DOI: 10.5061/dryad.bm2qp7n
title: Data from: Host plant phylogeny and abundance predict root-associated fungal community composition and diversity of mutualists and pathogens

description: • Interactions between plants and their root-associated fungi (RAF) may
 influence the relative abundance of tree species and determine forest
 community diversity. Such plant-soil feedbacks in turn depend on the
 degree to which spatial distance and phylogenetic relatedness of host
 trees structure pathogen and mutualist communities, but research detailing
 these aspects of RAF communities is lacking. Here, we characterize
 plant-RAF associations across a diverse plant community, focusing on the
 degree to which RAF communities are structured by spatial distance, host
 phylogenetic relatedness, and host abundance. We compare results for
 different functional groups, including both putative mutualists and
 pathogens, an aspect poorly examined hitherto. • We collected roots at
 regular intervals along ten 50 m by 2 m transects, then used DNA barcoding
 to identify host plants, and characterize the associated fungal community.
 Variance partitioning was used to measure the relative contributions of
 host phylogenetic relatedness and spatial distance to explaining RAF
 community composition. A weighted linear regression was used to measure
 the correlation between host abundance and RAF diversity. • Phylogenetic
 distance among hosts was a better predictor of RAF community composition
 than spatial distance, but this relationship was stronger for putative
 pathogens than for mutualists, suggesting that pathogens show stronger
 host preference than mutualists. Across all functional groups, RAF showed
 similar levels of spatial structure. Additionally, RAF communities of
 locally abundant plants were less diverse than RAF communities of rare
 plants. • Synthesis: We found that RAF communities are structured by the
 phylogenetic relatedness of hosts and, to a lesser extent, by spatial
 distance, with pathogens showing stronger host preference than mutualists.
 Abundant hosts had less diverse RAF communities than rare hosts, which is
 notable because abundant plants tend to experience weaker negative
 plant-soil feedback. Going forward, mechanisms underlying the host
 abundance-RAF diversity relationship warrant further investigation.
 Additionally, the survey approach presented here could be paired with
 experiments linking RAF community composition to plant recruitment.
description: Transect_dataData from ten 50 m by 2 m transects. Data includes all stems greater than 1 cm diameter at breast height, or greater 1 cm basal diameter for climbing plants.Sample_info_1Taxonomic information for root samples, derived from rbcl barcode sequences (rbcLa_root_library.fasta file).Sample_info_2Positions of each root tip sample. Coordinates are listed in decimal degrees.otu_table_standardizedOTU table of all fungi. OTUs found in negative controls were removed, and read counts were standardized by median sequencing depth.taxa_tableTaxonomic and functional guild assignments for all fungal OTUsrbcl_barcode_library_qiimerbcLa barcode reference library used to match root tip samples to plant species.rbcLa_root_libraryrbcLa amplicon sequences (Sanger) from each root sample