Bacterial communities of soybean root and non-root soil when exposed to two sizes of polybutylene adipate-co-terephthalate microplastics

The rhizosphere effect on biodegradable microplastic (BMP) degradation in agroecosystems remains poorly understood. This study investigated soybean root-driven acceleration of polybutylene adipate-co-terephthalate microplastics (PBAT-MPs) degradation in soil using quantitative proton nuclear magnetic resonance. Soil bacterial community analyses and metabolomic profiling demonstrated an adaptive evolution of Proteobacteria-dominated communities, particularly genera such as Bradyrhizobium and Ramlibacter, which were associated with PBAT hydrolysis and metabolite utilization. Consequently, given the comparable degrees of community specialization in both compartments, the increased microbial biomass in the root zone appears to be the primary mechanism driving the enhanced degradation of PBAT-MPs. These findings elucidate plant-mediated microbial strategies to mitigate soil biodegradable plastic persistence, informing sustainable mulch management in agroecosystems.