Sodium transporter that under salt stress mediates sodium exclusion in the phloem to prevent sodium transfer to young leaf blades and reproductive tissues. Na(+)(in) = Na(+)(out) Localizes to the plasma membrane. In roots, expressed in cells next to the protoxylem and the metaxylem I (PubMed:28488420). In basal nodes, expressed in the phloem of some diffuse vascular bundles (PubMed:28488420). HKT transporters are proposed to contain 4 pore-forming regions enclosed by transmembrane segments with each containing a potassium channel-like selectivity filter motif. Substitution of Pro-140, Arg-184, His-332 and Leu-395 in salt-tolerant cultivars indica Nona Bokra and Pokkali confers enhanced sodium transport activity. Belongs to the TrkH potassium transport family. HKT (TC 2.A.38.3) subfamily.