Cytochemical studies on Puccinia graminis f. sp. tritici in a compatible wheat host. I. Walls of intercellular hyphal cells and haustorium mother cells

Abstract

Walls of intercellular hyphae and haustorium mother cells of the stem rust fungus in wheat leaves were studied cytochemically using lectin probes, periodate-thiocarbohydrazide-silver proteinate or periodate-chromate-phosphotungstate staining, and protease treatment. Up to six possible layers in the haustorium mother cell walls and four in the hyphal walls were resolved. Three outer layers of the haustorium mother cell walls were continuous with the three outer layers of the hyphal walls. The two innermost layers of the haustorium mother cell walls were not continuous with the hyphal walls but formed part of the septum. These two layers differed from the other layers of the haustorium mother cell walls in having no affinity to concanavalin A. In both hyphal and haustorium mother cell walls, components with an affinity for concanavalin A were extractable with protease treatment. Wheat-germ lectin binding occurred throughout the fungal walls except in the two outermost layers. Periodate-sensitive glycosubstances were also common, but the amounts varied among layers. Although some of these glycosubstances were confirmed as polysaccharides containing sugars with vicinal hydroxyl groups, much of the glycosubstances present in the walls was sensitive to protease treatment, indicating a possible glycoprotein composition.