Comparative Epigenomics: Exploring Patterns of DNA Methylation throughout Flowering Plants

Methylation of cytosines in plants is a prominent epigenomic feature and is involved in critical functions such as transposon silencing and regulating gene expression. Here we present a comprehensive comparative epigenomics analyses of DNA methylomes of 34 different plant species from across the angiosperms using whole genome bisulphite sequencing data. Results indicate widespread variance in the amount and the use of CG, CHG, and CHH methylation across species. Genes with CG gene-body methylation, which are often associated with stable gene expression, and non-CG methylation, which are often associated with silencing, were classified for each species. Molecular evolutionary analyses of CG gene-body genes shows that these genes are generally conserved in multiple features over evolutionary time scales, whereas major differences in the use of CHG and CHH methylation suggests that different methylation pathways may predominate in different species.