HIGHLIGHTS-One of most intriguing questions in developmental plant biology, is how the cellular totipotency is generated, and results in the asexual embryogenesis.-Hormonal and stress signals play a key role in initiation of the embryogenic pathway by activation of cell division in somatic cells in planta and in in vitro cultured cells -DNA hypomethylation or histone acetylation as epigenetic events activate expression of specific transcription factor, hormonal or developmental genes being responsible for totipotent stage.-Ectopic expression of specific developmental genes can trigger somatic embryogenesis in vegetative plant organs.-Level of DNA methylation in dedifferentiated callus tissues is lowered during embryogenesis.-Epigenetic reprogramming is reflected by significant changes in transcript profiles during callus induction and somatic embryogenesis.