Extracellular and cellular mechanisms sustaining metal tolerance in ectomycorrhizal fungi

Authors

  • Marc Bellion,

    1. IFR 110, UMR 1136 INRA/UHP Interactions Arbres Micro-organismes, Université Henri Poincaré– Nancy I, Faculté des Sciences et Techniques, Vandoeuvre-les-Nancy Cedex, France
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  • Mikaël Courbot,

    1. IFR 110, UMR 1136 INRA/UHP Interactions Arbres Micro-organismes, Université Henri Poincaré– Nancy I, Faculté des Sciences et Techniques, Vandoeuvre-les-Nancy Cedex, France
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  • Christophe Jacob,

    1. IFR 110, UMR 1136 INRA/UHP Interactions Arbres Micro-organismes, Université Henri Poincaré– Nancy I, Faculté des Sciences et Techniques, Vandoeuvre-les-Nancy Cedex, France
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  • Damien Blaudez,

    1. IFR 110, UMR 1136 INRA/UHP Interactions Arbres Micro-organismes, Université Henri Poincaré– Nancy I, Faculté des Sciences et Techniques, Vandoeuvre-les-Nancy Cedex, France
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  • Michel Chalot

    1. IFR 110, UMR 1136 INRA/UHP Interactions Arbres Micro-organismes, Université Henri Poincaré– Nancy I, Faculté des Sciences et Techniques, Vandoeuvre-les-Nancy Cedex, France
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  • Editor: Richard Staples

  • Present address: Christophe Jacob, IFR 111, UMR 7567 CNRS/UHP Maturation des ARN et Enzymologie Moléculaire, Université Henri Poincaré– Nancy I, Faculté des Sciences et Techniques BP239, F54506 Vandoeuvre-les-Nancy Cedex, France.

Correspondence: Michel Chalot, Université Henri Poincaré– Nancy I, UMR INRA 1136 Interactions Arbres Micro-organismes, BP 239, 54506 Vandoeuvre-les-Nancy Cedex, France. Tel.: +33 3 83 68 42 38; fax: +33 3 83 68 42 92; e-mail: michel.chalot@scbiol.uhp-nancy.fr

Abstract

This review focuses on recent evidence that identifies potential extracellular and cellular mechanisms that may be involved in the tolerance of ectomycorrhizal fungi to excess metals in their environment. It appears likely that mechanisms described in the nonmycorrhizal fungal species are used in the ectomycorrhizal fungi as well. These include mechanisms that reduce uptake of metals into the cytosol by extracellular chelation through extruded ligands and binding onto cell-wall components. Intracellular chelation of metals in the cytosol by a range of ligands (glutathione, metallothioneins), or increased efflux from the cytosol out of the cell or into sequestering compartments are also key mechanisms conferring tolerance. Free-radical scavenging capacities through the activity of superoxide dismutase or production of glutathione add another line of defence against the toxic effect of metals.

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