Epiphytic ecology and nutrition for control of a wheat pathogen

控制小麦病原体的附生生态学和营养

• 批准号: MR/Y020103/1
• 负责人: Helen Eyles
• 金额: $ 75.68万
• 依托单位: UNIVERSITY OF EXETER
• 依托单位国家: 英国
• 项目类别: Fellowship
• 财政年份: 2024
• 资助国家: 英国
• 起止时间: 2024 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=MR%2FY020103%2F1
• 关键词: Epiphytic; ecology; nutrition; control; wheat

My research concerns a fungus, Zymoseptoria tritici (Zt), which attacks wheat plants, causing a disease known as Septoria tritici blotch (STB). STB costs the UK around £300 Million per year in lost wheat yields and in the cost of the fungicide used on the crops. Worse, the fungus is developing resistance to the fungicides available to treat it. This means that we need new methods to control the infection. To develop new ways to control Zt, it is necessary to gain a full understanding of the ways in which the fungus interacts with the wheat plant, and how that interaction can be affected by environmental conditions. In previous work, I showed that some isolates of Zt can grow on the leaf surface for around ten days before invading. The amount and duration of leaf surface growth varies between fungal isolates, and also when the same isolate infects different wheat varieties. Most plant pathogenic fungi, by contrast, can't obtain enough nutrients on the leaf surface to survive for more than 24 h. My FLF research programme aimed to determine the importance of this leaf surface growth phase for Zt, whether it is related to disease severity, and how inter-isolate differences in epiphytic growth are encoded in the genome. To understand fungal survival on the leaf surface, my project also aimed to determine what nutrients the fungus is using during this period, and how it interacts with other leaf surface microbes. My team and I are currently describing the epiphytic phenotypes of over 60 GFP-tagged isolates across a panel of wheat cultivars with varying degrees of resistance. We are linking these data to the genotypes and metabolite uptake profiles of the isolates to build a complete picture of the mechanisms underpinning surface survival. We have identified previously undescribed behaviours in Zt, including the ability to form biofilms. We have also carried out extensive field sampling, and are studying the interactions between Zt and other leaf surface microbes. During the next phase of the project, I will focus on three objectives: First, I will create reporter strains to visualise differences in nutrient uptake between isolates with different epiphytic phenotypes. The genes used to create these reporter strains will be based on the information gathered in the project so far, concerning the genetic and metabolic differences underlying epiphytic phenotypes. The reporters will allow us to visualise, in real time, how different isolates respond to changes in leaf surface nutrient availability due to, for e.g., fertilisation or pollen deposition. I will use this information to propose changes in fungicide/fertiliser application regimes that will optimise disease control. Secondly, I have shown that Zt can form biofilms, which have greater resistance to stresses such as drying, high temperature, and fungicides than do non-biofilm cells. I will determine whether and when biofilm formation occurs under field conditions and whether biofilms alter the outcome of fungicide treatment or survival of the pathogen during, for example, a heatwave. This work will help to develop weather-sensitive fungicide regimes and maximise fungicide efficacy, thus minimising the risk of further fungicide resistance emerging. Thirdly, I will explore options arising from our work to develop biocontrol of Zt. I will search our field-collected epiphyte library for organisms linked to increased/decreased disease in our related field data. I will then conduct experiments to see whether those linked to low disease are viable as biocontrol agents or, conversely, whether those linked to increased disease can be controlled, for example by working with Exeter's Citizen Phage Library to find phages that infect them. These three objectives will provide significant increases in our understanding of Zt infection biology and ecology alongside novel disease control mechanisms, which can then be tested in collaboration with our agricultural partners.

我的研究涉及一种真菌，即小麦发酵斑孢菌 (Zymoseptoria tritici，Zt)，它会侵袭小麦植株，引发一种名为小麦壳针孢 (STB) 的疾病，每年给英国造成约 3 亿英镑的小麦产量损失和杀菌剂成本。更糟糕的是，这种真菌正在对可用的杀菌剂产生抗药性，这意味着我们需要新的方法来控制感染。为了充分了解真菌与小麦植株相互作用的方式，以及这种相互作用如何受到环境条件的影响，我在之前的工作中证明了 Zt 的一些分离株可以在叶子表面生长大约一年。入侵前十天，不同真菌分离株的叶表面生长量和持续时间各不相同，而且当同一分离株感染不同小麦品种时，大多数植物病原真菌无法在叶表面获得足够的营养来生存。超过24 h. 我的 FLF 研究计划旨在确定叶表面生长阶段对 Zt 的重要性，是否与疾病严重程度相关，以及附生生长的隔离间差异如何在基因组中编码，以了解叶子上的真菌存活。我和我的团队目前正在描述一组 60 多个 GFP 标记分离株的附生表型。我们将这些数据与分离株的基因型和代谢物吸收谱联系起来，以构建支持表面存活的机制的完整图景，包括形成生物膜的能力。我们还进行了现场采样，并正在研究 Zt 和其他叶表面微生物之间的相互作用。在该项目的下一阶段，我将重点关注三个广泛的目标：首先，我将创建报告菌株以可视化差异。用于创建这些报告菌株的基因将基于迄今为止在该项目中收集的信息，涉及附生表型背后的遗传和代谢差异。生产者将使我们能够可视化。实时了解不同分离株如何响应由于受精或花粉沉积等原因导致的叶面养分有效性的变化，我将利用这些信息来建议改变杀菌剂/肥料施用方案，以优化杀真菌剂/肥料施用方案。其次，我已经证明，Zt 可以形成生物膜，与非生物膜细胞相比，生物膜对干燥、高温和杀菌剂等应激具有更强的抵抗力，我将确定在野外条件下是否以及何时形成生物膜。生物膜改变了杀菌剂处理的结果或病原体在热浪期间的存活，这项工作将有助于开发对天气敏感的杀菌剂方案并最大限度地提高杀菌剂的功效，从而最大限度地减少进一步杀菌剂耐药性的风险。第三，我将探索我们开发 Zt 生物防治工作所产生的选择。我将在我们的现场收集的附生植物库中搜索与我们相关现场数据中疾病增加/减少相关的生物体，然后进行实验，看看这些生物体是否存在。与低疾病相关的噬菌体是否可以作为生物防治剂，或者相反，是否可以控制与增加疾病相关的噬菌体，例如通过与埃克塞特公民噬菌体图书馆合作来寻找感染它们的噬菌体这三个目标将显着增加我们的能力。了解 Zt 感染生物学和生态学以及新型疾病控制机制，然后可以与我们的农业合作伙伴合作进行测试。