Cytology of basidiospore germination, penetration, and early colonization of Phaseolus vulgaris by Uromyces appendiculatus var. appendiculatus

Abstract

GOLD, R. E., and K. MENDGEN. 1984. Cytology of basidiospore germination, penetration, and early colonization of Phaseolus vulgaris by Uromyces appendiculatus var. appendiculatus. Can. J. Bot. 62: 1989Bot. 62: -2002. Cytological studies were done on a compatible interaction between Phaseolu.\ vulgaris and Uromyces appendiculatus var. appendiculatus. The cytoplasm of germinated basidiospores contained numerous microbodies in close association with lipid bodies. vacuoles, and endoplasmic reticulum. A single, polar germ tube commonly developed from a germinating basidiospore. The germ tubes tended to grow toward or along the junction lines between host epidermal cells. Appressorium formation in ca. 75% of all observations occurred less than 3.5 fLm away from the lines of juncture. A mucilaginous exudate was associated with germ tubes and appressoria along areas of contact between host and fungus. Epidermal wall papillae were often observed beneath basidiospores and appressoria but did not restrict entrance of the fungus. The fungus directly penetrated the epidermal cell and invaginated the host plasma membrane. The apex of the penetration peg expanded to form an ovate intraepidermal vesicle. Electron-opaque material occluded the penetration pore after migration of the usually binucleate protoplast into the vesicle. The intraepidermal vesicle developed apically and formed a multicellular primary hypha that initially was multinucleate and later became uninucleate or binucleate. jonction entre les cellules epidermiques de I'h6te. La formation d'appressorium dans ca. 75% de toutes les observations ont lieu amoins de 3.5 fLm des Iignes de jonction. Un exsudat mucilagineux est associe al'hyphe germinatif et aux appressoriums le long des surfaces de contact entre I'h6te et le champignon. Les papilles des parois epidermiques s'observent souvent sous les basidiospores et les appressoriums mais n'empechent pas l'entree du champignon. Le champignon penetre directement la paroi epidermique et invagine la plasmalemme de I'h6te. L'apex de l'hyphe de penetration se gontle pour former une vesicule intraepidermique ovoi'de. Un materiel opaque aux electrons obstrue le pore de penetration apres la migration du protoplaste usuellement binuclee dans la vesicule. La vesicule intraepidermique se developpe de fa<;on apicale et forme un hyphe multicellulaire primaire qui est multinuclee au depart et plus tard devient uninuclee ou binuclee. L'hyphe primaire se developpe alors dans les cellules epidermiques adjacentes soutendant les cellules du parenchyme palissadique et tapissant les espaces intercellulaires.[Traduit par le journal] Introduction Early studies of host penetration by rust basidiospore germlings were done by DeBary (\863), Reess (1870), Rathay (\881), Ward (\888), Fischer (\898), Eriksson (\911), Robinson (1913), and Waterhouse (\921). Ruth Alien later confirmed and expanded these initial studies with detailed descriptions and illustrations of basidiospore-derived rust infections (1930, 1932a, 1932b, 1934, 1935). Parallel to A...

Histopatologia da interação Alternaria solani e tomateiros resistente e suscetível

“…Apesar da aparente ausência de orientação do crescimento dos tubos germinativos, a maioria dos apressórios formou-se nas junções de células epidérmicas (Figuras 1 e 2), embora um número considerável tenha se formado sobre o complexo estomatal (Figura 2-B, C e F). A predominância de apressórios formados nas junções de células epidérmicas ocorre comumente em outras espécies de Alternaria e outros gêneros fúngicos (Murray & Maxwell, 1975;Gold & Mendgen, 1984;Aveling et al, 1994;McRoberts & Lennard, 1996). No entanto, essa tendência geral de os patógenos formarem apressórios nas junções de células, independentemente da espécie vegetal, pode significar que os estímulos para a formação de apressórios nessas espécies sejam características gerais da topografia foliar e das flutuações de nutrientes no microambiente das junções celulares.…”

Penetration and early colonization in basidiospore-derived infection ofMelampsora pulcherrima(Bub.) Maire onMercurialis annuaL.

“…The very limited development of M. pukhemma basidiospore germ tubes and their random behaviour on the surface of the host organ appear to be a commonly found aspect of basidiospore-derived germ tubes (GRAY et al 1983;HoPKIN et al 1988;MoRIN et al 1992), although GoLD and MENDGEN (1984a) in Uromyces appendiculatus var. appendiculatus report a tendency of the germ tube to grow along the host epidermal cell junction, probably due to some contact or chemical responses (WYNN and STAPLES 1981).…”

“…In fact several authors maintain it is more probable that basidiospore germ tubes penetrate through the epidermal areas near cell wall junctions towards which germ tube growth occurs (GoLD and MENDGEN 1984a;HoPKIN et al 1988;MoRIN et al 1992). From the number of penetration cases calculated on the observed «whole mounts» of M. annua inoculated leaves, it appears that basidiospore germ tube penetration of M. pukhemma occurs with the same probability through the periclinal or the anticlinal epidermal cell walls.…”

“…The structural and ultrastructural study of the early phases of infection of M. pulcherrima on the leaves of M. annua has the following purposes: 1) to help elucidate the still debated problem concerning the rust basidiospore-derived penetration pattern be it direct (through the epidermal cell walls) or indirect (through stomata), in relation to the characteristics of the host tegumental tissues and the presence of stomata on the organ involved in basid!ospore germling penetration; 2) to observe the penetration and early colonization of the monokaryotic infection process (intraepidermal structures and thence der-ived intracellular productions) of M. pulcherrima in comparison with the monokaryotic analogous structures of other rusts of which some reports have been published to-date (GoLD andMENDGEN 1984a, 1984b;GRAY et al 1983; GoLD and MENDGEN 1991; MoRIN et al 1992).…”

Surface polymers of the nematode-trapping fungus Arthrobotrys oligospora

“…Numerous electron microscopic studies suggest that adhesion of fungi to surfaces is mediated by extracellular polymers (EP) (Gold & Mendgen, 1984;Latge et al, 1986;Veenhuis et al, 1985;Mims & Richardson, 1989;Onyile et al, 1982;Hyde & Jones, 1989). According to these studies, the structure of such polymers varies from amorphous liquids to fibrillar polymers, and cytochemical and chemical analysis indicates that EP layers consist of polysaccharides and/or proteins or glycoproteins.…”