DISSECTING THE HORMONAL CONTROL OF THE SALT STRESS RESPONSE IN ARABIDOPSIS ROOTS

Abstract

Plant environmental responses involve dynamic changes in growth and signaling. However, little is known about how the progress through the transition from non-stress conditions to stress conditions is controlled. In this study, by using live imaging and transcriptome profiling, we characterized the key hormonal signaling pathways involved in transcriptional and growth regulation during salt stress and identified the time window and spatial domain of where they act in the root. Further, we focused on salt-mediated cortical cell swelling to understand the distinct functions of different cell types during salt stress. By using genetic and bioinformatic analyses, we found that ethylene regulates salt-mediated cortical cell swelling through auxin signaling in an endodermal dependent fashion. Together, our data reveal a sophisticated assortment of regulatory programs acting together to coordinate spatially patterned biological changes involved in the immediate and long-term response to a stressful shift in environment.