Diversity and Community Structure of Culturable Root Endophytic Fungi Isolated from Cryptomeria japonica Grown at Artificial Forests Along a Latitudinal Gradient
Yosuke Matsuda1*, Yudai Kitagami1, Toko Tanikawa2, Chien-Fan Chen3, Keisuke Obase4
1Laboratory of Forest Mycology, Graduate School of Bioresources, Mie University
2Laboratory of Plant and Soil system, Graduate School of Bioagricultural Sciences, Nagoya University
3Division of Botanical Garden, Taiwan Forestry Research Institute
4Hokkaido Research Center, Forestry and Forest Products Research Institute (FFPRI)
Endophyte is microbes that live inside of healthy plant organs without harming their growth during all or at least for some stages of life cycles. Fungal endophytes in the above-ground have been characterized well, but limited information is available for root endophytic fungi owing to the difficulty to discern them from soil fungi as well as root symbionts of mycorrhizal fungi. The aim of this study was to clarify diversity and community structures of culturable root endophytic fungi of coniferous Cryptomeria japonica (Cupressaceae) grown in different climatic zones. We collected C. japonica roots at 8 artificial forest stands along latitudinal gradients from cool temperate, Hokkaido, to subtropical climatic zones, Taiwan. When fungi appeared inside from surface-sterilized roots, they were defined as endophytes. Successfully cultured isolates were further used for DNA analyses to infer taxonomic affiliations. Extracted DNA was used for conventional Sanger sequences focusing on the ITS region. A total of 398 isolates were obtained from the 8 stands and divided into 112 operational taxonomic units (OTUs). The isolates accounted for 68.8% with the phylum Ascomycota being affiliated into the order Helotiales (29.5%) and Hypocreales (8.9%), otherwise Agaricales (13.4%) in the phylum Basidiomycota. Based on the dissimilarity of OTU communities depicted by a non-metric multidimensional scaling, the communities were significantly clustered with climate zones. The clustering was affected significantly by soil pH, EC and distances among study sites. These results suggested that diverse fungi were associated with C. japonica roots under the influence of climatic and soil environmental factors.