Molecular mechanisms of plant metal tolerance and homeostasis

Clemens, Stephan

doi:10.1007/s004250000458

Cited by 1,227 publications

(749 citation statements)

References 128 publications

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“…It is highly toxic and is readily taken up by plants, and so its accumulation in the food chain may pose serious threats to human health (Buchet et al, 1990). Cadmium accumulation in plants affects general root and shoot growth: it causes a reduction in photosynthesis, diminishes water and nutrient uptake (Sanità di Toppi & Gabrielli, 1999) and inhibits enzyme activities with subsequent disruption to cell transport processes and disturbance of cellular redox control (Clemens, 2001;Schützendübel & Polle, 2002). However, a number of plants, endemic to metal-rich soils, have evolved naturally selected metal hypertolerance, and can thrive in soil contaminated by metals.…”

Section: Introductionmentioning

confidence: 99%

The Brassica juncea BjCdR15, an ortholog of Arabidopsis TGA3, is a regulator of cadmium uptake, transport and accumulation in shoots and confers cadmium tolerance in transgenic plants

et al. 2009

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Summary• A bZIP transcription factor from Brassica juncea (BjCdR15) was isolated by the cDNA-amplified fragment length polymorphism technique after cadmium treatment. Sequence analysis indicated high similarity between BjCdR15 and Arabidopsis TGA3. In Arabidopsis, TGA3 transcription is also induced by cadmium; hence, we investigated whether BjCdR15 is involved in cadmium tolerance and whether it can functionally replace TGA3 protein in Arabidopsis tga3-2 mutant plants.• BjCdR15 expression was detected mainly in the epidermis and vascular system of cadmium-treated plants, and increased in roots and leaves after cadmium treatment. The overexpression of BjCdR15 in Arabidopsis and tobacco enhanced cadmium tolerance: overexpressing plants showed high cadmium accumulation in shoots. Conversely, Arabidopsis tga3-2 mutant plants showed high cadmium content in roots and inhibition of its transport to the shoot.• We demonstrated that BjCdR15 can functionally replace TGA3: in 35S:: BjCdR15-tga3-2 plants, the long-distance transport of cadmium from root to shoot was restored and these plants showed an increased cadmium content in shoots compared with all other assays. In addition, BjCdR15 ⁄ TGA3 regulated the synthesis of phytochelatin synthase and the expression of several metal transporters.• The results indicate that BjCdR15 ⁄ TGA3 transcription factors play a crucial role in the regulation of cadmium uptake by roots and in its long-distance root to shoot transport. BjCdR15 ⁄ TGA3 may thus be considered as useful candidates for potential biotechnological applications in the phytoextraction of cadmium from polluted soils.

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Section: Introductionmentioning

confidence: 99%

The Brassica juncea BjCdR15, an ortholog of Arabidopsis TGA3, is a regulator of cadmium uptake, transport and accumulation in shoots and confers cadmium tolerance in transgenic plants

et al. 2009

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“…The toxicity of Cd 2+ is due to its high reactivity with sulfhydryl groups, which leads to an inactivation of enzymes, and its interaction with binding sites of micronutrients, where Cd 2+ may displace e.g. Zn 2+ [3,4]. Living organisms, from bacteria to men, have evolved mechanisms enabling them to at least partially cope with Cd 2+ toxicity that was taken up.…”

Section: Introductionmentioning

confidence: 99%

Quantitative detection of changes in the leaf‐mesophyll tonoplast proteome in dependency of a cadmium exposure of barley (Hordeum vulgare L.) plants

et al. 2009

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Although the vacuole is the most important final store for toxic heavy metals like cadmium (Cd(2+)), our knowledge on how they are transported into the vacuole is still insufficient. It has been suggested that Cd(2+) can be transported as phytochelatin-Cd(2+) by an unknown ABC transporter or in exchange with protons by cation/proton exchanger (CAX) transporters. To unravel the contribution of vacuolar transporters to Cd(2+) detoxification, a quantitative proteomics approach was performed. Highly purified vacuoles were isolated from barley plants grown under minus, low (20 microM), and high (200 microM) Cd(2+ )conditions and protein levels of the obtained tonoplast samples were analyzed using isobaric tag for relative and absolute quantitation (iTRAQ). Although 56 vacuolar transporter proteins were identified, only a few were differentially expressed. Under low-Cd(2+) conditions, an inorganic pyrophosphatase and a gamma-tonoplast intrinsic protein (gamma-TIP) were up-regulated, indicating changes in energization and water fluxes. In addition, the protein ratio of a CAX1a and a natural resistance-associated macrophage protein (NRAMP), responsible for vacuolar Fe(2+) export was increased. CAX1a might play a role in vacuolar Cd(2+) transport. An increase in NRAMP activity leads to a higher cytosolic Fe(2+) concentration, which may prevent the exchange of Fe(2+) by toxic Cd(2+). Additionally, an ABC transporter homolog to AtMRP3 showed up-regulation. Under high Cd(2+) conditions, the plant response was more specific. Only a protein homologous to AtMRP3 that showed already a response under low Cd(2+) conditions, was up-regulated. Interestingly, AtMRP3 is able to partially rescue a Cd(2+)-sensitive yeast mutant. The identified transporters are good candidates for further investigation of their roles in Cd(2+) detoxification. AbstractAlthough the vacuole is the most important final store for toxic heavy metals like cadmium (Cd 2+ ), our knowledge on how they are transported into the vacuole is still scarce. It has been suggested that Cd 2+ can be transported either as phytochelatin-Cd 2+ by an unknown ABC transporter or in exchange with protons by CAX transporters. To unravel the contribution of vacuolar transporters to Cd 2+ detoxification, a quantitative proteomics approach was performed.Highly purified vacuoles were isolated from barley plants grown under minus, low (20 µM), and high (200 µM) Cd 2+ conditions and protein levels of the obtained tonoplast samples were analyzed using iTRAQ TM . Although, 56 vacuolar transporter proteins were identified, however only a few were differentially expressed. Under low-Cd 2+ conditions an inorganic pyrophosphatase and a γ-tonoplast intrinsic protein (γ-TIP) were upregulated, indicating changes in energization and water fluxes. In addition, the protein ratio of a calcium/proton exchanger (CAX1a) and an NRAMP, responsible for vacuolar Fe 2+ export were increased. CAX1a might play a role in vacuolar Cd 2+ transport. An increase in NRAMP activity leads to a higher cytosol...

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“…In response, the concept of phytoremediation has evoked considerable interest in studies on plant metal accumulation (1). Although there has been recent progress in molecular understanding of plant metal homeostasis (2), the mechanisms at the organismal level, such as the control of metal translocation from roots to shoots, remain to be identified.…”

Section: Introductionmentioning

confidence: 99%

Fractionation Mechanisms of Rare Earth Elements (REEs) in Hydroponic Wheat: An Application for Metal Accumulation by Plants

Ding

Liang

Zhang

et al. 2006

Environ. Sci. Technol.

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Fractionations of rare earth elements (REEs) in wheat (Triticum aestivum L.) were observed through application of exogenous mixed REEs under hydroponic conditions. Middle REE (MREE), light REE (LREE), and heavy REE (HREE) enrichments were found in roots, stems, and leaves, respectively, accompanied by the tetrad effect (an effect that can cause a split of REE patterns into four consecutive segments) in these organs. Investigations into REE speciation in roots and in the xylem sap with X-ray absorption spectroscopy (XAS) and nanometer-sized TiO 2 adsorption techniques, associated with other controlled experiments, demonstrated that REE fractionations in wheat were caused by the combined effects of chemical precipitation, cell wall absorption, and solution complexation by organic ligands in the xylem vessels. REE fractionations in wheat, which were derived from the small differences of chemical properties across REE series, may reflect a sensitive internal chemical environment that influences plant accumulation for REEs and their analogues actinide radionuclides.

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Molecular mechanisms of plant metal tolerance and homeostasis

Cited by 1,227 publications

References 128 publications

The Brassica juncea BjCdR15, an ortholog of Arabidopsis TGA3, is a regulator of cadmium uptake, transport and accumulation in shoots and confers cadmium tolerance in transgenic plants

The Brassica juncea BjCdR15, an ortholog of Arabidopsis TGA3, is a regulator of cadmium uptake, transport and accumulation in shoots and confers cadmium tolerance in transgenic plants

Quantitative detection of changes in the leaf‐mesophyll tonoplast proteome in dependency of a cadmium exposure of barley (Hordeum vulgare L.) plants

Fractionation Mechanisms of Rare Earth Elements (REEs) in Hydroponic Wheat: An Application for Metal Accumulation by Plants

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