title: The arbuscular mycorrhizal symbiosis influences sulfur starvation responses of Medicago truncatula.
abstract: Arbuscular mycorrhizal (AM) symbiosis is a mutualistic interaction that occurs between the large majority of vascular plants and fungi of the phylum Glomeromycota. In addition to other nutrients, sulfur compounds are symbiotically transferred from AM fungus to host plants; however, the physiological importance of mycorrhizal-mediated sulfur for plant metabolism has not yet been determined. We applied different sulfur and phosphate fertilization treatments to Medicago truncatula and investigated whether mycorrhizal colonization influences leaf metabolite composition and the expression of sulfur starvation-related genes. The expression pattern of sulfur starvation-related genes indicated reduced sulfur starvation responses in mycorrhizal plants grown at 1 mM phosphate nutrition. Leaf metabolite concentrations clearly showed that phosphate stress has a greater impact than sulfur stress on plant metabolism, with no demand for sulfur at strong phosphate starvation. However, when phosphate nutrition is high enough, mycorrhizal colonization reduces sulfur stress responses, probably as a result of symbiotic sulfur uptake. Mycorrhizal colonization is able to reduce sulfur starvation responses in M. truncatula when the plant's phosphate status is high enough that sulfur starvation is of physiological importance. This clearly shows the impact of mycorrhizal sulfur transfer on plant metabolism.
authors.affiliation: Max Planck Institute of Molecular Plant Physiology, Am Muehlenberg 1, 14476, Potsdam, Germany.
authors.forename: Daniela
authors.initials: D
authors.lastname: Sieh
authors.affiliation: Max Planck Institute of Molecular Plant Physiology, Am Muehlenberg 1, 14476, Potsdam, Germany.
authors.forename: Mutsumi
authors.initials: M
authors.lastname: Watanabe
authors.affiliation: Max Planck Institute of Molecular Plant Physiology, Am Muehlenberg 1, 14476, Potsdam, Germany.
authors.forename: Emanuel A
authors.initials: EA
authors.lastname: Devers
authors.affiliation: Max Planck Institute of Molecular Plant Physiology, Am Muehlenberg 1, 14476, Potsdam, Germany.
authors.forename: Franziska
authors.initials: F
authors.lastname: Brueckner
authors.affiliation: Max Planck Institute of Molecular Plant Physiology, Am Muehlenberg 1, 14476, Potsdam, Germany.
authors.forename: Rainer
authors.initials: R
authors.lastname: Hoefgen
authors.affiliation: Max Planck Institute of Molecular Plant Physiology, Am Muehlenberg 1, 14476, Potsdam, Germany.
authors.forename: Franziska
authors.initials: F
authors.lastname: Krajinski
mesh_terms: D017360:Arabidopsis / Q000187:drug effects / Q000235:genetics; D018533:Biomass; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D017343:Genes, Plant / Q000235:genetics; D055137:Glomeromycota / Q000187:drug effects / Q000502:physiology*; D046913:Medicago truncatula / Q000187:drug effects / Q000235:genetics / Q000378:metabolism* / Q000382:microbiology*; D055442:Metabolome / Q000187:drug effects / Q000235:genetics; D038821:Mycorrhizae / Q000187:drug effects / Q000502:physiology*; D010641:Phenotype; D010710:Phosphates / Q000494:pharmacology; D018515:Plant Leaves / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D010940:Plant Proteins / Q000378:metabolism; D025341:Principal Component Analysis; D013312:Stress, Physiological / Q000187:drug effects / Q000235:genetics; D013455:Sulfur / Q000172:deficiency* / Q000378:metabolism; D013559:Symbiosis / Q000187:drug effects / Q000235:genetics / Q000502:physiology*; D014158:Transcription, Genetic / Q000187:drug effects
chemical_list: D010710:Phosphates; D010940:Plant Proteins; D013455:Sulfur