WD40 repeat-containing protein 55 (WDR55) is one of the damaged DNA-binding WD40 (DWD) proteins in Arabidopsis, which is known to be involved in plant development of the reproductive and vegetative stages. In this study, we found that WDR55 was induced in plants treated with the phytohormone abscisic acid (ABA) or abiotic stresses, such as drought. Transgenic Arabidopsis plants that overexpress WDR55 showed ABA-hypersensitive phenotypes and tolerance to drought, whilst the wdr55 mutant showed the opposite results. In addition, transcriptome analysis showed that the transcript levels of ABA- and drought-responsive genes were increased in WDR55-overexpresing plants. Furthermore, some ABA-responsive genes, such as RD29B, were regulated through the histone modifications in its promoter region in a WDR55-dependent manner. Taken together, these results suggest that WDR55 plays as a positive regulator in ABA-mediated drought stress response in Arabidopsis.

中文翻译：

---

拟南芥WDR55积极参与ABA介导的干旱耐受性反应

含有WD40重复序列的蛋白质55（WDR55）是拟南芥中受损的DNA结合WD40（DWD）蛋白质之一，已知它参与生殖和营养阶段的植物发育。在这项研究中，我们发现WDR55是在用植物激素脱落酸（ABA）或非生物胁迫（例如干旱）处理的植物中诱导的。过表达WDR55的转基因拟南芥植物表现出ABA超敏表型和对干旱的耐受性，而wdr55突变体则表现出相反的结果。此外，转录组分析表明，ABA-和干旱应答基因的转录水平的增高WDR55-过度表达植物。此外，一些ABA响应基因，例如RD29B，通过其启动子区域中的组蛋白修饰以WDR55依赖性方式受到调控。两者合计，这些结果表明WDR55在拟南芥中ABA介导的干旱胁迫响应中起正调控作用。