Diversity, structure and regulation of microbial metallothionein: metal resistance and possible applications in sequestration of toxic metals

Chatterjee, Suman; Kumari, Supriya; Rath, Sonalin; Priyadarshanee, Monika; Das, Surajit

doi:10.1039/d0mt00140f

Cited by 56 publications

(27 citation statements)

References 180 publications

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“…In A. nidulans , little is known on metallothioneins (Cys-moiety rich, low molecular weight proteins); however, they can be potentially important to detoxify heavy metals including cadmium [ 46 , 49 ]. Out of the genes encoding proteins with more than 10% Cys content, only two genes (AN7290 and AN11757) showed up-regulation ( Table S5 ).…”

Section: Resultsmentioning

confidence: 99%

AtfA-Independent Adaptation to the Toxic Heavy Metal Cadmium in Aspergillus nidulans

et al. 2021

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Cadmium is an exceptionally toxic industrial and environmental pollutant classified as a human carcinogen. In order to provide insight into how we can keep our environment safe from cadmium contamination and prevent the accumulation of it in the food chain, we aim to elucidate how Aspergillus nidulans, one of the most abundant fungi in soil, survives and handles cadmium stress. As AtfA is the main transcription factor governing stress responses in A. nidulans, we examined genome-wide expression responses of wild-type and the atfA null mutant exposed to CdCl2. Both strains showed up-regulation of the crpA Cu2+/Cd2+ pump gene and AN7729 predicted to encode a putative bis(glutathionato)-cadmium transporter, and transcriptional changes associated with elevated intracellular Cys availability leading to the efficient adaptation to Cd2+. Although the deletion of atfA did not alter the cadmium tolerance of the fungus, the cadmium stress response of the mutant differed from that of a reference strain. Promoter and transcriptional analyses of the “Phospho-relay response regulator” genes suggest that the AtfA-dependent regulation of these genes can be relevant in this phenomenon. We concluded that the regulatory network of A. nidulans has a high flexibility allowing the fungus to adapt efficiently to stress both in the presence and absence of this important transcription factor.

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Section: Resultsmentioning

confidence: 99%

AtfA-Independent Adaptation to the Toxic Heavy Metal Cadmium in Aspergillus nidulans

et al. 2021

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“…We demonstrated plasmid-overexpression of CRS5 increased cadmium tolerance in S. cerevisiae for the first time (Figures 2B,C). CRS5 and CUP1 both encode MT in S. cerevisiae (Chatterjee et al, 2020), and Crs5p possesses a Cd(II)-binding ability (Pagani et al, 2007) (Supplementary Table 5). Gene deletion of crs5 did not lead to cadmium sensitivity (Culotta et al, 1994).…”

Section: Discussionmentioning

confidence: 99%

Genome-Scale Screening and Combinatorial Optimization of Gene Overexpression Targets to Improve Cadmium Tolerance in Saccharomyces cerevisiae

et al. 2021

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Heavy metal contamination is an environmental issue on a global scale. Particularly, cadmium poses substantial threats to crop and human health. Saccharomyces cerevisiae is one of the model organisms to study cadmium toxicity and was recently engineered as a cadmium hyperaccumulator. Therefore, it is desirable to overcome the cadmium sensitivity of S. cerevisiae via genetic engineering for bioremediation applications. Here we performed genome-scale overexpression screening for gene targets conferring cadmium resistance in CEN.PK2-1c, an industrial S. cerevisiae strain. Seven targets were identified, including CAD1 and CUP1 that are known to improve cadmium tolerance, as well as CRS5, NRG1, PPH21, BMH1, and QCR6 that are less studied. In the wild-type strain, cadmium exposure activated gene transcription of CAD1, CRS5, CUP1, and NRG1 and repressed PPH21, as revealed by real-time quantitative PCR analyses. Furthermore, yeast strains that contained two overexpression mutations out of the seven gene targets were constructed. Synergistic improvement in cadmium tolerance was observed with episomal co-expression of CRS5 and CUP1. In the presence of 200 μM cadmium, the most resistant strain overexpressing both CAD1 and NRG1 exhibited a 3.6-fold improvement in biomass accumulation relative to wild type. This work provided a new approach to discover and optimize genetic engineering targets for increasing cadmium resistance in yeast.

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“…Another class of secondary metabolites and chelating compounds involved in heavy metal detoxification are metallothioneins, which are produced by a wide range of organisms, including plants and bacteria. They are small cysteine-rich proteins, have a high metal-binding capacity and are, in fact, involved in metal detoxification and storage [ 168 ]. Metallothionein production is stimulated by heavy metals (e.g., Cd +2 , Zn +2 , Pb +2 , Cu, Cd); metallothioneins chelate hazardous metals and sequestrate them inside cells [ 168 , 169 ].…”

Section: Plant–bacteria Interactions In Rhizosphere and Defense From Heavy Metal Stressmentioning

confidence: 99%

“…They are small cysteine-rich proteins, have a high metal-binding capacity and are, in fact, involved in metal detoxification and storage [ 168 ]. Metallothionein production is stimulated by heavy metals (e.g., Cd +2 , Zn +2 , Pb +2 , Cu, Cd); metallothioneins chelate hazardous metals and sequestrate them inside cells [ 168 , 169 ]. In plants, metallothioneins are also involved in translocation and homeostasis of essential cations, such as Zn and Cu [ 169 ].…”

Section: Plant–bacteria Interactions In Rhizosphere and Defense From Heavy Metal Stressmentioning

confidence: 99%

Rhizosphere Microbial Communities and Heavy Metals

2021

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The rhizosphere is a microhabitat where there is an intense chemical dialogue between plants and microorganisms. The two coexist and develop synergistic actions, which can promote plants’ functions and productivity, but also their capacity to respond to stress conditions, including heavy metal (HM) contamination. If HMs are present in soils used for agriculture, there is a risk of metal uptake by edible plants with subsequent bioaccumulation in humans and animals and detrimental consequences for their health. Plant productivity can also be negatively affected. Many bacteria have defensive mechanisms for resisting heavy metals and, through various complex processes, can improve plant response to HM stress. Bacteria-plant synergic interactions in the rhizosphere, as a homeostatic ecosystem response to HM disturbance, are common in soil. However, this is hard to achieve in agroecosystems managed with traditional practices, because concentrating on maximizing crop yield does not make it possible to establish rhizosphere interactions. Improving knowledge of the complex interactions mediated by plant exudates and secondary metabolites can lead to nature-based solutions for plant health in HM contaminated soils. This paper reports the main ecotoxicological effects of HMs and the various compounds (including several secondary metabolites) produced by plant-microorganism holobionts for removing, immobilizing and containing toxic elements.

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Diversity, structure and regulation of microbial metallothionein: metal resistance and possible applications in sequestration of toxic metals

Abstract: Metallothioneins (MTs) are a group of cysteine-rich, universal, low molecular weight proteins distributed widely in almost all major taxonomic groups ranging from tiny microbes to highly organized vertebrates.

Cited by 56 publications

References 180 publications

AtfA-Independent Adaptation to the Toxic Heavy Metal Cadmium in Aspergillus nidulans

AtfA-Independent Adaptation to the Toxic Heavy Metal Cadmium in Aspergillus nidulans

Genome-Scale Screening and Combinatorial Optimization of Gene Overexpression Targets to Improve Cadmium Tolerance in Saccharomyces cerevisiae

Rhizosphere Microbial Communities and Heavy Metals

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