Applying cross-scale regulations to Sedum plumbizincicola for strengthening the bioremediation of the agricultural soil that contaminated by electronic waste dismantling and revealing the underlying mechanisms by multi-omics.

Abstract

Electronic waste dismantling has induced the surrounding agricultural soils suffered from combined contamination of heavy metals and organic pollutants. Lower efficiency and complex mechanisms of bioremediation remain to be resolved. Here, we adopted regulations to Sedum plumbizincicola cross aboveground and belowground scales to strengthen the bioremediation efficiency. Results showed that the S. plumbizincicola intercropping with the Astragalus sinicus L. that inoculated with Rhizobium had the highest performance in reduction of Cd, PBDEs and PCBs from soils by 0.11 mg/kg, 67.93 μg/kg and 38.91 μg/kg, respectively. Rhizosphere soil metabolomics analysis demonstrated that reductions in Cd and PBDEs significantly associated with 2-Methylhippuric acid and L-Saccharopine, which were involved in phenylalanine metabolism, biosynthesis of amino acids and lysine. Metagenomic analysis revealed that these functional pathways were mediated by Frankia, Mycobacterium, Blastococcus, etc. microbial taxa, which were also significantly altered by regulations. Moreover, regulation regimes significantly affected transcription genes of S. plumbizincicola. Functional annotation revealed that cross-scale regulations significantly improve bioremediation efficiency through microorganisms and metabolites in the rhizosphere and transcription genes of S. plumbizincicola, which were illustrated to promote plant growth and tolerance to environmental stress. Our integration of multi-omics provides comprehensive and deep insights into molecular mechanisms in the cross-scale regulations of S. plumbizincicola, which would favor remediation techniques advances for the soil contaminated by electronic waste dismantling.