The hormonal control of regeneration in plants

Plant cells have a profound capacity to regenerate their full array of tissues from already differentiated organs, as best demonstrated in in vitro regeneration systems. Although critical breakthroughs in in vitro organogenesis have outlined the role of hormones and their interactions in determination of cultured plant cell developmental fates, the underlying molecular mechanisms are still largely unexplored. Investigations have recently been empowered by the identification of key genes that function in regeneration, involved in hormonal biosynthesis, transport, signaling, and hormone interactions. The establishment of differential hormone-responsive patterns in organ regeneration zones is critical for de novo organ initiation. The present review focuses on recent findings providing insights into hormone-regulated plant regeneration at the molecular level and the formation of hormonal-response environments required for de novo regeneration.