FIGURE 3.

Forms of nitrogen present in soil and capabilities of mycorrhiza‐forming fungi to access and assimilate them with known key transporters and enzymes involved shown. Solid arrows represent known assimilation, whereas dashed arrows represent possible assimilation pathways. Red arrows indicate secretion of enzymes by fungi to degrade organic nutrient sources, green and blue arrows indicate inorganic and organic nitrogen sources, respectively (Belmondo et al., 2014; Cappellazzo et al., 2008; Fochi et al., 2017; López‐Pedrosa et al., 2006; Nehls et al., 2001; Stuart & Plett, 2020)