Light quality-regulated anthocyanin biosynthesis in Lilium leichtlinii subsp. maximowiczii bulbs: A multi-omics perspective

Abstract

This study elucidated the molecular mechanisms governing light spectrum-regulated coloration and secondary metabolism in Lilium leichtlinii subsp . maximowiczii bulbs during postharvest storage. Chromatic profiling demonstrated that continuous white (WLc) and blue light (BLc) treatments synergistically induced violet-red pigmentation (ΔE = 55.2 and 52.1 at day 12) through rapid anthocyanin biosynthesis (up to 79.39-fold accumulation), while continuous red light (RLc) promoted yellowish-brown discoloration via flavonoid pathway activation. Multi-omics integration showed WLc-mediated reprogramming of light signaling cascades and metabolic networks. Metabolomic analysis identified 177 differentially accumulated metabolites, with cyanidin-3-rutinoside (keracyanin, Fold Change [FC] = 316.53) as the predominant pigment. Transcriptomic profiling uncovered coordinated upregulation of phenylpropanoid ( PAL , C4H , CHS ) and anthocyanin pathway genes ( F3H , DFR , ANS , 3GT ), with 15,823 differentially expressed genes enriched in flavonoid biosynthesis (KEGG, p  < 0.01). Enzyme kinetic analysis highlighted hierarchical gene activation patterns: upstream pathway genes ( CHS , F3H ) exhibited peak expression at day 3, while downstream genes ( DFR , ANS ) gradually increased to synchronize pigment production. Phylogenetic validation confirmed >95% conservation of catalytic domains (2-OG oxygenase in LlF3H/LlANS; MGT motif in Ll3GT) across the Liliaceae family. Environmental factors such as storage temperature and packaging permeability were shown to modulate these light-responsive pathways. This work establishes a comprehensive spectral regulation network model, providing mechanistic insights for lily color breeding programs and spectrum-controlled postharvest technology development.