Figure 1. Mycorrhizal phenotypes of Medicago truncatula dmi3 mutant plants complemented by the pLeEXT1:DMI3 construct at 4 weeks post inoculation with Rhizophagus irregularis. (A) dmi3 mutant root carrying an empty vector, showing hyphae developing only on the root surface. (B) dmi3 mutant root complemented with the pDMI3:DMI3 construct showing dense arbuscule and vesicule formation. (C and D) dmi3 mutant root complemented with the pLeEXT1:DMI3 construct. (C) Showing hyphae developing on the root surface (arrow) and intracellular hyphae entering an epidermal cell (arrowhead). (D) intercellular colonisation in the cortex without arbuscule formation. Scale bars: 200 µm in (A and B); 25 µm in (C) and 100 µm in (D).