Plant cells are organised in files along the body axis and growth is maintained through divisions within these files of cells. In order to create a new three-dimensional organ however, plants trigger cells in a specific zone to undergo a different type of division, forming additional cell files. Vascular cells have the specific ability to undergo many of these formative divisions, generating the tissues that make up wood in trees and that are responsible for source-to-sink transport throughout the plant. Therefore, a clear understanding of these formative divisions holds great promise for increasing yield in agronomical important crops. Remarkably, despite this potential, virtually nothing is known about how vascular tissues are initially formed.
We recently identified the very first factor that is both necessary and sufficient to trigger formative divisions in the vascular tissue. This factor consists of two subunits, and the overlapping expression domains restrict the normal activity to a zone of young vascular cells; exactly where formative divisions occur. Strikingly however, when activated elsewhere, this factor can promote formative division in all cell types. This finding now enables me to answer several central unanswered questions in developmental biology, namely ‘what are the molecular and cellular mechanisms underlying the trigger to undergo formative divisions?’ and ‘how to restrict formative divisions to a small zone of competence?’.
In this project, I will use a multi-level approach encompassing transcriptomics, proteomics, cell biology and genetics both at the cellular and at the tissue level to provide answers to these fundamental questions. This work will present a major step forward in our understanding of organ formation, formative divisions in general and vascular tissue formation in particular. At the same time, I will use this information to take the initial, but essential, steps to modify plant architecture in agronomical important species.