Root traits and belowground herbivores relate to plant\u2013soil feedback variation among congeners

Rutger A Wilschut,Wim H Van Der Putten,Paolina Garbeva,Henk Martens,Stefan Geisen,Paula Harkes,Wouter Konings,Purva Kulkarni

doi:10.1038/s41467-019-09615-x

Rutger A Wilschut, Wim H Van Der Putten + Show 6 more

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https://doi.org/10.1038/s41467-019-09615-x

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Abstract

Plant–soil feedbacks contribute to vegetation dynamics by species-specific interactions between plants and soil biota. Variation in plant–soil feedbacks can be predicted by root traits, successional position, and plant nativeness. However, it is unknown whether closely related plant species develop more similar plant–soil feedbacks than more distantly related species. Where previous comparisons included plant species from distant phylogenetic positions, we studied plant–soil feedbacks of congeneric species. Using eight intra-continentally range-expanding and native Geranium species, we tested relations between phylogenetic distances, chemical and structural root traits, root microbiomes, and plant–soil feedbacks. We show that root chemistry and specific root length better predict bacterial and fungal community composition than phylogenetic distance. Negative plant–soil feedback strength correlates with root-feeding nematode numbers, whereas microbiome dissimilarity, nativeness, or phylogeny does not predict plant–soil feedbacks. We conclude that root microbiome variation among congeners is best explained by root traits, and that root-feeding nematode abundances predict plant–soil feedbacks.

Highlights

Plant–soil feedbacks contribute to vegetation dynamics by species-specific interactions between plants and soil biota
We examined how rhizosphere microbiome variation related to phylogenetic distance within this genus, as the microbiome is expected to underlie plant–soil feedback effects[12]
Plant–soil feedbacks can strongly differ between native plant species and introduced exotics, which may contribute to the success of non-native plant species in their new range[4,24,25]

Summary

Introduction

Plant–soil feedbacks contribute to vegetation dynamics by species-specific interactions between plants and soil biota. The effect of plant relatedness on plant–soil feedback effects on conspecifics has so far only been tested along a wide phylogenetic gradient[17] In these types of comparisons, deeply conserved traits, which show variation on higher taxonomic levels such as plant families, will likely determine the presence of a phylogenetic signal. Such studies may not be suitable to test whether phylogenetic distances can be used to understand variation in plant–soil feedbacks among closely related congeneric species. We test the hypothesis that differences in rhizosphere community composition and plant–soil feedback among rangeexpanding and congeneric native plant species, and the traits underlying this variation, are explained by their phylogenetic distances. Thereby, we relate plant–soil feedback effects to variations in soil community composition and belowground plant traits, and determine whether closely related plant species have a more comparable plant–soil feedback than more distantly related plant species

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