SRA

Ectomycorrhizal basidiomycetes and root-associated ascomycetes, including root-endophytic ascomycetes, are one of the most diverse and important belowground plant symbionts in dipterocarp rainforests. Our study aimed to compare the biodiversity, host association pattern, and community structure of ectomycorrhizal basidiomycetes with those of root-associated ascomycetes in a lowland dipterocarp rainforest in Southeast Asia. The host-plant chloroplast large-subunit of ribulose-1,5-bisphosphate caboxylase/oxygenase (rbcL) region, and fungal internal transcribed spacer 2 (ITS2) region were sequenced using a tag-encoded, massively parallel 454 pyrosequencing analysis to identify host plant and root-associated fungal taxa in root samples. In total, 1245 ascomycetous and 127 putative ectomycorrhizal basidiomycetous taxa were detected from 442 root samples. The putative ectomycorrhizal basidiomycetes were likely to be associated with phylogenetically closely related dipterocarp taxa to greater or lesser extents, whereas host association patterns of the root-associated ascomycetes were much less distinct. The community structure of the putative ectomycorrhizal basidiomycetes was possibly more influenced by the host genetic distances than that of the root-associated ascomycetes. This study also indicated that in dipterocarp rainforests, root-associated ascomycetes were characterized by high biodiversity and indistinct host association patterns, whereas ectomycorrhizal fungi showed less biodiversity and a strong host phylogenetic preference for dipterocarp trees. Our findings suggested that root-associated ascomycetes (e.g., root-endophytic ascomycetes, may have biodiversity hotspots in the tropics, whereas biodiversity of ectomycorrhizal basidiomycetes increased with host phylogenetic diversity.