Plant diversity and functional identity drive grassland rhizobacterial community responses after 15 years of CO2 and nitrogen enrichment

Daniel Revillini, Peter B. Reich, Nancy Collins Johnson

Research output: Contribution to journalArticlepeer-review


Improved understanding of bacterial community responses to multiple environmental filters over long time periods is a fundamental step to develop mechanistic explanations of plant–bacterial interactions as environmental change progresses. This is the first study to examine responses of grassland root-associated bacterial communities to 15 years of experimental manipulations of plant species richness, functional group and factorial enrichment of atmospheric CO2 (eCO2) and soil nitrogen (+N). Across the experiment, plant species richness was the strongest predictor of rhizobacterial community composition, followed by +N, with no observed effect of eCO2. Monocultures of C3 and C4 grasses and legumes all exhibited dissimilar rhizobacterial communities within and among those groups. Functional responses were also dependent on plant functional group, where N2-fixation genes, NO3−-reducing genes and P-solubilizing predicted gene abundances increased under resource-enriched conditions for grasses, but generally declined for legumes. In diverse plots with 16 plant species, the interaction of eCO2+N altered rhizobacterial composition, while +N increased the predicted abundance of nitrogenase-encoding genes, and eCO2+N increased the predicted abundance of bacterial P-solubilizing genes. Synthesis: Our findings suggest that rhizobacterial community structure and function will be affected by important global environmental change factors such as eCO2, but these responses are primarily contingent on plant species richness and the selective influence of different plant functional groups.

Original languageEnglish (US)
Pages (from-to)817-831
Number of pages15
JournalJournal of Ecology
Issue number4
StatePublished - Apr 2024


  • Rhizobacteria
  • elevated CO
  • environmental change
  • nitrogen deposition
  • optimal resource allocation
  • plant functional group

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics
  • Ecology
  • Plant Science


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