对抗大麦锈病和白粉病的策略

锈病和白粉病是麦类作物中危害极重的两类真菌病害。编码ABC转运蛋白的Lr34基因是小麦中非常著名的对真菌病具有广谱抗性的基因。超量表达Lr34的大麦对白粉病和叶锈病具有抗性，然而也出现了一些负面表型，严重影响了产量的提升。

来自瑞士的研究团队将小麦中的Ta-Lr34res 基因在病原菌诱导型启动子Hv-Ger4c启动下转化大麦。培养出的转基因植株不仅同样具有抗病效果，而且产量与不侵染病菌的常规植株同样高。
该研究为培育抗锈病和白粉病大麦提供了新的路径，同时表明了利用病原诱导型启动子驱动广谱抗病基因在改良作物抗病性上的应用价值。
Plant Biotechnol J. 2017 July 11
Pathogen-inducible Ta-Lr34res expression in heterologous barley confers disease resistance without negative pleiotropic effects
Author
Boni R, Chauhan H, Hensel G, Roulin A, Sucher J, Kumlehn J, Brunner S, Krattinger SG, Keller B*.
*: Department of Plant and Microbial Biology, University of Zurich, Switzerland.
Abstract
Plant diseases are a serious threat to crop production. The informed use of naturally occurring disease resistance in plant breeding can greatly contribute to sustainably reduce yield losses caused by plant pathogens. The Ta-Lr34res gene encodes an ABC transporter protein and confers partial, durable, and broad spectrum resistance against several fungal pathogens in wheat. Transgenic barley lines expressing Ta-Lr34res showed enhanced resistance against powdery mildew and leaf rust of barley. While Ta-Lr34res is only active at adult stage in wheat, Ta-Lr34res was found to be highly expressed already at the seedling stage in transgenic barley resulting in severe negative effects on growth. Here, we expressed Ta-Lr34res under the control of the pathogen-inducible Hv-Ger4c promoter in barley. Sixteen independent barley transformants showed strong resistance against leaf rust and powdery mildew. Infection assays and growth parameter measurements were performed under standard glasshouse and near-field conditions using a convertible glasshouse. Two Hv-Ger4c::Ta-Lr34res transgenic events were analysed in detail. Plants of one transformation event had similar grain production compared to wild-type under glasshouse and near-field conditions. Our results showed that negative effects caused by constitutive high expression of Ta-Lr34res driven by the endogenous wheat promoter in barley can be eliminated by inducible expression without compromising disease resistance. These data demonstrate that Ta-Lr34res is agronomically useful in barley. We conclude that the generation of a large number of transformants in different barley cultivars followed by early field testing will allow identifying barley lines suitable for breeding.

;