title: Sulfur uptake in the ectomycorrhizal fungus Laccaria bicolor S238N.
abstract: The importance of the ectomycorrhiza symbiosis for plant acquisition of phosphorus and nitrogen is well established whereas its contribution to sulfur nutrition is only marginally understood. In a first step to investigate the role of ectomycorrhiza in plant sulfur nutrition, we characterized sulfate and glutathione uptake in Laccaria bicolor. By studying the regulation of sulfate uptake in this ectomycorrhizal fungus, we found that in contrast to bacteria, yeast, and plants, sulfate uptake in L. bicolor was not feedback-inhibited by glutathione. On the other hand, sulfate uptake was increased by sulfur starvation as in other organisms. The activity of 3'-phosphoadenosine 5'-phosphosulfate reductase, the key enzyme of the assimilatory sulfate reduction pathway in fungi, was increased by sulfur starvation and decreased after treatment with glutathione revealing an uncoupling of sulfate uptake and reduction in the presence of reduced sulfur compounds. These results support the hypothesis that L. bicolor increases sulfate supply to the plant by extended sulfate uptake and the plant provides the ectomycorrhizal fungus with reduced sulfur.
authors.affiliation: Albert-Ludwigs-University of Freiburg, Institute of Forest Botany and Tree Physiology, Georges-Köhler-Allee 053, 79110, Freiburg, Germany.
authors.forename: Hounayda
authors.initials: H
authors.lastname: Mansouri-Bauly
authors.affiliation: Albert-Ludwigs-University of Freiburg, Institute of Forest Botany and Tree Physiology, Georges-Köhler-Allee 053, 79110, Freiburg, Germany.|The School of Forest and Ecosystem Science, University of Melbourne, Melbourne, Australia.
authors.forename: Jörg
authors.initials: J
authors.lastname: Kruse
authors.affiliation: Albert-Ludwigs-University of Freiburg, Institute of Forest Botany and Tree Physiology, Georges-Köhler-Allee 053, 79110, Freiburg, Germany.|Institute of Botany, University of Basel, Basel, Switzerland.
authors.forename: Zuzana
authors.initials: Z
authors.lastname: Sýkorová
authors.affiliation: Albert-Ludwigs-University of Freiburg, Institute of Forest Botany and Tree Physiology, Georges-Köhler-Allee 053, 79110, Freiburg, Germany.
authors.forename: Ursula
authors.initials: U
authors.lastname: Scheerer
authors.affiliation: Albert-Ludwigs-University of Freiburg, Institute of Forest Botany and Tree Physiology, Georges-Köhler-Allee 053, 79110, Freiburg, Germany. stanislav.kopriva@bbsrc.ac.uk.|John Innes Institute, Norwich, UK. stanislav.kopriva@bbsrc.ac.uk.
authors.forename: Stanislav
authors.initials: S
authors.lastname: Kopriva
mesh_terms: D000363:Agaricales / Q000201:enzymology / Q000378:metabolism*; D005978:Glutathione / Q000378:metabolism; D016014:Linear Models; D025282:Mycelium / Q000378:metabolism; D038821:Mycorrhizae / Q000201:enzymology / Q000378:metabolism*; D010088:Oxidoreductases / Q000378:metabolism; D013431:Sulfates / Q000378:metabolism / Q000493:pharmacokinetics*; D013438:Sulfhydryl Compounds / Q000378:metabolism; D013559:Symbiosis
chemical_list: D013431:Sulfates; D013438:Sulfhydryl Compounds; D010088:Oxidoreductases; C052449:3'-phosphoadenylyl-5'-phosphosulfate reductase; D005978:Glutathione