Heterothallic Type of Mating System for Cordyceps cardinalis

Cordyceps cardinalis successfully produced its fruiting bodies from multi-ascospore isolates. However, subcultures of multi-ascospore isolates could not produce fruiting bodies after few generations. Fruiting body production also differed from sector to sector of the same isolate. Single ascospore isolates were then co-inoculated in combinations of two to observe the fruiting characteristics. Combinations of certain isolates produced perithecial stromata formation, whereas other combinations did not produce any fruiting bodies. These results show that C. cardinalis is a heterothallic fungus, requiring two isolates of opposite mating types for fruiting body production. It was also shown that single ascospore isolates are hermaphrodites.

Successful Development of Cordyceps bassiana Stromata from Beauveria bassiana

A specimen of Beauveria bassiana was collected from Yang-yang of Gangwon province, Korea in October 2006. Conidial isolates were prepared from the specimen by the dilution method and inoculated in brown rice medium for fruiting body production. After nearly two months incubation for perithecial stromata developed from single isolates as well as from their combinations. They were determined as Cordyceps bassiana by observing the stromatal characters and their conidial structures. This is the first report of the development of C. bassiana from B. bassiana cultures.

Cultural Characteristics and Fruiting Body Production in Cordyceps bassiana

Single ascospore isolates of Cordyceps bassiana were observed for their colony pigmentation on Sabouraud Dextrose agar plus Yeast Extract (SDAY) plates and were inoculated in a brown rice medium for production of fruiting bodies. Colony pigmentation did not show any relationship with perithecial stromata formation. The isolates were also grown on opposite sides of SDAY agar plates and were observed for vegetative compatibility. Neither vegetative compatibility nor perithecial stromata could be found to be related to each other. It was concluded that fertile fruiting body production was independent of colony pigmentation and vegetative compatibility. Synnemata formation was found to be more common than perithecial stromata formation. This might be due to its highly conidiogenous anamorphic stage, i.e., Beauveria bassiana.