CAS and Shandong Province Key Laboratory of Experimental Marine Biology, Center for Ocean Mega-Science, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China.
Laboratory for Marine Biology and Biotechnology, Pilot National Laboratory for Marine Science and Technology (Qingdao), Qingdao 266071, China.
Int J Mol Sci. 2021 Sep 13;22(18):9877. doi: 10.3390/ijms22189877.
Cytosine methylation plays vital roles in regulating gene expression and plant development. However, the function of DNA methylation in the development of macroalgae remains unclear. Through the genome-wide bisulfite sequencing of cytosine methylation in holdfast, stipe and blade, we obtained the complete 5-mC methylation landscape of sporophyte. Our results revealed that the total DNA methylation level of sporophyte was less than 0.9%, and the content of CHH contexts was dominant. Moreover, the distribution of CHH methylation within the genes exhibited exon-enriched characteristics. Profiling of DNA methylation in three parts revealed the diverse methylation pattern of sporophyte development. These pivotal DMRs were involved in cell motility, cell cycle and cell wall/membrane biogenesis. In comparison with stipe and blade, hypermethylation of mannuronate C5-epimerase in holdfast decreased the transcript abundance, which affected the synthesis of alginate, the key component of cell walls. Additionally, 5-mC modification participated in the regulation of blade and holdfast development by the glutamate content respectively via glutamine synthetase and amidophosphoribosyl transferase, which may act as the epigenetic regulation signal. Overall, our study revealed the global methylation characteristics of the well-defined holdfast, stipe and blade, and provided evidence for epigenetic regulation of sporophyte development in brown macroalgae.
胞嘧啶甲基化在调控基因表达和植物发育中起着至关重要的作用。然而，DNA 甲基化在大型藻类发育中的功能尚不清楚。通过对固着器、茎和叶片中胞嘧啶甲基化的全基因组亚硫酸氢盐测序，我们获得了孢子体的完整 5-mC 甲基化图谱。研究结果表明，孢子体的总 DNA 甲基化水平小于 0.9%，且 CHH 结构域的含量占主导地位。此外，基因内 CHH 甲基化的分布呈现出外显子富集的特征。对三个部分的 DNA 甲基化进行分析，揭示了孢子体发育的多样化甲基化模式。这些关键的 DMRs 参与了细胞运动、细胞周期和细胞壁/膜生物发生。与茎和叶片相比，固着器中甘露糖 C5-差向异构酶的超甲基化降低了其转录丰度，这影响了海藻酸盐的合成，而海藻酸盐是细胞壁的关键成分。此外，通过谷氨酰胺合成酶和氨甲酰磷酸核糖转移酶，5-mC 修饰分别通过谷氨酸含量参与叶片和固着器的发育调控，这可能作为表观遗传调控信号。总的来说，本研究揭示了明确的固着器、茎和叶片的全甲基化特征，并为褐藻孢子体发育的表观遗传调控提供了证据。
