Programmed cell death: genes involved in signaling, regulation, and execution in plants and animals

Programmed cell death (PCD) is a suicide mechanism adopted by multicellular organisms that is essential for development and resistance to different forms of stress. In plants, PCD is involved from embryogenesis to death of the whole plant. PCD is genetically regulated and the molecular pathways involved in different forms of this process in animals are relatively more understood than in plants. At the morphological level, apoptosis, one of the forms of PCD in animals, and plant PCD have some similarities such as cell shrinkage, shrinkage of the nucleus, and DNA fragmentation. Because morphological characteristics are a product of the genetically encoded PCD mechanism, it is of interest to figure out how much of the apoptotic pathway is shared with plant PCD in terms of the genes involved. Evidence of some level of similarities has been gathered in the last decade, supporting conservation during signaling, regulation, and execution of apoptosis and plant PCD. A continued search into the genomes of plants has provided insights about homologues of apoptosis genes present in plants, and functional analysis provides evidence about which genes are carrying out similar roles during apoptosis and plant PCD. This review is aimed at updating on the progress of plant PCD mechanism research and highlighting some of the similarities and differences between plant and mammalian PCD mechanisms, with special focus on the commonalities.