Neighboring plant community attributes drive rhizobiome assemblages of a focal plant in a Kobresia meadow

The rhizosphere microbiome (i.e., rhizobiome) plays critical roles in modulating plant performance and fitness. Although plants in natural environments are inevitably affected by neighboring plants, less is known about how attributes of neighboring plant communities affect the rhizobiome of a focal plant. We evaluated the impacts of neighboring plant community attributes (e.g., above- and belowground plant species richness, identity, biomass and composition) on the richness and community composition of rhizosphere archaea, bacteria and fungi associated with Kobresia setchwanensis in an alpine meadow on the eastern Qinghai-Tibetan Plateau. We found that the richness of neighboring plant species both above- and belowground was poorly related to the rhizobiome richness of the focal plant. In contrast, the dissimilarity in aboveground rather than belowground plant community composition was positively correlated with the dissimilarity in the rhizobiome community composition. Aboveground plant community attributes posed stronger effects than belowground attributes on rhizobiome richness and community composition. The identities of neighboring plant species were the most important predictors of rhizobiome richness and community composition. Structural equation modeling further indicated that the effects of neighboring plant community attributes on the rhizobiome composition could be direct or indirect, by impacting bulk soil microbial communities. Our study provides empirical evidence that neighboring plant community attributes are important determinants of the rhizobiome communities of the focal plant in natural environments.

Automated summary

Neighboring plant community attributes, especially the identity of neighboring plant species, have a significant impact on the rhizobiome communities of focal plants. The attributes of aboveground plant communities have a stronger influence on rhizobiome richness and composition than belowground attributes.