Transcriptional response of Medicago truncatula sulphate transporters to arbuscular mycorrhizal symbiosis with and without sulphur stress

Clé WOS: 000304621200025 correspond à l'article SPE BAP IPM GEAPSI CT3 GAP CT1 SPE

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English. Sulphur is an essential macronutrient for plant growth, development, and response to various abiotic and biotic stresses due to its key role in the biosynthesis of many Scontaining compounds. Sulphate represents a very small portion of soil S pull and it’s the only form that plant roots can uptake and mobilize through H+-dependent cotransport processes implying sulphate transporters. Unlike the other organically bound forms of S, sulphate is normally leached from soils due to its solubility in water, thus reducing its availability to plants. Although our knowledge of plant sulphate transporters has been growing significantly in the last decades, little is still known about the effect of the arbuscular mycorrhiza interaction on sulphur uptake. Carbon, nitrogen and sulphur measurements in plant parts and expression analysis of genes encoding putative Medicago sulphate transporters (MtSULTRs) were performed to better understand the beneficial effects of mycorrhizal interaction on Medicago truncatula plants colonized by Glomus intraradices at different sulphate concentrations. Mycorrhization significantly promoted plant growth and sulphur content, suggesting increased sulphate absorption. In-silico analyses allowed identifying 8 putative MtSULTRs phylogenetically distributed over the 4 sulphate transporter groups. Some putative MtSULTRs were transcribed differentially in roots and leaves and affected by sulphate concentration, while others were more constitutively transcribed. Mycorrhizal-inducible and -repressed MtSULTRs transcripts were identified allowing to shed light on the role of mycorrhizal interaction in sulphate uptake.