title: Interactions of sterile-cultured lichen-forming ascomycetes with asbestos fibres.
abstract: Sterile cultured isolates of lichen-forming ascomycetes have not yet been used to investigate mycobiont-mineral substrate interactions under controlled conditions. In this study Candelariella vitellina, Xanthoparmelia tinctina and Lecanora rupicola mycobionts were isolated and inoculated with chrysotile fibres in the laboratory, in order to verify whether physical and chemical weathering processes, which were already described in the field, may be reproduced in vitro. Tight adhesion of hyphae to chrysotile fibres was observed in all species. The adhering hyphae affected the chemical composition of asbestos fibres, with the selective depletion of magnesium being a prominent feature, as is the case in field conditions. Oxalic acid and pulvinic acid, mycobiont-derived metabolites of X. tinctina and C. vitellina, were involved in the weathering action. Time and environmental factors and the absence of biological synergisms strongly limited the chemical weathering in vitro compared with what was observed in the field. Nevertheless, the results show that in vitro incubation of sterile-cultured lichen-forming fungi with minerals is a practicable experimental system to investigate the weathering effects of different mycobionts and fungal compounds under controlled conditions.
authors.affiliation: Dipartimento di Biologia, Vegetale Centre of Excellence for Plant and Microbial Biosensing, University of Torino, Torino 10125, Italy.
authors.forename: Sergio Enrico
authors.initials: SE
authors.lastname: Favero-Longo
authors.forename: Mariangela
authors.initials: M
authors.lastname: Girlanda
authors.forename: Rosmarie
authors.initials: R
authors.lastname: Honegger
authors.forename: Bice
authors.initials: B
authors.lastname: Fubini
authors.forename: Rosanna
authors.initials: R
authors.lastname: Piervittori
mesh_terms: D001194:Asbestos / Q000737:chemistry / Q000378:metabolism*; D001203:Ascomycota / Q000254:growth & development* / Q000648:ultrastructure; D025301:Hyphae / Q000378:metabolism; D008011:Lichens / Q000254:growth & development / Q000648:ultrastructure; D008277:Magnesium Oxide / Q000032:analysis; D008855:Microscopy, Electron, Scanning; D019016:Mineral Fibers / Q000032:analysis / Q000382:microbiology*; D012822:Silicon Dioxide / Q000032:analysis
chemical_list: D019016:Mineral Fibers; D001194:Asbestos; D008277:Magnesium Oxide; D012822:Silicon Dioxide