Transcriptomic and metabolomic insights reveal the mechanisms underlying varied flower colors on a single wintersweet tree

Chimonanthus precox (wintersweet) is a popular woody cut flower with a significant market potential. Among its ornamental traits, flower color is one of the most important attributes that profoundly affects its economic value. To elucidate the mechanisms underlying flower color formation in wintersweet, we used rare materials of C. precox with different flower colors from the same tree. We used liquid chromatography-tandem mass spectrometry (LC-MS/MS) and high-throughput sequencing to analyze differential anthocyanin compositions and transcripts in wintersweet petals with varying flower colors. Our results identified six types of anthocyanins in the petals, with the highest cyanidin content. accumulation of cyanidin-3-O-rutinoside and cyanidin-3-Oglucoside was found to be the primary cause of red coloration in the inner petals of wintersweet. Comparative analysis of the DEGs in the transcriptome led to the identification of 30 structural genes involved in anthocyanin biosynthesis. Heterologous transformation of Nicotiana tabacum revealed that CpDFR1 promotes anthocyanin biosynthesis. Additionally, we identified a potential MYB transcription factor that might regulate anthocyanin synthesis, with its expression level possibly accounting for color variation. This study provides preliminary insights into the mechanisms underlying color differences in petals from the same tree and offers a theoretical basis for the molecular breeding of flower color in wintersweet as well as new strategies for developing diverse color varieties.