Wound repair in plants guided by cell geometry

Abstract

In multicellular organisms, the shape of an organ is robust to unpredictable fluctuations. When parts of an organ are removed or damaged, it is often capable of regeneration, restoring its original shape. A central question is how restoration of shape occurs as the collective behavior of individual cells. Here, we use the plant root as an experimental system, surgically removing the tip that contains the organizing center and investigating how it restores its tapered shape. We discover that the transient activation of growth conflicts, which creates specific cell geometries following injury, is vital to this restoration. Using a combination of experimental approaches and computational modeling, we show that non-uniform growth among neighboring cell files generates conflicts, reshaping cuboidal cells into rhomboidal forms. These rhomboidal cells undergo anisotropic growth and establish an atypical diagonal division plane, both of which can be explained by elementary rules of microtubule dynamics. The resulting daughter cells, in turn, guide the growing cell files along an inclined path to restore the tapered morphology. Our findings reveal a two-step process: first, the activation of conflicting growth patterns to generate specific cell shapes, and second, the reorientation of cell division and growth in response to these shapes, recreating the tip-focused cell files that facilitate tapering. This previously unrecognized shape-forming mechanism reveals how local cell geometries, driven by growth conflicts, guide self-organized morphogenesis in plant wound repair.