Oryza rufipogon and nanoparticles mitigate nanoplastic toxicity by modulating lignin, cell wall thickening, and...

Nanoplastics (NPs) are increasingly harmful to plants. Oryza rufipogon (wild rice) possesses multi-faceted resilience characteristics. This study examined wild rice huaye3 (HY) tolerance to NPs and the impact of nano selenium (n-Se) on NP stress using the Oryza sativa cultivar meixiangzhan (MX) as a control. Under NPs stress, HY and MX showed different degrees of damage: unlike MX, which experienced a reduction in root and stem length exceeding 20 % and a 36.4 % decrease in chlorophyll ab relative to the control (CK), HY demonstrated superior growth, with root and stem length diminishing by only over 10 % and chlorophyll ab declining by 17.5 % compared to CK. HY also displayed increased lignin deposition, more intact cellular structure (as observed through TEM/SEM/CLSM), and enhanced antioxidant defences (SOD, POD, and GSH). After n-Se application, the stressed plants regained their normal growth (root length of MX and HY increased by 28.6 % and 11.7 %, respectively, under NPs + Se treatment compared to NPs treatment), and cellular structure was improved. Transcriptome analysis revealed distinct differentially expressed genes and key pathways in HY under NPs stress, such as stress signaling responses (MKK, TF, IAA), defense-related pathways (OsGPX5, Os07g0639400, Os06g0681600), as well as genes involved in cysteine (cysE), cellulose (OsCesA), phenylpropanoid biosynthesis, and lignin synthesis (OsCOMT, Os4CL3, OsCCR14/20). Our results suggest that HY may promote the synthesis of cell wall polysaccharides (lignin, cellulose) by regulating genes, such as OsCesA and Os4CL3, to improve its resistance to NPs. This study is crucial for addressing plant and environmental damage caused by NPs.