Culturable fungal endophytes in roots of Enkianthus campanulatus (Ericaceae)

Roots of plants in the genus Enkianthus, which belongs to the earliest diverging lineage in the Ericaceae, are commonly colonized by arbuscular mycorrhizal (AM) fungi. We documented the community of fungal root endophytes associated with Enkianthus species using a culture-based method for better understanding the members of root-colonizing fungi, except for AM fungi. Fungal isolates were successfully obtained from 610 out of 3,599 (16.9 %) root segments. Molecular analysis of fungal cultures based on ribosomal internal transcribed spacer (ITS) sequences yielded 63 operational taxonomical units (OTUs: 97 % sequence similarity cutoff) from 315 representative isolates. Further phylogenetic analysis showed that most (296 isolates) belonged to Ascomycota and were either members of Helotiales (Dermataceae, Hyaloscyphaceae, Phialocephala and Rhizoscyphus ericae aggregate), Oidiodendron, or other Pezizomycotina. Twenty-three out of 63 OTUs, which mainly consisted of Leotiomycetes, showed high similarities with reference sequences derived from roots of other ericaceous plants such as Rhododendron. The results indicated that Enkianthus houses variable root mycobionts including putative endophytic and mycorrhizal fungi in addition to AM fungi.