Low-affinity proton-dependent nitrate transporter. Not involved in dipeptides transport, but has a weak glucosinolate transport activity. Involved in phloem loading and nitrate remobilization from the older leaves to other tissues. Expressed in leaves and flowers. Detected in stems and siliques. Highest expression in the distal lamina of older leaves. Restricted to the sieve element and companion cell complex of the minor vein. Circadian-regulation. Expression increase during the light phase and decrease during the dark phase. No visible phenotype when grown under normal conditions. Growth retardation when starved of nitrogen. Belongs to the major facilitator superfamily. Proton-dependent oligopeptide transporter (POT/PTR) (TC 2.A.17) family.