Rhizosphere bacterial characteristics reveal the invasive advantage of Sphagneticola trilobata compared to the greening grass Axonopus compressus

Background: Due to the excellent invasive ability, the plant Sphagneticola trilobata p oses a severe threat to local ecosystems . We hypothesized that its invasive success is highly related to its ability of shaping a beneficial rhizosphere microbiome. To test this, we compared the rhizosphere bacterial communities of S. trilobata (SRS) and a common greening grass Axonopus compressus (ARS). Result: We found that S. trilobata cultivates a significantly more diverse and structurally distinct bacterial community, enriched with key taxa (Rhizobiales, Cytophagales, Pseudomonadaceae, Comamonadaceae, and Novosphingobium ) that are known as the groups associated with nitrogen fixation and plant growth promotion, and exhibited a more complex and cooperative interaction network than ARS. Functional predictions indicated an enhanced capacity for lipid and carbohydrate metabolism in SRS, suggesting efficient nutrient cycling around its rhizosphere. Crucially, a synthetic community (SynCom) constructed from SRS-enriched bacteria promoted the biomass of S. trilobata significantly and altered resource allocation towards roots under nutrient-poor conditions. Conclusion: Our findings provide strong evidence that S. trilobata engineers a specialized rhizosphere microbiome that confers direct competitive advantage compared with other local plants, revealing a key microbial mechanism underlying its successful invasion.