title: Cu,Zn superoxide dismutase and zinc stress in the metal-tolerant ericoid mycorrhizal fungus Oidiodendron maius Zn.
abstract: The sequence encoding a superoxide dismutase (SOD) was isolated from the cDNA library of a zinc-tolerant strain of the ericoid mycorrhizal fungus Oidiodendron maius, grown under zinc-stress conditions. Sequence homology to other SODs strongly suggests that it is a copper- and zinc-containing SOD. Functional complementation assays showed that the gene confers increased tolerance to zinc and copper stress to a Cu,ZnSOD-defective yeast mutant. Monitoring of transcript and protein levels following zinc stress suggests that OmSOD1 expression is controlled at the transcriptional level. The OmSod1 protein was found both in the cell extract and in the growth medium of viable fungal cultures. This is the first characterization of an extracellular Cu,ZnSOD in a mycorrhizal fungus. In nature, the presence of OmSod1 in the extracellular environment may also extend the protective role of this enzyme to the plant symbiont. This may be of particular interest from the perspective of using mycorrhizal fungi in bioremediation programmes.
authors.affiliation: Dipartimento di Biologia Vegetale dell'Università di Torino and Istituto per la Protezione delle Piante del CNR, Turin, Italy.
authors.forename: Marta
authors.initials: M
authors.lastname: Vallino
authors.forename: Elena
authors.initials: E
authors.lastname: Martino
authors.forename: Francesca
authors.initials: F
authors.lastname: Boella
authors.forename: Claude
authors.initials: C
authors.lastname: Murat
authors.forename: Marco
authors.initials: M
authors.lastname: Chiapello
authors.forename: Silvia
authors.initials: S
authors.lastname: Perotto
mesh_terms: D001203:Ascomycota / Q000187:drug effects / Q000201:enzymology* / Q000235:genetics / Q000502:physiology; D003300:Copper / Q000494:pharmacology; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism; D015966:Gene Expression Regulation, Fungal; D018869:Heat-Shock Response; D019216:Metals, Heavy / Q000494:pharmacology*; D008969:Molecular Sequence Data; D009154:Mutation; D038821:Mycorrhizae; D010802:Phylogeny; D018517:Plant Roots / Q000382:microbiology; D017422:Sequence Analysis, DNA; D013482:Superoxide Dismutase / Q000235:genetics / Q000378:metabolism; D014158:Transcription, Genetic; D029796:Vaccinium / Q000382:microbiology; D015032:Zinc / Q000494:pharmacology*
chemical_list: D005656:Fungal Proteins; D019216:Metals, Heavy; D003300:Copper; D013482:Superoxide Dismutase; D015032:Zinc