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Article|03 Jun 2022|OPEN
Epigenetic reprogramming of H3K27me3 and DNA methylation during leaf-to-callus transition in peach 
Beibei Zheng1,2 ,† , Jingjing Liu1,3 ,† , Anqi Gao1,3 , Xiaomei Chen1,3 and Lingling Gao1,3 , Liao Liao1,2 , Binwen Luo1,3 , Collins Otieno Ogutu1,2 , Yuepeng Han,1,2 ,
1CAS Key Laboratory of Plant Germplasm Enhancement and Specialty Agriculture, Wuhan Botanical Garden, The Innovative Academy of Seed Design of Chinese Academy of Sciences, Wuhan 430074, China
2Hubei Hongshan Laboratory, Wuhan 430070, China
3University of Chinese Academy of Sciences, 19A Yuquanlu, Beijing 100049, China
*Corresponding author. E-mail: yphan@wbgcas.cn
Both authors contributed equally to the study.

Horticulture Research 9,
Article number: uhac132 (2022)
doi: https://doi.org/10.1093/hr/uhac132
Views: 103

Received: 03 Apr 2022
Accepted: 29 May 2022
Published online: 03 Jun 2022

Abstract

Plant tissues are capable of developing unorganized cell masses termed calluses in response to the appropriate combination of auxin and cytokinin. Revealing the potential epigenetic mechanisms involved in callus development can improve our understanding of the regeneration process of plant cells, which will be beneficial for overcoming regeneration recalcitrance in peach. In this study, we report on single-base resolution mapping of DNA methylation and reprogramming of the pattern of trimethylation of histone H3 at lysine 27 (H3K27me3) at the genome-wide level during the leaf-to-callus transition in peach. Overall, mCG and mCHH were predominant at the genome-wide level and mCG was predominant in genic regions. H3K27me3 deposition was mainly detected in the gene body and at the TSS site, and GAGA repetitive sequences were prone to recruit H3K27me3 modification. H3K27me3 methylation was negatively correlated with gene expression. In vitro culture of leaf explants was accompanied by DNA hypomethylation and H3K27me3 demethylation, which could activate auxin- and cytokinin-related regulators to induce callus development. The DNA methylation inhibitor 5-azacytidine could significantly increase callus development, while the H3K27me3 demethylase inhibitor GSK-J4 dramatically reduced callus development. These results demonstrate the roles of DNA methylation and H3K27me3 modification in mediating chromatin status during callus development. Our study provides new insights into the epigenetic mechanisms through which differentiated cells acquire proliferative competence to induce callus development in plants.