Ascosporic iterative germination in Epichloe typhina

Ascospores of Epichloe typhina germinated and produced phialides and conidia within a 24 h period, but produced no mycelium. This type of microcycle conidiation was referred to as iterative germination. All attempts at producing mycelium from ascospores failed; ascospores developed conidia under all cultural conditions tried in the study. Conidia produced during the process were viable, and morphologically similar to those produced in culture by mycelium, and to those produced by the fungus on its host meadow grass, Sphenopholis obtusata. This is the first report of microcycle conidiation by ascospores. Since the ascospores required no thermal or precultural induction period, it was concluded that in contrast to this phenomenon by conidia of other fungi, iterative germination to form conidia by ascospores of E. typhina is obligatory.