High-affinity H(+)/sulfate cotransporter that mediates the uptake of the environmental sulfate by plant roots. Plays a central role in the regulation of sulfate assimilation. Unable to transport molybdate. Interaction with OASA1 negatively impacts the transporter activity. Homodimer. Interacts with OASA1 through its STAS domain. Expressed in lateral root cap, root hairs, epidermal and cortical cells of roots. In roots by sulfate starvation. Sel1 mutations in the gene lead to the resistance of the plant to selenate, a toxic analog of sulfate. Belongs to the SLC26A/SulP transporter (TC 2.A.53.1) family.