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.