Exploiting eIF4E-based and associated broad-spectrum recessive resistance to potyviruses in dicots and monocots.

该项目是沃里克HRI在双子叶芸苔属植物上的工作和Rothamsted研究在单子叶植物大麦上的工作之间的合作。主要目的是：在这些植物中开发基于隐性eIF4E的马铃薯Y病毒属抗性来源。植物基因eIF4E参与病毒的生活史是在芜菁花叶病毒（TuMV，马铃薯Y病毒属）和拟南芥的实验中首次发现的。随后发现基因eIF 4E或其同种型（eIF（iso）4E）负责一系列作物类型中对马铃薯Y病毒属的天然抗性。抗性的基础是马铃薯Y病毒需要这些基因中的一个来完成它们的生命周期。已知在这些基因中具有影响其编码的植物蛋白与病毒蛋白（VPg）之间的结合的特定改变的植物对感染具有抗性。我们已经证明eIF4E与芸苔属和大麦对马铃薯Y病毒的抗性相关。到目前为止，在其他植物类型中描述的涉及单独eIF4E的抗性对特定马铃薯Y病毒的所有菌株都无效。然而，我们已经表明，在芸苔属中，eIF4E与另一个基因（retr01）组合，赋予对马铃薯Y病毒（TuMV）的所有菌株的抗性。其他基因参与病毒VPg蛋白和eIF4E之间的相互作用，这些基因包括非常相似的基因eIF（iso）4E和其他相关基因（eIF4G、eIF4A和这些基因的同种型）。通过研究eIF（iso）4E和eIF（4E）基因在抗病和感病甘蓝型油菜和大麦品系中的自然变异，旨在寻找新的抗病来源，并了解抗病机制。我们将筛选代表芸苔属物种内95%遗传变异的植物集合和由多达800个地方品种组成的大麦多样性小组。将用马铃薯Y病毒属的信息分离株测试在eIF4E基因内不同的那些植物，以检查抗性/敏感性。将对赋予耐药性的任何eIF 4E或eIF（iso）4E变体进行测序。这将通过观察已经用化学物质突变的植物来确定eIF 4E和eIF（iso）4E等位基因的其他新变化来支持。将检测具有此类变化的品系对一组BaMMV和BaYMV分离株的抗性。目的是鉴定赋予对所有（或大多数）病毒分离株持久抗性的eIF4E形式。使用eIF 4 E可用的晶体结构，将从大麦和B生成eIF 4 E的模型。拉帕。大麦和B中与病毒抗性相关的eIF4 E结构单元（氨基酸）的天然和化学诱导变化。rapa将被映射到正常eIF4E蛋白的3D模型上。这些变化对大麦和B.然后将研究rapa eIF4E与病毒VPg蛋白结合的能力。这一工作的结果将为大麦和B的上级抗性基因的预测奠定基础。在育种中部署的芜菁eIF4E。与eIF 4 E组合的基因retr 01在B中赋予对TuMV的广谱抗性。将对芜菁进行精细定位，以确定该基因在植物基因组中的位置。该基因的序列将用于搜索数据库，以预测其功能，了解广谱抗性的机制以及retr 01如何与eIF4E相互作用。基于芸苔属和大麦中病毒抗性的最佳来源，与赋予抗性的基因相关的变化将用于设计育种者可用于通过正常育种方法（杂交）将抗性并入其优良育种群体的测定。该项目将提供对广谱抗性的科学基础的理解。一旦了解了这种机制，就有可能在广泛的经济上重要的作物物种中部署这种抗性。

The project is a collaboration between Warwick HRI working on the dicotyledonous brassica plants and Rothamsted Research working on the monocotyledonous plants barley. The main aim is to: exploit sources of recessive eIF4E-based resistance to potyviruses in these plants. The involvement of the plant gene eIF4E in the life-cycle of viruses was first discovered in experiments on Turnip mosaic virus (TuMV, a potyvirus) and Arabidopsis. Subsequently it was found that the genes eIF4E or its isoform (eIF(iso)4E) are responsible for natural resistance to potyviruses in a range of crop types. The basis of the resistance is that potyviruses require one of these genes in order to complete their life-cycle. It is known that plants with specific alterations in these genes that affect the binding between the plant protein it codes and a viral protein (VPg) are resistant to infection. We have shown that eIF4E is associated with resistance to potyviruses in brassica and barley. The resistances described so far in other plant types involving eIF4E alone are not effective against all strains of the particular potyvirus. However, we have shown that in a brassica, eIF4E in combination with another gene (retr01), confers resistance against all strains of the potyvirus (TuMV). Other genes are involved in the interaction between the viral VPg protein and eIF4E, these include a the very similar gene eIF(iso)4E and other associated genes (eIF4G, eIF4A and isoforms of these). By studying the natural variation in the eIF4E and eIF(iso)4E genes from resistant and susceptible Brassica rapa and barley lines we aim to find new sources of resistance and understand the mechanism of the resistance. We will screen a collection of plants representing 95% of the genetic variation available within the brassica species and a barley diversity panel consisting of up to 800 landraces. Those plants that differ within the eIF4E gene will be tested with informative isolates of the potyviruses to check for resistance/susceptibility. Any eIF4E or eIF(iso)4E variants conferring resistance will be sequenced. This will be supported by looking at plants that have been mutated with chemicals to identify other novel changes in eIF4E and eIF(iso)4E alleles. Lines with such changes will be tested for resistance to a panel of BaMMV and BaYMV isolates. The aim is to identify forms of eIF4E that confer resistance that is durable to all (or most) virus isolates. Using the crystal structures available for eIF4E a model will be generated for eIF4E from barley and B. rapa. Natural and chemically-induced changes in the building blocks (amino acids) of the eIF4E associated with virus resistance in barley and B. rapa will be mapped on the 3D model of the normal eIF4E proteins. The effect of the changes on the potential ability of barley and B. rapa eIF4E to bind to the viral VPg protein will then be investigated. The outcome of this work will be the prediction of superior resistance genes of barley and B. rapa eIF4E for deployment in breeding. A gene retr01 which in combination with eIF4E confers the broad-spectrum resistance to TuMV in B. rapa will be fine mapped to identify the gene's position in the plant genome. The sequence of the gene will be used to search databases to predict its function, understand the mechanism of the broad-spectrum resistance and how retr01 might interact with eIF4E. Based on the best sources of virus resistance in brassicas and barley, changes associated with the genes conferring resistance will be used to design assays which can be used by breeders to incorporate the resistances into their elite breeding stocks by normal breeding methods (crossing). The project will provide an understanding of the scientific basis of the broad-spectrum resistance. Once the mechanism is understood it should be possible to deploy such resistance in a wide range of economically important crop species.