Dynamic Chromatin Regulatory Programs During Embryogenesis of Hexaploid Wheat
    作者: Long Zhao, Yiman Yang, Jinchao Chen, Xuelei Lin, Hao Zhang, Hao Wang, Hongzhe Wang, Xiaomin Bie, Jiafu Jiang, Xiaoqi Feng, Xiangdong Fu, Xiansheng Zhang, Zhuo Du & Jun Xiao
    刊物名称: Genome Biology
    DOI:
    联系作者:
    英文联系作者:
    卷:
    摘要:
    Background
    Plant and animal embryogenesis have conserved and distinct features. Cell fate transitions occur during embryogenesis in both plants and animals. The epigenomic processes regulating plant embryogenesis remain largely elusive.
    Results
    Here, we elucidate chromatin and transcriptomic dynamics during embryogenesis of the most cultivated crop, hexaploid wheat. Time-series analysis reveals stage-specific and proximal–distal distinct chromatin accessibility and dynamics concordant with transcriptome changes. Following fertilization, the remodeling kinetics of H3K4me3, H3K27ac, and H3K27me3 differ from that in mammals, highlighting considerable species-specific epigenomic dynamics during zygotic genome activation. Polycomb repressive complex 2 (PRC2)-mediated H3K27me3 deposition is important for embryo establishment. Later H3K27ac, H3K27me3, and chromatin accessibility undergo dramatic remodeling to establish a permissive chromatin environment facilitating the access of transcription factors to cis-elements for fate patterning. Embryonic maturation is characterized by increasing H3K27me3 and decreasing chromatin accessibility, which likely participates in restricting totipotency while preventing extensive organogenesis. Finally, epigenomic signatures are correlated with biased expression among homeolog triads and divergent expression after polyploidization, revealing an epigenomic contributor to subgenome diversification in an allohexaploid genome.
    Conclusions
    Collectively, we present an invaluable resource for comparative and mechanistic analysis of the epigenomic regulation of crop embryogenesis.