The study of the regulation of cell proliferation in plants opens up new perspectives.
This balance between division and differentiation is also the basis for the incredible plasticity of plant development: Although the basic organization of the plant remains invariant, its architecture can profoundly change depending on light conditions, temperature etc ... The plants are sessile organisms, they can not move to escape adverse conditions, and their survival depends on the ability to adapt to changes around them. The regulation of cell proliferation is one of the key elements of this process. On the other hand, the meristematic cells that ensure continuous development of new organs, retain their ability to proliferate throughout the life of the plant, which can last up to thousands of years for some species, and gametes, these reproductive cells from meiosis late differ from these cells. The plants thus appear to have an exceptional ability to protect the integrity of their genome over the cell divisions, although each replication step is prone to errors. One of the mechanisms proposed to explain this observation is that the meristems, cells contain their center tanks that divide much more slowly than the cells of the periphery from which to initiate new organs such as leaves. This division idling would protect their genome too many injuries. Another possibility is that specific mechanisms exist to ensure the plants a particular loyalty in the DNA replication.
Finally, over the divisions, the cells acquire a specific identity although they all have the same genome. This is based on the establishment of an own gene expression program for each cell type. This program depends on the presence of specific proteins called transcription factors that directly regulate gene transcription but also changes in chromatin organization. Indeed, the DNA is associated with proteins known as histones that allow its compaction in the nucleus. Changes in these histones or in DNA itself called chromatin markings may promote the release and condensation of a given locus, and thus play a fundamental role in regulating gene expression. These markings must be reproduced in part during DNA replication, but the S phase of the cell cycle could also be favorable to the deposition of new brands.