Enhanced soil remediation of benzo[a]pyrene using combined white-rot fungus and plants: promoting substrate competition and community succession

Microbe-assisted phytoremediation is emerging as one of the most effective methods for degrading organic contaminants in soils through the interaction of plants and their associated rhizosphere microbes. However, the mechanisms behind plant-microbe interactions remain ambiguous. In this study, a 35-day pot experiment was conducted to remediate benzo[a]pyrene using rye (Secale cereale L.) and a white rot fungi (Trametes versicolor) solid-state fermentation agent. The benzo[a]pyrene removal efficiency, soil microbial community structure response, and the effect of Trametes versicolor (T. versicolor) on plant growth were investigated. Results indicated that white rot fungi-assisted phytoremediation was more effective in removing benzo[a]pyrene than plant or fungal treatments alone. The addition of T. versicolor and rye significantly increased dehydrogenase activity in the soil. Although T. versicolor reduced the richness and diversity of the microbial community, they promoted the growth of Chaetomium, Mortierella, Fusicolla. In contrast, the T. versicolor inhibited the growth of rye, and the root reactive oxygen species content in the combined plant-fungi remediation group was significantly higher than in the plant-only group. While this growth inhibition poses challenges for plant vigor, the combined plant - fungi system demonstrated excellent benzo[a]pyrene degradation efficiency and enhanced soil enzymatic activity. Therefore, this strategy may be particularly suitable for situations where pollutant removal is prioritized over biomass accumulation.