Elevated Atmospheric CO2 Modifies Mostly the Metabolic Active Rhizosphere Soil Microbiome in the Giessen FACE Experiment
David Rosado-Porto, Stefan Ratering, Massimiliano Cardinale, Corinna Maisinger, Gerald M. Moser, Marianna Deppe, Christoph Müller, Sylvia Schnell
Abstract
Abstract Elevated levels of atmospheric CO 2 lead to the increase of plant photosynthetic rates, carbon inputs into soil and root exudation. In this work, the effects of rising atmospheric CO 2 levels on the metabolic active soil microbiome have been investigated at the Giessen free-air CO 2 enrichment (Gi-FACE) experiment on a permanent grassland site near Giessen, Germany. The aim was to assess the effects of increased C supply into the soil, due to elevated CO 2 , on the active soil microbiome composition. RNA extraction and 16S rRNA (cDNA) metabarcoding sequencing were performed from bulk and rhizosphere soils, and the obtained data were processed for a compositional data analysis calculating diversity indices and differential abundance analyses. The structure of the metabolic active microbiome in the rhizospheric soil showed a clear separation between elevated and ambient CO 2 (p = 0.002); increased atmospheric CO 2 concentration exerted a significant influence on the microbiomes differentiation (p = 0.01). In contrast, elevated CO 2 had no major influence on the structure of the bulk soil microbiome (p = 0.097). Differential abundance results demonstrated that 42 bacterial genera were stimulated under elevated CO 2 . The RNA-based metabarcoding approach used in this research showed that the ongoing atmospheric CO 2 increase of climate change will significantly shift the microbiome structure in the rhizosphere.