Unveiling Soil Microbiome Adaptation and Survival Strategy Under Vanadium Stress in Nationwide Mining Environments

In the soils of vanadium (V) smelters, a diverse array of microorganisms relies on metabolic activities for survival amid stress. However, the characteristics and functions of soil microbiomes in V mining environments remain unexplored on a continental scale. This study thoroughly investigates the microbial diversity, community assembly, and functional potential of soil microbiome across 90 V smelters in China. Alpha diversity decreases significantly along the V gradient, with V emerging as the primary factor influencing community structure, followed by other environmental, climatic, and geographic factors. The null model reveals that V induces homogeneous selection, shaping co-occurrence patterns and leading to increased number of positive associations, particularly with keystone genera such as f_Gemmatimonadaceae, Nocardioides, Micromonospora, and Rubrobacter under higher V concentrations (>559.6 mg/kg). Moreover, a metagenomic analysis yields 67 metagenome-assembled genomes, unraveling the potential metabolic pathways of keystone taxa and their likely involvement in the V(V) reduction process. Nitrate and nitrite reductase (nirK, narG), and mtrABC are found to be taxonomically affiliated with Micromonospora. sp, FEN-1250. sp, Nocardioides. sp, etc. Additionally, the reverse citric acid cycle (rTCA) likely serves as the primary carbon fixation pathway, synthesizing alternative energy for putative V reducers, highlighting a potentially synergistic relationship between autotrophic and heterotrophic processes that supports microbial survival. Our findings comprehensively uncover the driving forces behind soil community variation under V stress, revealing robust strategies possibly employed by indigenous microorganisms to mitigate the impact of V. These insights hold potential for applications in bioremediation.