Transcriptomic Analysis of Dibenzofuran Degradation by Burkholderia sp. FM-2 Under Cd(II) Stress

Co-contamination with dibenzofuran (DBF) and cadmium (Cd(II)) poses a major challenge in environmental remediation. While Burkholderia sp. can degrade polycyclic aromatic hydrocarbons and tolerate heavy metals, the coordinated mechanism governing DBF degradation under high Cd(II) stress remains elusive. Here, we characterize Burkholderia sp. FM-2, which optimally degrades 600 mg/L DBF at pH 6.0 and 25 °C, achieving 91.8% removal within 48 h. FM-2 exhibits exceptional Cd(II) tolerance, with a minimum inhibitory concentration of 2000 mg/L. UPLC-MS/MS confirms DBF degradation via dioxygenase-mediated hydroxylation and sequential enzymatic reactions. Transcriptomics reveals, for the first time, concurrent upregulation of genes encoding RND efflux pumps, ABC transporters, P-type ATPases, and core DBF-degrading enzymes under high Cd(II) stress, enabling the synergistic maintenance of intracellular Cd(II) homeostasis and efficient DBF degradation. Collectively, FM-2 remediates DBF-Cd(II) co-contamination via coordinated transcriptional regulation of degradation and detoxification pathways, offering a promising strain resource and molecular basis for the bioremediation of co-contaminated environments.