Atlas of Contaminated Sites

Fungus, mycorrhizal

Oidiodendron maius G.L. Barron

An ericoid mycorrhizal fungus, symbiont of bilberries and other Ericaceae, plants that dominate acidic, poor soils where metals are more available. Strain O. maius Zn, isolated from bilberry roots in heavily contaminated soils and studied at the University of Turin, has become the model system for the molecular mechanisms of metal tolerance in mycorrhizal fungi.

How it works

Mechanisms
mycorrhizal support
Enzymes
superoxide dismutase

Contaminants

ContaminantEvidenceWhat was shown
Zinclaboratory

Two isolates from mycorrhizal roots of Vaccinium myrtillus in heavily contaminated soils grow better than isolates from unpolluted soils at increasing zinc salt concentrations, especially the highest. From strain Zn, yeast complementation identified a Cu,Zn superoxide dismutase also found in the extracellular medium, and two transporters, OmZnT1 (endoplasmic reticulum, sequestration) and OmFET (plasma membrane), which restore Zn tolerance in sensitive mutants.

Cadmiumlaboratory

Roots of Vaccinium myrtillus colonised by O. maius Zn and exposed to cadmium contain less Cd than non-mycorrhizal roots. Proteomics of Cd-exposed mycelium shows induction of Hsp90 chaperones, cytoskeletal proteins and, in common with zinc, Cu/Zn superoxide dismutase, ubiquitin and agmatinase.

Limits

Research on this fungus explains how the symbiont withstands metals; how it extends protection to the plant is, by the authors' own account, still poorly understood (Daghino et al. 2016; Casarrubia et al. 2020). All data are in vitro or from model systems: we found no field revegetation or remediation trial with this strain. Yeast complementation has acknowledged limits as a tool for studying the symbiosis.

Sources

Draft compiled from public sources, not yet reviewed.

Species that the literature reports acting on at least one of this one's contaminants, the closest first.

All plants and fungi