Protoplasts of Pyricularia oryzae P₂: Preparation and Regeneration into Hyphal Form

Abstract

Protoplasts of Pyricularia oryzae P₂, a rice blast mold, were prepared in high yield from the young mycelium of the fungus using lytic enzymes from Bacillus circulans WL12. The majority of the protoplasts had one nucleus per cell. The protoplasts formed a cell wall and eventually reverted to normal mycelial form in liquid medium. The process of regeneration was studied under phasecontrast and electron microscopes. The protoplast built a very thick wall prior to the protrusion of a germ-tube like hypha. Golgi apparatus-like structures appeared in the early stage of regeneration and disappeared later. Electron-transparent amorphous structures accumulated during regeneration. Lomasomes were observed in the regenerated cell walls.