Enhancing antioxidant capacity and modulating sensory traits by nano‑selenium foliar biofortification on field Leek moss.

Nano‑selenium presents a promising biofortification strategy for improving the nutritional and sensory quality of Leek moss (the flower stem of Allium tuberosum), yet its molecular basis remains unclear. In a randomized field trial, foliar nano‑selenium application enhanced antioxidant capacity-elevating T-AOC by 45%, SOD/POD/CAT by 20-35% at medium to high concentrations (7.5-10 mg/L), and GSH by 50%-while reducing MDA by 25%. Metabolomic profiling identified 170 differential metabolites, including upregulated flavonoids, phenolic acids, and vitamins (C, B5, B6), alongside reduced sulfurous volatiles such as ACSO and allicin, indicating enhanced nutritional quality and moderated pungency. Transcriptomic analysis revealed 4225 differentially expressed genes, with nano‑selenium specifically activating phenylpropanoid and MAPK signaling pathways, stimulating secondary metabolism and lignin biosynthesis, and repressing CSO biosynthetic genes responsible for pungent flavor. Weighted gene co-expression analysis confirmed nano‑selenium's unique regulatory modules enriched in phenylpropanoid metabolism and reactive oxygen species (ROS) responses. These multi-omics findings demonstrate that nano‑selenium outperforms sodium selenite in promoting antioxidant defense, enhancing beneficial metabolites, and modulating flavor and texture through coordinated transcriptional and metabolic reprogramming. Collectively, this study establishes nano‑selenium foliar biofortification as an effective, sustainable approach for improving both health-promoting and sensory traits of Leek moss.