Plants primed with CeO2 nanoparticles increased DNA methylation level to convey transgenerational salinity tolerance

Salt stress, a major abiotic stress worldwide, adversely affects crop yield and quality. Nano-priming has emerged as a promising strategy to enhance plant salt tolerance. However, whether nano-priming improved plant salt tolerance can be imparted to its next generation is rarely studied. Also, the mechanisms behind nano-priming induced transgenerational stress tolerance in plants are still unclear. Herein, we synthesized negatively charged cerium oxide nanoparticles coated with polyacrylic acid (PNC) and investigated the effects of PNC-priming on salt tolerance in Arabidopsis offspring seedlings. By employing whole-genome methylation sequencing (WGBS) and transcriptome sequencing (RNA-seq), we revealed the molecular mechanism behind PNC-priming transgenerational regulation of salt tolerance in Arabidopsis . The experimental results demonstrate that PNC-priming improved Arabidopsis offspring seedlings salt tolerance, an increase of 21.17% ( p < 0.05) and 52.15% ( p < 0.05) in fresh weight in shoots and roots, respectively. WGBS analysis revealed that PNC-priming induced the changes of DNA methylation in Arabidopsis offspring seedlings under salt stress. Integration of WGBS and RNA-seq data indicated that DNA methylation modulated the expression of genes response to peroxidase (POD) activity, osmotic stress, oxidative stress, and salt stress. PNC-priming also enhanced POD activity (15.69%, p < 0.05) in the offspring seedlings under 100 mM NaCl, thereby maintaining better reactive oxygen species (ROS) homeostasis. Overall, this study further confirms the transgenerational regulation of plant salt tolerance by nanomaterials and elucidates the underlying mechanisms. • Nanoceria-priming induces the changes of DNA methylation level in Arabidopsis offspring under salt stress. • Nanoceria-priming upregulates POD-related gene expression and thus increases POD enzyme activity in Arabidopsis offspring seedlings under salt stress. • Nano-priming is a novel strategy to transgenerationally improve plant stress tolerance.