title: Identification and functional characterization of a sulfate transporter induced by both sulfur starvation and mycorrhiza formation in Lotus japonicus.
abstract: Arbuscular mycorrhizas (AMs) are one of the most widespread symbioses in the world. They allow plants to receive mineral nutrients from the symbiotic fungus which in turn gets back up to 20% of plant carbon and completes its life cycle. Especially in low-nutrient conditions, AM fungi are capable of significantly improving plant phosphate and nitrogen acquisition, but fewer data are available about sulfur (S) nutrition. We focused on S metabolism in Lotus japonicus upon mycorrhizal colonization under sulfur starvation or repletion. We investigated both tissue sulfate concentrations and S-related gene expression, at cell-type or whole-organ level. Gene expression and sulfate tissue concentration showed that Rhizophagus irregularis colonization can improve plant S nutritional status under S starvation. A group 1 sulfate transporter, LjSultr1;2, induced by both S starvation and mycorrhiza formation, was identified. Its transcript was localized in arbuscule-containing cells, which was confirmed with a promoter-GUS assay, and its function was verified through phenotyping of TILLING mutants in nonmycorrhizal seedlings. LjSultr1;2 thus appears to encode a key protein involved in plant sulfate uptake. In contrast to phosphate transporters, a single gene, LjSultr1;2, seems to mediate both direct and symbiotic pathways of S uptake in L. japonicus.
authors.affiliation: Department of Life Science and Systems Biology, Università degli Studi di Torino, Viale Mattioli 25, I-10125, Torino, Italy.
authors.forename: Marco
authors.initials: M
authors.lastname: Giovannetti
authors.affiliation: Department of Life Science and Systems Biology, Università degli Studi di Torino, Viale Mattioli 25, I-10125, Torino, Italy.
authors.forename: Matteo
authors.initials: M
authors.lastname: Tolosano
authors.affiliation: Department of Life Science and Systems Biology, Università degli Studi di Torino, Viale Mattioli 25, I-10125, Torino, Italy.
authors.forename: Veronica
authors.initials: V
authors.lastname: Volpe
authors.affiliation: John Innes Centre, Norwich Research Park, Norwich, NR4 7UH, UK.|Botanical Institute, University of Cologne, Zülpicher Str. 47b, 50674, Cologne, Germany.
authors.forename: Stanislav
authors.initials: S
authors.lastname: Kopriva
authors.affiliation: Department of Life Science and Systems Biology, Università degli Studi di Torino, Viale Mattioli 25, I-10125, Torino, Italy.
authors.forename: Paola
authors.initials: P
authors.lastname: Bonfante
mesh_terms: D027321:Anion Transport Proteins / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D000070116:Lotus / Q000235:genetics / Q000378:metabolism* / Q000382:microbiology*; D038821:Mycorrhizae / Q000502:physiology*; D018517:Plant Roots / Q000382:microbiology; D013455:Sulfur / Q000378:metabolism* / Q000494:pharmacology*; D013559:Symbiosis; D014158:Transcription, Genetic
chemical_list: D027321:Anion Transport Proteins; D013455:Sulfur
keywords: LjSultr1;2; Lotus japonicus; Rhizophagus irregularis; arbuscular mycorrhizal (AM) symbiosis; direct and symbiotic pathways; group 1 sulfate transporter; sulfate nutrition