Higher Relative Abundance of Glomeromycota in Topsoil Under Caragana korshinskii Sand-Fixation Patterns in the Mu Us Sandy Land

Revegetation with native shrubs is central to combating desertification, yet whether and how plants reshape soil microbial communities in ways that may contribute to sand fixation remains poorly understood. Here, we compared three sand-fixation patterns, pure Caragana korshinskii (Cak), pure Corethrodendron fruticosum var. mongolicum (Cof), and mixed C. korshinskii with C. scoparium (CakCos), in the Mu Us Sandy Land using ITS high-throughput sequencing. We focused on the relative sequence abundance of Glomeromycota, a phylum consisting almost exclusively of arbuscular mycorrhizal fungi (AMF), as an indicator of potential AMF-related taxa. The relative abundance of Glomeromycota was 2.3–3.1 times higher in Cak and CakCos than in Cof, with Glomus and Septoglomus as the core enriched genera. Correlation and redundancy analyses identified soil moisture, total carbon, electrical conductivity, and carbon-to-nitrogen (C:N) ratio as key environmental factors associated with this pattern. FUNGuild-based bioinformatic predictions further suggested that C. korshinskii was associated with a shift in the fungal functional balance toward the AM guild while relative to saprotrophic and potentially pathogenic guilds. These findings are correlative and do not establish causation, but they suggest that C. korshinskii may act as an environmental filter that creates nutrient-rich “resource islands” and may be associated with the enrichment of Glomeromycota. Our findings contribute to the development of dryland restoration theory and provide a valuable microbial perspective for optimizing shrub selection in desertification control.