High-affinity transporter for external inorganic phosphate (By similarity). Required for phosphate acquisition in plant. Expressed in roots, stems and leaves. In roots by phosphate starvation. Plants overexpressing PHT1-1 accumulates almost twice the amount of phosphate in the shoots compared to the wild-type plants. Although related to the sugar transporter family, it does not transport sugars. Belongs to the major facilitator superfamily. phosphate:H(+) symporter (TC 2.A.1.9) family.