Fig. 3

Micrographs showing the developing protocorm of G. elata associated with Mycena. a Light micrograph showing the colonized region of a developing protocorm. The epidermal cell (E) contains intact fungal hyphae (arrow), and digested fungal hyphae (arrowhead) are present in the cortical cell (C). Scale bar = 10 μm. b In the epidermal cell, a number of intact fungal hyphae (F) are present and are separated from the host cytoplasm by an enveloping interfacial matrix and host plasma membrane. Scale bar = 2 μm. c The penetration of fungal hyphae into the cortical cell (arrow). Inside the cortical cell, fungal hyphae are digested and become compressed (arrowheads). Scale bar = 2 μm. d After fungal hyphae penetrate the cortical cell, the fungal wall becomes thickened (arrow) by wrapping around additional material of the interfacial matrix and/or host plasma membrane cover. Scale bar = 1 μm. e In the cortical cell, several electron-dense endocytic tubules (arrows) attach a digesting fungal hypha. In cross sections, the tubular networks appear as numerous vesicles. Scale bar = 1 μm. f A compressed fungal hypha is surrounded by numerous electron-dense endocytic tubules. Scale bar = 1 μm