Ammonium transporter probably involved in ammonium uptake from the soil. Contributes with AMT1-1 to the overall ammonium uptake capacity in roots under nitrogen-deficiency conditions. Highly expressed in roots. Expressed in root tips, root hairs, root epidermis, rhizodermis and cortex. By nitrogen deprivation. Highest expression at the end of the light period. Belongs to the ammonia transporter channel (TC 1.A.11.2) family.