Are Phytochelatins Involved in Differential Metal Tolerance or Do They Merely Reflect Metal-Imposed Strain?

Schat, Henk; Kalff, Mechteld M. A.

doi:10.1104/pp.99.4.1475

Cited by 142 publications

(56 citation statements)

References 20 publications

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“…Three protocols of root washing were tested to study their impact on the Cu content in plants treated with 2.5 mM Cu 2þ for 7 days (Table IS). The Cu contents after root washing with Pb(NO 3 ) 2 , which is a way to remove extra-cellular copper [12,63,69], were statistically similar to those washed with water. Cell viability assay was performed as described by Ma et al [36].…”

Section: Mineral Analysismentioning

confidence: 61%

Response to copper excess in Arabidopsis thaliana: Impact on the root system architecture, hormone distribution, lignin accumulation and mineral profile

Lequeux

Hermans

Lutts

et al. 2010

Plant Physiology and Biochemistry

343

196

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Section: Mineral Analysismentioning

confidence: 61%

Response to copper excess in Arabidopsis thaliana: Impact on the root system architecture, hormone distribution, lignin accumulation and mineral profile

Lequeux

Hermans

Lutts

et al. 2010

Plant Physiology and Biochemistry

343

196

View full text Add to dashboard Cite

“…Cu and Cd, linear relationships between degrees of toxicity, measured as growth inhibition, have been found in S. vulgaris, Zea mays and Triticum aestivum (Schat & Kalff, 1992 ; De Knecht et al, 1995 ;Keltjens & Van Beusichem, 1998, Sneller et al, 1999. Therefore PCs may be used as a biomarker of heavy metal toxicity.…”

Section: mentioning

confidence: 99%

Toxicity of arsenate in Silene vulgaris, accumulation and degradation of arsenate‐induced phytochelatins

et al. 1999

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The results presented in this paper describe the short-and long-term toxicity of arsenate in Silene vulgaris. Shortterm toxicity, measured as inhibition of root elongation, depended on phosphate nutrition, arsenate being much less toxic at high phosphate supply. At low phosphate levels more arsenic was taken up by the plants. Under chronic exposure, toxicity (measured as inhibition of biomass production) did not increase with time. In addition, the accumulation of phytochelatins (PCs) as a function of toxicity and duration of exposure was studied. Shortterm PC accumulation (over a 3 d period) was positively correlated with exposure. Isolation of peptide complexes from prolongedly exposed plants showed that PC # , PC $ and PC % were present, although the latter not until at least 3 d exposure. Arsenic co-eluted mainly with PC # and PC $ . Fractions containing PC % were devoid of As, probably due to dissociation of the complexes during extraction or elution. The breakdown of PCs after arresting As exposure was very slow. This could explain the continuous accumulation of PCs throughout longer periods of As exposure.Key words : Silene vulgaris, arsenic toxicity, arsenic detoxification, phytochelatins. Arsenic is taken up mainly by plant roots as arsenate (AsO % $−) (Macnair & Cumbes, 1987) through the phosphate-uptake system (Asher & Reay, 1979). Once the arsenate, As(V), is taken up it is reduced to arsenite, As(III), by glutathione (GSH) (Thompson, 1993). Only in phosphate-deficient conditions is arsenate subsequently methylated in plants (Nissen & Benson, 1982). Between the successive methylation steps, GSH serves to reduce the intermediate products (Scott et al., 1993 ;Thompson, 1993). Arsoniumphospholipids in freshwater plants (Nissen & Benson, 1982) and arsenic sugars in marine brown algae (Edmonds & Francesconi, 1981) have also been identified.Mostly there is little transport of As to the aboveground parts of the plants. Dicotyledonous plants appear to transport more As to the shoots than monocotyledonous plants (Otte, 1991). The form in *Author for correspondence (fax j31 20 444 7123 ; e-mail elsesnel!bio.vu.nl). which the As is transported is unknown. There is some indication that dimethylarsenic acid is transported to the shoots (Marin et al., 1993).Increased As levels may cause toxic symptoms in plants, such as a decrease in plant growth and fruit yield (Carbonell-Barrachina et al., 1995), root discoloration and root plasmolysis, wilting and necrosis of leaf tips and leaf margins (Machlis, 1941), and a decrease in photosynthetic capacity (Marin et al., 1993).Some authors have reported the accumulation of heavy metal-binding, thiol-rich phytochelatins (PCs) on exposure to As (Grill et al., 1986a(Grill et al., ,b, 1987Maitani et al., 1996). Phytochelatins have the structure (γ-glu-cys) n -gly, where n l 2-11 (Grill et al., 1985), and are produced in plants on exposure to a variety of heavy metals and metalloids (Gekeler et al., 1989). Phytochelatins are synthesized from GSH (Hayashi et ...

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“…109, 1995 of PCs than nontolerant ecotypes (Verkleij and Schat, 1989;Verkleij et al, 1990). Instead, PCs have been shown to accumulate to higher levels in nontolerant ecotypes than in tolerant ecotypes, presumably because of a higher concentration of free metal ions in the cytosol of the former than in the latter (Schat and Kalff, 1992).…”

mentioning

confidence: 99%

Comparison of Metallothionein Gene Expression and Nonprotein Thiols in Ten Arabidopsis Ecotypes (Correlation with Copper Tolerance)

1995

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Seedlings of 1 O Arabidopsis ecotypes were compared with respect to copper tolerance, expression of two metallothionein genes (MT1 and MT2), and nonprotein thiol levels. MT1 was uniformly expressed in all treatments, and MT2 was copper inducible in all 10 ecotypes. MT1 and MT2 mRNA levels were compared with various growth parameters for the 10 ecotypes in the presence of 40 /LM Cuz+. l h e best correlation ( R = 0.99) was obtained between MT2 mRNA and the rate of root extension. MT2 mRNA levels ako paralleled the recovery phase following inhibition by copper. Induction of MT2 mRNA was initiated at copper concentrations below the threshold for growth inhibition. In cross-induction experiments, Ag+, Cd2+, Zn2+, Ni2+, and heat shock all induced significant levels of MT2 gene expression, whereas AI3+ and salicylic acid did not. The correlation between copper tolerance and nonprotein thiol levels in the 10 ecotypes was not statistically significant. However, 2 ecotypes, Ws and Enkheim, previously shown to exhibit an acclimation response, had the highest levels of nonprotein thiols. We conclude that MT2 gene expression may be the primary determinant of ecotypic differences in the copper tolerance of nonpretreated Arabidopsis seedlings.

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Are Phytochelatins Involved in Differential Metal Tolerance or Do They Merely Reflect Metal-Imposed Strain?

Cited by 142 publications

References 20 publications

Response to copper excess in Arabidopsis thaliana: Impact on the root system architecture, hormone distribution, lignin accumulation and mineral profile

Response to copper excess in Arabidopsis thaliana: Impact on the root system architecture, hormone distribution, lignin accumulation and mineral profile

Toxicity of arsenate in Silene vulgaris, accumulation and degradation of arsenate‐induced phytochelatins

Comparison of Metallothionein Gene Expression and Nonprotein Thiols in Ten Arabidopsis Ecotypes (Correlation with Copper Tolerance)

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