Unraveling the distinct response patterns of abundant and rare fungi to vanadium at nationwide smelting sites

Fungi are essential members of the soil microbiome, exhibiting diverse response patterns to vanadium (V). However, the understanding for community response of both abundant and rare fungi remains poorly understood. This study employed ITS1-targeted amplicon sequencing to investigate the fungi microbiome across nationwide V smelters in China. Abundant and rare fungi were identified based on occurrence frequency and relative abundance. V exhibited a significant effect (p < 0.05) on abundant fungi diversity. Spatially structured environmental factors explained a greater proportion of variation in the abundant fungi (33.6 %), indicating a deterministic assembly pattern. In contrast, rare fungi showed a weaker association with environmental variables (10.2 %), suggesting a more stochastic assembly process. Interspecific association pattern of abundant fungi responded markedly to V levels compared to rare fungi. Keystone taxa in abundant subcommunity contributed more to the network stability, and were closely associated with functional potential related to vanadium detoxification and nutrient cycling, suggesting potential roles in community resilience under V stress. However, their specific functional roles remain to be experimentally validated. This study advances our understanding of fungal responses to vanadium contamination and offers a hypothesis-generating basis for future research aimed at utilizing the functional traits of fungal taxa in bioremediation strategies.