Screening,Cloning And Functional Analysis Of BHLH Related To Anthocyanin Synthesis Of Leaf In Paeonia Qiui

Paeonia qiui is a unique wild tree peony in China.Its leaves are purplish red at the early growth stage,with high leaf value.Based on the transcriptomics data of leaves of P.qiui,the bHLH transcription factor gene(PqbHLH1)related to anthocyanin synthesis in leaves was screened,and its function was confirmed by cloning,bioinformatics analysis,expression pattern analysis and functional verification.The main results are as follow:1.The length of the complete CDS sequence was 1920 bp,encoding 639 amino acids.It had two conserved domains that were MYB domain and helix loop helix domain.Cluster analysis showed that PqbHLH1 was polymerized with bHLH related to anthocyanin synthesis,such as AtbHLH2/EGL3 and AtbHLH1/GL3,and had high similarity with VvMYCA1 of grape and LcbHLH1 of Litchi chinensis.Subcellular localization showed that PqbHLH1 transcription factor was located in the nucleus.2.The results showed that the content of anthocyanin was higher at ealy stages than at late stages,which was consistent with the color change of leaves in tree peony.And the expression of PqCHS,PqF3’H,PqDFR and PqANS were all up-regulated at early stages and down-regulated at late stages.However,the expression of PqbHLH1 gene was lower in early stages,which was unconsistent with the content of anthocyanin.The expression of PqbHLH1 gene was tissue-specific.The expression level was higher in sepals and leaves,followed by petals,and lower in pistils and stamens.3.The main roots were reddish brown and accumulated a little anthocyanin in Arabidopsis that overexpressed PqbHLH1 gene,while the roots of wild-type Arabidopsis plants were light.The expression levels of structural genes such as AtCHS,AtCHI,AtF3 H,AtF3’H,AtUFGT and AtFLS in the overexpression lines were significantly higher than those in the wild type,and the contents of anthocyanin and flavonol were also up-regulated.