title: Fractionation and assimilation of Mg isotopes by fungi is species dependent.
abstract: Symbiotic ectomycorrhizal fungi mobilize nutrients from both organic and inorganic substrates and supply them to their host plants. Their role in mobilizing base cations and phosphorus from mineral substrates through weathering has received increasing attention in recent years but the processes involved remain to be elucidated. We grew selected ectomycorrhizal and nonmycorrhizal fungi in axenic systems containing mineral and organic substrates and examined their capacity to fractionate and assimilate stable isotopes of magnesium. The mycorrhizal fungi were significantly depleted in heavy isotopes with the lowest Δ26Mg values (the difference between δ26Mg in fungal tissue and δ26Mg in the substrate) compared with nonmycorrhizal fungi, when grown on mineral substrates containing granite particles. The ectomycorrhizal fungi accumulated significantly higher concentrations of Mg, K and P than the nonmycorrhizal fungi. There was a highly significant statistical relationship between δ26Mg tissue signature and mycelial concentration of Mg, with a clear separation between most ectomycorrhizal fungi and the nonmycorrhizal fungi. These results are consistent with the idea that ectomycorrhizal fungi have evolved efficient mechanisms to mobilize, transport and store Mg within their mycelia.
authors: Department of Forest Mycology and Plant Pathology, Uppsala BioCenter, Swedish University of Agricultural Sciences, Uppsala, SE, 750 07, Sweden.
authors: Zaenab A
authors: ZA
authors: Fahad
authors: Department of Earth Sciences, Uppsala University, Uppsala, SE, 752 36, Sweden.|Institut d'Ecologie et des Sciences de l'Environnement IEES Paris, équipe Géomicrobiologie des sols et des eaux, Université de Paris-Est Créteil Val de Marne, Créteil Cedex, FR, 94 010, France.
authors: Emile B
authors: EB
authors: Bolou-Bi
authors: Department of Aquatic Sciences and Assessment, Soil-Water-Environment Center, Swedish University of Agricultural Sciences, Uppsala, SE, 750 07, Sweden.
authors: Stephan J
authors: SJ
authors: Köhler
authors: Department of Forest Mycology and Plant Pathology, Uppsala BioCenter, Swedish University of Agricultural Sciences, Uppsala, SE, 750 07, Sweden.
authors: Roger D
authors: RD
authors: Finlay
authors: Department of Forest Mycology and Plant Pathology, Uppsala BioCenter, Swedish University of Agricultural Sciences, Uppsala, SE, 750 07, Sweden.
authors: Shahid
authors: S
authors: Mahmood
mesh_terms: D008274:Magnesium / Q000378:metabolism*; D038821:Mycorrhizae / Q000378:metabolism*; D010944:Plants / Q000382:microbiology*
chemical_list: D008274:Magnesium