Microplastics and Dechlorane Plus co-exposure amplifies their impacts on soybean plant

The co-existence of microplastics (MPs) and organic pollutants on agricultural ecosystems pose potential implications for both food safety and environmental integrity. The combined effects of MPs with Dechlorane Plus (DP), a newly listed banned flame retardant, remain unknown. This study explores the biological responses of soybean plants to exposure from polyethylene (PE) and polyvinyl chloride (PVC) MPs and DP. Results showed that combined exposure altered the activity of antioxidant enzymes and inhibited the growth of soybean plants, compared with DP or MPs exposure alone. DP markedly reduced both the root length and root weight of soybean plants in a dose-dependent manner. Proteomics profiling suggests that PE interacts with protein translation and modification pathways, particularly via the regulation of heat shock protein binding. High concentration DP (HDP) treatment group enhances the plant's stress resistance by regulating relevant proteins through the modulation of hydrogen peroxide catabolic protein expression and the formation of water channel proteins. In the combined treatments, low concentration DP with PVC triggered increased protein expression related to photosynthesis response, further demonstrating the enhanced inhibitory effects. This study for the first time maps the changes in the physiological and the molecular mechanisms of the impacts on higher plant caused by MPs and DP co-exposure.