Timing of root barriers controls soil-to-shoot integration of rhizosphere status

In roots, formation of the Casparian strip in the endodermal cell walls provides a means for selective solute movement by blocking apoplastic flow. This is under spatial surveillance by a receptor-ligand system termed the Schengen pathway. However, the physiological purpose of this is not clear, particularly under natural conditions. To address this, we created plants with an earlier onset of Casparian strips uncoupling barrier formation from the Schengen pathway. Within a complex growth setup, we find that this has severe consequences for a healthy microbiota and nitrogen-induced shoot growth, which provides insights into how root barriers integrate rhizosphere status. This creates a need for an updated nutrient use model that includes root barrier timing as an important factor for coordinating responses between above- and belowground tissues. ### Competing Interest Statement The authors have declared no competing interest.