The phytohormone abscisic acid (ABA) is a central regulator of acclimation to environmental stress; however, its contribution to differences in stress tolerance between species is unclear. To establish a comparative framework for understanding how stress hormone signalling pathways diverge across species, we studied the growth response of four Brassicaceae species to ABA treatment and generated transcriptomic and DNA affinity purification and sequencing datasets to construct a cross-species gene regulatory network (GRN) for ABA. Comparison of genes bound directly by ABA-responsive element binding factors suggests that cis-factors are most important for determining the target loci represented in the ABA GRN of a particular species. Using this GRN, we reveal how rewiring of growth hormone subnetworks contributes to stark differences in the response to ABA in the extremophyte Schrenkiella parvula. Our study provides a model for understanding how divergence in gene regulation can lead to species-specific physiological outcomes in response to hormonal cues.

植物激素脱落酸 (ABA) 是适应环境压力的中心调节剂；然而，它对物种间胁迫耐受性差异的贡献尚不清楚。为了建立一个比较框架来了解应激激素信号通路如何在物种间分化，我们研究了四种十字花科物种对 ABA 处理的生长反应，并生成了转录组和 DNA 亲和纯化和测序数据集，以构建跨物种基因调控网络 (GRN)为 ABA。与 ABA 反应元件结合因子直接结合的基因的比较表明，顺式因子对于确定特定物种的 ABA GRN 中代表的目标基因座是最重要的。使用这个 GRN，我们揭示了生长激素子网络的重新布线如何导致极端植物 Schrenkiella parvula对 ABA 反应的明显差异。我们的研究提供了一个模型，用于了解基因调控的差异如何导致针对激素信号的物种特异性生理结果。