Morphological aspects of rice (var. Piauí) roots at 35 DAG on control (non-inoculated) and colonized by A103, A105, A104 and A101 fungi, unstained (d) or stained with methyl blue (others). (A) Non-inoculated control; (B–H) intercellular melanized hyphae forming structures resembling anastomoses (arrows) (B), a loose intracellular hyphal loop (arrow) (C), melanized intracellular microsclerotia (arrows) (E and F), a cross-section showing melanized intracellular microsclerotium (arrow) in the cortex region tissue of root (D), intracellular melanized septate hyphae (arrowhead) and a cell surrounded by melanized septate hyphae (arrow) (G), an intraradical chlamydospore-like structure (asterisk) in the vascular bundle region (H) formed by A103 fungus in the rice roots; (I–L) intracellular hyphae (arrowheads) (I), melanized intracellular microsclerotia (arrows) (K and L) formed by A105 fungus in rice roots; (M–R) intracellular hyphae (arrowhead) stained with methyl blue (M and N), intercellular melanized hyphae forming structures resembling anastomoses (arrows) (O), an early developmental stage of an intracellular microsclerotia (arrows) (P and Q), melanized microsclerotia (R) formed by A104 fungus in the rice roots; (S) intracellular melanized septate hyphae (arrowhead) and melanized microsclerotia (white arrows) formed by A101 fungus (R). DAG (days after germination). Bar = 20 μm.