A local accumulation of the Ralstonia solanacearum PopA protein in transgenic tobacco renders a compatible plant-pathogen interaction incompatible
A local accumulation of the Ralstonia solanacearum PopA protein in transgenic tobacco renders a compatible plant-pathogen interaction incompatible
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DOI：
10.1046/j.1365-313x.2001.01155.x
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发表时间：
2001-11-01
期刊：
影响因子：
7.2
通讯作者：
Keller, H
中科院分区：
文献类型：
--
作者：
Belbahri, L;Boucher, C;Keller, H
当植物识别病原体衍生分子（激发子）时，它们会激活抗病反应。通常，识别会导致过敏反应（HR），其特征是感染部位的局部宿主细胞死亡。在这里，我们描述了一种在植物中产生 HR 的基因工程方法，无论入侵的微生物是否产生公认的诱导子。为此，我们创建了转基因烟草植物，其中来自烟草的 hsr203J 基因的病原体诱导启动子控制来自青枯菌的 popA 引发子基因的表达。由于PopA本身也诱导hsr203J启动子，因此转基因植物在病原体感染位点迅速积累细菌引发子。激发子在植物组织中转化为其完全活性的衍生物 PopA1-PopA3，这表明先前观察到的加工事件不依赖于细菌 III 型分泌系统。诱导的PopA积累的结果是局部HR和转基因植物对卵菌病原体的高度抗性。该系统在不同烟草品种之间的杂交中发挥作用，我们表明工程抗性而不是相关的细胞死亡依赖于水杨酸信号级联。尽管该方法在产生卵菌抗性方面非常有效，但诱导的 HR 可能会影响植物健康。因此，其应用需要仔细选择单个转基因品系并用各种病原体进行试验。
Plants activate disease resistance responses when they recognize pathogen-derived molecules (elicitors). Frequently, recognition results in a hypersensitive response (HR), which is characterized by local host cell death at the infection site. Here we describe a genetic engineering approach to generate an HR in plants, whether or not an invading micro-organism produces a recognized elicitor. To that aim we created transgenic tobacco plants in which the pathogen-inducible promoter of the hsr203J gene from tobacco controls the expression of the popA elicitor gene from Ralstonia solanacearum. Because PopA itself also induces the hsr203J promoter, transgenic plants rapidly accumulate the bacterial elicitor in the pathogen infection sites. The elicitor becomes converted in plant tissues into its fully active derivatives PopA1-PopA3, showing that the previously observed processing events are not dependent on the bacterial type III secretion system. The outcome of induced PopA accumulation is a localized HR and a high degree of resistance of the transgenic plants to an oomycete pathogen. The system is functional in hybrids between different tobacco varieties, and we show that the engineered resistance, but not the associated cell death, is dependent on the salicylic acid signalling cascade. Although the approach is powerful in generating oomycete resistance, the induced HR might affect plant health. Its application thus requires a careful selection of individual transgenic lines and trials with various pathogens.