CeO₂ nanoparticles downregulate the expression of AhRbohB6 and AhRbohC18 to improve salt tolerance in peanut

Peanut (Arachis hypogaea L.) holds a pivotal role as a vital oil crop globally. However, its yield and quality often suffer severely due to salt stress. Although nanomaterials have significant potential for enhancing the salt tolerance of crops, research regarding in peanuts remains relatively scarce. Furthermore, our comprehension of the mechanisms and crucial responsive genes involved in nano-enhanced crop salt tolerance is still limited. In this study, we found that foliar application of polyacrylic acid-coated nanoceria (PNC, at 0.6 mM for 5 d) markedly increased the biomass of peanut seedlings under NaCl treatment (at 300 mM for 5 d). Further research found that the PNC application triggered the several processes, including reduced production of reactive oxygen species (ROS), improved antioxidant capacity, and increased K⁺/Na⁺ ratio in peanut seedlings. Transcriptome sequencing (RNA-Seq) results suggest that the enhanced salt stress alleviation effects of PNC in peanuts are likely linked to the regulation of the ROS scavenging system, plant hormone signal transduction, starch and sucrose metabolism activation, and glutathione metabolism. Moreover, RNA-Seq and real time fluorescence quantitative PCR (qRT-PCR) analysis revealed that PNC treatment significantly down-regulated the relative expression levels of most AhRboh genes. Further validation through the virus-induced gene silencing (VIGS) experiment showed that silencing the AhRbohB6 and AhRbohC18 genes conferred enhanced peanut salt tolerance, characterized by decreased ROS content and increased K⁺/Na⁺ ratio. Collectively, our results indicate that AhRbohB6 and AhRbohC18 are key responsive genes involved in PNC-mediated re-establishment of ROS and K⁺/Na⁺ homeostasis, thereby improving salt tolerance in peanuts. This study provides theoretical guidance and practical references for using PNC to enhance crop salt tolerance.