Flower color is one of the most ornamental values of Meconopsis wilsonii, but very limited studies have been reported on its flower color formation. The UDP-glycosyltransferase (UGT) gene family plays a crucial role in plant flower color formation. In this study, the full-length transcriptome data of M. wilsonii was used to identify MwUGTs, focusing on protein physicochemical properties’ subcellular localization, and phylogenetic relationships. In addition, sequence analysis, expression pattern analysis, subcellular localization, and functional validation of MwUGT2 were also performed. A total of 26 MwUGTs were identified in full-length transcriptome and clustered into eight subgroups. Phylogenetic analysis and KEGG database annotation showed that MwUGT2 is associated with anthocyanin synthesis and accumulation. Subsequently, based on the expression of MwUGT2 during flower development and in different tissues, it was preliminarily determined that MwUGT2 plays a role in the flower bud stage. Subcellular localization assays suggested that MwUGT2 is present in the nucleus and cytoplasm. Overexpression in Nicotiana tabacum showed that MwUGT2 significantly increased the content of Cyanidin-3-O-glucoside and resulted in dark pink flowers in transgenic plants. In summary, our findings suggest that MwUGT2 plays a crucial role in the biosynthesis of anthocyanin and will also contribute to understanding the mechanisms of flower color formation in M. wilsonii.

Camellia reticulata ‘Tongzimian’ is the lightest-colored cultivar within the species, yet the molecular mechanism underlying its color formation remains elusive. In this study, ‘Tongzimian’ was used to observe phenotypic characteristics during flowering. Through multi-omics analyses, key substances and genes associated with petal fading were identified, clarifying the role of the CrANS gene in regulating floral coloration. Targeted anthocyanin metabolomics showed that procyanidin is the main pigment in ‘Tongzimian’ petals, with cyanidin serving as the key pigment driving color transformation. Transcriptome analysis revealed that low CrANS expression at full bloom is the primary factor reducing cyanidin content. Overexpressing CrANS demonstrated that the gene strongly promotes anthocyanin synthesis in tobacco corollas, thereby deepening flower color. The study suggests that a balance between cyanidin and procyanidin is central in regulating petal color transformation. Collectively, this research provides a novel framework for flower color dilution and supports molecular breeding of flower color in C. reticulata .