DOI: 10.5061/dryad.515j4
title: Data from: Native soilborne pathogens equalise differences in competitive ability between plants of contrasting nutrient-acquisition strategies

description: Soilborne pathogens can contribute to the maintenance of local plant
 diversity by reducing differences in competitive ability between
 co-occurring plant species. It has been hypothesized that efficient
 phosphorus (P) acquisition by plants in P-impoverished ecosystems might
 trade off against resistance to root pathogens. This could help explain
 high plant diversity in severely nutrient-impoverished ecosystems.
 However, empirical evidence of such a trade-off remains scarce. In
 hyperdiverse shrublands in south-western Australia, non-mycorrhizal
 cluster-rooted Proteaceae are very efficient at acquiring P. However,
 Proteaceae co-occur with many other plant species using other
 P-acquisition strategies, such as ectomycorrhizal (ECM) associations. In a
 glasshouse experiment, we grew Proteaceae and ECM plant species from
 hyperdiverse shrublands alone and in competition with each other, and in
 the presence or absence of native soilborne pathogens (Phytophthora spp.).
 We hypothesized that native Phytophthora species are more detrimental to
 Proteaceae than co-occurring ECM plants, due to a trade-off between highly
 efficient P-acquisition and pathogen defence, and that this equalizes
 differences in competitive ability between these two plant groups. When
 seedlings were grown alone, biomass of non-mycorrhizal plants was reduced
 in the presence of Phytopthora, while ECM species were unaffected by this
 pathogen. When non-mycorrhizal and ECM species were planted together, ECM
 plants grew better in the presence of Phytophthora than in its absence,
 because Phytophthora reduced the growth of the non-mycorrhizal
 competitors. Growth of ECM plants was positively correlated with per cent
 root colonization by ECM fungi, but this was only significant when ECM
 plants were grown in the presence of Phytophthora. Synthesis. Our study
 shows that native soilborne pathogens equalized differences in competitive
 ability between seedlings of contrasting nutrient-acquisition strategies,
 thus supporting the hypothesis proposing a trade-off between highly
 efficient P-acquisition and resistance against root pathogens. We found
 that non-mycorrhizal cluster-rooted species may be the most efficient at
 acquiring the growth-limiting resource, but that co-occurring ECM species
 are better defended against root pathogens. Our results suggest that
 native soilborne pathogens and ECM contribute to the maintenance of the
 plant hyperdiversity in severely P-impoverished ecosystems.
description: biomass and colonisation
 Experiment 1"strategy" =
 nutrient acquisition strategy, either ectomycorrhizal (EM) or cluster
 root; "inocula" = pathogen streatment, either sterile, strong
 (P. arenaria), or mix (several strains); "species" = plant
 species used; "rep" = number of the replicate; "shoot"
 = shoot biomass (in grams); "root" = root biomass (in grams);
 "total" = total seedling biomass (in grams); "EM" =
 ectomycorrhizal root colonisation (%)exp1
 data.csvNatPatExp2"pot" = pot number where seedlings were located; "strategy" = nutrient acquisition strategy, either ectomycorrhizal (EM) or cluster root; "inocula" = pathogen streatment, either sterile or mix (several strains); "species" = plant species used; "rep" = number of the replicate; "shoot" = shoot biomass (in grams); "root" = root biomass (in grams); "total" = total seedling biomass (in grams); "EM" = ectomycorrhizal root colonisation (%)exp2.full2.csv