Format: ORAL

Chuangchao Zhou, Yushuai Wang, Yalan Wang, Cai Li, Tian Tang

State Key Laboratory of Biocontrol and Guangdong Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen University, Guanghzou, China

DNA methylation plays an important role in plant response to environmental stress whereas its contribution to long-term adaptation remains elusive. Here we estimate evolutionary rates of methylation gain and loss in mangroves and the potential role of natural selection using population epigenomic analysis. Mangroves exhibit a high ratio of gain over loss of CG methylation. Cytosine sites in CG context, particularly in the promoter regions, are under significant selection to remain methylated in mangroves but not in non-mangroves. We also analyzed available expression profiling data of mangroves and found that gains of CG DNA methylation in both promoter and coding regions are associated with reduced expression variation in stress. Our results suggest that DNA methylation are favored by selection in plants under stress adaptation, perhaps due to its impact on maintaining transcriptional homeostasis.