Overlooked aspects of CrRLK1L–RALF signaling

SummaryPlant development relies on the ability of cells to coordinate growth with the cell wall's biomechanical status. Rapid alkalinization factors (RALFs) and their Catharanthus roseus RLK1‐like (CrRLK1L) kinase receptors form a dynamic signaling system linking wall sensing to growth regulation. RALF–CrRLK1L signaling triggers subminute responses, ion fluxes, wall stiffening, and receptor clustering, positioning it as a core regulator of real‐time growth modulation. RALFs also act structurally by compacting pectins, introducing a feedback loop between wall composition and signaling. Frequent co‐expression and heteromerization of CrRLK1Ls with multiple RALFs argue for a flexible, combinatorial logic rather than simple one‐ligand‐one‐receptor models. This Tansley Insight outlines a conceptual framework in which flexible, modular receptor–ligand networks could underlie dynamic cell wall monitoring.