Towards a hierarchical gene regulatory network underlying somatic embryogenesis.

Genome-editing technologies have advanced in recent years but designing future crops remains limited by current methods of improving somatic embryogenesis (SE) capacity. In this Opinion, we provide an update on the molecular event by which the phytohormone auxin promotes the acquisition of plant cell totipotency through evoking massive changes in transcriptome and chromatin accessibility. We propose that the chromatin states and individual totipotency-related transcription factors (TFs) from disparate gene families organize into a hierarchical gene regulatory network underlying SE. We conclude with a discussion of the practical paths to probe the cellular origin of the somatic embryo and the epigenetic landscape of the totipotent cell state in the era of single-cell genomics.