Fig 2. Proposed pathway of nitrogen assimilation and glutaminolysis in M. oryzae based on sequence homology.

Nitrogen is assimilated and distributed via glutamine synthetase (Gln1 and Gln2) and glutamate synthase (Glt1) or anabolic NADP-dependent glutamate dehydrogenase (Gdh1) and Gln1-2 [24, 25]. Glutaminolysis [26] involves NAD-dependent glutamate dehydrogenase (Mgd1). Enzymes are depicted as solid circles with the adjacent bar graphs showing the relative expression levels of the encoding genes in WT (black bar) and Δasd4 mutant strains (red bar) following 3 h and 16 h growth in GMM with 10 mM NH₄ ⁺ as the sole nitrogen source. Results were normalized against the expression of the β-tubulin gene TUB2. Values are the average of three results from at least two independent biological replicates. Error bars are standard deviation.