Identification Of Key Genes For Anthocyanin Biosynthesis In Prickly Ash By Combined Transcriptome And Metabolome Analysis

Prickly ash is an economically important tree in China and can be divided into green and red prickly ash according to the color of the peel at the commercial maturity stage.Green prickly ash have a greenish peel;red prickly ash have a red peel.Prickly ash peel color is an important indicator of prickly ash quality and the accumulation of anthocyanins is the main reason for the red color of prickly ash.The key genes and expression patterns of anthocyanin synthesis in prickly ash have not been elucidated yet,and it is important to study the genes related to anthocyanin biosynthesis in prickly ash to improve the quality of prickly ash planting resources.In this paper,transcriptomic and metabolomic analyses of green and red prickly ash fruits at different periods revealed that:(1)Flavonoids and flavonols are the main flavonoid metabolites of prickly ash,and the total flavonoid content of red prickly ash fruits is higher than that of green prickly ash.Anthocyanins were very low in green prickly ash and accumulated in large amounts in red prickly ash.Prickly ash anthocyanins are dominated by cyanidin,with the highest content of cyanidin-3-O-galactoside and cyanidin-3-O-glucoside.Anthocyanins were the most significant differential metabolites between green and red prickly ash.(2)The differentially expressed genes in green and red prickly ash were enriched in prickly ash growth and development and metabolic processes,mainly structural genes and transcription factors.(3)The UFGT and ANS genes are key genes for anthocyanin biosynthesis in prickly ash;ANS genes are mainly expressed during the color change phase and UFGT genes are mainly expressed during the ripening phase.(4)The overall pattern of anthocyanin biosynthesis in prickly ash is as follows: during the expansion stage,the accumulation of precursors is mainly completed and ANS starts to be expressed in large quantities;during the color change stage,anthocyanin precursors are mainly synthesized through ANS and UFGT expression is increased;during the ripening stage,UFGT is expressed in large quantities to promote the rapid synthesis and accumulation of anthocyanins,resulting in the redness of prickly ash peel.Based on transcriptome and metabolome analyses,this paper identifies the main components of anthocyanin in prickly ash,identifies key genes for anthocyanin biosynthesis in prickly ash and reveals the expression pattern of genes related to anthocyanin biosynthesis,aiming to provide useful references for subsequent in-depth studies on prickly ash color traits and provide ideas for improving the quality of prickly ash germplasm resources.