Multiomics Insights into the Ecotoxicological Effects of Soil Microplastics on Crop Plants

Microplastics (MPs) have become pervasive contaminants. This is due to plastic mulching, wastewater irrigation, and sludge application. Concentrations of MPs in intensive farming regions have been recorded at 41,741 particles/kg. MPs are absorbed by crop roots and leaves and then travel to reproductive organs. In these organs, they cause oxidative stress, genotoxicity, and toxicity, which disrupts nutrient uptake, photosynthesis, and crop yield. This review summarizes 20 years (2003-2024) of studies on MP-distribution in soil-crop systems and their phytotoxicity mechanisms, highlighting the pioneering role of multiomics methods. Genomic analyses show that MPs cause DNA damage and change the expression levels of stress-response genes. Transcriptomics identifies disrupted pathways. These pathways are in carbohydrate metabolism, plant hormones, and antioxidant defense. Proteomics uncovers post-translational modifications. These affect nutrient transporters. Metabolomics further highlights disturbances in glycolysis, amino acid synthesis, and ROS-scavenging metabolites. Despite these advances, integrating multiomics data sets to elucidate systemic "gene-protein-metabolite" networks remains challenging. Key knowledge gaps include MP-protein binding mechanisms, the development of crop-specific biomarkers, and the interaction of MPs with costressors. Future research should prioritize integrated transcriptomic-metabolomic profiling to identify stress-response pathways, use X-ray crystallography to map MP-protein interactions, and develop MP-resilient crop varieties. Multiomics integration is essential for decoding the toxicity of the MPs and formulating mitigation strategies to safeguard the sustainability of agriculture.