Plant Receptor‐Like Kinase‐Mediated Drought Stress Response Mechanism—From Root Sensing to Stomatal Regulation

ABSTRACT

Drought is a multifaceted environmental constraint that alters water dynamics across the soil‐plant‐atmosphere system. In order to survive under drought stress, plants must respond at several levels from cellular signalling to whole‐plant hydraulic regulation. Although receptor‐like kinases (RLKs) have been reported to play important roles in these responses, they are often studied within individual molecular pathways rather than as integrators of environmental and physiological processes. Here, we review RLK‐mediated drought signalling organised across three interconnected spatial scales. At the root–soil interface, RLKs perceive osmotic and mechanical cues to regulate root architecture, aquaporin dynamics and apoplastic barrier formation, thereby tuning root hydraulic conductivity. Over long distances, RLK‐peptide modules and reactive oxygen species waves transmit water‐deficit signals from roots to shoots via xylem transport and cell‐to‐cell propagation, while RLK‐dependent vascular differentiation preserves hydraulic safety. In leaves, RLKs modulate stomatal aperture through ion‐channel regulation, ROS‐calcium signalling, cell‐wall mechanosensing and developmental reprogramming of stomatal density. Importantly, we highlight how these pathways operate across distinct temporal scales—from rapid electrochemical responses to long‐term anatomical remodelling—and identify key unresolved questions, including how signalling specificity is achieved among redundant RLK members and how hydraulic and biochemical cues are integrated. By linking RLK‐mediated signalling to whole‐plant physiological responses, this review offers potential avenues for enhancing crop drought resilience through targeted modulation of RLK pathways.