Life cycle and mating compatibility in the Japanese white jelly mushroom, Tremella yokohamensis

In this study, white jelly mushrooms that were collected in Tottori Prefecture, Japan, were identified as Tremella yokohamensis by phylogenetic analysis of the rDNA-ITS region. Fluorescent microscopic analysis using 4',6-diamidino-2-phenylindole staining to visualize the nuclei in each cell revealed that basidiospores isolated from the fruiting body were monokaryotic. Furthermore, monokaryotic yeasts were germinated from these basidiospores and the resulting crossed mycelium was dikaryotic and bore clamp cells, suggesting a heterothallic lifecycle for this species. Crossing between compatible yeast strains, such as TUFC 101924 and TUFC 101925, that were isolated from the same fruiting body, successfully induced development of the filamentous stage bearing clamp connections after 7 d of incubation on Kagome vegetable juice agar medium. Mating compatibility tests employing 15 basidiospore isolates revealed that this fungus possess a bipolar mating system. The results indicated that T. yokohamensis is a heterothallic and bipolar mushroom.