Figure 1.

Root nodules showing regions of active nitrogen fixation, and a model of nitrogen efflux and assimilation with the interaction of nodulin 26/glutamine synthetase (GS). Fixed nitrogen within the symbiosome space can be transported by the nodulin 26. GS which bind to the C-terminal domain of nodulin 26 serves as a site in the symbiosome membrane for rapid assimilation ammonia, and then gets released into the infected cell’s cytosol. GS, glutamine synthetase; Glu, glutamate; Gln, glutamine; AA, amino acid.