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The arbuscular mycorrhizal symbiosis influences sulfur starvation responses of Medicago truncatula
Author(s) -
Sieh Daniela,
Watanabe Mutsumi,
Devers Emanuel A.,
Brueckner Franziska,
Hoefgen Rainer,
Krajinski Franziska
Publication year - 2013
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1111/nph.12034
Subject(s) - sulfur , medicago truncatula , symbiosis , biology , sulfur metabolism , rhizophagus irregularis , phosphate , botany , starvation response , nutrient , metabolism , ecology , chemistry , arbuscular mycorrhizal , biochemistry , bacteria , organic chemistry , genetics
Summary 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 M edicago 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.