State Key Laboratory of Crop Biology, Shandong Collaborative Innovation Center of Fruit & Vegetable Quality and Efficient Production, Key Laboratory of Biology and Genetic Improvement of Horticultural Crops in Huang-Huai Region, Ministry of Agriculture, College of Horticulture Science and Engineering, Shandong Agricultural University, Tai'an, Shandong 271018, PR China.
State Key Laboratory of Crop Biology, Shandong Collaborative Innovation Center of Fruit & Vegetable Quality and Efficient Production, Key Laboratory of Biology and Genetic Improvement of Horticultural Crops in Huang-Huai Region, Ministry of Agriculture, College of Horticulture Science and Engineering, Shandong Agricultural University, Tai'an, Shandong 271018, PR China.
Plant Sci. 2019 Feb;279:59-69. doi: 10.1016/j.plantsci.2018.11.002. Epub 2018 Nov 13.
The cucumber (Cucumis sativus L.), an economically important vegetable crop, is often infected by Pseudoperonospora cubensis (P. cubensis), which results in inhibited growth and reduced yield. WRKY transcription factors (TFs) play critical roles in plant disease resistance. However, little is known about the function of WRKY TFs in cucumber downy mildew resistance. In this study, we reported that CsWRKY50, a cucumber WRKY subgroup Ⅱc TF localized in the nucleus, plays an important role in cucumber defense responses to downy mildew. In addition, several putative cis-acting elements involved in abiotic stress responsiveness were also identified in the CsWRKY50 promoter. Expression analysis revealed that CsWRKY50 can be induced by P. cubensis infection, abiotic stress and diverse signaling molecules. The overexpression of CsWRKY50 in cucumber enhanced the resistance of the plant to the fungal pathogen P. cubensis. In addition, less ROS accumulated in 35S:CsWRKY50 transgenic plants infected by the pathogen due to the higher expression levels of antioxidant enzymes. Importantly, after P. cubensis infection, the transcript levels of several hormone-related defense genes were also upregulated in transgenic plants, including SA- and JA-responsive genes and SA-synthesis genes. Collectively, our results indicate that CsWRKY50 positively regulates cucumber disease resistance to P. cubensis via multiple signaling pathways.
黄瓜（Cucumis sativus L.）是一种经济上重要的蔬菜作物，常受到古巴假霜霉菌（Pseudoperonospora cubensis，P. cubensis）的感染，导致生长受阻和产量降低。WRKY 转录因子（TFs）在植物抗病性中起着关键作用。然而，关于 WRKY TFs 在黄瓜霜霉病抗性中的功能知之甚少。本研究报道了黄瓜 WRKY 亚家族Ⅱc TF 家族的 CsWRKY50，其定位于细胞核，在黄瓜对霜霉病的防御反应中起重要作用。此外，还鉴定了 CsWRKY50 启动子中涉及非生物胁迫反应的几个假定顺式作用元件。表达分析表明，CsWRKY50 可以被古巴假霜霉菌感染、非生物胁迫和多种信号分子诱导。在黄瓜中过表达 CsWRKY50 增强了植物对真菌病原体古巴假霜霉菌的抗性。此外，由于抗氧化酶的表达水平较高，病原体感染后，35S:CsWRKY50 转基因植物中 ROS 积累减少。重要的是，在古巴假霜霉菌感染后，几种与激素相关的防御基因的转录水平也在转基因植物中上调，包括 SA 和 JA 响应基因和 SA 合成基因。总之，我们的研究结果表明，CsWRKY50 通过多种信号通路正向调控黄瓜对古巴假霜霉菌的抗病性。
