Fig. 2
From: Stress, nutrients and genotype: understanding and managing asparagine accumulation in wheat grain
Synthesis and functions of asparagine. Nitrate (NO3−) is absorbed from the soil and reduced to ammonia (NH4+) through nitrate reductase (NR) and nitrite reductase (NiR). Ammonia is assimilated via glutamate dehydrogenase (GDH) and glutamine synthetase (GS) to form glutamine (Glu), which is then used to form asparagine (Asn) alongside aspartate (Asp). Asparagine mobilises nitrogen from source to sink tissues during germination, vegetative growth, senescence, and seed filling, as well as during stress. Detoxification of ammonia may also be an important function of asparagine accumulation when nitrogen (N) is abundant and during stress when ammonia accumulates