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，Zymoseptoria triumph（Zt），它攻击小麦植物，引起一种称为Septoria triumph blotch（STB）的疾病。STB每年使英国损失约3亿英镑的小麦产量和用于作物的杀真菌剂的成本。更糟糕的是，这种真菌正在对现有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。为了开发控制Zt的新方法，有必要充分了解真菌与小麦植物相互作用的方式，以及这种相互作用如何受到环境条件的影响。在以前的工作中，我发现Zt的一些分离物可以在入侵前在叶表面生长约10天。叶表面生长的量和持续时间在真菌分离物之间变化，并且当同一分离物感染不同的小麦品种时也是如此。相比之下，大多数植物病原真菌不能在叶面获得足够的营养以存活超过24 h。我的FLF研究计划的目的是确定这个叶面生长阶段的重要性Zt，它是否与疾病的严重程度，以及如何在基因组中编码的附生生长隔离间的差异。为了了解真菌在叶面上的生存，我的项目还旨在确定真菌在此期间使用的营养物质，以及它如何与其他叶面微生物相互作用。我和我的团队目前正在描述一组具有不同程度抗性的小麦品种中60多个GFP标记的菌株的附生表型。我们正在将这些数据与分离株的基因型和代谢物吸收谱联系起来，以建立支撑表面存活的机制的完整图像。我们已经确定了Zt中以前未描述的行为，包括形成生物膜的能力。我们还进行了广泛的实地采样，并正在研究Zt和其他叶面微生物之间的相互作用。在该项目的下一阶段，我将专注于三个目标：首先，我将创建报告菌株，以可视化具有不同附生表型的分离株之间的营养吸收差异。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关于附生表型的遗传和代谢差异的信息。报道者将使我们能够真实的可视化不同的分离物如何对叶面养分可用性的变化作出反应，例如，受精或花粉沉积。我将利用这些信息提出改变杀菌剂/化肥施用制度的建议，以优化疾病控制。其次，我已经表明，Zt可以形成生物膜，这比非生物膜细胞对干燥，高温和杀真菌剂等应激具有更大的抵抗力。我将确定是否以及何时在田间条件下发生生物膜形成，以及生物膜是否改变杀真菌剂处理的结果或病原体在例如热浪期间的存活。这项工作将有助于开发对天气敏感的杀真菌剂制度，并最大限度地提高杀真菌剂的功效，从而最大限度地减少进一步出现杀真菌剂耐药性的风险。第三，我将探索我们开发Zt生物防治工作中产生的选择。我将搜索我们的现场收集的真菌库的有机体链接到增加/减少疾病在我们的相关领域的数据。然后，我将进行实验，看看那些与低疾病有关的生物是否可以作为生物控制剂，或者相反，那些与疾病增加有关的生物是否可以被控制，例如，通过与埃克塞特的公民噬菌体库合作，找到感染它们的细菌。这三个目标将大大增加我们对Zt感染生物学和生态学的理解，以及新的疾病控制机制，然后可以与我们的农业合作伙伴合作进行测试。