College of Horticulture, Northwest A&F University, Yangling, People's Republic of China.
Key Laboratory of Horticultural Plant Biology and Germplasm Innovation in Northwest China, Ministry of Agriculture, Northwest A&F University, Yangling, People's Republic of China.
Plant Cell Environ. 2019 Nov;42(11):2979-2998. doi: 10.1111/pce.13600. Epub 2019 Jul 16.
Accumulation of stilbene phytoalexins stimulates resistance mechanisms against the grapevine fungus Uncinula necator. However, the defensive mechanisms triggered by stilbene synthase (STS) genes, remain largely unknown. Here, we report the function and molecular mechanism of the stilbene synthase gene VpSTS29/STS2 from Vitis pseudoreticulata in the regulation of plant responses to powdery mildew. Stilbene synthesis occurred mainly in root tips and mesophyll cells of transgenic grapevines via transport through the vascular bundles. Overexpression of VpSTS29/STS2 in Vitis vinifera increased the abundance of STSs in mesophyll tissue and resulted in the accumulation of biologically active resveratrol derivatives at the invasion site. Similarly, expression of VpSTS29/STS2 in Arabidopsis increased resistance to Golovinomyces cichoracearum. The VpSTS29/STS2-expressing Arabidopsis lines showed increased piceid accumulation together with more local hypersensitive reactions, inhibition of mycelial growth, and a reduced incidence of pathogens. Transcriptome profiling analyses demonstrated that VpSTS29/STS2-induced defences led to reprograming of global gene expression and activation of salicylic acid (SA) signalling, thus increasing expression of WRKY-MYB transcription factors and other defence response genes. We propose a model for resveratrol-mediated coordination of defence responses in which SA participates in a positive feedback loop.
芪类植物抗毒素的积累会刺激葡萄孢真菌 Uncinula necator 的抗性机制。然而，芪合酶（STS）基因触发的防御机制在很大程度上仍然未知。在这里，我们报告了葡萄科假虎刺（Vitis pseudoreticulata）中的芪合酶基因 VpSTS29/STS2 在调节植物对白粉病反应中的功能和分子机制。芪类物质的合成主要发生在转基因葡萄藤的根尖和叶肉细胞中，通过维管束运输。VpSTS29/STS2 在酿酒葡萄中的过表达增加了叶肉组织中 STS 的丰度，并导致生物活性白藜芦醇衍生物在入侵部位的积累。同样，VpSTS29/STS2 在拟南芥中的表达增加了对 Golovinomyces cichoracearum 的抗性。表达 VpSTS29/STS2 的拟南芥系表现出更多的 piceid 积累，同时伴随着局部过敏反应增加、菌丝生长抑制和病原体发病率降低。转录组分析表明，VpSTS29/STS2 诱导的防御反应导致了全局基因表达的重新编程和水杨酸（SA）信号的激活，从而增加了 WRKY-MYB 转录因子和其他防御反应基因的表达。我们提出了一个白藜芦醇介导的防御反应协调模型，其中 SA 参与正反馈回路。
