Differential growth is an emergent property of mechanochemical feedback mechanisms in curved plant organs
Ankit Walia, Ross Carter, Raymond Wightman, Elliot M. Meyerowitz, Henrik Jönsson, Alexander M. Jones
Abstract
Differential growth is central to eukaryotic morphogenesis. We showed using cellular imaging, simulations, and perturbations that light-induced differential growth in a curved organ, the Arabidopsis thaliana apical hook, emerges from the longitudinal expansion of subepidermal cells, acting in parallel with a differential in the material properties of epidermal cell walls that resist expansion. The greater expansion of inner hook cells that results in apical hook opening is gated by wall alkalinity and auxin, both of which are depleted upon illumination. We further identified mechanochemical feedback from wall mechanics to light stimulated auxin depletion, which may contribute to gating hook opening under mechanical restraint. These results highlight how plant cells coordinate growth among tissue layers by linking mechanics and hormonal gradients with the cell wall remodeling required for differential growth. • Inner side hook cells show differential irreversible extensibility • Auxin and pH gate growth but do not explain differential extension • Subepidermal longitudinal force accelerates opening and CMT reorientation • Light-triggered depletion in auxin signaling is gated by wall properties Walia and Carter et al. show that differential growth during hook opening is an emergent property of mechanochemical feedback mechanisms in Arabidopsis. Light-induced differential growth emerges from the longitudinal expansion of subepidermal cells, acting in parallel with a differential in the material properties of epidermal cell walls that resist expansion.