Small RNA-mediated epigenetic modifications in plants

Epigenetic modifications in plants can be directed and mediated by small RNAs (sRNAs). This regulation is composed of a highly interactive network of sRNA-directed DNA methylation, histone, and chromatin modifications, all of which control transcription. Identification and functional characterization of components of the siRNA-directed DNA methylation pathway have provided insights into epigenetic pathways that form heterochromatin and into chromatin-based pathways for gene silencing, paramutation, genetic imprinting, and epigenetic reprogramming. Next-generation sequencing technologies have facilitated new discoveries and have helped create a basic blueprint of the plant epigenome. As the multiple layers of epigenetic regulation in plants are dissected, a more comprehensive understanding of the biological importance of epigenetic marks and states has been developed.

Research highlights▶ Small RNAs play a direct role in modulating epigenetic modifications in plants. ▶ Plant-specific RNA polymerases produce heterochromatic small interfering RNAs. ▶ A signaling network of sRNAs controls DNA methylation and histone modifications. ▶ sRNAs mediate paramutation, requiring genes involved in small RNA biogenesis. ▶ sRNA production and mobilization reinforce transposon silencing in gametogenesis.