"The study of plant biology is useful in two ways. Under a basic research perspective, it yields basic knowledge on processes that are specific to plants and distinguish them from animals. From an applied perspective, this knowledge can lead to an improvement in the quality or the productivity of crops. Any given aspect of plant biology can be considered to be fully dissected only after the genes that control it have been identified, which makes its eventual controlled perturbation possible. Plant genetic research can also help to understand the conserved functions of such genes in different organisms as well as to establish their biotechnological potential. In this proposal, I aim (1) to identify genes important for leaf morphogenesis in the model plant Arabidopsis thaliana, as inferred from the effects of their loss of function on cell size and cell number; (2) to characterize the effects of their constitutive expression in Arabidopsis thaliana, in order to assess their potential application as plant growth modulators; (3) to characterize the effects of their heterologous expression in an animal model system (Caenorhabditis elegans), in order to assess their potential pharmacological use and the eventual conservation of their functions in the control of cell proliferation; and (4) to knock down the putative orthologs of these genes in Caenorhabditis, in an attempt to establish their potential use as regulators of cell proliferation."