Abstract
Heavy metal contamination poses an escalating global challenge to soil ecosystems, with hyperaccumulators playing a crucial role in environmental remediation and resource recovery. The enrichment of diazotrophs and resulting nitrogen accumulation promoted hyperaccumulator growth and facilitated phytoremediation. Nonetheless, the regulatory mechanism of hyperaccumulator biological nitrogen fixation has remained elusive. Here, we report the mechanism by which arsenic regulates biological nitrogen fixation in the arsenic-hyperaccumulator Pteris vittata. Field investigations and greenhouse experiments, based on multi-omics approaches, reveal that elevated arsenic stress induces an enrichment of key diazotrophs, enhances plant nitrogen acquisition, and thus improves plant growth. Metabolomic analysis and microfluidic experiments further demonstrate that the upregulation of specific root metabolites plays a crucial role in recruiting key diazotrophic bacteria. These findings highlight the pivotal role of nitrogen-acquisition mechanisms in the arsenic hyperaccumulation of Pteris vittata, and provide valuable insights into the plant stress resistance.