The biophysical basis of flat organ morphogenesis from fluctuating cellular growth – GrowFlat

How do tissues and organs grow to reach well-defined shapes? For instance, thin tissues, such as animal epithelia and plant leaves, are typically flat, whereas the default state of a growing thin sheet is curved. How is flat shape achieved? Here we address this question in Arabidopsis leaves, a system amenable to live-imaging of growth, biophysical experiments, and genetic manipulation. We hypothesize that cell-to-cell growth heterogeneity enables cells to sense variations in leaf curvature and maintain flatness. We aim to test this hypothesis using experimental and theoretical biophysics with cell biology. We will (i) characterize the relationship between cell-to-cell heterogeneity, cell mechanics, and leaf flatness, (ii) build a theoretical framework to model a thin active growing sheet in 3D space, and (iii) characterize the combinatorial regulation of flatness through model predictions and experimental tests. Altogether, we expect to shed light on the robustness of morphogenesis.