Limits...
Lead tolerance and accumulation in Hirschfeldia incana, a Mediterranean Brassicaceae from metalliferous mine spoils.

Auguy F, Fahr M, Moulin P, Brugel A, Laplaze L, Mzibri ME, Filali-Maltouf A, Doumas P, Smouni A - PLoS ONE (2013)

Bottom Line: The functional characterization of HiHMA4 and HiMT2a was achieved using Arabidopsis T-DNA insertional mutants.Pb content and primary root growth analysis confirmed the role of these two genes in Pb tolerance and accumulation.H. incana could be considered as a good experimental model to identify genes involved in lead tolerance and accumulation in plants.

View Article: PubMed Central - PubMed

Affiliation: Institut de Recherche pour le Développement, Unité Mixte de Recherche Diversité Adaptation et Développement des Plantes, Montpellier, France.

ABSTRACT
Lead is a heavy metal of particular concern with respect to environmental quality and health. The lack of plant species that accumulate and tolerate Pb is a limiting factor to understand the molecular mechanisms involved in Pb tolerance. In this study we identified Hirschfeldia incana, a Brassicaceae collected from metalliferous mine spoils in Morocco, as a Pb accumulator plant. H. incana exhibited high Pb accumulation in mine soils and in hydroponic cultures. Major Pb accumulation occurred in the roots and a part of Pb translocated from the roots to the shoots, even to the siliques. These findings demonstrated that H. incana is a Pb accumulator species. The expression of several candidate genes after Pb-exposure was measured by quantitative PCR and two of them, HiHMA4 and HiMT2a, coding respectively for a P1B-type ATPase and a metallothionein, were particularly induced by Pb-exposure in both roots and leaves. The functional characterization of HiHMA4 and HiMT2a was achieved using Arabidopsis T-DNA insertional mutants. Pb content and primary root growth analysis confirmed the role of these two genes in Pb tolerance and accumulation. H. incana could be considered as a good experimental model to identify genes involved in lead tolerance and accumulation in plants.

Show MeSH
Quantitative analysis of the expression levels of ATM3, CNGC1, GS2, HMA4, MRP3, MT2a and PCS1 genes.Expression profiles were obtained from (A) roots and (B) leaves of H. incana and A. thaliana, Pb-treated or not for 3 days. ATM3: ATP-binding cassette transporter of mitochondrial protein, CNGC1: cyclic nucleotide-gated channel, GS2: glutathione synthetase, HMA4: heavy metal ATPase, MRP3: multidrug resistance-associated protein, MT2a: metallothionein and PCS1: phytochelatin synthase. The tubulin gene was used as reference gene and the calibration was done against the roots or the leaves of plants cultivated without Pb. Data are expressed as relative expression level (treated/control ratio) and are the average (± SE) of three independent replicates composed by nine seedlings. * and **Significant difference of values at p<0.05 and p<0.01, respectively, by Student’s t-test in comparison between H. incana and A. thaliana. Dashed line indicates a fold change of 2.
© Copyright Policy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC3646990&req=5

pone-0061932-g005: Quantitative analysis of the expression levels of ATM3, CNGC1, GS2, HMA4, MRP3, MT2a and PCS1 genes.Expression profiles were obtained from (A) roots and (B) leaves of H. incana and A. thaliana, Pb-treated or not for 3 days. ATM3: ATP-binding cassette transporter of mitochondrial protein, CNGC1: cyclic nucleotide-gated channel, GS2: glutathione synthetase, HMA4: heavy metal ATPase, MRP3: multidrug resistance-associated protein, MT2a: metallothionein and PCS1: phytochelatin synthase. The tubulin gene was used as reference gene and the calibration was done against the roots or the leaves of plants cultivated without Pb. Data are expressed as relative expression level (treated/control ratio) and are the average (± SE) of three independent replicates composed by nine seedlings. * and **Significant difference of values at p<0.05 and p<0.01, respectively, by Student’s t-test in comparison between H. incana and A. thaliana. Dashed line indicates a fold change of 2.

Mentions: The expression profile of the selected genes in response to Pb treatment was determined in H. incana and in the non-tolerant A. thaliana (Figure 5). Seedlings previously grown on the standard medium were transferred to Pb medium (100 and 40 µM Pb(NO3)2 respectively for H. incana and A. thaliana) for a further 3 days. For the selected genes, basic gene expression levels were low in both plants and organs (data not shown). In roots of H. incana, an important increase of transcript levels (fold change >2) associated to Pb-treatment was observed for five out of the seven target genes studied: HiATM3, HiGS2, HiHMA4, HiMRP3 and HiMT2a but, among these, only ATM3, GS2 and HMA4 have a significant expression greater than that obtained in A. thaliana (Figure 5A). In leaves of H. incana, Pb treatment enhanced approximately by two-fold the expression of HiHMA4 and more than eight-fold the expression of HiMT2a (Figure 5B). The expression of these genes was not significantly increased in Pb-treated plants of A. thaliana. These two genes, HiHMA4 and HiMT2a, were particularly affected in both roots and leaves suggesting putative roles in lead tolerance and accumulation in H. incana.


Lead tolerance and accumulation in Hirschfeldia incana, a Mediterranean Brassicaceae from metalliferous mine spoils.

Auguy F, Fahr M, Moulin P, Brugel A, Laplaze L, Mzibri ME, Filali-Maltouf A, Doumas P, Smouni A - PLoS ONE (2013)

Quantitative analysis of the expression levels of ATM3, CNGC1, GS2, HMA4, MRP3, MT2a and PCS1 genes.Expression profiles were obtained from (A) roots and (B) leaves of H. incana and A. thaliana, Pb-treated or not for 3 days. ATM3: ATP-binding cassette transporter of mitochondrial protein, CNGC1: cyclic nucleotide-gated channel, GS2: glutathione synthetase, HMA4: heavy metal ATPase, MRP3: multidrug resistance-associated protein, MT2a: metallothionein and PCS1: phytochelatin synthase. The tubulin gene was used as reference gene and the calibration was done against the roots or the leaves of plants cultivated without Pb. Data are expressed as relative expression level (treated/control ratio) and are the average (± SE) of three independent replicates composed by nine seedlings. * and **Significant difference of values at p<0.05 and p<0.01, respectively, by Student’s t-test in comparison between H. incana and A. thaliana. Dashed line indicates a fold change of 2.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3646990&req=5

pone-0061932-g005: Quantitative analysis of the expression levels of ATM3, CNGC1, GS2, HMA4, MRP3, MT2a and PCS1 genes.Expression profiles were obtained from (A) roots and (B) leaves of H. incana and A. thaliana, Pb-treated or not for 3 days. ATM3: ATP-binding cassette transporter of mitochondrial protein, CNGC1: cyclic nucleotide-gated channel, GS2: glutathione synthetase, HMA4: heavy metal ATPase, MRP3: multidrug resistance-associated protein, MT2a: metallothionein and PCS1: phytochelatin synthase. The tubulin gene was used as reference gene and the calibration was done against the roots or the leaves of plants cultivated without Pb. Data are expressed as relative expression level (treated/control ratio) and are the average (± SE) of three independent replicates composed by nine seedlings. * and **Significant difference of values at p<0.05 and p<0.01, respectively, by Student’s t-test in comparison between H. incana and A. thaliana. Dashed line indicates a fold change of 2.
Mentions: The expression profile of the selected genes in response to Pb treatment was determined in H. incana and in the non-tolerant A. thaliana (Figure 5). Seedlings previously grown on the standard medium were transferred to Pb medium (100 and 40 µM Pb(NO3)2 respectively for H. incana and A. thaliana) for a further 3 days. For the selected genes, basic gene expression levels were low in both plants and organs (data not shown). In roots of H. incana, an important increase of transcript levels (fold change >2) associated to Pb-treatment was observed for five out of the seven target genes studied: HiATM3, HiGS2, HiHMA4, HiMRP3 and HiMT2a but, among these, only ATM3, GS2 and HMA4 have a significant expression greater than that obtained in A. thaliana (Figure 5A). In leaves of H. incana, Pb treatment enhanced approximately by two-fold the expression of HiHMA4 and more than eight-fold the expression of HiMT2a (Figure 5B). The expression of these genes was not significantly increased in Pb-treated plants of A. thaliana. These two genes, HiHMA4 and HiMT2a, were particularly affected in both roots and leaves suggesting putative roles in lead tolerance and accumulation in H. incana.

Bottom Line: The functional characterization of HiHMA4 and HiMT2a was achieved using Arabidopsis T-DNA insertional mutants.Pb content and primary root growth analysis confirmed the role of these two genes in Pb tolerance and accumulation.H. incana could be considered as a good experimental model to identify genes involved in lead tolerance and accumulation in plants.

View Article: PubMed Central - PubMed

Affiliation: Institut de Recherche pour le Développement, Unité Mixte de Recherche Diversité Adaptation et Développement des Plantes, Montpellier, France.

ABSTRACT
Lead is a heavy metal of particular concern with respect to environmental quality and health. The lack of plant species that accumulate and tolerate Pb is a limiting factor to understand the molecular mechanisms involved in Pb tolerance. In this study we identified Hirschfeldia incana, a Brassicaceae collected from metalliferous mine spoils in Morocco, as a Pb accumulator plant. H. incana exhibited high Pb accumulation in mine soils and in hydroponic cultures. Major Pb accumulation occurred in the roots and a part of Pb translocated from the roots to the shoots, even to the siliques. These findings demonstrated that H. incana is a Pb accumulator species. The expression of several candidate genes after Pb-exposure was measured by quantitative PCR and two of them, HiHMA4 and HiMT2a, coding respectively for a P1B-type ATPase and a metallothionein, were particularly induced by Pb-exposure in both roots and leaves. The functional characterization of HiHMA4 and HiMT2a was achieved using Arabidopsis T-DNA insertional mutants. Pb content and primary root growth analysis confirmed the role of these two genes in Pb tolerance and accumulation. H. incana could be considered as a good experimental model to identify genes involved in lead tolerance and accumulation in plants.

Show MeSH