Transcription factor of the NAC family associated with the grain protein content (GPC). Accelerates senescence and increases nutrient remobilization from leaves to developing grains. The tetraploid cultivated wheat (T.durum) contains one additional gene coding for a functional protein (NAM-A1) and one extra pseudogene (NAM-B1) (PubMed:17124321). Plays a weaker role in terminal senescence than NAM-A1. Highest expression in flag leaves. Expressed in green spikes, peduncles and stamens. Increased expression during grain maturation and senescence. Not induced during flower development. The NAC domain includes a DNA-binding domain and a dimerization domain. No visible phenotype. High grain protein content (GPC) is a desirable trait in breadmaking and pasta wheat varieties because of its positive effects on quality and nutritional value while Low GPC is a desirable trait for barley malt and beer production.