Identification of mycobionts in an achlorophyllous orchid, Cremastra aphylla (Orchidaceae), based on molecular analysis and basidioma morphology

Mycorrhizal fungi were isolated and cultured from rhizomes of mycoheterotrophic Cremastra aphylla (Orchidaceae) plants collected in 3 sites across Japan. In total, 5 Cr. aphylla individuals were collected, and 10 fungal isolates were obtained. Sequence analysis of the internal transcribed spacer regions (ITS) of nuclear ribosomal DNA from the fungal samples revealed that all isolates belonged to the genus Coprinellus in the family Psathyrellaceae. All isolates from each site were of the same phylotype. In total, 3 ITS phylotypes were detected. One of the isolates produced fruiting bodies and was identified as Co. domesticus on the basis of macro- and microscopic characteristics of the basidiomata and ITS sequence data. In this study, the sharing of saprobic Psathyrellaceae fungus by the mycoheterotrophic and leafy Cremastra species was newly confirmed.