The interface between the powdery mildew haustorium and the cytoplasm of the susceptible barley epidermal cell.

Abstract

The host–parasite interface separating the haustorium of Erysiphe graminis and the cytoplasm of the barley epidermal cell is an invaginated portion of the host plasmalemma which becomes thicker, more osmophilic, highly invaginated toward the haustorium, and which loses its transparent central stratum. This extrahaustorial membrane is always 1–4 μm distant from the haustorial wall and at first is covered with a thin layer of normal cytoplasm. Later, the host cytoplasm greatly increases in volume, becomes much less dense, and organelles become less confined.