Remediation of combined pesticide contamination by plant growth-promoting and degrading consortia and their effects on vegetable rhizosphere microecology

To investigate the efficacy of multifunctional microbial consortia in remediating combined pesticide contamination in the vegetable-soil system and their impact on the rhizosphere microecology of vegetables, this study used bacterial strains isolated and screened from the rhizosphere of pak choi cultivated in pesticide-contaminated fields. Four functional microbial consortia were constructed: plant growth-promoting (T1), pesticide-degrading (T2), dual-functional growth-promoting and degrading (T3), and multifunctional integrated (T4). Through pot experiments, the remediation effect of different consortia on combined pesticide contamination in the soil-pak choi system and their influence on plant quality were systematically evaluated, and high-throughput sequencing was employed to elucidate the underlying rhizosphere microecological mechanisms. The results demonstrated that: 1) The T3 consortium achieved the highest pesticide degradation efficiency in both soil and pak choi, with an average increase of 44.3% and 49.1%, respectively, compared to the control (CK), demonstrating significantly superior performance compared to the other consortia (P < 0.05); 2) T3 treatment significantly promoted pak choi growth (biomass increased by 76.5%), improved nutritional quality (with increases of 15.4%, 17.1%, and 15.2% in vitamin C, soluble sugar, and total protein content, respectively), and enhanced soil fertility; 3) Rhizosphere microbiome analysis revealed that T3 treatment specifically enriched the genera Burkholderia and Massilia. Their relative abundances increased approximately threefold and twofold compared to the T1 and T2 groups, respectively, exhibiting significant positive correlation with pesticide degradation rates. The findings indicate that the growth-promoting and pesticide-degrading microbial consortium (T3) achieves both efficient pesticide degradation and crop quality improvement through the synergistic modulation of rhizosphere functional microbial communities. This study provides a theoretical basis and a promising strategy for the in situ remediation of combined pesticide contamination in agricultural fields.