Earthworm stress adaptation: The pivotal role of viruses in microplastic‑cadmium co-exposure

The impact of composite pollutants on the soil ecological environment has garnered increasing attention, particularly the combined contamination of microplastics (MPs) and heavy metals, which poses a significant threat to soil ecosystem stability and security. This study selected Eisenia fetida as the model organism to investigate the interactions of cadmium (Cd) concentration, MPs concentration, and MPs particle size on soil biota using an orthogonal experimental design. The key stress response nodes under pollutants exposure were identified through CCA-TOPSIS modeling, whereas microbial community succession and functional regulatory genes were characterized by contour analysis coupled with metagenomic sequencing. The results revealed that VP93 helped earthworm in detoxification by lysing Escherichia and Enterobacter , while the HSP90A gene enhances this clearance efficiency. Pseudomonas enhances quorum sensing in bacterial communities and increases the abundance of bacteriophages through the mcp gene-mediated chemotactic system; And the glk gene in earthworms regulates glucokinase, while the paaF gene in soil regulates fatty acid metabolism for energy supply, thus forming a virus-microbe energy-signal transduction axis to assist earthworms in maintaining life in complex polluted environments. These findings offer scientific insights and a novel model framework for assessing ecological security risks associated with MPs and Cd co-contamination. • Introduction of a CCA-TOPSIS model to identify key stress response nodes. • Earthworms use Vibrio phage VP93 to lyse Escherichia and Enterobacter , reducing toxicity. • In earthworms, the glk regulates glucokinase for energy; in soil, the paaF supports FAM. • In Pseudomonas , the mcp gene activates quorum sensing to increase pollutant resistance. • Massilia produces cyclodextrin to encapsulate and neutralize environmental pollutants.