Involved in nitrate transport, but does not seem to be able to mediate transport by its own (PubMed:8180624). Acts as a dual component transporter with NAR2 (system 2) (PubMed:8180624). Involved in a high affinity transport specific for nitrate (PubMed:8567664). Up-regulated after a long nitrate induction period. Belongs to the major facilitator superfamily. Nitrate/nitrite porter (TC 2.A.1.8) family.