Integrated multi-omics analysis reveals responsive regulation of Pistia stratiotes to combined nanoplastic and cadmium stress

Aquatic plants are increasingly exposed to complex environmental pollutants, including nanoplastics (NPs) and heavy metals such as cadmium (Cd), yet the underlying mechanisms of their combined effects remain unclear. This study employed an integrated multi-omics approach, combining transcriptomics, proteomics, metabolomics, and physiological analyses, to investigate the responses of Pistia stratiotes (P. stratiotes) to NPs, Cd, and their co-exposure. Co-stress significantly impaired photosynthetic performance by downregulating key components of photosystems I and II, electron transport, and adenosine triphosphate (ATP) synthesis, accompanied by reductions in chlorophyll and carotenoid contents. Concurrently, antioxidant defense and secondary metabolite pathways were strongly activated, including enhanced α-linolenic acid metabolism and jasmonic acid biosynthesis, promoting accumulation of candidate metabolites such as Vicenin-2, 2-hydroxylinolenic acid, and Goshonoside F2. Elevated activities of superoxide dismutase (SOD) and catalase (CAT), along with increased malondialdehyde (MDA) levels, indicate intensified oxidative stress and compensatory detoxification. Correlation analysis and partial least squares structural equation modeling (PLS-SEM) further revealed that stress signaling positively associated with antioxidant defenses and secondary metabolism while negatively impacting photosynthetic efficiency, indicating coordinated short-term regulation under combined NPs and Cd exposure. Overall, this study provides an integrated framework illustrating how P. stratiotes balances energy limitation and oxidative defense under emerging composite pollution, providing novel insights into aquatic plant responsive regulation. • Multi-omics reveals responses of P. stratiotes to nanoplastics (NPs), cadmium (Cd), and co-stress. • Co-exposure suppresses photosynthesis via downregulation of photosystems, electron transport, and ATP synthesis. • Antioxidant and secondary metabolism (jasmonic acid, phenylpropanoid pathways) are strongly induced. • Candidate metabolites show coordinated changes with antioxidant and secondary metabolic responses. • PLS-SEM modeling shows a trade-off between enhanced defense and reduced photosynthetic efficiency. • An integrated framework is proposed to elucidate stress-responsive regulation in aquatic plants under combined pollution.