Glomus iranicum var. Tenuihypharum as a Biofertilizer Modulates Soil Microbial Community Composition and Enhances Soil Carbon Dynamics in Nectarine Cultivation

Abstract

The development of biofertilization strategies based on arbuscular mycorrhizal fungi (AMF) represents a promising approach to enhance crop productivity and soil health while reducing the environmental footprint of conventional fertilization. This study evaluated the effects of Glomus iranicum var. tenuihypharum inoculation on soil physicochemical properties, abundance and diversity of soil microbial communities, and physiological performance of nectarine ( Prunus persica var. nucipersica ) under Mediterranean field conditions. Soil inoculation with G. iranicum var. tenuihypharum significantly increased soil organic carbon, microbial biomass, and basal respiration, together with enhanced plant photosynthetic rate and stomatal conductance. These improvements were accompanied by early, but transient shifts in soil microbial community composition. The structure of the fungal community exhibited a marked alteration at the initial sampling point (30 days after application). Nevertheless, the differences in fungal community composition between inoculated and control soils diminished by the second sampling (90 days after application). This trend suggests a transient shift in plant–soil communication dynamics. Bacterial assemblages also responded, showing a reduction in Actinobacteria (e.g., Rubrobacter , Solirubrobacter ) and an increase in Acidobacteria and Gammaproteobacteria. Additionally, the abundance of the ammonia‐oxidizing archaeon Nitrososphaera increased following inoculation, suggesting potential effects on nitrification processes. Overall, Glomus iranicum var. tenuihypharum enhanced soil carbon storage and microbial activity, while stimulating plant physiological performance, without causing long‐lasting alterations to the native microbiome. These results highlight the potential of products containing Glomus iranicum var. tenuihypharum as biofertilizers as part of a sustainable strategy to improve soil functionality, nutrient cycling, and crop productivity in Mediterranean fruit agroecosystems.