Characterization of the anthocyanin biosynthesis pathway at the metabolic level in the red leaves of Pistacia chinensis

Pistacia chinensis is a tree species with colorful leaves and great ornamental value. The molecular mechanism of its anthocyanin biosynthesis has been described from the transcriptional level. However, the type of anthocyanin cannot be obtained from the transcription level, which leads to the ambiguity of anthocyanin biosynthesis pathway. In this study, the pathway of anthocyanin biosynthesis was described from the metabolic level. A total of 27 anthocyanins, five procyanidins, and six flavones were identified and quantified in the red leaves of P. chinensis in autumn using UPLC-MS/MS. The dominant anthocyanin in P. chinensis leaves was cyanidin-3-Ogalactoside, and its content was 121.10 ng/g, which accounted for 95.88% of the total anthocyanins. The content of methylated and acylated anthocyanins was very low, indicating that the anthocyanins in P. chinensis leaves were not prone to methylation and acylation. In addition, procyanidin B1, procyanidin B3, afzelin, and quercetin-3-O-glucoside were identified, and their contents were 12.00 ng/g, 12.84 ng/g, 5.44 ng/g, and 13.72 ng/g, respectively. These metabolites were clearly mapped on the anthocyanin biosynthesis pathway. The anthocyanins biosynthesis in P. chinensis leaves is mainly via the dihydroquercetin pathway. Overall, these results enhanced our understanding of the biochemical basis of leaf coloration in autumn.

Automated summary

This study described the biosynthesis pathway of anthocyanins in Pistacia chinensis leaves from the metabolic level. Various anthocyanins, procyanidins, and flavones were identified and quantified. The dominant anthocyanin in P. chinensis leaves was cyanidin-3-O-galactoside, and methylated and acylated anthocyanins were present in low amounts.