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Article|19 May 2023|OPEN
The combination of DNA methylation and positive regulation of anthocyanin biosynthesis by MYB and bHLH transcription factors contributes to the petal blotch formation in Xibei tree peony
Jin Zhu1,2,3 , Yizhou Wang1,2,3 , Qianyu Wang1,2,3 and Bing Li1,2,3 , Xiaohan Wang1,2,3 , Xian Zhou1,2,3 , Hechen Zhang4 , Wenzhong Xu1,2,3 , Shanshan Li1,2,3 , Liangsheng Wang,1,2,3 ,
1Key Laboratory of Plant Resources, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
2China National Botanical Garden Beijing 100093, China
3University of Chinese Academy of Sciences, Beijing 100049, China
4Horticulture Research Institute, Henan Academy of Agricultural Sciences, Zhengzhou 450002, China
*Corresponding author. E-mail:

Horticulture Research 10,
Article number: uhad100 (2023)
Views: 243

Received: 25 Jul 2022
Accepted: 05 May 2023
Published online: 19 May 2023


Xibei tree peony is a distinctive cultivar group that features red–purple blotches in petals. Interestingly, the pigmentations of blotches and non-blotches are largely independent of one another. The underlying molecular mechanism had attracted lots of attention from investigators, but was still uncertain. Our present work demonstrates the factors that are closely related to blotch formation in Paeonia rockii ‘Shu Sheng Peng Mo’. Non-blotch pigmentation is prevented by the silencing of anthocyanin structural genes, among which PrF3HPrDFR, and PrANS are the three major genes. We characterized two R2R3-MYBs as the key transcription factors that control the early and late anthocyanin biosynthetic pathways. PrMYBa1, which belongs to MYB subgroup 7 (SG7) was found to activate the early biosynthetic gene (EBG) PrF3H by interacting with SG5 member PrMYBa2 to form an ‘MM’ complex. The SG6 member PrMYBa3 interacts with two SG5 (IIIf) bHLHs to synergistically activate the late biosynthetic genes (LBGs) PrDFR and PrANS, which is essential for anthocyanin accumulation in petal blotches. The comparison of methylation levels of the PrANS and PrF3H promoters between blotch and non-blotch indicated a correlation between hypermethylation and gene silencing. The methylation dynamics of PrANS promoter during flower development revealed a potential early demethylating reaction, which may have contributed to the particular expression of PrANS solely in the blotch area. We suggest that the formation of petal blotch may be highly associated with the cooperation of transcriptional activation and DNA methylation of structural gene promoters.