Arbuscular mycorrhizal fungi improve the competitive advantage of a native plant relative to a congeneric invasive plant in growth and nutrition.

Plant invasions severely threaten natural ecosystems, and invasive plants often outcompete native plants across various ecosystems. Arbuscular mycorrhizal (AM) fungi, serving as beneficial microorganisms for host plants, can greatly influence the competitive outcomes of invasive plants against native plants. However, it remains unclear how AM fungi alter the competitive balance between native and invasive species. A competitive experiment was conducted using an invasive paired with a native congener . Specifically, both species were inoculated with (M) or without (M) the fungus under intraspecific (Intra-) and interspecific (Inter-) competition. Plant traits were measured and analyzed regarding the growth and nutrition of both species. The results exhibited that the AM fungus significantly increased the height, diameter, biomass, C, N, and P acquisition of both the invasive and the native . The root mycorrhizal colonization and the mycorrhizal dependency of native were greater than those of invasive . Under M, the Inter-competition inhibited the growth and nutrition of invasive compared to the Intra- competition. Further, native exhibited higher competitiveness than invasive in growth and nutrition. Meanwhile, the AM fungus significantly improved the competitiveness of native over invasive . In conclusion, AM fungus improved the competitive advantage of native over invasive in growth and nutrition, potentially contributing to native species competitively resisting the invasion of exotic species. These findings emphasize the importance of AM fungi in helping native plants resist the invasion of exotic plants and further contribute to understanding plant invasion prevention mechanisms.