Integrated transcriptome and metabolome analysis unveils the mechanism of color transition in Camellia reticulata ‘Tongzimian’

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 .