Towards protecting the UK landscape; a novel method to screen for resistance to ash dieback while mitigating herbivory tradeoffs.

英国在处理影响我们树木的外来入侵害虫及病原体方面的往绩欠佳，尤其是考虑到（i）植物及植物产品的庞大贸易量及（ii）树木病原体对环境及社会的影响。没有任何树木疾病的情况下有一个更高的姿态比灰枯死-唯一的植物疾病，导致政府的紧急眼镜蛇小组会议两次！最近的树木疾病爆发凸显并暴露了过去生物安全措施和树木健康资金的一些不足之处（Woodward & Boa 2013）。例如，奥利弗·拉克姆（1939-2015）在他的优秀著作《白蜡树》中呼吁彻底改变我们对树木的态度，复兴“在英国被可耻地忽视的"病理学”。但这不仅仅是需要提高植物病理学技能，而是需要采用最先进的分子技术，为英国和全球的树木生物学做出宝贵的贡献。事实上，如果分子技术更早地应用于ADB，可能不需要将近20年的时间来确定ADB的致病因子是Hymenoscyphus fraxineus，而不是已知在欧洲存在了150多年的Hymenoscyphus albidus。因此，根据欧盟法律，英国不可能限制白蜡树的进口。该提案使用“代谢物分析”，这是一种帮助解决ADB的尖端分子技术。我们最初研究了耐受性和易感性丹麦白蜡树的“代谢概况”，因为丹麦人已经与亚行斗争了20多年。使用可以测量这些小分子“重量”的复杂设备，我们可以列出它们在耐受性和易感性灰烬中的存在/不存在以及相对丰度的列表。我们的工作已经研究了近20，000种这样的小分子，并确定了数百种区分耐受性和敏感性的灰。其中至少有50-60种确实具有“歧视性”，可以用来开发一种观察英国白蜡树的方法。然而，我们的工作也发现了一些完全出乎意料的事情。我们所知道的一些化合物是参与阻止昆虫吃植物是目前在非常低的水平，在宽容的灰相比，敏感的灰。这可能是至关重要的。为什么？为什么？我们目前正在承诺数百万英镑用于选择对ADB有耐受性的英国灰。然而，任何培育对ADB有抗性的英国白蜡树的策略都需要考虑它们将成为祖母绿白蜡虫（一种原产于中国的破坏性金龟子）的合适食物来源。自20年前到达北美以来，绿白蜡虫已经杀死了数千万棵白蜡树，最近在莫斯科以西250公里处有报道。重要的是要进一步调查我们的初步数据表明，选择抗ADB的树木有非常低的水平，这些抗进食化合物，技术上称为环烯醚萜苷，我们可能无意中选择增强的敏感性祖母绿ash borer.This应用程序的目的是建立在这些最近的研究结果，确定的功能，可以区分宽容和敏感的丹麦白蜡树。我们现在寻求资金来进一步发展这种方法，并建立必要的工具：（i）通过筛选特定的小分子特征来区分耐受和易感的英国白蜡种质;（ii）确定低水平的这些抗草食性化合物是否与白蜡枯梢病的耐受性密切相关（ADB）;（iii）生成耐受性和敏感性英国白蜡树叶的详细代谢物组（存在于样品中的小分子）。监测所选英国白蜡树顶枯抗性种质的代谢组学特征的能力可以确保选择程序不会无意中选择对绿白蜡螟的易感性。

The UK' s track record in dealing with alien invasive pests and pathogens affecting our trees is poor, particularly when considering (i) the enormous volume of trade in plants and plant products and (ii) the environmental and societal impacts of tree pathogens. No case of tree diseases has a higher profile than ash dieback - the only plant disease that has resulted in the Government's emergency COBRA group meeting twice! Recent spates of tree diseases have highlighted and exposed some of the deficiencies in past biosecurity measures and funding for tree health (Woodward & Boa 2013). For example in his excellent book "The Ash Tree" Oliver Rackham (1939-2015) called for a radical change in our attitude towards trees and a revival in 'the science of pathology' which 'has been scandalously neglected in Britain'. But it is not just the need to improve plant pathology skills but to embrace state-of-the-art molecular technologies to make valuable contributions to tree biology in the UK and worldwide. Indeed has molecular technologies been applied to ADB earlier it may not have taken nearly 20 years to identify the causal agent of ADB as Hymenoscyphus fraxineus and not Hymenoscyphus albidus which was known to have exist in Europe for more than 150 years. As a consequence there was no possibility under EU law to restrict imports of ash trees to Britain. This proposal uses "metabolite profiling", a cutting edge molecular technology to help address ADB. We initially looked at the "metabolic profile" of tolerant and susceptible Danish ash, as the Danes have been battling ADB for more than 20 years. Using sophisticated equipment that can measure the "weight" of these small molecules we can make of list of their presence/absence and relative abundance in in tolerant and susceptible ash. Our work has looked at nearly ~20,000 such small molecules and identified several hundred that discriminate tolerant from susceptible ash. Of these at least 50-60 are really "discriminatory" and can be used to develop a method to look at British ash trees. However our work also discovered something totally unexpected. Some compounds that we know are involved in stopping insects eating plants were present in very low levels in tolerant ash compared to susceptible ash. Now this could be critically important. Why? We are currently committing millions of pounds towards selecting British ash with tolerance to ADB. However, any strategy for breeding British ash trees resistant to ADB will need to consider that they will be suitable food sources for emerald ash borer (Agrilus planipennis), a destructive jewel beetle native to China. Emerald ash borer has killed tens of millions of ash trees since its arrival in North America 20 years ago and has recently been reported 250 km west of Moscow. It is important to further investigate our preliminary data that suggest trees selected for resistance to ADB have very low levels these anti-feeding compounds, technically known as iridoid glycosides we may be unwittingly be selecting for enhanced susceptibility to emerald ash borer.This application is designed to build on these very recent findings that identified features which could discriminate between tolerant and susceptible Danish ash trees. We now seek funding to develop this methodology further and establish the necessary tools to: (i) discriminate tolerant and susceptible British ash germplasm by screening for specific small molecule signatures; (ii) determine whether low levels of these anti-herbivory compounds are intimately associated with tolerance to ash dieback (ADB) and; (iii) generate a detailed metabolome (small molecules existing in samples) of tolerant and susceptible British ash leaves. The ability to monitor metabolomics signatures of selected British ash dieback resistant germplasm can ensure selection programmes are not inadvertently selecting for susceptibility to Emerald Ash Borer.