Integrative Biology Journals

JOURNAL OF FORESTRY RESEARCH ›› 2023, Vol. 34 ›› Issue (1): 21-35.DOI: 10.1007/s11676-021-01424-7

• Original Paper •    

Epigenetic modification associated with climate regulates betulin biosynthesis in birch

Jiang Wang1,2, Bowei Chen1,2, Shahid Ali1,2, Tianxu Zhang1,2, Yu Wang2, He Zhang2, Lishan Wang2, Yonglan Zhang2, Linan Xie1,2, Tingbo Jiang1, Jing Yin2, Heike W. Sederoff3, Gaurav Zinta4, Ronald R. Sederoff3,q, Yuhua Li1,2,r, Qingzhu Zhang1,2,s   

  1. 1 State Key Laboratory of Tree Genetics and Breeding, Northeast Forestry University, 150040, Harbin, People’s Republic of China
    2 College of Life Sciences, Northeast Forestry University, 150040, Harbin, People’s Republic of China
    3 Forest Biotechnology Group, Department of Forestry and Environmental Resources, North Carolina State University, 27695, Raleigh, NC, USA
    4 Biotechnology Division, CSIR-Institute of Himalayan Bioresource Technology, 176061, Palampur, India
  • Received:2021-08-05 Accepted:2021-10-19 Online:2021-12-04
  • Contact: Ronald R. Sederoff, Yuhua Li, Qingzhu Zhang

Abstract:

The Betula genus contains pentacyclic triterpenoid betulin known for its environmental adaptation and medicinal properties. However, the mechanisms underlying betulin biosynthesis responding to climate change remain unclear. In this study, the role of epigenetic modification (DNA methylation) in betulin biosynthesis was examined and how climatic factors influence it. Whole-genome bisulfite sequencing was performed for greenhouse-grown Chinese white birch (Betula platyphylla Sukaczev) treated with DNA methylation inhibitor zebularine (ZEB) and a natural birch population in Northeast China. ZEB treatment significantly affected the CHH methylation level of transposable elements and betulin content in a hormesis dose-dependent manner. The methylation and expression of bHLH9, a key transcriptional factor controlling betulin biosynthesis, were also consistently affected by ZEB treatment as a hormetic dose–response. In the natural population, there was a positive correlation between promoter methylation of bHLH9 and summer precipitation, while winter temperature was negatively correlated. Thus climate-dependent methylation of bHLH9 regulates the expression of downstream genes involved in betulin biosynthesis. This study highlights the role of environmental signals to induce epigenetic changes that result in betulin production, possibly helping to develop resilient plants to combat ongoing climate change and enhance secondary metabolite production.

Key words: Epigenetics, DNA methylation, Betulin, bHLH9 transcription factor, Hormesis, Climate change, Secondary metabolite