DNA methylation dynamics in the shoot apical meristem.

The shoot apical meristem (SAM) is pivotal for plant development, acting as the source of all aerial tissues and the origin of the gametes. Despite extensive knowledge of the regulation of stem cell pool size, organ initiation, and patterning at the SAM periphery, the epigenetic landscape of SAM cells remains largely unexplored. Here, we review recent attempts to characterize the spatio-temporal dynamics of DNA methylation in the SAM, including its role in stress responses, memory, control of the activity of transposable elements in the initiation of reproductive cell lineages, and its association with stem cell fate. We highlight several technological opportunities for future epigenetic studies of the SAM, especially at the single-cell level. These include the use of spatial DNA methylation sequencing, joint transcriptome-methylome analysis, and the use of stochastic DNA methylation changes for cell lineage tracing.