Brassinosteroid (BR) signaling leads to the nuclear accumulation of the BRASSINAZOLE-RESISTANT 1 (BZR1) transcription factor, which plays dual roles in activating or repressing the expression of thousands of genes. BZR1 represses gene expression by recruiting histone deacetylases, but how it activates transcription of BR-induced genes remains unclear. Here, we show that BR reshapes the genome-wide chromatin accessibility landscape, increasing the accessibility of BR-induced genes and reducing the accessibility of BR-repressed genes in Arabidopsis. BZR1 physically interacts with the BRAHMA-associated SWI/SNF (BAS)-chromatin-remodeling complex on the genome and selectively recruits the BAS complex to BR-activated genes. Depletion of BAS abrogates the capacities of BZR1 to increase chromatin accessibility, activate gene expression, and promote cell elongation without affecting BZR1’s ability to reduce chromatin accessibility and expression of BR-repressed genes. Together, these data identify that BZR1 recruits the BAS complex to open chromatin and to mediate BR-induced transcriptional activation of growth-promoting genes.

油菜素类固醇 (BR) 信号传导导致油菜唑抗性 1 (BZR1) 转录因子在核中积累，该转录因子在激活或抑制数千个基因的表达中发挥双重作用。 BZR1 通过招募组蛋白脱乙酰酶来抑制基因表达，但它如何激活 BR 诱导基因的转录仍不清楚。在这里，我们发现 BR 重塑了拟南芥中全基因组染色质可及性景观，增加了 BR 诱导基因的可及性并降低了 BR 抑制基因的可及性。 BZR1 与基因组上的 BRAHMA 相关 SWI/SNF (BAS) 染色质重塑复合物发生物理相互作用，并选择性地将 BAS 复合物招募到 BR 激活的基因上。 BAS 的耗尽会消除 BZR1 增加染色质可及性、激活基因表达和促进细胞伸长的能力，而不影响 BZR1 降低染色质可及性和 BR 抑制基因表达的能力。总之，这些数据表明 BZR1 招募 BAS 复合物来打开染色质并介导 BR 诱导的生长促进基因的转录激活。