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Journal ArticleDOI

Phytoremediation and Microorganisms-Assisted Phytoremediation of Mercury-Contaminated Soils: Challenges and Perspectives.

TL;DR: In this paper, the potential use of transgenic plants in Hg-phytoremediation is discussed, and the beneficial interactions between plants and microorganisms (bacteria and fungi) that are Hg resistant and secrete plant growth promoting compounds are reviewed.
Abstract: Mercury (Hg) pollution is a global threat to human and environmental health because of its toxicity, mobility and long-term persistence. Although costly engineering-based technologies can be used to treat heavily Hg-contaminated areas, they are not suitable for decontaminating agricultural or extensively-polluted soils. Emerging phyto- and bioremediation strategies for decontaminating Hg-polluted soils generally involve low investment, simple operation, and in situ application, and they are less destructive for the ecosystem. Current understanding of the uptake, translocation and sequestration of Hg in plants is reviewed to highlight new avenues for exploration in phytoremediation research, and different phytoremediation strategies (phytostabilization, phytoextraction and phytovolatilization) are discussed. Research aimed at identifying suitable plant species and associated-microorganisms for use in phytoremediation of Hg-contaminated soils is also surveyed. Investigation into the potential use of transgenic plants in Hg-phytoremediation is described. Recent research on exploiting the beneficial interactions between plants and microorganisms (bacteria and fungi) that are Hg-resistant and secrete plant growth promoting compounds is reviewed. We highlight areas where more research is required into the effective use of phytoremediation on Hg-contaminated sites, and conclude that the approaches it offers provide considerable potential for the future.
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Journal ArticleDOI
01 Aug 2021
TL;DR: In this paper, the authors focus on the mechanisms of uptake, transport, and accumulation of common heavy metals such as mercury (Hg), lead (Pb), cadmium (Cd), chromium (Cr), zinc (Zn), copper (Cu) and Arsenic (As) in hyperaccumulator plants.
Abstract: Phytoremediation is an economically viable green technology that utilizes hyperaccumulator plants to remove heavy metals (HM) from the soil. Hyperaccumulators are adept at sequestering high concentrations of HM in aerial parts and intracellular detoxification of HM through cell wall binding, organic acids, chelation and sequestration. Excess HM activate oxidative stress defense mechanisms and initiate synthesis of stress-related proteins in plants. Plethora of studies have assessed the feasibility of phytoextraction and demonstrated that high biomass and metal hyperaccumulation are the two basic requirements for making the process efficient. However, biochemical pathways involved in HM uptake, translocation and sequestration in these plants are not fully understood. Thus, more fundamental understanding of the traits and mechanisms involved in hyperaccumulation is needed to optimize phytoextraction. In this review, we aim to focus on the mechanisms of uptake, transport, and accumulation of common HM such as mercury (Hg), lead (Pb), cadmium (Cd), chromium (Cr), zinc (Zn), copper (Cu) and Arsenic (As) in hyperaccumulator plants. We will also discuss prominent metallophytes and their phytoremediation strategies. This study will be helpful in understanding the pathways involved in the uptake and translocation of HM by hyperaccumulators. It would also assist in gaining knowledge about the adaptation strategy used by plants to achieve homeostasis.

41 citations

DOI
02 Nov 2021
TL;DR: The public and environmental health consequences of mercury methylation have drawn much attention and considerable research to Hg methylation processes and their dynamics in diverse environmen... as discussed by the authors,.
Abstract: The public and environmental health consequences of mercury (Hg) methylation have drawn much attention and considerable research to Hg methylation processes and their dynamics in diverse environmen...

31 citations

Journal ArticleDOI
TL;DR: In this paper, the thiol-functionalized expanded perlite (thiol-Exp-p) was employed in the self-cementation of the alkali-activated volcanic tuff (VT) as both lightweight aggregate and adsorbent to enhance the S/S of the Hg-contaminated soil.

20 citations

Journal ArticleDOI
TL;DR: In this paper , the thiol-functionalized expanded perlite (thiol-Exp-p) was employed in the self-cementation of the alkali-activated volcanic tuff (VT) as both lightweight aggregate and adsorbent to enhance the S/S of the Hg-contaminated soil.

19 citations

References
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Journal ArticleDOI
TL;DR: The Molecular Evolutionary Genetics Analysis (Mega) software implements many analytical methods and tools for phylogenomics and phylomedicine and has additionally been upgraded to use multiple computing cores for many molecular evolutionary analyses.
Abstract: The Molecular Evolutionary Genetics Analysis (Mega) software implements many analytical methods and tools for phylogenomics and phylomedicine. Here, we report a transformation of Mega to enable cross-platform use on Microsoft Windows and Linux operating systems. Mega X does not require virtualization or emulation software and provides a uniform user experience across platforms. Mega X has additionally been upgraded to use multiple computing cores for many molecular evolutionary analyses. Mega X is available in two interfaces (graphical and command line) and can be downloaded from www.megasoftware.net free of charge.

21,952 citations

Journal ArticleDOI
TL;DR: ITOL 3 is the first tool which supports direct visualization of the recently proposed phylogenetic placements format, and its account system has been redesigned to simplify the management of trees in user-defined workspaces and projects.
Abstract: Interactive Tree Of Life (http://itol.embl.de) is a web-based tool for the display, manipulation and annotation of phylogenetic trees. It is freely available and open to everyone. The current version was completely redesigned and rewritten, utilizing current web technologies for speedy and streamlined processing. Numerous new features were introduced and several new data types are now supported. Trees with up to 100,000 leaves can now be efficiently displayed. Full interactive control over precise positioning of various annotation features and an unlimited number of datasets allow the easy creation of complex tree visualizations. iTOL 3 is the first tool which supports direct visualization of the recently proposed phylogenetic placements format. Finally, iTOL's account system has been redesigned to simplify the management of trees in user-defined workspaces and projects, as it is heavily used and currently handles already more than 500,000 trees from more than 10,000 individual users.

4,190 citations

Journal ArticleDOI
TL;DR: A broad overview of the evidence for an involvement of each mechanism in heavy metal detoxification and tolerance is provided.
Abstract: Heavy metals such as Cu and Zn are essential for normal plant growth, although elevated concentrations of both essential and non-essential metals can result in growth inhibition and toxicity symptoms. Plants possess a range of potential cellular mechanisms that may be involved in the detoxification of heavy metals and thus tolerance to metal stress. These include roles for the following: for mycorrhiza and for binding to cell wall and extracellular exudates; for reduced uptake or efflux pumping of metals at the plasma membrane; for chelation of metals in the cytosol by peptides such as phytochelatins; for the repair of stress-damaged proteins; and for the compartmentation of metals in the vacuole by tonoplast-located transporters. This review provides a broad overview of the evidence for an involvement of each mechanism in heavy metal detoxification and tolerance.

2,751 citations

Journal ArticleDOI
11 Oct 2012
TL;DR: It is envisioned that in the not too distant future, plant growth-promoting bacteria (PGPB) will begin to replace the use of chemicals in agriculture, horticulture, silviculture, and environmental cleanup strategies.
Abstract: The worldwide increases in both environmental damage and human population pressure have the unfortunate consequence that global food production may soon become insufficient to feed all of the world's people. It is therefore essential that agricultural productivity be significantly increased within the next few decades. To this end, agricultural practice is moving toward a more sustainable and environmentally friendly approach. This includes both the increasing use of transgenic plants and plant growth-promoting bacteria as a part of mainstream agricultural practice. Here, a number of the mechanisms utilized by plant growth-promoting bacteria are discussed and considered. It is envisioned that in the not too distant future, plant growth-promoting bacteria (PGPB) will begin to replace the use of chemicals in agriculture, horticulture, silviculture, and environmental cleanup strategies. While there may not be one simple strategy that can effectively promote the growth of all plants under all conditions, some of the strategies that are discussed already show great promise.

2,094 citations

Journal ArticleDOI
TL;DR: The fact that bacteria use this phytohormone to interact with plants as part of their colonization strategy, including phyto-stimulation and circumvention of basal plant defense mechanisms, is highlighted.
Abstract: Diverse bacterial species possess the ability to produce the auxin phytohormone indole-3-acetic acid (IAA). Different biosynthesis pathways have been identified and redundancy for IAA biosynthesis is widespread among plant-associated bacteria. Interactions between IAA-producing bacteria and plants lead to diverse outcomes on the plant side, varying from pathogenesis to phytostimulation. Reviewing the role of bacterial IAA in different microorganism–plant interactions highlights the fact that bacteria use this phytohormone to interact with plants as part of their colonization strategy, including phytostimulation and circumvention of basal plant defense mechanisms. Moreover, several recent reports indicate that IAA can also be a signaling molecule in bacteria and therefore can have a direct effect on bacterial physiology. This review discusses past and recent data, and emerging views on IAA, a well-known phytohormone, as a microbial metabolic and signaling molecule.

1,583 citations