Integrative Physiological-Biochemical and Multi-Omics Analyses Reveal Regulatory Mechanisms Governing Growth,...

Quinoa is a protein-rich crop and an excellent dietary source of selenium. While selenium application enhances growth and selenium accumulation, its tolerance and underlying molecular mechanisms in quinoa remain unclear. Physiological and biochemical analyses showed that 7.5-12.5 kg/ha is the optimal selenium rate, significantly improving plant height, leaf area, stem strength, photosynthetic performance, and antioxidant capacity, thereby promoting nutrient accumulation. Selenium application markedly increased seed selenium levels (SeG2: 2763.52 μg/kg; SeG4: 5120.82 μg/kg vs CK: 18.85 μg/kg), with SeMet as the dominant form (1113.18 μg/kg). Multiomics analysis revealed significant enrichment of multiple selenium-related pathways, including flavonoid, anthocyanin, and lipid biosynthesis. Twenty DEGs (CqHMT1, CqML, CqMMT, CqGST, CqTTS, CqAGT5, CqANR, CqCHS, CqDAT1, CqLOX2.1, CqDES1) were verified by qRT-PCR, the selenium transport pathway was preliminarily constructed. This study clarifies selenium accumulation and nutritional changes in quinoa, providing new strategies for selenium-enriched agricultural production.