Isolation and identification of mycorrhizal fungi associated with Stigmatodactylus sikokianus (Maxim. ex Makino) Rauschert (Orchidaceae)

The mycorrhizal fungi of Stigmatodactylus sikokianus (Orchidaceae) were isolated and identified to be nearly related to Sebacina spp. in Sebacinaceae (Basidiomycota) by a neighbor-joining phylogenetic analysis based on the sequences of the ITS region of nuclear rDNA. In spite of the geographically separated samplings, high sequence similarity was found among the obtained DNA sequences, which suggested that S. sikokianus might be highly specialized to the group of fungi. It is known that Sebacina spp. are saprobes or ectomycorrhiza-forming fungi. The mycorrhizal fungi of S. sikokianus were regarded to be saprobic from the environment of their habitats.