Shaping inheritance: how distinct reproductive strategies influence DNA methylation memory in plants.

ABSTRACT

DNA methylation is a major epigenetic mark involved in the silencing of genes and transposable elements (TEs). DNA methylation varies significantly across the plant life cycle, but is efficiently reinforced during reproduction, ensuring stable silencing of TEs. Plants are remarkably flexible in their mode of reproduction and numerous species, including crops, can propagate asexually, skipping one or more of these critical reinforcement steps. In this review, we summarize recent advances in the characterization of DNA methylation inheritance in sexual and asexual plants. We argue that because most epigenetic reinforcement appears to occur during seed formation, methylomes of asexual seeds should resemble that of their sexual counterparts. Conversely, clonally propagated plants are expected to be hypomethylated and undergo frequent stochastic epigenetic changes. Last, we provide insights on how the use of nonmodel organisms will advance our understanding of epigenetic inheritance in plants.