Identification and functional characterization of a sulfate transporter induced by both sulfur starvation and mycorrhiza formation in Lotus japonicus

• Published in: The New phytologist Vol. 204; no. 3; pp. 609 - 619
• Main Authors: Giovannetti, Marco, Tolosano, Matteo, Volpe, Veronica, Kopriva, Stanislav, Bonfante, Paola
• Format: Journal Article
• Language: English
• Published: England Academic Press 01.11.2014; New Phytologist Trust; Wiley Subscription Services, Inc
• Subjects: Anion Transport Proteins - metabolism; arbuscular mycorrhizal (AM) symbiosis; Arbuscular mycorrhizas; carbon; Colonization; direct and symbiotic pathways; Fungi; Gene expression; Gene Expression Regulation, Plant - drug effects; Genes; group 1 sulfate transporter; Life cycle; Life cycles; LjSultr1;2; Lotus - genetics; Lotus - metabolism; Lotus - microbiology; Lotus corniculatus var. japonicus; Lotus japonicus; Metabolism; Mineral nutrients; mutants; Mycorrhizae - physiology; mycorrhizal fungi; Mycorrhizas; nitrogen; Nutrient cycles; Nutrients; Nutrition; Nutritional status; phenotype; Phenotyping; Phosphates; Plant nutrition; Plant roots; Plant Roots - microbiology; Plants; repletion; Rhizophagus; Rhizophagus irregularis; Seedlings; Starvation; sulfate nutrition; Sulfate transporter; Sulfates; Sulfur; Sulfur - metabolism; Sulfur - pharmacology; Sulphur; Symbionts; Symbiosis; Tissue; Transcription; Transcription, Genetic; transporters; Uptake; vesicular arbuscular mycorrhizae; arbuscular mycorrhizal (AM) symbiosis; sulfate nutrition; direct and symbiotic pathways; Lotus japonicus; group 1 sulfate transporter; LjSultr1;2; Rhizophagus irregularis
• ISSN: 0028-646X; 1469-8137
• DOI: 10.1111/nph.12949

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.