Figure 5.

Ultrastructural alterations in Piriformospora indica‐colonized Arabidopsis cells. (A) Early biotrophic colonization stage at which colonized root cells are alive as indicated by the integrity of the cytosol and mitochondria. The vacuoles in noncolonized neighbouring cells show an intact tonoplast. The intracellular hypha is surrounded by the plant plasma membrane (arrows). (B, C) As intracellular colonization proceeds, colonized cells undergo cell death indicated by lysis of the cytosol (asterisks), whereas organelles do not show morphological alterations. CW, root cell wall; CY, cytosol; H, hypha; LB, lipid bodies; M, mitochondrium; MVB, multivesicular bodies; P, plastids; V, vacuole. Bars, 2 µm.