An international team of scientists at National Agriculture and Food Research Organization, Salk Institute for Biological Studies and Howard Hughes Medical Institute, have discovered the dynamics of DNA methylation during seed development and germination. The work, published in Genome Biology on September 15, 2017, offers insight into the regulatory role of DNA methylation in the association with dormancy.

　　

Unlike animals, plants can pause their life cycle as dormant seeds. In both plants and animals, DNA methylation is involved in the regulation of gene expression and genome integrity. In animals, reprogramming erases and re-establishes DNA methylation during development. However, knowledge of reprogramming or reconfiguration in plants has been limited to pollen and the central cell. To better understand epigenetic reconfiguration in the embryo, which forms the plant body, the team compared time-series methylomes of dry and germinating seeds to publicly available seed development methylomes.

　　

Time-series whole genome bisulfite sequencing reveals extensive gain of CHH methylation during seed development and drastic loss of CHH methylation during germination. These dynamic changes in methylation mainly occur within transposable elements. Active DNA methylation during seed development depends on both RNA-directed DNA methylation and heterochromatin formation pathways, whereas global demethylation during germination occurs in a passive manner. However, an active DNA demethylation pathway is initiated during late seed development.

　　

This study provides new insights into dynamic DNA methylation reprogramming events during seed development and germination and suggests possible mechanisms of regulation. The observed sequential methylation/demethylation cycle suggests an important role of DNA methylation in seed dormancy.

　　

Publication

Kawakatsu T, Nery JR, Castanon R, Ecker JR. (2017) Dynamic DNA methylation reconfiguration during seed development and germination. Genome Biology 18: 171

　　

This work was funded by the Gordon and Betty Moore Foundation and the Japan Society for the Promotion of Sciences.