Trace metal ions are strongly associated with the structural variation in vineyard soil microbial communities along...

Microorganisms play a crucial role in soil ecosystems by facilitating nutrient cycling and enhancing soil fertility, which in turn significantly affects plant growth. However, current knowledge on changes in soil microbial communities and their drivers in vineyards under anthropogenic management along altitude gradients is still limited. To address this gap, we employed high-throughput sequencing to examine variations in microbial community composition, diversity, co-occurrence networks, and assembly processes in vineyard soils across an altitude gradient (2,017-2,738 m), and further identified the important correlates associated with these variations. The results indicate that altitude gradients significantly shape the composition and diversity of microbial communities in vineyard soils (p < 0.05). With increasing altitude gradient, the relative abundance of the bacterial phyla Bacteroidetes and Entotheonellaeota increases significantly, while that of Gemmatimonadetes decreases significantly. The fungal phyla Ascomycota, Olpidiomycota, and Chytridiomycota reach their highest levels at elevated altitudes. Furthermore, the α-diversity of microbial communities, bacterial network complexity, and the stochastic processes governing both bacterial and fungal communities all exhibit unimodal patterns. Notably, the complexity of the fungal network progressively increases with altitude gradient, primarily through an increase in the fraction of negative correlations among fungal taxa, which may represent a potential ecological strategy for enhancing community stability or resilience to changing environmental conditions. A pronounced distance-decay pattern is evident in microbial communities. Total nitrogen (TN) and exchangeable magnesium (EMg) are identified as important correlates influencing community composition. Hierarchical partitioning reveals that trace metal ions account for a relatively larger fraction of community variability than soil nutrients in our analysis. Available potassium (AK), available phosphorus (AP), and total phosphorus (TP) are associated with the complexity of both bacterial and fungal networks. Additionally, available zinc (AZn) is identified as an important correlate of fungal network complexity. Stochastic processes governing microbial communities are primarily driven by drift and dispersal limitation, with available copper (ACu) and available iron (AFe) showing stronger explanatory power for the assembly of bacterial and fungal communities. In summary, interactions between fungal taxa play a crucial role in enhancing their environmental adaptability, and trace metal ions are among the most important correlates of bacterial and fungal community structure along altitude gradients in vineyards. These findings provide a theoretical basis for future efforts aimed at understanding and potentially managing soil microbial communities in vineyard systems, although a direct link to soil quality improvement requires further investigation.