[Plant Growth-promoting Bacteria Alleviate the Toxic Effects of Soil Microplastics and Heavy Metal Complex Pollution in ].

The coexistence of microplastics and heavy metals in soil can lead to more intricate environmental effects. While plant growth-promoting bacteria have been widely recognized for enhancing the remediation of heavy metal-contaminated soils, little research has been conducted to investigate whether they can alleviate the stress of microplastic-heavy metal composite contamination on plants. We investigated the effects of isolated and screened plant growth-promoting bacteria on the growth and cadmium （Cd） accumulation of under the composite pollution of Cd and polypropylene （PP） with different particle sizes （6.5 and 830 μm） in pot experiments and analyzed their effects on the composition of rhizosphere bacterial communities using high-throughput sequencing. Seven strains of bacteria were isolated and screened from soil contaminated with heavy metal-microplastic composites, identified as and spp. All exhibited plant growth-promoting characteristics, including IAA production, siderophores, phosphorus solubilization, and potassium solubilization. Inoculation of plant growth-promoting bacteria increased the length and dry weight of , effectively alleviating the stress caused by PP+Cd compound pollution. Plant growth-promoting bacteria increased soil available potassium and available phosphorus content, mitigating the decrease in soil mineral nutrients caused by PP+Cd composite pollution. PP+Cd compound pollution and plant growth-promoting bacterial inoculation affected the composition of the rhizosphere bacterial community of , influencing dominant populations such as Proteobacteria, Firmicutes, and Actinobacteria. This study observed that the isolated and screened plant growth-promoting bacteria can effectively alleviate the plastic-heavy metal complex pollution caused by This provides a theoretical basis and data support for the remediation of microplastic heavy metal complex-contaminated soil biological pollution.