Pigment profile and gene analysis revealed the reasons of petal color difference of crabapples

Crabapples have high ornamental value because of their bright and colorful flowers. Thus, in order to reveal the reasons for the difference in crabapples petals color, color parameters, chlorophyll, carotenoid, and total anthocyanin contents as well as the composition and content of anthocyanin-related flavonoids, and the expression levels of anthocyanin biosynthesis-related genes in petals of five crabapples were measured in this study. The relationship between flower color and possible influencing factors was also analyzed. The results of this study show that anthocyanins play a dominant role in crabapple petal coloration. A total of four flavan-3-ols, three anthocyanins, three flavonols, two dihydroflavones, and one dihydrochalcone were identified and quantified from crabapple peal. Data reveal that cyanidin-3-O-galactoside is the most abundant in crabapple petals among anthocyanins. Data show that total anthocyanin content gradually increased while expression levels of gene coded phenylalanine ammonia lyase (PAL), chalcone isomerase (CHI), dihydroflavonol 4-reductase (DFR), anthocyanidin synthase (ANS), anthocyanidin reductase (ANR), and UDP-glucose: flavonoid 3-O-glucosyltransferase (UFGT) in the anthocyanin biosynthetic pathway all trended upward. The results obtained in this study provide new reference data and insights on reasons of crabapple petal coloring differences.