Divergence in a stress regulatory network underlies differential growth control

Abstract

The phytohormone abscisic acid (ABA) is a central regulator of acclimation during environmental stress. While some plants exhibit tremendous stress resilience, it has been unclear whether differences in ABA response underlie such adaptations. Here we establish a cross-species gene regulatory network (GRN) for ABA to identify broadly conserved, core components of the ABA signaling network and peripheral pathways exhibiting species-specific connectivity. Genes that are broadly conserved in the network share promoter architecture and patterns of gene expression. Networks associated with growth hormones exhibited highly divergent wiring of their ABA network leading to changes in the physiological outcome of signaling. Together our study provides a model for understanding how GRN subcircuits deploy different growth regulatory states across ecologically diverse species.