Root economic space is associated with rhizosphere microbial divergence via root metabolite‐mediated pathways in degraded grasslands
Year: 2026
Type: article
Abstract: Grasslands worldwide are experiencing severe degradation due to overgrazing, climate change and anthropogenic disturbances, resulting in substantial declines in biodiversity and ecosystem functioning. Although degradation is known to alter soil properties and disrupt plant–microbe interactions, it remains poorly understood how the root economic space (RES) and its associated rhizosphere metabolites drive the divergent responses of bacterial and fungal community in degraded grasslands. Elucidating these mechanisms is essential for developing effective microbiome‐based restoration strategies. We employed a multi‐omics approach, integrating 16S rRNA and ITS amplicon sequencing with metabolomic profiling, to investigate the rhizosphere microbiomes and metabolites of four plant species across three sites in the Inner Mongolian steppe. We measured root functional traits related to the root collaboration gradient (specific root length and root diameter) and the root conservation gradient (root tissue density and root nitrogen content), along with key soil properties, to disentangle their roles in shaping microbial community structure and diversity. Bacterial communities were significantly structured by host species identity. The root collaboration gradient was directly or indirectly associated with bacterial diversity via metabolite‐mediated pathways, with rhizosphere exudate composition accounting for over 85% of the variation, highlighting plants' capacity to sustain tight associations with bacterial communities under degradation stress. In contrast, fungal communities were largely unresponsive to rhizosphere metabolites and instead structured by degradation‐altered soil properties (e.g. pH, nitrogen), which explained 79.72% of the variance, with the root conservation gradient contributing an additional 20.14%. Network analyses further revealed more cohesive bacterial co‐occurrence patterns, while fungal networks exhibited higher modularity and greater sensitivity to environmental conditions under degradation. These findings demonstrate a robust link between root economic space and rhizosphere microbiome structure. Our study provides an integrative framework that connects plant functional traits and root metabolites to microbial communities in degraded grasslands and highlights the prospect for using targeted plant–metabolite–microbe interactions to enhance restoration outcomes by selecting species that promote beneficial microbial communities. Read the free Plain Language Summary for this article on the Journal blog.
Source: Functional Ecology
Language: English
Subfield: Plant Science
Domain: Life Sciences
SDG: Life on land
Open Access status: gold
Estimated APC paid: $3,000
Awards: G7821058912, G8107776835
OpenAlex ID: W7161986367