The mechanism of plants and effective microorganisms combined remediation of heavily TNT-contaminated soil

High concentrations of energetic compounds in soil pose a serious threat to the ecology and human health. In this study, a combination of plant–microbe remediation was used to remediate soil contaminated with high TNT concentrations. This study aimed to reveal the remediation efficiency, metabolic potential, and microbial community structure in high-concentration TNT-contaminated soils following combined remediation. Five plants and microorganisms were combined to remediate soil contaminated with high concentrations of TNT (1434 mg/kg). The TNT residues in the soil were only 69–125 mg/kg after 60 days. The combined plant-microbe remediation enhanced the soil nitrogen cycle, carbon cycle, and phosphorus metabolism. Untargeted metabolome gas chromatography-mass spectrometry analysis showed that the combined remediation restored fatty acid metabolism, amino acid metabolism, and sugar metabolism pathways in TNT-contaminated soil. Subsequent 16S rRNA diversity analysis showed that the combined microbial agents occupied soil ecological niches. Interaction network analysis showed that phytomicrobial remediation improved the rate of recovery of TNT-contaminated soil by reshaping the microbial structure and metabolic cycles.