Fig. 6

Schematic diagram of early post-penetration growth in susceptible rice cells. Pre-penetration: M. oryzae conidium (white; three-celled) germinates and forms an appressorium (circle) containing one nucleus (blue circle). Post-penetration: (Stage 1) The appressorium penetrates the host cell wall, forming an anucleate filamentous primary hypha (gray) with the tip BIC (red). (Stage 2) The tip of the filamentous primary hypha swells and the tip BIC becomes the side BIC (red). The primary hypha remains anucleate. (Stage 3) Nuclear division occurs in the appressorium. (Stage 4) One mitotic nucleus migrates into the bulbous portion of the primary hyphal tip, while the other nucleus remains in the appressorium. (Stage 5) The first septum forms in the filamentous portion of the primary hypha (blue line), finalizing the establishment of the effector-secreting BIC-associated cell. (Stage 6) Polarized growth resumes from the BIC-associated cell