New UK potato varieties with late blight and potato cyst nematode resistance, reduced bruising and improved processing quality

马铃薯是英国和世界上极为重要的作物，在世界粮食安全中发挥着关键作用。然而，产量以及加工和消费的适用性由于目前可用品种的几个缺点而大大降低。对许多疾病和害虫的易感性，特别是由致病疫霉（Phytophthora infestans）引起的晚疫病（爱尔兰马铃薯饥荒的原因）和由马铃薯胞囊线虫引起的根部损害，是主要问题。在凉爽的条件下储存土豆会提高还原糖的水平（冷诱导的甜味），导致（在高水平的氨基酸天冬酰胺的线路中）在油炸或烘烤后产生潜在的损害健康的丙烯酰胺。土豆也容易在碰伤时变黑，导致相当大的浪费，增加了消费者的成本。植物抗病基因通过检测病原体分子然后激活防御机制来发挥作用。虽然马铃薯携带了100多个抗性基因，但栽培品种缺乏能够检测和击败晚疫病（LB）的基因。幸运的是，一些野生种的马铃薯表现出对LB的抗性，我们已经从这些亲戚中追踪并分离出LB抗性基因。然后可以使用转基因方法将这些基因导入马铃薯，从而产生具有有效抗性的品种。为了确保这种抗性是持久的，在该项目中，我们的目标是将联合收割机三种不同的LB抗性基因组合，以使LB病原体更难以绕过这种保护。当马铃薯储存在凉爽的条件下时，它们可以积累高水平的还原糖，如葡萄糖，以及高水平的天冬酰胺。在油炸过程中，这些物质转化为一种叫做丙烯酰胺的有毒分子。美国Simplot公司通过沉默块茎中的两种植物基因（转化酶和天冬酰胺合成酶），降低了块茎中的葡萄糖和天冬酰胺水平，从而降低了丙烯酰胺含量，减少了油炸时的发黑。瘀伤后产生的布朗宁是由酶（PPO）与细胞酚类化合物的相互作用引起的。同样，使用沉默，Simplot已经实现了更低的PPO水平，特别是在块茎中，并降低了块茎对擦伤损伤的敏感性。在美国，辛普劳正处于将这些具有低丙烯酰胺和擦伤控制基因（LABC）特性的马铃薯品种商业化的后期阶段。利兹已经用表达抑制PCN的蛋白质的根改造了土豆。一种是干扰PCN神经系统的小肽。另一种是蛋白酶的抑制剂，这种蛋白酶被线虫用来定殖植物根部。在这个项目中，我们的目标是将这些特性联合收割机结合到流行的马铃薯品种Maris Piper和Agria中。我们将在一个T-DNA上设计三个LB抗性基因，连接到植物基因选择标记进行转化，并在田间测试功效。我们还将把联合收割机LB抗性基因和LABC基因结合起来进行田间试验，最后我们将把联合收割机LB抗性和LABC与PCN抗性基因结合起来进行田间试验。在与Simplot的合作中，我们将为每个构建体生产至少100株植物，并筛选携带简单DNA插入物的品系和所有基因的功能。目标是选择适合随后商业化的植物品系。在这些实验中，我们还将生成关于多个基因（在我们的情况下，多达9个基因）可以在一个事件中传递并且仍然所有功能的效率的非常有用的信息。这一信息将有助于其他人通过转基因方法在其他作物中同时传递多种有用的基因。

Potatoes are an extremely important UK and world crop with a key role in world food security. However yields, and suitability for processing and consumption, are much reduced by several shortcomings in currently available varieties. Susceptibility to many diseases and pests, particularly late blight caused by Phytophthora infestans (cause of the Irish potato famine) and root damage caused by potato cyst nematodes, are major problems. Storing potatoes in cool conditions elevates levels of reducing sugars (cold-induced sweetening), resulting (in lines with high levels of the amino acid asparagine) in potentially health-damaging acrylamide production after frying or roasting. Potatoes are also susceptible to blackening upon bruising, resulting in considerable waste, raising costs to consumers. Plant disease resistance genes function by detecting molecules from a pathogen and then activating defence mechanisms. Although potatoes carry 100s of resistance genes, cultivated varieties lack those enabling it to detect and defeat the late blight (LB) organism. Fortunately, some wild species of potato show resistance to LB, and we have tracked down and isolated LB resistance genes from some of these relatives. Such genes can then be introduced into potato using GM methods, resulting in varieties with effective resistance. To ensure this resistance is long lasting, in this project we aim to combine three different LB resistance genes, to make it more difficult for the LB pathogen to by-pass this protection. When potatoes are stored in cool conditions, they can accumulate high levels of reducing sugars such as glucose, and also high levels of asparagine. During frying, these are converted to a toxic molecule called acrylamide. By silencing two plant genes (invertase and asparagine synthetase) specifically in tubers, the American company Simplot has reduced levels of glucose and asparagine in tubers, resulting in lower acrylamide and less blackening upon frying. The browning that results upon bruising is caused by the interaction of an enzyme (PPO) with cellular phenolic compounds. Again, using silencing, Simplot have achieved lower PPO levels specifically in tubers and reduced susceptibility of tubers to bruising damage. Simplot are in advanced stages of commercialising potato varieties with these low acrylamide and bruise control genes (LABC) traits in the US.Researchers in U. Leeds have engineered potatoes with roots that express proteins that inhibit PCN. One is a small peptide that interferes with the PCN nervous system. The other is an inhibitor of a protease used by the nematode to colonize the plant root. In combination, these proteins can greatly reduce losses to nematodes even on heavily infested land.In this project we aim to combine these traits in the popular potato varieties Maris Piper and Agria. We will engineer the three genes for LB resistance on one T-DNA, linked to a plant gene selectable marker for transformation, and test efficacy in the field. We will also combine LB resistance genes with LABC genes and test in the field, and finally we will combine LB resistance and LABC with PCN resistance genes and test in the field. In partnership with Simplot, we will produce at least 100 plants for each construct and screen them for lines that carry simple DNA inserts and for functionality of all the genes that were delivered. The goal is to select plant lines that are suitable for subsequent commercialization. During these experiments, we will also generate very useful information about the efficiency with which multiple genes (in our case, up to 9 genes) can be delivered in one event, and still all function. This information will be useful to others setting out to simultaneously deliver multiple useful genes by GM methods in other crops.