Vegetative development of Uromyces appendiculatus var. appendiculatus in Phaseolus vulgaris

Abstract

GOLD, R. E., and K. MENDGEN. 1984. Vegetative development of Uromyces appendiculatus var. appendiculatus in Phaseolus vulgaris. Can. J. Bot. 62: 2003Bot. 62: -2010. The morphology of intercellular and intracellular hyphae derived from basidiospores of Uromyces appendiculatus var. appendiculatus is described. Light and electron microscopic observations of the bean tust fungus were made on susceptible leaves of Phaseolus vulgaris from 3 to 10 days after inoculation. Following egress from invaded epidermal and palisade parenchyma cells, the fungus grew rapidly and developed extensive intercellular mycelium. An amorphous to fibrillar extracellular matrix was deposited between fungal and host cell walls. Intercellular hyphae grew c10sely appressed to the mesophyll cells and penetrated them to form intracellular hyphae from either a terminal or nonterminal mother cell. Intracellular hyphae were fingerlike, sometimes septate, and generally remained terminal in the invaded mesophyll cell. Occasionally the fungus exited the cell to become an interc.ellular hypha or an intracellular hypha in an adjacent host cell. The plant rarely exhibited a resistantlike reaction at sites of penetration into mesophyll cells.

Rust Basidiospore Germlings and Disease Initiation

“…52) (Colley, 1918;Alien, 1930;Pady, 1935;Gold and Mendgen, 1984b) and electron-microscopic studies (Figs. 53, 54) (Gold et ai" 1979;Littlefield and Heath, 1979;Gray et ai" 1983;Gold and Mendgen, 1984b) have confirmed this. Improved methods of location (Zeyen and Bushnell, 1981) should promote future microscopical analyses of intracellu lar infection structures.…”

“…The extracellular, slimelike substance commonly associated with infection structures will be termed the extracellular matrix (see Gold and Mendgen, 1984b;Mims and Richardson, 1989;Nicholson and Epstein, this volume).…”

“…Several light- (Fig. 52) (Colley, 1918;Alien, 1930;Pady, 1935;Gold and Mendgen, 1984b) and electron-microscopic studies (Figs. 53, 54) (Gold et ai" 1979;Littlefield and Heath, 1979;Gray et ai" 1983;Gold and Mendgen, 1984b) have confirmed this.…”

Host cell responses in susceptible hard pine tissue infected with Endocronartium harknessii

“…However, some recent studies (Chong and Harder 1982;Harder et al 1978) have noted alterations to the host cytoplasm, particularly the endoplasmic reticulum system, in cells invaded by D-haustoria. In the relatively few studies (e.g., Al-Khesraji and Loesel 1981;Gold and Mendgen 1984) that have been done on the compatible reaction to monkaryotic (M)-haustoria (sensu Littlefield and Heath 1979), host cytoplasmic alterations have generally appeared to be less elaborate than those observed in studies dealing with dikaryotic infections. This may imply, as Harder and Chong (1984) have suggested, a less specialized nature to the host-parasite relationship from basidiospore infections.…”