Micro- and nanoplastics in the environment are of great concern due to their large specific surface area, low surface polarity, and easy adsorption and accumulation of other pollutants. Combined exposure to nanoplastics (NPs) and arsenic (As) poses a significant threat to aquatic plants, but the underlying molecular mechanisms of combined exposure remain unclear.

Researchers from the Wuhan Botanical Garden of the Chinese Academy of Sciences conducted a comprehensive multi-omics analysis of aquatic plant (Vallisneria denseserrulata) under single or combined exposure to NPs and As.

They revealed different degrees of inhibition on the physiological traits of V. denseserrulata under different stress conditions, demonstrating that NPs-As co-stress showed the most pronounced physiological inhibition compared to either stress alone, with As exerting dominant effects.

The integrated transcriptomic and metabolomic analysis revealed three key defense mechanisms of V. denseserrulata in response to NPs and As co-stress. First, carbon fixation and photosynthesis antenna protein pathways regulated photosynthetic intensity in response to NPs-As co-contamination. Second, energy conversion through up-regulated biosynthetic pathways reduced the damage of V. denseserrulata.

Finally, the stimulation of phenylpropane metabolism and fatty acid metabolism affected lipid peroxidation and antioxidant activity, thereby enhancing growth and mitigating toxicity.

These findings have important implications for the ecological risk assessment of emerging contaminants and the protection of vulnerable aquatic ecosystems. Further cross-species validation can confirm the generalizability of these key pathways and biomarkers of stress resistance.

The study titled "Drilling into the physiology, transcriptomics, and metabolomics to enhance insight on Vallisneria denseserrulata responses to nanoplastics and metalloid co-stress" was published in the Journal of Cleaner Production.

This study was supported by the National Natural Science Foundation of China, the Sino-Africa Joint Research Center of CAS, and the Hubei Provincial Natural Science Foundation of China, etc.