Plasticizers determine a deeper reshape of soil virome than microplastics

Viruses play a crucial role in shaping local and global biogeochemical cycles, supporting bacterial survival in diverse environments by encoding auxiliary metabolic genes involved in energy acquisition, stress tolerance, and the degradation of organics. However, how plastic pollution influences soil viromes remains largely unexplored, in particular when microplastics and plasticizers are involved in the process. In this study, we conducted an incubation experiment where soil samples from rice fields were exposed to microplastics—polyethylene and polyvinyl chloride and the plasticizer diethyl phthalate to assess their effects on viral communities. After controlled incubation, second- and third-generation sequencing, along with advanced bioinformatics, were used to determine whether viral taxa were impacted by these contaminants. Our results revealed that diethyl phthalate exposure led to a 3.15-fold increase in the proportion of viral sequences in the treated samples compared to control soils, significantly surpassing the modest increases observed for polyethylene (13.08%) and polyvinyl chloride (48.59%). These shifts were accompanied by changes in viral diversity, functional gene content, and virus-host interactions. Notably, we identified virus-encoded auxiliary metabolic genes, such as the 3-oxoadipate enol-lactonase (PcaD) gene, which are critical for phthalate degradation. This finding underscores the direct role of phages in facilitating microbial adaptation and pollutant degradation in contaminated soils, suggesting that viral auxiliary metabolic genes could be harnessed for targeted bioremediation strategies to mitigate the environmental impact of plastic pollutants.