are taken up and transported across different cellular compartments and plant tissues via various transporters for essential or beneficial nutrients, e.g. As by phosphate and silicon transporters, and Cd by manganese (Mn), zinc (Zn), and iron (Fe) transporters. These transport processes are subjected to interactions with nutrients and the regulation at the transcriptional and post-translational levels. Complexation with thiol-rich compounds, such as phytochelatins, and sequestration in the vacuoles are the common mechanisms for detoxification and for limiting their translocation. A number of genes involved in toxic metal uptake, transport, and detoxification have been identified, offering targets for genetic manipulation via gene editing or transgenic technologies. Natural variations in toxic metal accumulation exist within crop germplasm, and some of the quantitative trait loci underlying these variations have been cloned, paving the way for marker-assisted breeding of low metal accumulation crops. Using plants to extract and remove toxic metals from soil is also possible, but this phytoremediation approach requires metal hyperaccumulation for efficiency. Knowledge gaps and future research needs are also discussed.
Collapse
Affiliation(s)
- Fang-Jie Zhao
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, Jiangsu 210095, China.
| | - Zhong Tang
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, Jiangsu 210095, China
| | - Jia-Jun Song
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, Jiangsu 210095, China
| | - Xin-Yuan Huang
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, Jiangsu 210095, China
| | - Peng Wang
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, Jiangsu 210095, China
| |
Collapse
|
15
|
Uraguchi S, Nagai K, Naruse F, Otsuka Y, Ohshiro Y, Nakamura R, Takanezawa Y, Kiyono M. Development of affinity bead-based in vitro metal-ligand binding assay reveals dominant cadmium affinity of thiol-rich small peptides phytochelatins beyond glutathione. Metallomics 2021; 13:6445037. [PMID: 34850059 DOI: 10.1093/mtomcs/mfab068] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Accepted: 11/17/2021] [Indexed: 11/12/2022]
Abstract
For a better understanding of metal-ligand interaction and its function in cells, we developed an easy, sensitive, and high-throughput method to quantify ligand-metal(loid) binding affinity under physiological conditions by combining ligand-attached affinity beads and inductively coupled plasma-optical emission spectrometry (ICP-OES). Glutathione (GSH) and two phytochelatins (PC2 and PC3, small peptides with different numbers of free thiols) were employed as model ligands and attached to hydrophilic beads. The principle of the assay resembles that of affinity purification of proteins in biochemistry: metals binding to the ligand on the beads and the rest in the buffer are separated by a spin column and quantified by ICP-OES. The binding assay using the GSH-attached beads and various metal(loid)s suggested the different affinity of the metal-GSH interactions, in accordance with the order of the Irving-Williams series and the reported stability constants. The binding assay using PC2 or PC3-attached beads suggested positive binding between PCs and Ni(II), Cu(II), Zn(II), Cd(II), and As(III) in accordance with the number of thiols in PC2 and PC3. We then conducted the competition assay using Cd(II), Mn(II), Fe(II), Cu(II), and Zn(II), and the results suggested a better binding affinity of PC2 with Cd(II) than with the essential metals. Another competition assay using PC2 and GSH suggested a robust binding affinity between PCs and Cd(II) compared to GSH and Cd(II). These results suggested the dominance of PC-Cd complex formation in vitro, supporting the physiological importance of PCs for the detoxification of cadmium in vivo. We also discuss the potential application of the assay.
Collapse
Affiliation(s)
- Shimpei Uraguchi
- Department of Public Health, School of Pharmacy, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo 108-8641, Japan
| | - Kenichiro Nagai
- Medicinal Research Laboratories, School of Pharmacy, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo, 108-8641, Japan
| | - Fumii Naruse
- Department of Public Health, School of Pharmacy, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo 108-8641, Japan
| | - Yuto Otsuka
- Department of Public Health, School of Pharmacy, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo 108-8641, Japan
| | - Yuka Ohshiro
- Department of Public Health, School of Pharmacy, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo 108-8641, Japan
| | - Ryosuke Nakamura
- Department of Public Health, School of Pharmacy, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo 108-8641, Japan
| | - Yasukazu Takanezawa
- Department of Public Health, School of Pharmacy, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo 108-8641, Japan
| | - Masako Kiyono
- Department of Public Health, School of Pharmacy, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo 108-8641, Japan
| |
Collapse
|
16
|
Genotoxicity and Cytotoxicity Induced in Zygophyllum fabago by Low Pb Doses Depends on the Population’s Redox Plasticity. HORTICULTURAE 2021. [DOI: 10.3390/horticulturae7110455] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Lead (Pb) soil contamination remains a major ecological challenge. Zygophyllum fabago is a candidate for the Pb phytostabilisation of mining tailings; nevertheless, the cytogenotoxic effects of low doses of Pb on this species are still unknown. Therefore, Z. fabago seeds collected from non-mining (NM) and mining (M) areas were exposed to 0, 5 and 20 µM Pb for four weeks, after which seedling growth, Pb cytogenotoxic effects and redox status were analyzed. The data revealed that Pb did not affect seedling growth in M populations, in contrast to the NM population. Cell cycle progression delay/arrest was detected in both NM and M seedlings, mostly in the roots. DNA damage (DNAd) was induced by Pb, particularly in NM seedlings. In contrast, M populations, which showed a higher Pb content, exhibited lower levels of DNAd and protein oxidation, together with higher levels of antioxidants. Upon Pb exposure, reduced glutathione (GSH) and non-protein thiols were upregulated in shoots and were unaffected/decreased in roots from the NM population, whereas M populations maintained higher levels of flavanols and hydroxycinnamic acids in shoots and triggered GSH in roots and shoots. These differential organ-specific mechanisms seem to be a competitive strategy that allows M populations to overcome Pb toxicity, contrarily to NM, thus stressing the importance of seed provenance in phytostabilisation programs.
Collapse
|
17
|
Chen L, Liu J, Zhang W, Zhou J, Luo D, Li Z. Uranium (U) source, speciation, uptake, toxicity and bioremediation strategies in soil-plant system: A review. JOURNAL OF HAZARDOUS MATERIALS 2021; 413:125319. [PMID: 33582470 DOI: 10.1016/j.jhazmat.2021.125319] [Citation(s) in RCA: 70] [Impact Index Per Article: 23.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Revised: 01/23/2021] [Accepted: 02/02/2021] [Indexed: 06/12/2023]
Abstract
Uranium(U), a highly toxic radionuclide, is becoming a great threat to soil health development, as returning nuclear waste containing U into the soil systems is increased. Numerous studies have focused on: i) tracing the source in U contaminated soils; ii) exploring U geochemistry; and iii) assessing U phyto-uptake and its toxicity to plants. Yet, there are few literature reviews that systematically summarized the U in soil-plant system in past decade. Thus, we present its source, geochemical behavior, uptake, toxicity, detoxification, and bioremediation strategies based on available data, especially published from 2018 to 2021. In this review, we examine processes that can lead to the soil U contamination, indicating that mining activities are currently the main sources. We discuss the relationship between U bioavailability in the soil-plant system and soil conditions including redox potential, soil pH, organic matter, and microorganisms. We then review the soil-plant transfer of U, finding that U mainly accumulates in roots with a quite limited translocation. However, plants such as willow, water lily, and sesban are reported to translocate high U levels from roots to aerial parts. Indeed, U does not possess any identified biological role, but provokes numerous deleterious effects such as reducing seed germination, inhibiting plant growth, depressing photosynthesis, interfering with nutrient uptake, as well as oxidative damage and genotoxicity. Yet, plants tolerate U toxicity via various defense strategies including antioxidant enzymes, compartmentalization, and phytochelatin. Moreover, we review two biological remediation strategies for U-contaminated soil: (i) phytoremediation and (ii) microbial remediation. They are quite low-cost and eco-friendly compared with traditional physical or chemical remediation technologies. Finally, we conclude some promising research challenges regarding U biogeochemical behavior in soil-plant systems. This review, thus, further indicates that the combined application of U low accumulators and microbial inoculants may be an effective strategy for the bioremediation of U-contaminated soils.
Collapse
Affiliation(s)
- Li Chen
- State Key Laboratory of Grassland Agro-ecosystems; Key Laboratory of Grassland Livestock Industry Innovation, Ministry of Agriculture and Rural Affairs; Engineering Research Center of Grassland Industry, Ministry of Education, Gansu Tech Innovation Center of Western China Grassland Industry; College of Pastoral Agriculture Science and Technology, Lanzhou University, Lanzhou 730000, Gansu, PR China
| | - Jinrong Liu
- State Key Laboratory of Grassland Agro-ecosystems; Key Laboratory of Grassland Livestock Industry Innovation, Ministry of Agriculture and Rural Affairs; Engineering Research Center of Grassland Industry, Ministry of Education, Gansu Tech Innovation Center of Western China Grassland Industry; College of Pastoral Agriculture Science and Technology, Lanzhou University, Lanzhou 730000, Gansu, PR China.
| | - Weixiong Zhang
- Third Institute Geological and Mineral Exploration of Gansu Provincial Bureau of Geology and Mineral Resources, Lanzhou 730030, Gansu, PR China
| | - Jiqiang Zhou
- Gansu Nonferrous Engineering Exploration & Design Research Institute, Lanzhou 730030, Gansu, PR China
| | - Danqi Luo
- State Key Laboratory of Grassland Agro-ecosystems; Key Laboratory of Grassland Livestock Industry Innovation, Ministry of Agriculture and Rural Affairs; Engineering Research Center of Grassland Industry, Ministry of Education, Gansu Tech Innovation Center of Western China Grassland Industry; College of Pastoral Agriculture Science and Technology, Lanzhou University, Lanzhou 730000, Gansu, PR China
| | - Zimin Li
- Université catholique de Louvain (UCLouvain), Earth and Life Institute, Soil Science, Louvain-La-Neuve 1348, Belgium.
| |
Collapse
|
18
|
Liu J, Zhang J, Kim SH, Lee HS, Marinoia E, Song WY. Characterization of Brassica rapa metallothionein and phytochelatin synthase genes potentially involved in heavy metal detoxification. PLoS One 2021; 16:e0252899. [PMID: 34086824 PMCID: PMC8177407 DOI: 10.1371/journal.pone.0252899] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Accepted: 05/24/2021] [Indexed: 11/18/2022] Open
Abstract
Brassica rapa is an important leafy vegetable that can potentially accumulate high concentrations of cadmium (Cd), posing a risk to human health. The aim of the present study was to identify cadmium detoxifying molecular mechanisms in B. rapa using a functional cloning strategy. A cDNA library constructed from roots of B. rapa plants treated with Cd was transformed into the Cd sensitive yeast mutant strain DTY167 that lacks the yeast cadmium factor (YCF1), and resistant yeast clones were selected on Cd containing media. Two hundred genes potentially conferring cadmium resistance were rescued from the surviving yeast clones and sequenced. Sequencing analysis revealed that genes encoding for metallothionein (MT)1, MT2a, MT2b and MT3, and phytochelatin synthase (PCS)1 and PCS2 accounted for 35.5%, 28.5%, 4%, 11.3%, 18.7% and 2%, respectively of the genes identified. MTs and PCSs expressing DTY167 cells showed resistance to Cd as well as to Zn. PCS1 expressing yeast cells were also more resistant to Pb compared to those expressing MTs or PCS2. RT-PCR results showed that Cd treatment strongly induced the expression levels of MTs in the root and shoot. Furthermore, the different MTs and PCSs exhibited tissue specific expression. The results indicate that MTs and PCS genes potentially play a central role in detoxifying Cd and other toxic metals in B. rapa.
Collapse
Affiliation(s)
- Jiayou Liu
- International Research Center for Environmental Membrane Biology, Department of Horticulture, Foshan University, Foshan, Guangdong, China
| | - Jie Zhang
- International Research Center for Environmental Membrane Biology, Department of Horticulture, Foshan University, Foshan, Guangdong, China
| | - Sun Ha Kim
- College of Agriculture and Life Sciences, Chungnam National University, Daejeon, Korea
| | - Hyun-Sook Lee
- College of Agriculture and Life Sciences, Chungnam National University, Daejeon, Korea
| | - Enrico Marinoia
- International Research Center for Environmental Membrane Biology, Department of Horticulture, Foshan University, Foshan, Guangdong, China
| | - Won-Yong Song
- International Research Center for Environmental Membrane Biology, Department of Horticulture, Foshan University, Foshan, Guangdong, China
- College of Agriculture and Life Sciences, Chungnam National University, Daejeon, Korea
- * E-mail:
| |
Collapse
|
19
|
Hu X, Li T, Xu W, Chai Y. Distribution of cadmium in subcellular fraction and expression difference of its transport genes among three cultivars of pepper. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2021; 216:112182. [PMID: 33798868 DOI: 10.1016/j.ecoenv.2021.112182] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2020] [Revised: 02/25/2021] [Accepted: 03/20/2021] [Indexed: 06/12/2023]
Abstract
Cadmium (Cd) tolerance mechanisms in plant are mainly divided into two categories: evasion mechanism and tolerance mechanism. However, due to the complexity of the mechanism of Cd absorption and accumulation in crops, there are still disputes and controversies about Cd toxicity to plants and the mechanism of Cd tolerance in plants. The Cd absorption and accumulation mechanism in edible parts of pepper remains unknown. The present study characterized three pepper cultivars with different cadmium tolerance under cadmium stress. One high-Cd-accumulation type (X55), a medium-Cd-accumulation type (Daguo 99) and a low-Cd-accumulation type (Luojiao 318) were selected to study distribution characteristics of Cd in subcellular fractions of the three pepper varieties as well as expression difference of key Cd accumulation and tolerance genes under different cadmium levels. The results showed that under Cd stress, X55 and Daguo 99 mainly migrated Cd from root to stems and leaves, while Luojiao318 migrated it to the fruit. The Cd concentration in the subcellular fractions of pepper roots, stems, leaves and fruits was as follow: cell wall (F1) > organelle (F2) > cell soluble fraction (F3). The roots, stems and leaf cells of X55 have strong Cd compartmentalization capacity. The fruit cells of Daguo 99 have strong Cd compartmentalization capacity, while the roots of Luojiao318 have strong ability to inhibit Cd absorption. Under Cd stress, HMA1, HMA2 and NRAMP1-6 were up-regulated in roots, stems and fruits of the three varieties. FTP1-2 and FTP1-3 genes were significantly up-regulated in different materials, except the roots of Daguo 99. Under Cd treatment, PCS gene expression of pepper showed an order of that of X55 > Luojiao 318 >Daguo 99. The present study revealed that the cell wall of pepper played an important role in Cd separation and resistance. The difference in Cd accumulation ability of the pepper varieties may be related to differences in main expression sites and expression levels of HMA, NRAMP, FTP and PCS genes.
Collapse
Affiliation(s)
- Xiaoting Hu
- College of Resources and Environmental Sciences, Southwest University, Chongqing 400715, PR China
| | - Tao Li
- College of Resources and Environmental Sciences, Southwest University, Chongqing 400715, PR China
| | - Weihong Xu
- College of Resources and Environmental Sciences, Southwest University, Chongqing 400715, PR China.
| | - Yourong Chai
- College of Agronomy and Biotechnology, Southwest University, Chongqing 400715, PR China
| |
Collapse
|
20
|
Peco JD, Higueras P, Campos JA, Olmedilla A, Romero-Puertas MC, Sandalio LM. Deciphering lead tolerance mechanisms in a population of the plant species Biscutella auriculata L. from a mining area: Accumulation strategies and antioxidant defenses. CHEMOSPHERE 2020; 261:127721. [PMID: 32745740 DOI: 10.1016/j.chemosphere.2020.127721] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Revised: 07/06/2020] [Accepted: 07/13/2020] [Indexed: 06/11/2023]
Abstract
The uptake and distribution of Pb and the mechanisms involved in the metal tolerance have been investigated in a mine population of Biscutella auriculata. Seedlings were exposed to 125 μM Pb(NO3)2 for 15 days under semihydroponic conditions. The results showed an increase in the size of Pb-treated seedlings and symptoms of toxicity were not observed. ICP-OES analyses showed that Pb accumulation was restricted to root tissue. Imaging of Pb accumulation by dithizone histochemistry revealed the presence of the metal in vacuoles and cell wall in root cells. The accumulation of Pb in vacuoles could be stimulated by an increase in phytochelatin PC2 content. Pb did not promote oxidative damage and this is probably due the increase of antioxidative defenses. In the leaves, Pb produced a significant increase in superoxide dismutase activity, while in roots an increase in catalase and components of the Foyer- Halliwell-Asada cycle were observed. The results indicated that Biscutella auriculata has a high capacity to tolerate Pb and this is mainly due to a very efficient mechanism to sequester the metal in roots and a capacity to avoid oxidative stress. This species could therefore be very useful for phytostabilization and repopulation of areas contaminated with Pb.
Collapse
Affiliation(s)
- J D Peco
- Escuela Técnica Superior de Ingenieros Agrónomos, Universidad de Castilla-La Mancha (UCLM), Ronda de Calatrava 7, 13071, Ciudad Real, Spain; Instituto de Geología Aplicada, Universidad de Castilla-La Mancha (UCLM), Plaza de Manuel Meca 1, 13400, Almadén, Ciudad Real, Spain
| | - P Higueras
- Instituto de Geología Aplicada, Universidad de Castilla-La Mancha (UCLM), Plaza de Manuel Meca 1, 13400, Almadén, Ciudad Real, Spain
| | - J A Campos
- Escuela Técnica Superior de Ingenieros Agrónomos, Universidad de Castilla-La Mancha (UCLM), Ronda de Calatrava 7, 13071, Ciudad Real, Spain
| | - A Olmedilla
- Department of Biochemistry and Molecular and Cellular Biology of Plants, Estación Experimental Del Zaidín, Consejo Superior de Investigaciones Científicas (CSIC), Apartado 419 E, 18080, Granada, Spain
| | - M C Romero-Puertas
- Department of Biochemistry and Molecular and Cellular Biology of Plants, Estación Experimental Del Zaidín, Consejo Superior de Investigaciones Científicas (CSIC), Apartado 419 E, 18080, Granada, Spain
| | - L M Sandalio
- Department of Biochemistry and Molecular and Cellular Biology of Plants, Estación Experimental Del Zaidín, Consejo Superior de Investigaciones Científicas (CSIC), Apartado 419 E, 18080, Granada, Spain.
| |
Collapse
|
21
|
Szopiński M, Sitko K, Rusinowski S, Zieleźnik-Rusinowska P, Corso M, Rostański A, Rojek-Jelonek M, Verbruggen N, Małkowski E. Different strategies of Cd tolerance and accumulation in Arabidopsis halleri and Arabidopsis arenosa. PLANT, CELL & ENVIRONMENT 2020; 43:3002-3019. [PMID: 32890409 DOI: 10.1111/pce.13883] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/09/2020] [Revised: 08/18/2020] [Accepted: 08/31/2020] [Indexed: 06/11/2023]
Abstract
Pseudometallophytes are commonly used to study the evolution of metal tolerance and accumulation traits in plants. Within the Arabidopsis genus, the adaptation of Arabidopsis halleri to metalliferous soils has been widely studied, which is not the case for the closely related species Arabidopsis arenosa. We performed an in-depth physiological comparison between the A. halleri and A. arenosa populations from the same polluted site, together with the geographically close non-metallicolous (NM) populations of both species. The ionomes, growth, photosynthetic parameters and pigment content were characterized in the plants that were growing on their native site and in a hydroponic culture under Cd treatments. In situ, the metallicolous (M) populations of both species hyperaccumulated Cd and Zn. The NM population of A. halleri hyperaccumulated Cd and Zn while the NM A. arenosa did not. In the hydroponic experiments, the NM populations of both species accumulated more Cd in their shoots than the M populations. Our research suggests that the two Arabidopsis species evolved different strategies of adaptation to extreme metallic environments that involve fine regulation of metal homeostasis, adjustment of the photosynthetic apparatus and accumulation of flavonols and anthocyanins.
Collapse
Affiliation(s)
- Michał Szopiński
- Plant Ecophysiology Team, Institute of Biology, Biotechnology and Environmental Protection, Faculty of Natural Sciences, University of Silesia in Katowice, Katowice, Poland
| | - Krzysztof Sitko
- Plant Ecophysiology Team, Institute of Biology, Biotechnology and Environmental Protection, Faculty of Natural Sciences, University of Silesia in Katowice, Katowice, Poland
| | | | - Paulina Zieleźnik-Rusinowska
- Plant Ecophysiology Team, Institute of Biology, Biotechnology and Environmental Protection, Faculty of Natural Sciences, University of Silesia in Katowice, Katowice, Poland
| | - Massimiliano Corso
- Laboratory of Plant Physiology and Molecular Genetics, Université Libre de Bruxelles, Brussels, Belgium
| | - Adam Rostański
- Botany and Nature Protection Team, Institute of Biology, Biotechnology and Environmental Protection, Faculty of Natural Sciences, University of Silesia in Katowice, Katowice, Poland
| | - Magdalena Rojek-Jelonek
- Plant Cytogenetics and Molecular Biology Group, Institute of Biology, Biotechnology and Environmental Protection, Faculty of Natural Sciences, University of Silesia in Katowice, Katowice, Poland
| | - Nathalie Verbruggen
- Laboratory of Plant Physiology and Molecular Genetics, Université Libre de Bruxelles, Brussels, Belgium
| | - Eugeniusz Małkowski
- Plant Ecophysiology Team, Institute of Biology, Biotechnology and Environmental Protection, Faculty of Natural Sciences, University of Silesia in Katowice, Katowice, Poland
| |
Collapse
|
22
|
Jalali J, Gaudin P, Ammar E, Lebeau T. Bioaugmentation coupled with phytoextraction for the treatment of Cd and Sr, and reuse opportunities for phosphogypsum rare earth elements. JOURNAL OF HAZARDOUS MATERIALS 2020; 399:122821. [PMID: 32516651 DOI: 10.1016/j.jhazmat.2020.122821] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/05/2020] [Revised: 04/18/2020] [Accepted: 05/06/2020] [Indexed: 06/11/2023]
Abstract
The environmental and health impacts caused by phosphogypsum (PG) make it necessary to carefully manage these wastes. Bioaugmentation of a PG-compost mix with Bacillus cereus was associated with Trifolium pratense or Helianthus annuus for the phytoextraction of metal trace elements (MTE). In hydroponics, MTE concentrations in sunflower shoots are higher than in clover; however, as opposed to clover, it regulates their accumulation. The MTE accumulation levels by plants cultivated in pots with the PG-compost mix are much lower than in hydroponics due to lower concentration in available MTE. The bacteria-plant coupling has served to raise MTE concentrations, especially for rare earth elements (REE), i.e., Ce, La, Nd, Y, in the AP of sunflower, by factors of 4.4, 38.3, 3.4 and 21, respectively, compared to non-bioaugmented control. The translocation factor was also increased for all MTE and is ranged between 1.1 for Sr and 6.8 for Y. Moreover, the presence of bacteria raises plant biomass by a factor of 3.7 for shoots and 2.9 for the roots as regards clover. Results showed that in addition to phytoextraction of REE elements, all providing the promise of some kind of economic opportunity, the dispersion of PG stockpiles dust and erosion should be reduced.
Collapse
Affiliation(s)
- Jihen Jalali
- Laboratory of Planetology and Geodynamics of Nantes, UMR 6112 CNRS, Faculty of Sciences and Technology of Nantes, BP 92208, 44322, Nantes Cedex 3, France; Laboratory of Environmental Sciences and Sustainable Development (LASED), University of Sfax, National Engineering School of Sfax, BP 1173, 3038, Sfax, Tunisia; Tunisian Chemical Group, Mdhilla-Gafsa facility, B.P. 215, 2100, Gafsa, Tunisia
| | - Pierre Gaudin
- Laboratory of Planetology and Geodynamics of Nantes, UMR 6112 CNRS, Faculty of Sciences and Technology of Nantes, BP 92208, 44322, Nantes Cedex 3, France
| | - Emna Ammar
- Laboratory of Environmental Sciences and Sustainable Development (LASED), University of Sfax, National Engineering School of Sfax, BP 1173, 3038, Sfax, Tunisia
| | - Thierry Lebeau
- Laboratory of Planetology and Geodynamics of Nantes, UMR 6112 CNRS, Faculty of Sciences and Technology of Nantes, BP 92208, 44322, Nantes Cedex 3, France.
| |
Collapse
|
23
|
Li M, Barbaro E, Bellini E, Saba A, Sanità di Toppi L, Varotto C. Ancestral function of the phytochelatin synthase C-terminal domain in inhibition of heavy metal-mediated enzyme overactivation. JOURNAL OF EXPERIMENTAL BOTANY 2020; 71:6655-6669. [PMID: 32936292 PMCID: PMC7586750 DOI: 10.1093/jxb/eraa386] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2020] [Accepted: 08/17/2020] [Indexed: 05/03/2023]
Abstract
Phytochelatin synthases (PCSs) play essential roles in detoxification of a broad range of heavy metals in plants and other organisms. Until now, however, no PCS gene from liverworts, the earliest branch of land plants and possibly the first one to acquire a PCS with a C-terminal domain, has been characterized. In this study, we isolated and functionally characterized the first PCS gene from a liverwort, Marchantia polymorpha (MpPCS). MpPCS is constitutively expressed in all organs examined, with stronger expression in thallus midrib. The gene expression is repressed by Cd2+ and Zn2+. The ability of MpPCS to increase heavy metal resistance in yeast and to complement cad1-3 (the null mutant of the Arabidopsis ortholog AtPCS1) proves its function as the only PCS from M. polymorpha. Site-directed mutagenesis of the most conserved cysteines of the C-terminus of the enzyme further uncovered that two twin-cysteine motifs repress, to different extents, enzyme activation by heavy metal exposure. These results highlight an ancestral function of the PCS elusive C-terminus as a regulatory domain inhibiting enzyme overactivation by essential and non-essential heavy metals. The latter finding may be relevant for obtaining crops with decreased root to shoot mobility of cadmium, thus preventing its accumulation in the food chain.
Collapse
Affiliation(s)
- Mingai Li
- Department of Biodiversity and Molecular Ecology, Research and Innovation Centre, Fondazione Edmund Mach, San Michele all’Adige, Trento, Italy
| | - Enrico Barbaro
- Department of Biodiversity and Molecular Ecology, Research and Innovation Centre, Fondazione Edmund Mach, San Michele all’Adige, Trento, Italy
| | - Erika Bellini
- Dipartimento di Biologia, Università di Pisa, Pisa, Italy
| | - Alessandro Saba
- Dipartimento di Patologia Chirurgica, Medica, Molecolare e dell’Area Critica, Università di Pisa, Pisa, Italy
| | | | - Claudio Varotto
- Department of Biodiversity and Molecular Ecology, Research and Innovation Centre, Fondazione Edmund Mach, San Michele all’Adige, Trento, Italy
- Correspondence: ,
| |
Collapse
|
24
|
Zhang X, Yang H, Schaufelberger M, Li X, Cao Q, Xiao H, Ren Z. Role of Flavonol Synthesized by Nucleus FLS1 in Arabidopsis Resistance to Pb Stress. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2020; 68:9646-9653. [PMID: 32786845 DOI: 10.1021/acs.jafc.0c02848] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Lead (Pb) is an important pollutant of worldwide concern with respect to extensive pollution sources and highly toxic effect. Flavonol can improve plant resistance to abiotic stress and is also responsible for the alleviating effect under Pb stress. The relationship between Pb stress and flavonol and the knowledge about the mechanisms of flavonol function are very limited. Pb affected the energy metabolism process and, thus, inhibited plant growth and development. Flavonol accumulation controlled by FLS1 (flavonol synthase) could alleviate the toxic effect. Importantly, nes (mutant of NES that allows FLS1 to enter the nucleus expression) showed better growth status and lighter oxidative damage than NES (N-terminal nucleus exclusion signal peptide prevents FLS1 from entering the nucleus expression), which indicated that nucleus flavonol synthesized by nucleus FLS1 plays a key role in plant resistance to Pb stress. Although FLS1 signals were detected in the cell membrane, cytoplasm, and nucleus, membrane flavonol, cytoplasm flavonol, and nucleus flavonol were not exercising their function in the corresponding position. The expression of nucleus FLS1 intervened in the total content and composition of flavonol. The results also revealed that nucleus flavonol could regulate the ascorbate metabolism for alleviating the damage on the chloroplast, thus maintaining the photophosphorylation pathway. Our findings provided new insights for the molecular basis of Pb tolerance and response mechanism of the plant.
Collapse
Affiliation(s)
- Xu Zhang
- School of Architecture and Urban Planning, Shandong Jianzhu University, Jinan, Shandong 250101, People's Republic of China
| | - Huanhuan Yang
- School of Life Sciences, Shandong University, Qingdao, Shandong 266237, People's Republic of China
| | - Myriam Schaufelberger
- Department of Plant and Microbial Biology, University of Zurich, 8008 Zürich, Switzerland
| | - Xinxin Li
- College of Agriculture and Life Sciences, Cornell University, Ithaca, New York 14850, United States
| | - Qingqing Cao
- School of Architecture and Urban Planning, Shandong Jianzhu University, Jinan, Shandong 250101, People's Republic of China
| | - Huabin Xiao
- School of Architecture and Urban Planning, Shandong Jianzhu University, Jinan, Shandong 250101, People's Republic of China
| | - Zhen Ren
- School of Architecture and Urban Planning, Shandong Jianzhu University, Jinan, Shandong 250101, People's Republic of China
| |
Collapse
|
25
|
Uraguchi S, Ohshiro Y, Otsuka Y, Tsukioka H, Yoneyama N, Sato H, Hirakawa M, Nakamura R, Takanezawa Y, Kiyono M. Selection of Agar Reagents for Medium Solidification Is a Critical Factor for Metal(loid) Sensitivity and Ionomic Profiles of Arabidopsis thaliana. FRONTIERS IN PLANT SCIENCE 2020; 11:503. [PMID: 32499794 PMCID: PMC7243937 DOI: 10.3389/fpls.2020.00503] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Accepted: 04/03/2020] [Indexed: 06/11/2023]
Abstract
For researchers in the plant metal field, the agar reagent used for the solid plate medium is a problematic factor because application of different agar types and even a different lot of the same agar type can mask the plant metal-related phenotypes and impair the reproducibility. In this study, we systematically assessed effects of different agar reagents on metal(loid) sensitivity and element accumulation of the Arabidopsis metal sensitive mutants. Three established mutants (cad1-3, cad1-6, and abcc1/2), and three different types of purified agar reagents (Type A, Type E, and Nacalai) with two independent batches for each reagent were subjected to the analyses. First, we found that element concentrations in the agar reagents largely varied among the agar types. Then the effects of agar reagents on the mutant metal(loid)-sensitivity were examined under As(III), Hg(II), Cd(II), and excess Zn(II) conditions. A significant variation of the mutant metal(loid)-sensitivity was observed among the different agar plates but the variation depended on the combination of metal(loid) stress and agar reagents. Briefly, the type-dependent variation was more evident under As(III) and Hg(II) than Cd(II) or excess Zn(II) conditions. A lot-dependent variation was also observed for Type A and Type E but not for Nacalai: hypersensitive phenotypes of cad1-3, cad1-6, and abcc1/2 under As(III) or Hg(II) treatments were diminished when different batches of the Type A or Type E agar types were used. We also found a significant variation of As and Hg accumulation in the wild-type and cad1-3. Plant As and Hg concentrations were remarkably higher and the difference between the genotypes was more evident when grown with Type A agar plates. We finally analyzed ionomic profiles in the plants exposed to As(III) stress. Agar-type specific ionomic changes in cad1-3 were more observed with the Type A plates than with the Nacalai plates. The presented results overall suggest that suitability of agar reagents for metal(loid)-related phenotyping depends on the experimental design, and an inappropriate selection of agar reagents can mask even very clear phenotypes of the established mutant like cad1-3. We also discuss perspectives on the agar problem in the plant metal study.
Collapse
|
26
|
Höreth S, Pongrac P, van Elteren JT, Debeljak M, Vogel-Mikuš K, Weber M, Braun M, Pietzenuk B, Pečovnik M, Vavpetič P, Pelicon P, Arčon I, Krämer U, Clemens S. Arabidopsis halleri shows hyperbioindicator behaviour for Pb and leaf Pb accumulation spatially separated from Zn. THE NEW PHYTOLOGIST 2020; 226:492-506. [PMID: 31898330 DOI: 10.1111/nph.16373] [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: 06/12/2019] [Accepted: 12/01/2019] [Indexed: 05/14/2023]
Abstract
Lead (Pb) ranks among the most problematic environmental pollutants. Background contamination of soils is nearly ubiquitous, yet plant Pb accumulation is barely understood. In a survey covering 165 European populations of the metallophyte Arabidopsis halleri, several field samples had indicated Pb hyperaccumulation, offering a chance to dissect plant Pb accumulation. Accumulation of Pb was analysed in A. halleri individuals from contrasting habitats under controlled conditions to rule out aerial deposition as a source of apparent Pb accumulation. Several elemental imaging techniques were employed to study the spatial distribution and ligand environment of Pb. Regardless of genetic background, A. halleri individuals showed higher shoot Pb accumulation than A. thaliana. However, dose-response curves revealed indicator rather than hyperaccumulator behaviour. Xylem sap data and elemental imaging unequivocally demonstrated the in planta mobility of Pb. Highest Pb concentrations were found in epidermal and vascular tissues. Distribution of Pb was distinct from that of the hyperaccumulated metal zinc. Most Pb was bound by oxygen ligands in bidentate coordination. A. halleri accumulates Pb whenever soil conditions render Pb phytoavailable. Considerable Pb accumulation under such circumstances, even in leaves of A. thaliana, strongly suggests that Pb can enter food webs and may pose a food safety risk.
Collapse
Affiliation(s)
- Stephan Höreth
- Department of Plant Physiology, University of Bayreuth, 95440, Bayreuth, Germany
| | - Paula Pongrac
- Department of Plant Physiology, University of Bayreuth, 95440, Bayreuth, Germany
- Jožef Stefan Institute, 1000, Ljubljana, Slovenia
| | | | - Marta Debeljak
- National Institute of Chemistry, 1000, Ljubljana, Slovenia
| | - Katarina Vogel-Mikuš
- Jožef Stefan Institute, 1000, Ljubljana, Slovenia
- Biotechnical Faculty, University of Ljubljana, 1000, Ljubljana, Slovenia
| | - Michael Weber
- Department of Plant Physiology, University of Bayreuth, 95440, Bayreuth, Germany
| | - Manuel Braun
- Department of Plant Physiology, University of Bayreuth, 95440, Bayreuth, Germany
| | - Björn Pietzenuk
- Molecular Genetics and Physiology of Plants, Ruhr University Bochum, 44801, Bochum, Germany
| | | | | | | | - Iztok Arčon
- Jožef Stefan Institute, 1000, Ljubljana, Slovenia
- University of Nova Gorica, 5000, Nova Gorica, Slovenia
| | - Ute Krämer
- Molecular Genetics and Physiology of Plants, Ruhr University Bochum, 44801, Bochum, Germany
| | - Stephan Clemens
- Department of Plant Physiology, University of Bayreuth, 95440, Bayreuth, Germany
- Bayreuth Center for Ecology and Environmental Research, University of Bayreuth, 95440, Bayreuth, Germany
| |
Collapse
|
27
|
Chumpol J, Siri S. In vivo formation of spherical and rod lead nanoparticles in root cells of water velvet (Azolla pinnata). Biotechnol Appl Biochem 2020; 67:991-999. [PMID: 31821601 DOI: 10.1002/bab.1871] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2019] [Accepted: 12/02/2019] [Indexed: 11/10/2022]
Abstract
Several plant species survive in the metal-contaminated environment by minimization of detrimental effects of metal exposure and cellular accumulation, but little is known about their capability to transform the uptake metal ions into nanoparticles, especially in nonspherical shapes. This work firstly reported the in vivo formation of spherical and rod-shaped lead nanoparticles (PbNPs) from the uptake lead ions in root cells of water velvet (Azolla pinnata). The energy-dispersive X-ray fluorescence analysis revealed the high level of lead (67.21 ± 0.70%) and the modulated levels of sulfur, potassium, and calcium in the treated roots. Fourier-transform infrared spectroscopy spectral analysis suggested the changes of biochemical constituents in Pb-treated roots, including carbohydrates, organic compounds, proteins, and nucleic acids. Transmission electron microscope (TEM) images revealed the formation of spherical, short rod, and long rod PbNPs dominantly in epidermal, cortical, and vascular cells in the plant roots, respectively. The analyses of energy-dispersive X-ray spectroscopy, high-resolution TEM, and selected area diffraction TEM indicated the body-centered tetragonal lattice of lead oxide nanoparticles (PbONPs) in the root cells.
Collapse
Affiliation(s)
- Jiraporn Chumpol
- School of Biology, Institute of Science, Suranaree University of Technology, Nakhon Ratchasima, Thailand
| | - Sineenat Siri
- School of Biology, Institute of Science, Suranaree University of Technology, Nakhon Ratchasima, Thailand
| |
Collapse
|
28
|
Zhu J, Fang XZ, Dai YJ, Zhu YX, Chen HS, Lin XY, Jin CW. Nitrate transporter 1.1 alleviates lead toxicity in Arabidopsis by preventing rhizosphere acidification. JOURNAL OF EXPERIMENTAL BOTANY 2019; 70:6363-6374. [PMID: 31414122 PMCID: PMC6859734 DOI: 10.1093/jxb/erz374] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2019] [Accepted: 08/05/2019] [Indexed: 05/04/2023]
Abstract
Identification of the mechanisms that control lead (Pb) concentration in plants is a prerequisite for minimizing dietary uptake of Pb from contaminated crops. This study examines how nitrate uptake by roots affects Pb uptake and reveals a new resistance strategy for plants to cope with Pb contamination. We investigated the interaction between nitrate transporter (NRT)-mediated NO3- uptake and exposure to Pb in Arabidopsis using NRT-related mutants. Exposure to Pb specifically stimulated NRT1.1-mediated nitrate uptake. Loss of function of NRT1.1 in nrt1.1-knockout mutants resulted in greater Pb toxicity and higher Pb accumulation in nitrate-sufficient growth medium, whereas no difference was seen between wild-type plants and null-mutants for NRT1.2, NRT2.1, NRT2.2, NRT2.4, and NRT2.5. These results indicate that only NRT1.1-mediated NO3- uptake alleviated Pb toxicity in the plants. Further examination indicated that rhizosphere acidification, which favors Pb entry to roots by increasing its availability, is prevented when NRT1.1 is functional and both NO3- and NH4+ are present in the medium.
Collapse
Affiliation(s)
| | | | - Yu Jie Dai
- State Key Laboratory of Plant Physiology and Biochemistry, College of Natural Resources and Environmental Science, Zhejiang University, Hangzhou, China
| | - Ya Xin Zhu
- State Key Laboratory of Plant Physiology and Biochemistry, College of Natural Resources and Environmental Science, Zhejiang University, Hangzhou, China
| | - Hong Shan Chen
- State Key Laboratory of Plant Physiology and Biochemistry, College of Natural Resources and Environmental Science, Zhejiang University, Hangzhou, China
| | - Xian Yong Lin
- State Key Laboratory of Plant Physiology and Biochemistry, College of Natural Resources and Environmental Science, Zhejiang University, Hangzhou, China
- Correspondence: or
| | | |
Collapse
|
29
|
Clemens S. Safer food through plant science: reducing toxic element accumulation in crops. JOURNAL OF EXPERIMENTAL BOTANY 2019; 70:5537-5557. [PMID: 31408148 DOI: 10.1093/jxb/erz366] [Citation(s) in RCA: 50] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2019] [Accepted: 07/31/2019] [Indexed: 05/24/2023]
Abstract
Natural processes and human activities have caused widespread background contamination with non-essential toxic elements. The uptake and accumulation of cadmium (Cd), arsenic (As), and lead (Pb) by crop plants results in chronic dietary exposure and is associated with various health risks. Current human intake levels are close to what is provisionally regarded as safe. This has recently triggered legislative actions to introduce or lower limits for toxic elements in food. Arguably, the most effective way to reduce the risk of slow poisoning is the breeding of crops with much lower accumulation of contaminants. The past years have seen tremendous progress in elucidating molecular mechanisms of toxic element transport. This was achieved in the model systems Arabidopsis thaliana and, most importantly, rice, the major source of exposure to As and Cd for a large fraction of the global population. Many components of entry and sequestration pathways have been identified. This knowledge can now be applied to engineer crops with reduced toxic element accumulation especially in edible organs. Most obvious in the case of Cd, it appears likely that subtle genetic intervention has the potential to reduce human exposure to non-essential toxic elements almost immediately. This review outlines the risks and discusses our current state of knowledge with emphasis on transgenic and gene editing approaches.
Collapse
Affiliation(s)
- Stephan Clemens
- Department of Plant Physiology, and Bayreuth Center of Ecology and Environmental Research, University of Bayreuth, Bayreuth, Germany
| |
Collapse
|
30
|
Clemens S. Metal ligands in micronutrient acquisition and homeostasis. PLANT, CELL & ENVIRONMENT 2019; 42:2902-2912. [PMID: 31350913 DOI: 10.1111/pce.13627] [Citation(s) in RCA: 61] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2019] [Revised: 07/22/2019] [Accepted: 07/23/2019] [Indexed: 05/09/2023]
Abstract
Acquisition and homeostasis of micronutrients such as iron (Fe) and zinc (Zn) pose specific challenges. Poor solubility and high reactivity require controlled synthesis and supply of ligands to complex these metals extracellularly and intracellularly. Cytosolic labile pools represent only a minute fraction of the total cellular content. Several low-molecular-weight ligands are known in plants, including sulfur ligands (cysteine and peptides), nitrogen/oxygen ligands (S-adenosyl-l-methionine-derived molecules and histidine), and oxygen ligands (phenolics and organic acids). Some ligands are secreted into the extracellular space and influence the phytoavailability of metal ions. A second principal function is the intracellular buffering of micronutrients as well as the facilitation of long-distance transport in xylem and phloem. Furthermore, low-molecular-weight ligands are involved in the storage of metals, predominantly in vacuoles. A detailed molecular understanding is hampered by technical limitations, in particular the difficulty to detect and quantify cellular metal-ligand complexes. More, but still too little, is known about ligand synthesis and the transport across membranes, either with or without a complexed metal. Metal ligands have an immediate impact on human well-being. Engineering metal ligand synthesis and distribution in crops has tremendous potential to improve the nutritional quality of food and to tackle major human health risks.
Collapse
Affiliation(s)
- Stephan Clemens
- Department of Plant Physiology and Bayreuth Center of Ecology and Environmental Research, University of Bayreuth, Universitätsstrasse 30, 95447, Bayreuth, Germany
| |
Collapse
|
31
|
Ziegler P, Sree KS, Appenroth KJ. Duckweed biomarkers for identifying toxic water contaminants? ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2019; 26:14797-14822. [PMID: 30397749 DOI: 10.1007/s11356-018-3427-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2018] [Accepted: 10/08/2018] [Indexed: 06/08/2023]
Abstract
Surface or ground waters can be contaminated with numerous toxic substances. The duckweeds Lemna minor and Lemna gibba are widely used for assaying waterborne toxicity to higher plants in terms of growth inhibition and photosynthetic pigment reduction. These tests cannot, however, in themselves determine the nature of the agents responsible for toxicity. Morphological, developmental, physiological, biochemical, and genetic responses of duckweeds to exposure to toxic water contaminants constitute biomarkers of toxic effect. In principle, the very detection of these biomarkers should enable the contaminants having elicited them (and being responsible for the toxicity) to be identified. However, in practice, this is severely compromised by insufficient specificity of biomarkers for their corresponding toxicants and by the lack of documentation of biomarker/toxin relationships. The present contribution illustrates the difficulties of using known water contaminant-related duckweed biomarkers to identify toxins, and discusses possibilities for achieving this goal.
Collapse
Affiliation(s)
- Paul Ziegler
- Department of Plant Physiology, University of Bayreuth, Universitätsstr. 30, 95440, Bayreuth, Germany.
| | - Kandregula Sowjanya Sree
- Department of Environmental Science, Central University of Kerala, Tejaswini Hills, Periye, 671316, India
| | - Klaus-Jürgen Appenroth
- Matthias-Schleiden Institute, Department of Plant Physiology, Friedrich-Schiller-University Jena, Dornburger Str. 159, 07743, Jena, Germany
| |
Collapse
|
32
|
Kumar A, Prasad MNV. Plant-lead interactions: Transport, toxicity, tolerance, and detoxification mechanisms. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2018; 166:401-418. [PMID: 30290327 DOI: 10.1016/j.ecoenv.2018.09.113] [Citation(s) in RCA: 93] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2018] [Revised: 09/18/2018] [Accepted: 09/25/2018] [Indexed: 05/18/2023]
Abstract
Natural and human activities introduced an excess level of toxic lead (Pb) to the environment. Pb has no known biological significance and its interactions with plants lead to the production of reactive oxygen species (ROS). Pb and/or ROS have the potential to cause phytotoxicity by damaging the tissue ultrastructure, cellular components, and biomolecules. These damaging effects may possibly result in the inhibition of normal cellular functioning, physiological reactions, and overall plant performances. ROS play a dual role and act as a signaling molecule in plant defense system. This system encircles enzymatic and non-enzymatic antioxidative mechanisms. Catalase, superoxide dismutase, peroxidase, and enzymes from the ascorbate-glutathione cycle are the major enzymatic antioxidants, while non-enzymatic antioxidants include phenols, flavonoids, ascorbic acid, and glutathione. Pb removal from contaminated sites using plants depend on the plant's Pb accumulation capacity, Pb-induced phytotoxicity, and tolerance and detoxification mechanisms plants adopted to combat against this phytotoxicity. However, the consolidated information discussing Pb-plant interaction including Pb uptake and its translocation within tissues, Pb-mediated phytotoxic symptoms, antioxidative mechanisms, cellular, and protein metabolisms are rather limited. Thus, we aimed to present a consolidated information and critical discussions focusing on the recent studies related to the Pb-induced toxicity and oxidative stress situations in different plants. The important functions of different antioxidants in plants during Pb stress have been reviewed. Additionally, tolerance responses and detoxification mechanisms in the plant through the regulation of gene expression, and glutathione and protein metabolisms to compete against Pb-induced phytotoxicity are also briefly discussed herein.
Collapse
Affiliation(s)
- Abhay Kumar
- Department of Plant Sciences, University of Hyderabad, Hyderabad, Telangana 500046, India.
| | | |
Collapse
|
33
|
Ahmadi H, Corso M, Weber M, Verbruggen N, Clemens S. CAX1 suppresses Cd-induced generation of reactive oxygen species in Arabidopsis halleri. PLANT, CELL & ENVIRONMENT 2018; 41:2435-2448. [PMID: 29879753 DOI: 10.1111/pce.13362] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2018] [Revised: 04/12/2018] [Accepted: 05/25/2018] [Indexed: 05/11/2023]
Abstract
The molecular analysis of metal hyperaccumulation in species such as Arabidopsis halleri offers the chance to gain insights into metal homeostasis and into the evolution of adaptation to extreme habitats. A prerequisite of metal hyperaccumulation is metal hypertolerance. Genetic analysis of a backcross population derived from Arabidopsis lyrata × A. halleri crosses revealed three quantitative trait loci for Cd hypertolerance. A candidate gene for Cdtol2 is AhCAX1, encoding a vacuolar Ca2+ /H+ antiporter. We developed a method for the transformation of vegetatively propagated A. halleri plants and generated AhCAX1-silenced lines. Upon Cd2+ exposure, several-fold higher accumulation of reactive oxygen species (ROS) was detectable in roots of AhCAX1-silenced plants. In accordance with the dependence of Cdtol2 on external Ca2+ concentration, this phenotype was exclusively observed in low Ca2+ conditions. The effects of external Ca2+ on Cd accumulation cannot explain the phenotype as they were not influenced by the genotype. Our data strongly support the hypothesis that higher expression of CAX1 in A. halleri relative to other Arabidopsis species represents a Cd hypertolerance factor. We propose a function of AhCAX1 in preventing a positive feedback loop of Cd-elicited ROS production triggering further Ca2+ -dependent ROS accumulation.
Collapse
Affiliation(s)
- Hassan Ahmadi
- University of Bayreuth, Department of Plant Physiology, and Bayreuth Center of Ecology and Environmental Research, Bayreuth, Germany
| | - Massimiliano Corso
- Université Libre de Bruxelles, Laboratory of Plant Physiology and Molecular Genetics, Brussels, Belgium
| | - Michael Weber
- University of Bayreuth, Department of Plant Physiology, and Bayreuth Center of Ecology and Environmental Research, Bayreuth, Germany
| | - Nathalie Verbruggen
- Université Libre de Bruxelles, Laboratory of Plant Physiology and Molecular Genetics, Brussels, Belgium
| | - Stephan Clemens
- University of Bayreuth, Department of Plant Physiology, and Bayreuth Center of Ecology and Environmental Research, Bayreuth, Germany
| |
Collapse
|
34
|
Agnihotri A, Gupta P, Dwivedi A, Seth CS. Counteractive mechanism (s) of salicylic acid in response to lead toxicity in Brassica juncea (L.) Czern. cv. Varuna. PLANTA 2018; 248:49-68. [PMID: 29564629 DOI: 10.1007/s00425-018-2867-0] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2018] [Accepted: 02/17/2018] [Indexed: 06/08/2023]
Abstract
Salicylic acid alleviates lead toxicity in Brassica juncea (L.) by promoting growth under non-stress and activating stress-defense mechanism (s) under lead stress conditions. It also boosts the ascorbate-glutathione cycle and thus helps in minimizing oxidative and DNA damage. Brassica juncea plants were exposed to different concentrations (0, 500, 1000 and 2000 mg kg-1) of lead (Pb) and subsequently sprayed with 0.5 mM of salicylic acid (SA) to check for morphological and leaf gas exchange parameters like transpiration rate (E), stomatal conductance (GH2O), net photosynthetic rate (A) and maximum quantum yield of PS II (Fv/Fm). Leaf epidermis by scanning electron microscopy (SEM), enzymatic and non-enzymatic components of ascorbate-glutathione (AsA-GSH) cycle, DNA damage by comet assay, lipid peroxidation and endogenous SA quantification by HPLC were analyzed. Lead accumulation in root, shoot and its sub-cellular distribution ratio (SDR) and localization was also determined using atomic absorption spectroscopy (AAS) and rhodizonate-dye staining method, respectively. Results revealed that notable amount of Pb was accumulated in root and shoot in dose-dependent manner which significantly (P ≤ 0.05) posed the toxicity on the majority of morphological parameters, structural integrity of epidermal and guard cells, photosynthetic pigments, malondialdehyde (MDA) and H2O2 content. Notable decrease in leaf gas exchange parameters, Fv/Fm, poor performance of AsA-GSH cycle and striking amount of DNA damage, was found as well. However, SA revoked Pb toxicity to a great extent by promoting growth, chlorophyll content, improving the A, Fv/Fm, boosting the overall performance of AsA-GSH cycle and by lessening the DNA damage.
Collapse
Affiliation(s)
| | - Praveen Gupta
- Department of Botany, University of Delhi, Delhi, 110007, India
| | - Anuj Dwivedi
- Department of Botany, University of Delhi, Delhi, 110007, India
- National Institute of Plant Genome Research, Aruna Asaf Ali Marg, New Delhi, 110067, India
| | | |
Collapse
|
35
|
Uraguchi S, Sone Y, Ohta Y, Ohkama-Ohtsu N, Hofmann C, Hess N, Nakamura R, Takanezawa Y, Clemens S, Kiyono M. Identification of C-terminal Regions in Arabidopsis thaliana Phytochelatin Synthase 1 Specifically Involved in Activation by Arsenite. PLANT & CELL PHYSIOLOGY 2018; 59:500-509. [PMID: 29281059 DOI: 10.1093/pcp/pcx204] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2017] [Accepted: 12/16/2017] [Indexed: 05/16/2023]
Abstract
Phytochelatins (PCs) are major chelators of toxic elements including inorganic arsenic (As) in plant cells. Their synthesis confers tolerance and influences within-plant mobility. Previous studies had shown that various metal/metalloid ions differentially activate PC synthesis. Here we identified C-terminal parts involved in arsenite- [As(III)] dependent activation of AtPCS1, the primary Arabidopsis PC synthase. The T-DNA insertion in the AtPCS1 mutant cad1-6 causes a truncation in the C-terminal regulatory domain that differentially affects activation by cadmium (Cd) and zinc (Zn). Comparisons of cad1-6 with the AtPCS1 null mutant cad1-3 and the double mutant of tonoplast PC transporters abcc1/2 revealed As(III) hypersensitivity of cad1-6 equal to that of cad1-3. Both cad1-6 and cad1-3 showed increased As distribution to shoots compared with Col-0, whereas Zn accumulation in shoots was equally lower in cad1-6 and cad1-3. Supporting these phenotypes of cad1-6, PC accumulation in the As(III)-exposed plants were at trace level in both cad1-6 and cad1-3, suggesting that the truncated AtPCS1 of cad1-6 is defective in PCS activity in response to As(III). Analysis of a C-terminal deletion series of AtPCS1 using the PCS-deficient mutant of fission yeast suggested important regions within the C-terminal domain for As(III)-dependent PC synthesis, which were different from the regions previously suggested for Cd- or Zn-dependent activation. Interestingly, we identified a truncated variant more strongly activated than the wild-type protein. This variant could potentially be used as a tool to better restrict As mobility in plants.
Collapse
Affiliation(s)
- Shimpei Uraguchi
- Department of Public Health, School of Pharmacy, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo, 108-8641 Japan
| | - Yuka Sone
- Department of Public Health, School of Pharmacy, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo, 108-8641 Japan
| | - Yumika Ohta
- Department of Public Health, School of Pharmacy, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo, 108-8641 Japan
| | - Naoko Ohkama-Ohtsu
- Institute of Agriculture, Tokyo University of Agriculture and Technology, 3-5-8 Saiwaicho, Fuchu, Tokyo, 183-8509 Japan
| | - Christian Hofmann
- Department of Plant Physiology, University of Bayreuth, Universitätsstrasse 30, D-95440 Bayreuth, Germany
| | - Natalia Hess
- Department of Plant Physiology, University of Bayreuth, Universitätsstrasse 30, D-95440 Bayreuth, Germany
| | - Ryosuke Nakamura
- Department of Public Health, School of Pharmacy, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo, 108-8641 Japan
| | - Yasukazu Takanezawa
- Department of Public Health, School of Pharmacy, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo, 108-8641 Japan
| | - Stephan Clemens
- Department of Plant Physiology, University of Bayreuth, Universitätsstrasse 30, D-95440 Bayreuth, Germany
| | - Masako Kiyono
- Department of Public Health, School of Pharmacy, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo, 108-8641 Japan
| |
Collapse
|
36
|
Uraguchi S, Tanaka N, Hofmann C, Abiko K, Ohkama-Ohtsu N, Weber M, Kamiya T, Sone Y, Nakamura R, Takanezawa Y, Kiyono M, Fujiwara T, Clemens S. Phytochelatin Synthase has Contrasting Effects on Cadmium and Arsenic Accumulation in Rice Grains. PLANT & CELL PHYSIOLOGY 2017; 58:1730-1742. [PMID: 29016913 PMCID: PMC5914395 DOI: 10.1093/pcp/pcx114] [Citation(s) in RCA: 58] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2017] [Accepted: 08/03/2017] [Indexed: 05/18/2023]
Abstract
Phytochelatin (PC) synthesis has been well demonstrated as a major metal tolerance mechanism in Arabidopsis thaliana, whereas its contribution to long-distance element transport especially in monocots remains elusive. Using rice as a cereal model, we examined physiological roles of Oryza sativa phytochelatin synthase 1 (OsPCS1) in the distribution and detoxification of arsenic (As) and cadmium (Cd), two toxic elements associated with major food safety concerns. First, we isolated four different transcript variants of OsPCS1 as well as one from OsPCS2. Quantitative real-time reverse transcription-PCR (RT-PCR) of each OsPCS transcript in rice seedlings suggested that expression of OsPCS1full, the longest OsPCS1 variant, was most abundant, followed by OsPCS2. Heterologous expression of OsPCS variants in PCS-deficient mutants of Schizosaccharomyces pombe and A. thaliana suggested that OsPCS1full possessed PCS activity in response to As(III) and Cd while the activity of other PCS variants was very low. To address physiological functions in toxic element tolerance and accumulation, two independent OsPCS1 mutant rice lines (a T-DNA and a Tos17 insertion line) were identified. The OsPCS1 mutants exhibited increased sensitivity to As(III) and Cd in hydroponic experiments, showing the importance of OsPCS1-dependent PC synthesis for rice As(III) and Cd tolerance. Elemental analyses of rice plants grown in soil with environmentally relevant As and Cd concentrations showed increased As accumulation and decreased Cd accumulation in grains of the T-DNA line. The Tos17 mutant also exhibited the reduced Cd accumulation phenotype. These contrasting effects on As and Cd distribution to grains suggest the existence of at least partially distinct PC-dependent pathways for As and Cd.
Collapse
Affiliation(s)
- Shimpei Uraguchi
- Department of Public Health, School of Pharmacy, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo 108-8641, Japan
- Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan
- Department of Plant Physiology, University of Bayreuth, Universitätsstrasse 30, D-95440 Bayreuth, Germany
| | - Nobuhiro Tanaka
- Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Christian Hofmann
- Department of Plant Physiology, University of Bayreuth, Universitätsstrasse 30, D-95440 Bayreuth, Germany
| | - Kaho Abiko
- Department of Public Health, School of Pharmacy, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo 108-8641, Japan
| | - Naoko Ohkama-Ohtsu
- Institute of Agricultural Science, Tokyo University of Agriculture and Technology, 3-5-8 Saiwaicho, Fuchu, Tokyo 183-8509, Japan
| | - Michael Weber
- Department of Plant Physiology, University of Bayreuth, Universitätsstrasse 30, D-95440 Bayreuth, Germany
| | - Takehiro Kamiya
- Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Yuka Sone
- Department of Public Health, School of Pharmacy, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo 108-8641, Japan
| | - Ryosuke Nakamura
- Department of Public Health, School of Pharmacy, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo 108-8641, Japan
| | - Yasukazu Takanezawa
- Department of Public Health, School of Pharmacy, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo 108-8641, Japan
| | - Masako Kiyono
- Department of Public Health, School of Pharmacy, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo 108-8641, Japan
| | - Toru Fujiwara
- Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Stephan Clemens
- Department of Plant Physiology, University of Bayreuth, Universitätsstrasse 30, D-95440 Bayreuth, Germany
- Corresponding author: E-mail, ; Fax, +49-921-552642
| |
Collapse
|
37
|
Application of selective extraction and reverse phase chromatography with three detectors – PAD, FLD and ESI MS for characterization of platinum metabolites and identification of phytochelatins in Sinapis alba L. tissues. Microchem J 2017. [DOI: 10.1016/j.microc.2017.01.025] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
|
38
|
Phytochelatin 2 accumulates in roots of the seagrass Enhalus acoroides collected from sediment highly contaminated with lead. Biometals 2017; 30:249-260. [DOI: 10.1007/s10534-017-9998-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2016] [Accepted: 02/02/2017] [Indexed: 11/25/2022]
|
39
|
Kühnlenz T, Hofmann C, Uraguchi S, Schmidt H, Schempp S, Weber M, Lahner B, Salt DE, Clemens S. Phytochelatin Synthesis Promotes Leaf Zn Accumulation of Arabidopsis thaliana Plants Grown in Soil with Adequate Zn Supply and is Essential for Survival on Zn-Contaminated Soil. PLANT & CELL PHYSIOLOGY 2016; 57:2342-2352. [PMID: 27694524 DOI: 10.1093/pcp/pcw148] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2016] [Accepted: 08/10/2016] [Indexed: 06/06/2023]
Abstract
Phytochelatin (PC) synthesis is essential for the detoxification of non-essential metals such as cadmium (Cd). In vitro experiments with Arabidopsis thaliana seedlings had indicated a contribution to zinc (Zn) tolerance as well. We addressed the physiological role of PC synthesis in Zn homeostasis of plants under more natural conditions. Growth responses, PC accumulation and leaf ionomes of wild-type and AtPCS1 mutant plants cultivated in different soils representing adequate Zn supply, Zn deficiency and Zn excess were analyzed. Growth on Zn-contaminated soil triggers PC synthesis and is strongly impaired in PC-deficient mutants. In fact, the contribution of AtPCS1 to tolerating Zn excess is comparable with that of the major Zn tolerance factor MTP1. For plants supplied with a normal level of Zn, a significant reduction in leaf Zn accumulation of AtPCS1 mutants was detected. In contrast, AtPCS1 mutants grown under Zn-limited conditions showed wild-type levels of Zn accumulation, suggesting the operation of distinct Zn translocation pathways. Contrasting phenotypes of the tested AtPCS1 mutant alleles upon growth in Zn- or Cd-contaminated soil indicated differential activation of PC synthesis by these metals. Experiments with truncated versions identified a part of the AtPCS1 protein required for the activation by Zn but not by Cd.
Collapse
Affiliation(s)
- Tanja Kühnlenz
- Department of Plant Physiology, University of Bayreuth, Universitätsstrasse 30, D-95440 Bayreuth, Germany
| | - Christian Hofmann
- Department of Plant Physiology, University of Bayreuth, Universitätsstrasse 30, D-95440 Bayreuth, Germany
| | - Shimpei Uraguchi
- Department of Plant Physiology, University of Bayreuth, Universitätsstrasse 30, D-95440 Bayreuth, Germany
- Present address: Department of Public Health, School of Pharmacy, Kitasato University, Tokyo, Japan
| | - Holger Schmidt
- Department of Plant Physiology, University of Bayreuth, Universitätsstrasse 30, D-95440 Bayreuth, Germany
| | - Stefanie Schempp
- Department of Plant Physiology, University of Bayreuth, Universitätsstrasse 30, D-95440 Bayreuth, Germany
| | - Michael Weber
- Department of Plant Physiology, University of Bayreuth, Universitätsstrasse 30, D-95440 Bayreuth, Germany
| | - Brett Lahner
- Purdue University, Horticulture and Landscape Architecture, West Lafayette, IN, USA
| | - David E Salt
- Purdue University, Horticulture and Landscape Architecture, West Lafayette, IN, USA
- Institute of Biological and Environmental Sciences, University of Aberdeen, Aberdeen, UK
| | - Stephan Clemens
- Department of Plant Physiology, University of Bayreuth, Universitätsstrasse 30, D-95440 Bayreuth, Germany stephan.clemens@uni-bayreuth
| |
Collapse
|
40
|
Kader M, Lamb DT, Mahbub KR, Megharaj M, Naidu R. Predicting plant uptake and toxicity of lead (Pb) in long-term contaminated soils from derived transfer functions. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2016; 23:15460-15470. [PMID: 27117154 DOI: 10.1007/s11356-016-6696-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/12/2016] [Accepted: 04/12/2016] [Indexed: 06/05/2023]
Abstract
Regulatory assessment of lead (Pb) in contaminated soils is still expressed primarily as total Pb concentrations in soil. In this study, we estimated effective concentrations (ECx) of Pb to Cucumis sativa L. (cucumber) focusing primarily on pore-water Pb data from 10 different soils after 12 weeks ageing. Phytotoxicity expressed in terms of Pb(2+) was observed to occur in the nanomolar range in neutral to alkaline soils (EC50 values 90 to 853 nM) and micromolar levels for acidic soils (EC50 values 7.35 to 9.66 μM). Internal Pb concentrations relating to toxicity (PT50) in roots and shoots also decreased with increasing pore-water pH (R (2) = 0.52 to 0.53). From a series of dose-response studies, we developed transfer functions predicting Pb uptake in C. sativa and we validated these functions with long-term Pb contaminated soils. The significant independent parameters were pore-water Pb(2+) and dissolved Pb plus dissolved organic carbon (DOC). The observed RMSE for the Pb-DOC model and Pb(2+) were 2.6 and 8.8, respectively. The Pb-DOC model tended to under-predict Pb, whilst Pb(2+) tended to over-predict accumulation despite reasonable RMSE values. Further validation is needed in soils with higher pore-water Pb solubility.
Collapse
Affiliation(s)
- Mohammed Kader
- Global Centre for Environmental Remediation (GCER), The University of Newcastle (UoN), Callaghan, NSW, 2308, Australia.
- Cooperative Research Centre for Contamination Assessment and Remediation of the Environment (CRC CARE), Advanced Technology Building, Callaghan, NSW, 2308, Australia.
| | - Dane T Lamb
- Global Centre for Environmental Remediation (GCER), The University of Newcastle (UoN), Callaghan, NSW, 2308, Australia
- Cooperative Research Centre for Contamination Assessment and Remediation of the Environment (CRC CARE), Advanced Technology Building, Callaghan, NSW, 2308, Australia
| | - Khandaker Rayhan Mahbub
- Global Centre for Environmental Remediation (GCER), The University of Newcastle (UoN), Callaghan, NSW, 2308, Australia
- Cooperative Research Centre for Contamination Assessment and Remediation of the Environment (CRC CARE), Advanced Technology Building, Callaghan, NSW, 2308, Australia
| | - Mallavarapu Megharaj
- Global Centre for Environmental Remediation (GCER), The University of Newcastle (UoN), Callaghan, NSW, 2308, Australia
- Cooperative Research Centre for Contamination Assessment and Remediation of the Environment (CRC CARE), Advanced Technology Building, Callaghan, NSW, 2308, Australia
| | - Ravi Naidu
- Global Centre for Environmental Remediation (GCER), The University of Newcastle (UoN), Callaghan, NSW, 2308, Australia
- Cooperative Research Centre for Contamination Assessment and Remediation of the Environment (CRC CARE), Advanced Technology Building, Callaghan, NSW, 2308, Australia
| |
Collapse
|
41
|
Clemens S, Ma JF. Toxic Heavy Metal and Metalloid Accumulation in Crop Plants and Foods. ANNUAL REVIEW OF PLANT BIOLOGY 2016; 67:489-512. [PMID: 27128467 DOI: 10.1146/annurev-arplant-043015-112301] [Citation(s) in RCA: 519] [Impact Index Per Article: 64.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Arsenic, cadmium, lead, and mercury are toxic elements that are almost ubiquitously present at low levels in the environment because of anthropogenic influences. Dietary intake of plant-derived food represents a major fraction of potentially health-threatening human exposure, especially to arsenic and cadmium. In the interest of better food safety, it is important to reduce toxic element accumulation in crops. A molecular understanding of the pathways responsible for this accumulation can enable the development of crop varieties with strongly reduced concentrations of toxic elements in their edible parts. Such understanding is rapidly progressing for arsenic and cadmium but is in its infancy for lead and mercury. Basic discoveries have been made in Arabidopsis, rice, and other models, and most advances in crops have been made in rice. Proteins mediating the uptake of arsenic and cadmium have been identified, and the speciation and biotransformations of arsenic are now understood. Factors controlling the efficiency of root-to-shoot translocation and the partitioning of toxic elements through the rice node have also been identified.
Collapse
Affiliation(s)
- Stephan Clemens
- Department of Plant Physiology, University of Bayreuth, 95440 Bayreuth, Germany;
| | - Jian Feng Ma
- Institute of Plant Science and Resources, Okayama University, Kurashiki 710-0046, Japan;
| |
Collapse
|
42
|
Kühnlenz T, Westphal L, Schmidt H, Scheel D, Clemens S. Expression of Caenorhabditis elegans PCS in the AtPCS1-deficient Arabidopsis thaliana cad1-3 mutant separates the metal tolerance and non-host resistance functions of phytochelatin synthases. PLANT, CELL & ENVIRONMENT 2015; 38:2239-47. [PMID: 25764348 DOI: 10.1111/pce.12534] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2015] [Revised: 02/19/2015] [Accepted: 03/06/2015] [Indexed: 05/22/2023]
Abstract
Phytochelatin synthases (PCS) play key roles in plant metal tolerance. They synthesize small metal-binding peptides, phytochelatins, under conditions of metal excess. Respective mutants are strongly cadmium and arsenic hypersensitive. However, their ubiquitous presence and constitutive expression had long suggested a more general function of PCS besides metal detoxification. Indeed, phytochelatin synthase1 from Arabidopsis thaliana (AtPCS1) was later implicated in non-host resistance. The two different physiological functions may be attributable to the two distinct catalytic activities demonstrated for AtPCS1, that is the dipeptidyl transfer onto an acceptor molecule in phytochelatin synthesis, and the proteolytic deglycylation of glutathione conjugates. In order to test this hypothesis and to possibly separate the two biological roles, we expressed a phylogenetically distant PCS from Caenorhabditis elegans in an AtPCS1 mutant. We confirmed the involvement of AtPCS1 in non-host resistance by showing that plants lacking the functional gene develop a strong cell death phenotype when inoculated with the potato pathogen Phytophthora infestans. Furthermore, we found that the C. elegans gene rescues phytochelatin synthesis and cadmium tolerance, but not the defect in non-host resistance. This strongly suggests that the second enzymatic function of AtPCS1, which remains to be defined in detail, is underlying the plant immunity function.
Collapse
Affiliation(s)
- Tanja Kühnlenz
- Department of Plant Physiology, University of Bayreuth, Universitätsstrasse 30, Bayreuth, 95440, Germany
| | - Lore Westphal
- Department of Stress and Developmental Biology, Leibniz Institute of Plant Biochemistry, Weinberg 3, Halle, 06120, Germany
| | - Holger Schmidt
- Department of Plant Physiology, University of Bayreuth, Universitätsstrasse 30, Bayreuth, 95440, Germany
| | - Dierk Scheel
- Department of Stress and Developmental Biology, Leibniz Institute of Plant Biochemistry, Weinberg 3, Halle, 06120, Germany
| | - Stephan Clemens
- Department of Plant Physiology, University of Bayreuth, Universitätsstrasse 30, Bayreuth, 95440, Germany
| |
Collapse
|