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Petroleum contamination poses a serious threat to soil ecosystems, demanding effective and green remediation solutions. This study developed a kind of synergistic strategy combining the plant Tagetes erecta with microbial agent and biochar for treating petroleum-contaminated soil. After a 90-day remediation period, the combined treatment achieved a total petroleum hydrocarbon degradation rate of 76.6 % and reduced all 16 priority polycyclic aromatic hydrocarbons below detection limits. Metabolomic analysis identified 1022 metabolites and revealed significant differences in metabolic profiles, both between rhizosphere and nonrhizosphere soils and between the combined treatment and plant‑only treatment. KEGG pathway and key metabolite analyses revealed that treatments with the microbial agent upregulated the nonribosomal peptide structures pathway and the associated metabolite surfactin. This finding suggests a potential enhancement of biosurfactant-mediated hydrocarbon emulsification. Metabolic pathways related to plant-microbe interactions, such as eicosanoid and arachidonic acid metabolism, were also enriched. Furthermore, the levels of antibacterial metabolites like 3,6-diiodo-9H-carbazole showed decrease in the soil, whereas the levels of plant auxin precursor indole-3-butyric acid increased. These results demonstrate that the remediation approach used in this study can enhance petroleum contaminant degradation by modulating the soil metabolic network and strengthening biological interactions. This strategy dissects the differential metabolic responses under the combined plant-microbe-biochar remediation, providing new insights for the green and sustainable remediation of petroleum-contaminated soil.
Fang et al. (Thu,) studied this question.