Wang Maojun, Wang Pengcheng, Tu Lili, Zhu Sitao, Zhang Lin, Li Zhonghua, Zhang Qinghua, Yuan Daojun, Zhang Xianlong
National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan 430070, Hubei, China.
National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan 430070, Hubei, China
Nucleic Acids Res. 2016 May 19;44(9):4067-79. doi: 10.1093/nar/gkw238. Epub 2016 Apr 11.
Epigenetic modifications are highlighted for their great importance in regulating plant development, but their function associated with single-cell differentiation remains undetermined. Here, we used the cotton fibre, which is the epidermal hair on the cotton ovule, as a model to investigate the regulatory role of DNA methylation in cell differentiation. The level of CHH (H = A, T, or C) DNA methylation level was found to increase during fibre development, accompanied by a decrease in RNA-directed DNA methylation (RdDM). Examination of nucleosome positioning revealed a gradual transition from euchromatin to heterochromatin for chromatin dynamics in developing fibres, which could shape the DNA methylation landscape. The observed increase in DNA methylation in fibres, compared with other ovule tissue, was demonstrated to be mediated predominantly by an active H3K9me2-dependent pathway rather than the RdDM pathway, which was inactive. Furthermore, integrated multi-omics analyses revealed that dynamic DNA methylation played a role in the regulation of lipid biosynthesis and spatio-temporal modulation of reactive oxygen species during fibre differentiation. Our study illustrates two divergent pathways mediating a continuous increase of DNA methylation and also sheds further light on the epigenetic basis for single-cell differentiation in plants. These data and analyses are made available to the wider research community through a comprehensive web portal.
表观遗传修饰因其在调控植物发育中的重要作用而备受关注，但其与单细胞分化相关的功能仍未明确。在此，我们以棉花纤维（棉花胚珠上的表皮毛）为模型，研究DNA甲基化在细胞分化中的调控作用。研究发现，在纤维发育过程中，CHH（H = A、T或C）DNA甲基化水平升高，同时RNA介导的DNA甲基化（RdDM）降低。对核小体定位的研究揭示了发育中的纤维染色质动力学从常染色质到异染色质的逐渐转变，这可能塑造了DNA甲基化格局。与其他胚珠组织相比，纤维中观察到的DNA甲基化增加主要由活跃的H3K9me2依赖性途径介导，而非无活性的RdDM途径。此外，综合多组学分析表明，动态DNA甲基化在纤维分化过程中对脂质生物合成的调控以及活性氧的时空调节中发挥作用。我们的研究阐明了介导DNA甲基化持续增加的两条不同途径，也进一步揭示了植物单细胞分化的表观遗传基础。这些数据和分析通过一个综合网站向更广泛的研究群体公开。
