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

Abstract Background: Due to the excellent invasive ability, the plant Sphagneticola trilobata poses 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.