Extracellular and cellular mechanisms sustaining metal tolerance in ectomycorrhizal fungi.
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.
Bellion
Marc
M
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.
Courbot
Mikaël
M
Jacob
Christophe
C
Blaudez
Damien
D
Chalot
Michel
M
D002614:Chelating Agents / Q000378:metabolism; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism; D005658:Fungi / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism; D019216:Metals, Heavy / Q000378:metabolism / Q000494:pharmacology*; D038821:Mycorrhizae / Q000187:drug effects* / Q000378:metabolism
D002614:Chelating Agents; D005656:Fungal Proteins; D019216:Metals, Heavy