Chromium contamination affects the fungal community and increases the complexity and stability of the network in long-term contaminated soils

Chromium (Cr) contamination can adversely affect soil ecology, yet our knowledge of how fungi respond to Cr contamination at heavily contaminated field sites remains relatively limited. This study employed high-throughput sequencing technology to analyze fungal community characteristics in soils with varying Cr concentrations. The results showed that Cr contamination significantly influenced soil fungi's relative abundance and structure. Mantel test analysis identified hexavalent chromium (Cr(VI)) as the primary factor affecting the structure of the soil fungal community. In addition, FUNGuild functional prediction analysis exhibited that Cr contamination reduced the relative abundance of Pathotroph and Symbiotroph trophic types. High concentrations of Cr may lead to a drop in the relative abundance of Animal Pathogens. Molecular ecological network analysis showed that Cr contamination increased interactions among soil fungi, thereby enhancing the stability and complexity of the network. Within these networks, specific keystone taxa, such as the genus Phanerochaete, exhibited properties capable of removing or reducing the toxicity of heavy metals. Our studies suggest that Cr contamination can alter indigenous fungal communities in soil systems, potentially impacting soil ecosystem function.