Drought stress poses a substantial challenge to plant growth and agricultural productivity worldwide. Upon water depletion, plants activate an abscisic acid (ABA) signaling pathway, leading to stomatal closure to reduce water loss. The MYB family of transcription factors plays diverse roles in growth, development, stress responses and biosynthesis, yet their involvement in stomatal regulation remains unclear. Here, we demonstrate that ABA significantly upregulates the expression of MYB41, MYB74, and MYB102, with MYB41 serving as a key regulator that induces the expression of both MYB74 and MYB102. Through luciferase assays, chromatin immunoprecipitation (ChIP) assays and electrophoretic mobility shift assays (EMSA), we reveal that MYB41 engages in positive feedback regulation by binding to its own promoter, thus amplifying its transcription in Arabidopsis (Arabidopsis thaliana). Furthermore, our investigation showed that MYB41 recruits BRAHMA (BRM), the core ATPase subunit of the SWI/SNF complex, to the MYB41 promoter, facilitating the binding of HISTONE DEACETYLASE 6 (HDA6). This recruitment triggers epigenetic modifications, resulting in reduced MYB41 expression characterized by elevated H3K27me3 levels and concurrent decreases in H3ac, H3K27ac, and H3K14ac levels in wild-type plants compared to brm knockout mutant plants. Our genetic and molecular analyses show that ABA mediates autoregulation of the MYB41-BRM module, which intricately modulates stomatal movement in A. thaliana. This discovery sheds light on a drought response mechanism with the potential to greatly enhance agricultural productivity.

中文翻译：

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脓酸介导的 MYB41-BRAHMA 模块的自动调节增强了拟南芥的耐旱性


干旱胁迫对全球植物生长和农业生产力构成了重大挑战。水分耗尽后，植物会激活脱落酸 （ABA） 信号通路，导致气孔关闭以减少水分流失。转录因子的 MYB 家族在生长、发育、应激反应和生物合成中发挥着多种作用，但它们在气孔调节中的参与仍不清楚。在这里，我们证明 ABA 显着上调 MYB41、MYB74 和 MYB102 的表达，其中 MYB41 是诱导 MYB74 和 MYB102 表达的关键调节因子。通过荧光素酶测定、染色质免疫沉淀 （ChIP） 测定和电泳迁移率变化测定 （EMSA），我们揭示了 MYB41 通过与自身的启动子结合来参与正反馈调节，从而扩增其在拟南芥 （Arabidopsis thaliana） 中的转录。此外，我们的研究表明，MYB41 将 SWI/SNF 复合物的核心 ATP 酶亚基 BRAHMA （BRM） 募集到 MYB41 启动子上，促进组蛋白脱乙酰酶 6 （HDA6） 的结合。这种募集触发表观遗传修饰，导致 MYB41 表达降低，其特征是野生型植物的 H3K27me3 水平升高，与 brm 敲除突变植物相比，H3ac、H3K27ac 和 H3K14ac 水平同时降低。我们的遗传和分子分析表明，ABA 介导 MYB41-BRM 模块的自动调节，该模块错综复杂地调节 A. thaliana 的气孔运动。这一发现揭示了一种有可能大大提高农业生产力的干旱反应机制。