Teliospores of smut fungi - Teliospore walls and the development of ornamentation studied by electron microscopy

The walls of mature teliospores and the development of ornamentation, as se en by transmission electron microscopy;are described for 37 genera of smut fungi, based on observations of ca. 120 species and on literature. Structur al diversity of mature teliospore walls is due to differences in spore wall layers forming the spore wall (endosporium, middle layer, exosporium, orna mentation) and to different elements forming the ornamentation (exosporium, ornaments, sheath, hyphal wall, adjacent fungal cells, material of the hos t). During teliosporogenesis the outer layers are usually deposited first. At the beginning of the formation of the ornamentation the plasma membrane may be smooth or undulated carrying the developing ornaments on its tips or in its depressions. The ornamentation of some genera appears similar when seen by scanning electron microscopy, but can be the product of different d evelopmental patterns (e.g., warts of species of Farysia, Tilletia, and Ust ilago), however, warty and reticulate ornamentation can both be produced by similar developmental processes (shown, e.g., for species of Cintractia an d Tilletia). Typical structures of title mature teliospore wall and develop mental patterns based on homologous similarities are described for the foll owing groups of genera or species: Macalpinomyces, Melanopsichium, Sporisor ium, and Ustilago infecting members of the family Poaceae; Kuntzeomyces, Te sticularia, and Trichocintractia; Anthracoidea. Cintractia, Heterotolypospo rium piluliforme, and Tolyposporium junci; Glomosporium, Sorosporium, and T hecaphora; Conidiosporomyces, Erratomyces, Ingoldiomyces. Neovossia, Oberwi nkleria, and Tilletia; Entyloma, and genera of the Doassansia group; Liroa, Microbotryum, Sphacelotheca, Ustilago infecting dicotyledons, and Zundelio myces; Aurantiosporium, Fulvisporium, and Ustilentyloma. Special characteri stics of the teliospore wall were observed for the genera Dermatosorus, Doa ssinga, Entorrhiza, Farysia, Mycosyrinx, Rhamphospora, and some species of Tolyposporium.