Multi-omics dissection of CeO2 and ZnO nanoparticle-mediated saline and alkaline stress tolerance in grain amaranth

Lan, Shixia

PLANT NANO BIOLOGY

2026

18

Xu, P; Wan, JP

Soil salinization is reducing agricultural productivity. Amaranth shows promise for cultivation in such soils, but the mechanisms underlying its responses to saline and alkaline stress remain poorly understood. In this study, Amaranthus cruentus was used to investigate how foliar-applied cerium oxide nanoparticles (CeNP) and zinc oxide nanoparticles (ZnONP) enhance amaranth performance under saline (NaCl) and alkaline (Na2CO3, pH 8.5) stress. Nanoparticles alleviated stress-induced growth inhibition, restoring seedling height and enhancing root development. Compared with NaCl stress, CeNP and ZnONP increased seedling height by 11.15% and 11.32%, and root fresh weight by 32.71% and 23.04% under NaCl stress, respectively. Additionally, they similarly enhanced seedling height by 12.61% and 13.10% under alkaline stress. Consistently, SPAD value and chlorophyll declined under both stresses, indicating severe oxidative damage; however, nanoparticle treatments facilitated seedling growth by modulating antioxidant capacity and osmoprotectant accumulation. Alkaline stress triggered a stronger transcriptional disturbance than saline stress. Key gene networks were enriched in ion transport, reactive oxygen species detoxification and redox balance, cell wall remodeling, and osmotic adjustment. WGCNA identified growth trait-associated modules and transcription factors associated with saline and alkaline tolerance. Combined transcriptome and metabolome pathway analysis identified coordinated regulation of glutathione and riboflavin metabolism, tryptophan metabolism, linked to auxin signaling, phenylpropanoid/flavonoid biosynthesis, and ABC transporter pathways. Overall, CeNP and ZnONP enhance amaranth resilience to saline and alkaline stress by coordinately regulating ion homeostasis, antioxidant defense, carbon- and hormone-related metabolism, and transport processes. These findings provide insights for applying nanobiotechnology to sustain crop productivity in saline and alkaline environments.