Hu Huizhen, Tang Yiwei, Wu Jian, Chen Feizhi, Yang Yidan, Pan Xuancheng, Dong Xiang, Jin Xianda, Liu Sheng, Du Xuezhu
Southwest Research Center for Landscape Architecture Engineering, State Forestry and Grassland Administration, Yunnan Province Engineering Research Center for Functional Flower Resources and Industrialization, College of Landscape Architecture and Horticulture Sciences, Southwest Forestry University, Kunming, China.
State Key Laboratory of Biocatalysis and Enzyme Engineering, Hubei Collaborative Innovation Center for Green Transformation of Bio-Resources, Hubei Key Laboratory of Industrial Biotechnology, College of Life Sciences, Hubei University, Wuhan, China.
Front Plant Sci. 2021 Aug 19;12:663536. doi: 10.3389/fpls.2021.663536. eCollection 2021.
The plant mediator is a highly conserved protein complex that interacts with transcription factors (TFs) and RNA polymerase II (RNAP II) to relay regulatory information during transcription. Plant immune response is one of the biological processes that is orchestrated by this regulatory mechanism. s, an important oil crop, is severely attacked by a devastating disease Sclerotinia stem rot. Here, we explored broad-spectrum disease resistant roles of mediator subunit 16 (BnMED16) and its host defense mechanism against fugal pathogen . We found that expression was significantly increased by infection, and its homologous overexpression resulted in rapid and comprehensive defense responses from the beginning to the end. This affected signal transduction with multiple channels including pathogen recognition, intracellular Ca concentration, reactive oxygen species (ROS) accumulation and clearance, and activation of mitogen-activated protein kinase (MAPK) signaling cascades initially. Subsequently, pathogen-/defense-related genes and hormone-responsive pathways were highly activated, which resulted in enhanced cell wall and secretion of defense proteases. Furthermore, the biochemical analysis showed that BnMED16 interacts with BnMED25 and BnWRKY33. Additionally, BnMED25 also interacts with TFs BnMYC2, BnCOI1, and BnEIN3 of the JA/ET signal transduction pathway. Taken together, we proposed a hypothetical model that BnMED16 confers resistance by enhancing BnMED25-mediated JA/ET defense pathways and BnWRKY33-activated defense signaling in . The overexpressing lines with enhanced broad-spectrum disease resistance could be useful for breeding -resistant oilseed rape varieties, as well as serving as basis for further strategy development in resistance breeding.
植物中介体是一种高度保守的蛋白质复合体，它与转录因子（TFs）和RNA聚合酶II（RNAP II）相互作用，在转录过程中传递调控信息。植物免疫反应是由这种调控机制精心编排的生物过程之一。油菜是一种重要的油料作物，受到毁灭性病害油菜菌核病的严重侵袭。在这里，我们探索了中介体亚基16（BnMED16）的广谱抗病作用及其对真菌病原体的宿主防御机制。我们发现，油菜菌核病菌感染显著增加了BnMED16的表达，其同源过表达导致从开始到结束的快速而全面的防御反应。这最初影响了包括病原体识别、细胞内Ca浓度、活性氧（ROS）积累和清除以及丝裂原活化蛋白激酶（MAPK）信号级联激活在内的多个通道的信号转导。随后，与病原体/防御相关的基因和激素响应途径被高度激活，从而导致细胞壁增强和防御蛋白酶分泌增加。此外，生化分析表明，BnMED16与BnMED25和BnWRKY33相互作用。此外，BnMED25还与茉莉酸/乙烯（JA/ET）信号转导途径的转录因子BnMYC2、BnCOI1和BnEIN3相互作用。综上所述，我们提出了一个假设模型，即BnMED16通过增强BnMED25介导的JA/ET防御途径和BnWRKY33激活的防御信号来赋予油菜抗性。具有增强的广谱抗病性的油菜过表达系可用于培育抗病油菜品种，也可为抗性育种的进一步策略开发提供基础。
