Screening,cloning And Functional Verification Of MYB Related To Leaf Anthocyanin Synthesis In Paeonia Qiui

Paeonia qiui is a wild species of tree peony which is unique to China.Its new leaves are purplish red before flowering.With the development of the leaves,the purplish-red are gradually disappeared,this phenomenon lasts for about 1 month.Therefore,Paeonia qiui has a potential ornamental value in leaves.In this study,the transcriptomics analysis was conducted from the red stage leaf and green stage leaf in P.qiui,and two R2R3-MYB transcription factor genes related to anthocyanin biosynthesis were screened.The two genes sequences were cloned,and bioinformatics analysis,expression pattern analysis and functional studies were performed on these two genes.The main results are as follow:1.The contents of chlorophyll,carotenoid and flavonol were gradually increased during the development of tree peony leaves,the contents in green leaf stage were significantly higher than that of red leaf stage;anthocyanin and proanthocyanin contents were gradually decreased and appeared the same trend,its contents were higher in red leaf stage than that of in green leaf stage.The results showed that the purplish-red faded was mainly caused by the decrease of anthocyanin content,and the increase of chlorophyll,carotenoid and flavonol content.2.Two MYB transcription factor genes related to anthocyanin synthesis were cloned from the tree peony leaves,named PqMYB113 and PqMYB4,respectively.The lengths of the complete CDS sequences were 801 bp and 693 bp,encoding 266 and 230 amino acids,respectively,belonging to the R2R3-MYB transcription factor.It also had typical MYB family conserved domains and functional domain.PqMYB113 had a motif6 and an ANDV motif related to anthocyanin synthesis,and the PqMYB4 had a strong inhibitory EAR motif.3.The expression levels of PqCHS,PqF3 H,PqF3'H,PqDFR and PqANS appeared the same trend and reached the maximum in S3 during the development of tree peony leaves.The expression levels of PqCHS,PqF3 H,PqDFR and PqANS were the lowest in S5,the expression levels of PqF3'H was the lowest in S1.In addition,the expression levels of PqCHI,PqFLS and PqLAR were the highest in S4,the expression of PqCHI and PqLAR was the lowest in S1,and the expression of PqFLS was the lowest in S5.The expression level of PqANR was the highest in S2 and lowest in S5.4.the expression level of PqMYB113 in the red leaf stage was significantly higher than that in the green leaf stage,while the expression level of PqMYB4 in the green leaf stagewas significantly higher than that in the red leaf stage.PqMYB113 and PqMYB4 were expressed in all tissues of tree peony,the expression level of PqMYB113 in other tissues was lower than that in the leaves(except for the S5stage).PqMYB4 was highly expressed in green tissues,such as leaves and sepals,and its expression level was significantly higher than other tissues(petal,stamen,pistil).PqMYB113 was positively correlated with the expression level of PqDFR?PqANS?anthocyanin content,while PqMYB4 was negatively correlated with anthocyanin content.