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.

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Kinetic effect of lead exposure on lead accumulation in (A) shoots and (B) roots of H. incana.Seedlings were grown on hydroponic system and lead treatments were done after 2 weeks by adding 50, 100 and 300 µM Pb(NO3)2 in fresh medium. Data are the average (± SE) of three independent measurements.
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pone-0061932-g003: Kinetic effect of lead exposure on lead accumulation in (A) shoots and (B) roots of H. incana.Seedlings were grown on hydroponic system and lead treatments were done after 2 weeks by adding 50, 100 and 300 µM Pb(NO3)2 in fresh medium. Data are the average (± SE) of three independent measurements.

Mentions: A four-day kinetic study, in hydroponic conditions, was achieved to confirm the transport of lead from roots to shoots in H. incana (Figure 3). Three Pb concentrations were tested (50, 100 and 300 µM Pb(NO3)2). In the study period and with these concentrations of Pb, no visual damage could be observed neither in leaves and roots. The profiles of lead accumulation in roots or in shoots were similar for the different concentrations with a proportional response to the Pb concentration in the medium. In hydroponic conditions, lead accumulation in roots and shoots was found to be dose and time dependent: roots showed more accumulation than shoots at the same concentration and exposure periods. In the shoots, a slow but constant increase of lead content after a latency period of 24 hours was observed for the three concentrations (Figure 3A). In the roots, the levels of Pb gradually increased with time of exposure for expected values of 42, 69 and 121 mg.g−1 DW for respectively 50, 100 and 300 µM of Pb in the medium. A slight decrease of the curve was observed for the last points of kinetics for the 50 µM concentration and a plateau for the 100 µM concentration (Figure 3B). Finally a maximum of translocation was observed at day-4 for 300 µM of Pb in the medium where 3% of total Pb in the plant were localized in the shoots.


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)

Kinetic effect of lead exposure on lead accumulation in (A) shoots and (B) roots of H. incana.Seedlings were grown on hydroponic system and lead treatments were done after 2 weeks by adding 50, 100 and 300 µM Pb(NO3)2 in fresh medium. Data are the average (± SE) of three independent measurements.
© Copyright Policy
Related In: Results  -  Collection

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

pone-0061932-g003: Kinetic effect of lead exposure on lead accumulation in (A) shoots and (B) roots of H. incana.Seedlings were grown on hydroponic system and lead treatments were done after 2 weeks by adding 50, 100 and 300 µM Pb(NO3)2 in fresh medium. Data are the average (± SE) of three independent measurements.
Mentions: A four-day kinetic study, in hydroponic conditions, was achieved to confirm the transport of lead from roots to shoots in H. incana (Figure 3). Three Pb concentrations were tested (50, 100 and 300 µM Pb(NO3)2). In the study period and with these concentrations of Pb, no visual damage could be observed neither in leaves and roots. The profiles of lead accumulation in roots or in shoots were similar for the different concentrations with a proportional response to the Pb concentration in the medium. In hydroponic conditions, lead accumulation in roots and shoots was found to be dose and time dependent: roots showed more accumulation than shoots at the same concentration and exposure periods. In the shoots, a slow but constant increase of lead content after a latency period of 24 hours was observed for the three concentrations (Figure 3A). In the roots, the levels of Pb gradually increased with time of exposure for expected values of 42, 69 and 121 mg.g−1 DW for respectively 50, 100 and 300 µM of Pb in the medium. A slight decrease of the curve was observed for the last points of kinetics for the 50 µM concentration and a plateau for the 100 µM concentration (Figure 3B). Finally a maximum of translocation was observed at day-4 for 300 µM of Pb in the medium where 3% of total Pb in the plant were localized in the shoots.

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
Related in: MedlinePlus