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Consecutive monoculture problems significantly suppress the yield and quality of Rehmannia glutinosa Libosch.Previous studies have shown that the spent substrate of Pleurotus eryngii Quel positively affects monoculture problems.However, the mechanisms underlying these effects remain unclear.Thus, in the present study, we conducted experiments to reveal the potential mechanisms of this organism.The soil not previously exposed to R.glutinosa for 15 years, the soil planted with R.glutinosa for one year, and the remediated soil which mixed the soil planted with R.glutinosa for one year with P.eryngii spent substrate were obtained for cultivating R.glutinosa, and the corresponding treatments were regarded as the first year planting (FP), the second year planting (SP), and the remedial second year planting (RSP), respectively.At harvest, the roots were sampled to assess the dry weight, and the rhizosphere soils were sampled to quantify the nutrient and phenolic acids concentrations, and analyse the fungal community composition.The results showed that the most R.glutinosa roots were gained in the FP and then the RSP, while no roots were harvested in the SP.The application of spent P.eryngii substrate improved the soils nutrition, but decreased the phenolic acids contents.The fungal composition within the soils was significantly different: five serious pathogens which were not detected in the FP soil were detected in the SP soil.However, four of five pathogens were not detected in the RSP soil.Additionally, two potential beneficial fungi that were not detected in the SP soil were found in the RSP soil, and one of them was also detected in the FP soil.These results indicated that the allelochemicals and pathogens increased when R.glutinosa was consecutively monocultured.However, the application of P.eryngii spent substrate revised these conditions.The alleviatory effects of the spent substrate likely reflect a synergetic effect, including the supplement of soil nutrition, the degradation of allelochemicals, and the remediation of the unbalanced microbial community.