Pleomorphic conidiogenesis among strains of Knufia cryptophialidica

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Abstract
Pleomorphic conidiogenesis was examined in four strains of Knufia cryptophialidica Hutchison & Untereiner in culture. The ex-type strain (DAOM 216555) was the most plastic, exhibiting various patterns of conidiogenesis, and was the only strain that produced phialides, that is, the most important diagnostic structure of the genus, although many of these phialides were aberrant and produced abnormally swollen conidia that appeared to lack cytoplasm. Subsequently, hyphae emerged from the aberrant phialides and some of these hyphae later disarticulated to form thallic-arthric conidia. The ex-type strain ceased to produce normal phialides after several serial transfers onto malt extract agar. Endoconidiogenesis in K. cryptophialidica, reported here for the first time, involved subdivision of conidiogenous cells by septation and schizolysis through the septa, and their release was by rupture and subsequent degeneration of the conidiogenous cell wall. Both thallic-arthric and endogenous conidia occurred in all strains and may serve as more reliable diagnostic characters of K. cryptophialidica than phialidic conidia.Key words: black meristematic fungus, endoconidia, phialides.