The life and legacy of the root endodermis: A spatiotemporal view of function and development

The root endodermis forms a selective interface between the soil environment and the vasculature, which is essential for radial transport. Traditionally defined by its barriers, it is increasingly understood that the endodermis is a dynamic tissue in which development, cell wall modification, and signaling are integrated. Moreover, evidence is emerging that this tissue contains several cell files with individual identity, which may play distinct physiological roles in integrating environmental responses. Based on this, we present here a spatiotemporal perspective on endodermal function, following its progression from early specification to eventual termination during secondary growth. We give an overview of the endodermal life cycle, from early specification and barrier differentiation to its eventual replacement during secondary growth. We propose that the endodermis functions as a transient regulatory interface in which cell identity programs, positional cues, barrier surveillance pathways, and environmental responses converge to control transport and signaling. In this view, the endodermis is not simply a passive diffusion barrier, but a developmentally patterned, tunable tissue that actively adjusts radial permeability during root growth. Its influence extends beyond its lifespan, shaping subsequent developmental trajectories and plant-environment interactions.