State Key Laboratory of Crop Stress Biology for Arid Areas/Shaanxi Key Laboratory of Apple, College of Horticulture, Northwest A & F University, Yangling, Shaanxi 712100, China.
Plant Sci. 2020 Oct;299:110611. doi: 10.1016/j.plantsci.2020.110611. Epub 2020 Jul 25.
Abiotic stresses threaten the productivity and quality of economically important perennial fruit crops such as apple (Malus × domestica Borkh.). WRKY transcription factors play various roles in plant responses to abiotic stress, but little is known regarding WRKY genes in apple. Here, we carried out functional characterization of an apple Group IIa WRKY gene (MdWRKY30). qRT-PCR analysis found that MdWRKY30 expression was induced by salt and drought stress. A subcellular localization assay showed that MdWRKY30 is localized to the nucleus. A transactivation assay found that MdWRKY30 has no transcriptional activation activity. A Y2H assay indicated that MdWRKY26, MdWRKY28, and MdWRKY30 interact with each other to form heterodimers and homodimers. Transgenic analysis revealed that the overexpression of MdWRKY30 in Arabidopsis enhanced salt and osmotic tolerance in the seedling stage, as well as during the seed germination and greening cotyledon stages. MdWRKY30 overexpression enhanced tolerance to salt and osmotic stresses in transgenic apple callus through transcriptional regulation of stress-related genes. Together, our results demonstrate that MdWRKY30 is an important regulator of salinity and osmotic stress tolerance in apple.
非生物胁迫威胁着经济上重要的多年生水果作物（如苹果）的生产力和品质。WRKY 转录因子在植物对非生物胁迫的响应中发挥着各种作用，但关于苹果中的 WRKY 基因知之甚少。在这里，我们对一个苹果 Group IIa WRKY 基因（MdWRKY30）进行了功能表征。qRT-PCR 分析发现 MdWRKY30 的表达受盐和干旱胁迫诱导。亚细胞定位实验表明 MdWRKY30 定位于细胞核。一个转录激活实验发现 MdWRKY30 没有转录激活活性。一个 Y2H 实验表明 MdWRKY26、MdWRKY28 和 MdWRKY30 相互作用形成异源二聚体和同源二聚体。转基因分析表明，在拟南芥中过表达 MdWRKY30 增强了幼苗期、种子萌发期和绿色子叶期的耐盐和耐渗胁迫能力。MdWRKY30 过表达通过对胁迫相关基因的转录调控增强了转基因苹果愈伤组织对盐和渗透胁迫的耐受性。总之，我们的研究结果表明，MdWRKY30 是苹果耐盐和耐渗胁迫的一个重要调节因子。
