Neighboring trees regulate the root-associated pathogenic fungi on the host plant in a subtropical forest.

Keke Cheng,Shixiao Yu

doi:10.1002/ece3.6094

Abstract

Root‐associated fungi and host‐specific pathogens are major determinants of species coexistence in forests. Phylogenetically related neighboring trees can strongly affect the fungal community structure of the host plant, which, in turn, will affect the ecological processes. Unfortunately, our understanding of the factors influencing fungal community composition in forests is still limited. In particular, investigation of the relationship between the phytopathogenic fungal community and neighboring trees is incomplete. In the current study, we tested the host specificity of members of the root‐associated fungal community collected from seven tree species and determined the influence of neighboring trees and habitat variation on the composition of the phytopathogenic fungal community of the focal plant in a subtropical evergreen forest. Using high‐throughput sequencing data with respect to the internal transcribed spacer (ITS) region, we characterized the community composition of the root‐associated fungi and found significant differences with respect to fungal groups among the seven tree species. The density of conspecific neighboring trees had a significantly positive influence on the relative abundance of phytopathogens, especially host‐specific pathogens, while the heterospecific neighbor density had a significant negative impact on the species richness of host‐specific pathogens, as well as phytopathogens. Our work provides evidence that the root‐associated phytopathogenic fungi of a host plant depend greatly on the tree neighbors of the host plant.

Highlights

It has been challenging for ecologists to understand the mechanisms by which abundant species coexist in plant communities for decades
Based on second-generation sequencing data, we explored the composition of the root-associated fungal community on different host tree species, categorized fungi to potential pathogen that infect plants, and addressed the following questions: (a) Is the composition of the root-associated fungal and phytopathogenic fungal communities controlled by the host plant?; (b) Does the variation in neighboring plants and habitat influence the composition of the total and phytopathogenic fungal communities?; and (c) How do the densities and phylogenetic relatedness of the neighboring trees and habitat variation affect the abundance and richness of phytopathogens, especially host-specific pathogens?
We defined the composition of root-associated fungal communities in seven plant species from a subtropical forest through the use of a second-generation sequencing approach

Summary

| INTRODUCTION

It has been challenging for ecologists to understand the mechanisms by which abundant species coexist in plant communities for decades. Only a few such studies have reported on the interaction between host plants and their root-associated fungal community, and the influence of habitat variation and neighboring plants, taking phylogenetic distance of neighboring plants into consideration. We explored the relationship between the root-associated fungal community of the host species and the impacts of neighboring trees and environmental variation in a subtropical forest. Based on second-generation sequencing data, we explored the composition of the root-associated fungal community on different host tree species, categorized fungi to potential pathogen that infect plants, and addressed the following questions: (a) Is the composition of the root-associated fungal and phytopathogenic fungal communities controlled by the host plant?; (b) Does the variation in neighboring plants and habitat influence the composition of the total and phytopathogenic fungal communities?; and (c) How do the densities and phylogenetic relatedness of the neighboring trees and habitat variation affect the abundance and richness of phytopathogens, especially host-specific pathogens?

| MATERIALS AND METHODS

Findings

| DISCUSSION