Mechanical coordination of counter-gradient growth maintains organ curvature in the apical hook
How growing tissues convert mechanical tension into signals that stabilize form remains a central question in morphogenesis. Curved organ shapes in plants arise from differential growth, yet how such curvature is actively maintained while organs continuously grow remains poorly understood. In etiolated seedlings, the apical hook provides a tractable model to dissect this process. Using quantitative imaging, computational modelling and genetic perturbations, we show that antagonistic growth gradients at apical and basal regions are both necessary and sufficient to maintain hook curvature, with cuticle integrity being critical for establishing these counter-gradients. Mechanical cues linked to cuticle structure, coupled with reactive oxygen species (ROS), coordinate hook cellular growth anisotropy. These findings reveal that apical hook development is not a simple transition between differential growth repression and promotion phases, but a highly dynamic, tightly regulated process wherein mechanical and biochemical signals coordinate organ-scale morphogenesis, fundamentally reshaping how we understand developmental growth.
How growing tissues convert mechanical tension into signals that stabilize form remains a central question in morphogenesis. Curved organ shapes in plants arise from differential growth, yet how such curvature is actively maintained while organs continuously grow remains poorly understood. In etiolated seedlings, the apical hook provides a tractable model to dissect this process. Using quantitative imaging, computational modelling and genetic perturbations, we show that antagonistic growth gradients at apical and basal regions are both necessary and sufficient to maintain hook curvature, with cuticle integrity being critical for establishing these counter-gradients. Mechanical cues linked to cuticle structure, coupled with reactive oxygen species (ROS), coordinate hook cellular growth anisotropy. These findings reveal that apical hook development is not a simple transition between differential growth repression and promotion phases, but a highly dynamic, tightly regulated process wherein mechanical and biochemical signals coordinate organ-scale morphogenesis, fundamentally reshaping how we understand developmental growth.
Umea Plant Science Centre