ABSTRACT Among all the major environmental challenges, drought stress causes considerable damage to plant growth and agricultural productivity. Drought stress directly promotes the accumulation of abscisic acid (ABA) via the activation of genes that encode enzymes involved in ABA biosynthesis, which protect the plant against water-limiting conditions. At the same time, the expression of genes that encode ABA-hydroxylases that inactivate the newly synthesized ABA, is repressed by drought stress. These phenomena occur through epigenetic modifications via the reversible processes of histone acetylation and deacetylation, also known as chromatin remodeling, which is an important regulatory mechanism that responds to various environmental stresses. Recently, we had reported that the chromatin remodeling complex HDA9-PWR-ABI4 promotes the development of drought tolerance through the deacetylation of CYP707A1/2 genes that encode the major enzymes involved in ABA catabolism. Here, we discuss the role of HDA9 and PWR in regulating drought stress by modulating the acetylation status of the CYP707A genes.

中文翻译：

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染色质重塑复合物 HDA9-PWR-ABI4 表观遗传调节植物的干旱胁迫反应

摘要 在所有主要的环境挑战中，干旱胁迫对植物生长和农业生产力造成相当大的损害。干旱胁迫通过激活编码参与 ABA 生物合成的酶的基因直接促进脱落酸 (ABA) 的积累，从而保护植物免受水分限制条件的影响。同时，编码使新合成的 ABA 失活的 ABA 羟化酶的基因的表达受到干旱胁迫的抑制。这些现象通过组蛋白乙酰化和去乙酰化的可逆过程（也称为染色质重塑）通过表观遗传修饰发生，染色质重塑是响应各种环境压力的重要调节机制。最近，我们曾报道染色质重塑复合物 HDA9-PWR-ABI4 通过编码参与 ABA 分解代谢的主要酶的 CYP707A1/2 基因的脱乙酰化促进耐旱性的发展。在这里，我们讨论了 HDA9 和 PWR 通过调节 CYP707A 基因的乙酰化状态在调节干旱胁迫中的作用。