Abstract：
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.
摘要：
干旱胁迫对全球植物生长和农业生产力构成了重大挑战。随着水的枯竭，植物激活脱落酸（ABA）信号通路，导致气孔关闭以减少水分流失。MYB家族的转录因子在生长中起着不同的作用,发展,应激反应和生物合成，然而，他们参与气孔调节仍不清楚。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。通过荧光素酶检测,染色质免疫沉淀（ChIP）测定和电泳迁移率变化测定（EMSA），我们发现MYB41通过结合自身的启动子参与正反馈调控，从而放大其在拟南芥（拟南芥）中的转录。此外，我们的调查显示，MYB41招募了BRAHMA(BRM)，SWI/SNF复合物的核心ATP酶亚基，MYB41启动子,促进组蛋白脱乙酰酶6(HDA6)的结合。这种招募会引发表观遗传修饰，导致MYB41表达减少，其特征是H3K27me3水平升高，同时H3ac降低，H3K27ac,与brm敲除突变植物相比,野生型植物中的H3K14ac水平。我们的遗传和分子分析表明，ABA介导MYB41-BRM模块的自我调节，复杂地调节拟南芥的气孔运动。这一发现揭示了干旱响应机制，有可能大大提高农业生产力。
