Development of suspension culture technology and hormone effects on anthocyanin biosynthesis for red Cyclocarya paliurus cells

Plant cell culture is a good way to produce anthocyanins owing to its outstanding advantages of short cycles and no limitation on natural environments. However, this method has not been widely used due to the lack of elite cell lines, low yield, and relatively high cost. In the present paper, suspension culture technology of red Cyclocarya paliurus cells was developed to produce anthocyanins, and the effects of hormones on anthocyanin biosynthesis in the cultured cells were investigated through omics. Under the optimized culture conditions and hormones combination, total anthocyanins yield reached 20.81 mg/L. A total of 23 compounds were identified and quantified in the cultured cells by targeted metabolomic analysis of anthocyanins. Hormones showed significant effects on anthocyanins accumulation, and the content of cyanidin-3-O-galactoside and cyanidin-3-O-glucoside increased 1.92 and 1.68 times than that of the control group respectively. Compared with the control group, the optimized hormone combination upregulated the expression levels of key genes in the anthocyanin biosynthesis pathway (flavonoid 3′-hydroxylase (F3′H), dihydroflavonol 4-reductase (DFR), leucocyanidin reductase (LAR), leucoanthocyanidin dioxygenase (LDOX), and anthocyanin-3-O-glucosyltransferase (3GT)) and Transcription factors (TFs) (MYB5, MYB86, ERF003, ERF024, and bZIP44), meanwhile downregulated the expression levels of pathway genes (flavonoid 3′,5′-hydroxylase (F3′5′H) and anthocyanin reductase (ANR)) and TFs (MYB4, MYC2, and bHLH137). Integrative analysis of metabolome and transcriptome indicated that the optimized hormones combination changed TFs’ expression, which further led to the expression change of anthocyanin biosynthesis pathway genes and eventually resulted in a significant increment of anthocyanins biosynthesis in the cultured cells.