Beneficial microbial consortia effectively alleviated plant stress caused by the synergistic toxicity of microplastics and cadmium

Combined pollution from microplastics and heavy metals has garnered research interest because of the potential for complex interactions between these contaminants. Composite functional bacteria present significant benefits in the bioremediation of contaminated soils and have attracted widespread attention. Researchers have yet to elucidate how effectively plant growth-promoting bacterial (PGPB) consortia mitigate the stress induced by combined pollution from microplastics and heavy metals. Pot experiments indicate that combined polyvinyl chloride (PVC) + cadmium (Cd) pollution results in "synergistic toxicity" relative to Cd or PVC pollution alone. The application of PGPB consortia inoculants is more effective than the use of single strains in alleviating stress caused by PVC + Cd pollution. The combined inoculant increased bioenergy plant sorghum growth and biomass and increased the contents of total nitrogen, total phosphorus, total potassium, available potassium, and available phosphorus in the soil. Under combined PVC + Cd pollution conditions, PGPB inoculation affected the composition of the sorghum rhizosphere bacterial community. Cooccurrence network analysis revealed that the PGPB consortia can alter soil bacterial community diversity and increase the stability of soil bacterial communities. PGPB consortia can alter the composition of soil metabolites and impact various metabolic pathways. These changes increase the ability of sorghum plants to respond to PVC + Cd stress. This study revealed that the use of combined PGPB affects the soil inorganic nutrient content and the functional composition of bacterial communities, effectively alleviating stress caused by combined microplastic and heavy metal pollution. These findings provide technical support for the development of bioremediation strategies tailored to address combined microplastic and heavy metal pollution. • PGPB consortia can more effectively alleviate synergistic toxicity. • PGPB consortia improve soil mineral content. • PGPB consortia change the composition of rhizosphere bacterial communities. • PGPB consortia alter rhizobacterial interactions. • PGPB consortia alter rhizospheric metabolic functions.