DOI: 10.5061/dryad.ncjsxksth
title: Data from: Location, but not defensive genotype, determines ectomycorrhizal community composition in Scots pine (Pinus sylvestris L.) seedlings

description: 1. For successful colonisation of host roots, ectomycorrhizal (EM) fungi
 must overcome host defence systems, and defensive phenotypes have
 previously been shown to affect the community composition of EM fungi
 associated with hosts. Secondary metabolites, such as terpenes, form a
 core part of these defence systems, but it is not yet understood whether
 variation in these constitutive defences can result in variation in
 colonisation of hosts by specific fungal species. 2. We planted seedlings
 from twelve maternal families of Scots pine (Pinus sylvestris) of known
 terpene genotype reciprocally in the field in each of six sites. After
 three months we characterised the mycorrhizal fungal community of each
 seedling using a combination of morphological categorisation and molecular
 barcoding, and assessed the terpene chemodiversity for a subset of the
 seedlings. We examined whether parental genotype or terpene chemodiversity
 affected the diversity or composition of a seedling’s mycorrhizal
 community. 3. While we found that terpene chemodiversity was highly
 heritable, we found no evidence that parental defensive genotypeor
 defensive phenoytpeaffected associations with EM fungi. Instead, we found
 that the location of seedlings, both within and between sites, was the
 only determinant of the diversity and makeup of EM communities. 4. These
 results suggest that while EM community composition varies within Scotland
 at both large and small scales, variation in constitutive defensive
 compounds does not determine the EM communities of closely cohabiting pine
 seedlings. Patchy distributions of EM fungi at small scales may render any
 genetic variation in associations with different species unrealisable in
 field conditions. The case for selection on traits mediating associations
 with specific fungal species may thus be overstated, at least in
 seedlings.
description: This dataset is the result of a study investing the effect of
 Scots pine (<em>Pinus sylvestris </em>L.) defensive genotype,
 considered as the abundance of the terpene
 Δ<sup>3</sup>-carene, on the community composition of
 ectomycorrhizal fungi of seedlings. The experiment was
 a fully-reciprocal transplant: six populations of Scots pine in Scotland
 were chosen (three from the west, three from the east), and seed from two
 maternal trees at each population was collected. One maternal tree at each
 site was known to have a low Δ<sup>3</sup>-carene abundance,
 and one was known to have a high Δ<sup>3</sup>-carene
 abundance. Seeds were germinated, and planted into three grids at each
 population. Each grid was 50cm x 50cm in total extent, with 5cm intervals.
 3 - 5 seedlings per maternal family were planted in each grid at each
 site, resulting in a fully reciprocal cross. At the end
 of the experiment, seedlings were harvested. The community composition of
 EM fungi on each seedling was characterised through morphotyping, counting
 the number of root tips of each morphotype on each seedling, as well as
 the number of non-mycorrhizal root tips. The identities of morphotypes
 were then confirmed through molecular barcoding with ITS. For a subset of
 seedlings from 4 growth sites, terpene profiles were generated from needle
 tissue using GCMS. This allowed us to assess both the
 effect of maternal family and terpene character on the EM community
 composition of different seedlings across multiple sites, to investigate
 whether either variable affected association frequency with particular
 fungal species.
description: This dataset contains the full datasets used for the analysis, as
 well as scripts containing the code to run the models. For the MCMCglmm
 community turnover models,.Rdata files are also present containing the
 model runs reported in the manuscript. Please see README.txt for further
 information on the contents of each data file.