Stem Cell-Like Cells and Plant Regeneration pp. 1-60
Authors: (A.S. Blervacq, A. Lucau-Danila, J.P. Couillerot, F. Morcillo, F. Aberlenc-Bertossi, S. Hawkins, T.J. Tranbarger, J.L. Verdeil, Université Lille Nord de France, and others)
Abstract: Totipotency and pluripotency are concepts currently used to explain the ability of stem cells to produce the diverse differentiated cell types during multicellular development of plants and animals. While totipotent or pluripotent stem cells are well described in plants, the molecular, physical and cellular processes that occur prior to and leading up to the formation of stem cells are less understood. As in the animal kingdom, plant totipotent stem cells include the single-celled zygote that establishes the bipolar multicellular body. In contrast to animals, totipotent plant stem cells can also originate from certain differentiated somatic cells. In this chapter, we provide evidence to support the hypothesis that in vitro induced plant cell dedifferentiation occurs in specific somatic cells called competent cells usually located near vascular tissues. These competent cells are able to reach the stem cell-like status under in vitro appropriate conditions. In this context, both cellular and molecular components are greatly modified during the cell reactivation stage and also during commitment towards the specific morphogenetic pathway. Physiological determinants, typically associated with stress, related to the in vitro induced acquisition and expression of toti- or pluripotency are described in this chapter. A practical perspective is given to optimize the toti- or pluripotency expression during in vitro plant regeneration. Finally, the putative role of neighbor cells surrounding localised competent cells in the tissue, and stem cell-like lineage are discussed.