Polystyrene Nanoplastics Impair Transcriptional Resilience to Salt Stress in Rice

Nanoplastics (NPs) and salinity increasingly co-occur in agricultural systems. Here, we investigated how polystyrene NPs (502 nm, 10 mg L-1) impair rice (Oryza sativa L.) recovery from salt (50 mM NaCl). During stress, NPs synergistically amplified ionic toxicity, elevating Na+/K+ ratios 48% above additive predictions. Crucially, this synergism intensified to 60% during recovery, preventing homeostasis restoration. Transcriptomic analysis revealed that NP-salt interactions shifted from additive to antagonistic poststress, disrupting trehalose pathway regulation critical for osmotic adjustment. Additionally, coexposed plants failed to switch from stress- to growth-associated gene modules, exhibiting 34% fewer differentially expressed genes than salt-only plants. These findings demonstrate that NPs compromise transcriptional resilience by disrupting adaptive reprogramming, emphasizing the need for recovery-inclusive risk assessments.