Exploitation of genomic knowledge for sustainable resistance to the crop pest Globodera pallida

植物寄生线虫每年给全球农业造成的损失估计为1250亿美元。土豆胞囊线虫每年给英国土豆产业造成的损失估计为5000万GB。控制往往依赖于既对环境有害，也可能对人类健康有害的杀线虫剂。它们通常是英国经济马铃薯种植的必需品。这项工作将使用的新技术可以在不损害环境的情况下控制植物寄生线虫。一种蛋白质及其在细胞中发挥的作用，如果提供指定它的密码的基因变得不活跃，就可能被取消。这可能是一种自然的效果，可以保护细胞免受某些病毒等移动遗传因素的影响。其基础是一些病毒制造了中间分子(RNA)的双链，而不是正常的单链。当每一个新的蛋白质分子形成时，它都参与了遗传密码的读取。通过将双链形式的RNA引入细胞，可以实验地诱导自然的基因沉默效应。这可能会导致生物体使其自身的一个基因沉默。这是一种实验操作，是通过向细胞中引入一个与要沉默的基因完全匹配的序列来实现的。这被称为RNA干扰(RNAi)，这种效应最早是在自由生活的线虫吞下dsRNA后表现出来的。通过将dsRNA引入一系列生物体而产生的相同效果。植物可以被改造，以产生感兴趣的dsRNA。RNAi提供了一个强大的实验工具。个别感兴趣的基因可以被特定地沉默，并研究其影响。我们建立了利用RNAi技术分析植物寄生线虫特定基因功能的方法。我们已经确定了线虫为有效地在植物中取食而必须表达的基因。其他人则使用这种方法来沉默植物中单个基因的功能。同时，我们还使用了其他方法来定义哪些植物基因必须在根中局部表达，线虫才能成功摄食。在这项提议中，我们将在马铃薯植株中表达少量已知的使特定线虫基因沉默的dsRNA分子。当动物从植物中摄食时吞下dsRNA后，就会发生沉默。我们还将针对一些植物基因，这些基因必须是活跃的，线虫才能正常觅食。这种方法的主要优点是不会产生新的蛋白质。目前还没有已知的依据表明任何特定的dsRNA在人类饮食或环境中是有害的。因此，它比目前使用成本效益较低的杀虫剂或控制程序要好得多。DsRNA将由基因开关(启动子)驱动，该基因开关(启动子)仅在线虫在根中觅食的地方自然活跃，而不是在其块茎或叶片中。安全的dsRNA甚至不会出现在我们吃的马铃薯块茎中。这些基因的沉默将阻止线虫的发展，从而阻止它对作物造成的损害。这项工作将提供一种方法，帮助满足英国马铃薯种植者减少杀虫剂使用的迫切需求。它将允许消费者青睐但目前受到线虫破坏的品种广泛种植，而不会对食品安全构成任何风险。这种方法将不会对环境造成损害，并通过消除目前对昆虫有害的杀虫剂来促进对昆虫的自然控制。该方法具有比该方法中开发的更广泛的潜力。目前的应用为在改善无脊椎动物和英国土豆田里以无脊椎动物为食的环境中进行竞争性和可持续的英国土豆种植奠定了基础。

Plant parasitic nematodes cause estimated annual losses to global agriculture of $125b . Potato cyst nematode costs the UK potato industry an estimated £50 m/year. Control often depends on nematicides that are both harmful to the environment and possibly human health. They are often essential for economic potato cropping in the UK. The new technology to be used in this work can control plant parasitic nematodes without harming the environment. A protein and the role it plays in a cell can be abolished if the gene that provides the code specifying it becomes inactive. This is a natural effect that probably protecting cells from mobile genetic elements such as certain viruses. Its basis is that the some viruses make a double not the normal single strand of the intermediary molecule (RNA). It is involved in the reading of the genetic code when each new protein molecule is made. The natural gene silencing effect can be induced experimentally by introducing the double stranded form of RNA to a cell. This can cause an organism to silence one of its own genes. This is experimental manipulation is achieved by introducing to a cell a sequence that matches precisely that of the gene to be silenced. This is termed RNA interference (RNAi) and the effect was first demonstrated for the free-living nematode Caenorhabditis elegans after it swallowed dsRNA. The same effect induced by introducing dsRNA to a range of organisms. Plants can be modified to make the dsRNA of interest. RNAi provides a powerful experimental tool. Individual genes of interest can be specifically silenced and the effects of this studied. We established the use of RNAi for analyses to function of particular genes of plant parasitic nematodes. We have identified genes the nematode must express to feed in plants effectively. Others have used the approach to silence the function of individual genes in plants. In parallel we have used other methods to define which plant genes must express locally in roots for a nematode to feed successfully. In this proposal we will express in the potato plant a small number of dsRNA molecules known to silence particular nematode genes. Silencing will occur after the animal has swallowed the dsRNA when feeding from the plant. We will also target a few plant genes that must be active for the nematode to feed normally. The key advantage of the approach is that no novel protein is made. There is no known basis for any particular dsRNA to be harmful in either the human diet or to the environment. It is therefore highly preferable to current use of pesticides or control procedures that are less cost effective. The dsRNA will be driven from a gene switch (promoter) that is naturally active just where the nematode feeds in the root and not in its tubers or leaves. The safe dsRNA will not even be in the potato tubers we eat. The silencing of these genes will prevent the development of the nematode and so stop the damage it causes to the crop. The work will provide an approach that helps meet the urgent need for UK potato growers to reduce pesticide use. It will allow cultivars favoured by consumers but currently damaged by nematode to be widely grown without any risk to food safety. The approach will have no environmental harm and allow natural control of insects to flourish by eliminating pesticides that currently harm them. The approach has wider potential than to be developed in the approach. The current application represents a basis for competitive and sustainable UK potato cropping in an improved environment for invertebrates and those that feed on them in UK potato fields.