Penetration of yeast-phase cells of Mycotypha microspora by Piptocephalis fimbriata

Penetration of Y-phase and M-phase cells by P. fimbriata has been investigated by means of transmission electron microscopy. The thick wall of the Y-phase cell becomes eroded enzymatically where it is contacted by the appressorium of the germ-tube and penetration is effected by means of a broad infection hypha. Penetration of the thin wall of the M-phase hypha is effected by a narrow peg arising from the appressorium.