Title Endophytic fungi associated with leaves of Betulaceae inJapan

Diversity and species composition of endophytic fungi on leaves of 11 tree 10 species in Betulaceae were studied, with reference to climatic, tree species, and seasonal 11 variations. A total of 186 fungal isolates were obtained from 190 leaves collected in a 12 subalpine, a cool temperate, and a subtropical forest in Japan and were divided into 46 13 operational taxonomic units (OTUs) according to the base sequences of D1/D2 region of 14 LSU rDNA. The two most frequent OTUs were Muscodor sp. and Nemania sp. in 15 Xylariaceae, followed by Gnomonia sp., Glomerella acutata, Apiosporopsis sp., Asteroma 16 sp., and Cladosporium cladosporioides. The similarities of OTU composition in endophytic 17 2 fungal assemblages on leaves of Betulaceae were generally low among the forests of 1 different climatic regions. Fungal OTU compositions were relatively similar between two 2 Betula species in subalpine forest, whereas seven tree species in cool temperate forest were 3 divided into three groups according to the similarity of endophytic fungal assemblages on 4 the leaves, with four Carpinus species assigned into two of the three groups. The similarity 5 of endophytic fungal assemblages between August and October was relatively high in 6 subalpine forest, whereas the seasonal changes were generally greater (i.e. the similarities 7 among sampling dates were lower) in cool temperate forest. 8