Cell wall signaling across spatial and temporal scales

Plants constantly monitor the status of their cell walls and respond by regulating cell expansion, cell wall synthesis, and cell wall remodeling. Cell wall signaling (CWS) includes the mechanisms by which plants monitor the status of their cell walls and trigger response mechanisms to balance cell wall strength with extensibility to regulate turgor-driven cell expansion. CWS can be induced by alterations, disruptions, or damage to the cell wall, as well as by biotic and abiotic stresses, and CWS can crosstalk with hormone signaling, either through direct interaction of signaling components or by hormone synthesis as a CWS response. Here, we review the mechanisms of CWS and responses in Arabidopsis across spatial scales from the molecular interactions that occur during CWS transduction, to cellular and cell wall reorganization in response to CWS, to the growth and developmental consequences of cell wall changes at the whole-plant level. We also discuss the timeline of CWS and responses, from the initial perception and signal transduction events that happen within seconds or minutes of CWS, to the long-term transcriptional, metabolic, and cellular remodelling that occur within hours, and finally the lifetime changes that can develop in response to chronic CWS and cell wall stress.