Low-affinity proton-dependent nitrate transporter. Involved in constitutive nitrate uptake. Not involved in histidine or dipeptides transport. Involved in (+)-abscisic acid (ABA) transport, but not in gibberellin, indole-3-acetic acid or jasmonic acid import. Mediates cellular ABA uptake. Nitrate does not compete with abscisic acid as a substrate of NPF4.6 (PubMed:24084651). Expressed in root hairs and in epidermis of both root tips and mature regions of roots. Detected in shoots, stems, flowers, siliques and imbibed seeds. Expressed in vascular tissues in cotyledons, trus leaves, hypocotyls, roots and inflorescence stems. Not regulated by nitrate. Down-regulated upon nematode infection. Reduced effect of ABA on seed germination and postgermination growth and increased number of open stomata. Belongs to the major facilitator superfamily. Proton-dependent oligopeptide transporter (POT/PTR) (TC 2.A.17) family.