Figure 6.

Dynamics of EcM development. Transition from soil-borne mycelium towards functional symbiosis requires a two-step transcriptional reprogramming. Initial contact with a plant host, when entering the rhizosphere, marks the first step and results in priming of the mycelium with roles suggested for ROS signaling and terpenes. The second step corresponds to functional differentiation between ExM and EcM with differential expression of CAZymes, SSPs, nitrogen (amino acid and ammonium) and sugar transporters. At this point, both fungal mantle and Hartig net are well-developed and visible. ROS = reactive oxygen species; SSP = small secreted protein; aa = amino acid.