Developmental programs interact with ABA to coordinate root suberization in Arabidopsis.

Suberin lamellae, which provide a hydrophobic protective barrier against biotic and abiotic stresses, are widely deposited in various cell types during plant development and in response to stress. However, it remains unclear how developmental programs interact with stress responses to direct the precise spatiotemporal pattern of suberin deposition. In this study, we found that SHORT-ROOT (SHR), together with its downstream factor MYB36, guided suberization specifically in the root endodermis. Despite a partial dependence on ABA, the suberization mediated by SHR and MYB36 appeared to derive from a slow readout of developmental programs, in contrast to the rapid but transient suberization induced by ABA. Furthermore, we found the MYB39 transcription factor functioned as a common downstream hub of the SHR/MYB36 pathway and the ABA-triggered response. MYB39 could directly bind to the FAR5 (alcohol-forming fatty acyl-coenzyme A reductase) promoter to activate its expression. In addition, overexpression of MYB39 dramatically increased the amount of suberization in Arabidopsis roots. Our results provide important insights into the interaction between developmental programs and environmental stimuli in root suberization in Arabidopsis.