Invasive Chinese tallow is associated with distinct rhizosphere microbial communities, core microbiomes, and functional potential relative to native Loblolly pine

Abstract

Plant invasions frequently reshape belowground microbial communities, yet their effects on rhizosphere microbiome structure and function remain poorly understood. We compared the rhizosphere bacterial and fungal microbiomes of invasive Chinese tallow (Triadica sebifera) and native Loblolly pine (Pinus taeda) using 16S rRNA gene and ITS amplicon sequencing, together with microbial, functional, and soil analyses. Chinese tallow exhibited significantly greater bacterial and fungal richness and distinct microbial community composition than Loblolly pine. The invasive rhizosphere was enriched in plant-beneficial bacterial taxa, including Streptomyces, Bradyrhizobium, and Rhizobium, and ectomycorrhizal-associated fungi such as Russula and Cenococcum. This enrichment is consistent with enhanced nutrient acquisition, plant growth promotion, and stress tolerance, potentially favoring Chinese tallow establishment and persistence. Further, core microbiome and co-occurrence network analyses revealed extensive reorganization of persistent (Streptomyces, Russula) and highly connected microbial taxa that may be associated with Chinese tallow invasion. Functional predictions indicated greater representation of carbohydrate degradation, nitrogen fixation, plant growth promotion, nutrient mineralization, and ectomycorrhizal guilds in the Chinese tallow rhizosphere, whereas lignin degradation and saprotrophic or pathogen-associated fungal guilds were relatively more abundant under Loblolly pine. Soil physicochemical properties were also strongly correlated with dominant bacterial and fungal taxa, indicating that host-mediated microbial recruitment and environmental filtering jointly shaped rhizosphere community assembly. Overall, our findings identify rhizosphere microbiome reassembly as an important belowground feature associated with Chinese tallow invasion.