Table_3_Transgenerational Epigenetic Inheritance Under Environmental Stress by Genome-Wide DNA Methylation Profiling in Cyanobacterium.DOCX

Epigenetic modifications such as DNA methylation are well known as connected with many important biological processes. Rapid accumulating evidence shows environmental stress can generate particular defense epigenetic changes across generations in eukaryotes. This transgenerational epigenetic inheritance in animals and plants has gained interest over the last years. Cyanobacteria play very crucial role in the earth, and as the primary producer they can adapt to nearly all diverse environments. However, few knowledge about the genome wide epigenetic information such as methylome information in cyanobacteria, especially under any environment stress, was reported so far. In this study we profiled the genome-wide cytosine methylation from a model cyanobacterium Synechocystis sp. PCC 6803, and explored the possibility of transgenerational epigenetic process in this ancient single-celled prokaryote by comparing the DNA methylomes among normal nitrogen medium cultivation, nitrogen starvation for 72 h and nitrogen recovery for about 12 generations. Our results shows that DNA methylation patterns in nitrogen starvation and nitrogen recovery are much more similar with each other, significantly different from that of the normal nitrogen. This study reveals the difference in global DNA methylation pattern of cyanobacteria between normal and nutrient stress conditions and reports the evidence of transgenerational epigenetic process in cyanobacteria. The results of this study may contribute to a better understanding of epigenetic regulation in prokaryotic adaptation to and survive in the ever changing environment.

表观遗传修饰，如 DNA 甲基化，已被广泛认知其与众多重要生物学过程的相关性。迅速累积的证据表明，环境压力能够在真核生物中跨代产生特定的防御性表观遗传改变。在过去几年中，动物和植物中的这种跨代表观遗传传承引起了广泛关注。蓝细菌在地球上扮演着至关重要的角色，作为初级生产者，它们能够适应几乎所有多样化的环境。然而，关于蓝细菌全基因组表观遗传信息，例如甲基化组信息，尤其是在任何环境压力下的信息，迄今为止报道甚少。在本研究中，我们对模式蓝细菌 Synechocystis sp. PCC 6803 的全基因组胞嘧啶甲基化进行了分析，并通过比较正常氮源培养基培养、氮饥饿 72 小时以及约 12 代氮源恢复条件下的 DNA 甲基化组，探索了这种古老的单一细胞原核生物中跨代表观遗传过程的可能性。我们的结果表明，氮饥饿和氮源恢复条件下的 DNA 甲基化模式彼此之间更为相似，与正常氮源条件下的甲基化模式显著不同。本研究揭示了蓝细菌在正常和营养胁迫条件下全球 DNA 甲基化模式的差异，并报告了蓝细菌中跨代表观遗传过程的证据。本研究的结果可能有助于更深入地理解原核生物在适应和生存于不断变化的环境中的表观遗传调控机制。