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/T021608/1
• 负责人: Helen Eyles
• 金额: $ 118.24万
• 依托单位: UNIVERSITY OF EXETER
• 依托单位国家: 英国
• 项目类别: Fellowship
• 财政年份: 2020
• 资助国家: 英国
• 起止时间: 2020 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=MR%2FT021608%2F1
• 关键词: Epiphytic; ecology; nutrition; control; wheat

My research concerns a fungus, Zymoseptoria tritici, 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 beginning to develop resistance to the fungicides that are available to treat it. This means that we need new methods to control the infection. To develop new ways to control Z. tritici, 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 Z. tritici 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. If the particular wheat variety is resistant to a particular Z. tritici isolate, then that isolate will never invade the leaf. However, it appears that such 'avirulent' isolates can persist on the leaf surface instead, and even reproduce there, making new spores for dispersal to more susceptible wheat plants. Most plant pathogenic fungi, by contrast, can't obtain enough nutrients on the leaf surface to survive for more than 24 hours. I therefore want to determine, firstly, how important this leaf surface growth phase is for Z. tritici, and whether it is related to how effective the fungus is at causing disease. I also want to find out whether some isolates are more likely than others to spend a prolonged period of time on the leaf surface, and whether such differences in behaviour can be attributed to differences in the genomes of the fungal isolates. Secondly, I aim to determine what nutrients the fungus is using when it is on the leaf surface. For example, the fungus might be relying on internal lipid stores, or taking advantage of nutrients that are exuded from the leaf, or of agricultural inputs like fertilisers. Alternatively, it might be able to secrete enzymes which digest structural components of the leaf such as waxes, to obtain nutrients from those. The fungus might also be able to take advantage of the activities of other microbes on the leaf surface which secrete such enzymes, or which cause nutrients to leak from the leaf by damaging the leaf surface. Thirdly, therefore, I intend to sample wheat leaves in the field and use metagenomics to study which microbes are present on the leaf surface. I will then compare these microbial communities, taking note of how severely affected the wheat in each field was by Z. tritici, to look for correlations between the presence of particular microbes and the promotion of fungal infection. Having obtained these data about leaf surface growth in Z. tritici, I intend to use them to build a detailed picture of what the fungus needs to survive throughout this first period of infection, before it enters the leaf; or to persist and reproduce on the leaf surface if the wheat is resistant and it cannot enter. This will allow me to identify any vulnerabilities the fungus has that we might be able to exploit in order to control the disease. For instance, if leaf surface growth is boosted by the presence of fertiliser, then it may be possible to increase the usefulness of fungicides by inter-relating the timings of fertiliser and fungicide application. Alternatively, if the fungus relies on a particular metabolic pathway to obtain nutrients, then that pathway could be targeted for new forms of chemical or other control. Or, if the fungus gains a large advantage sharing the leaf surface with a particular bacterium, then controlling that bacterium, perhaps via bio-control with a competing bacterium that is not able to promote fungal growth, might indirectly control the fungus.

我的研究涉及一种真菌，Zymoseptoria tritici，它攻击小麦植物，引起了一种称为Septoria tritici斑点（STB）的疾病。 STB每年的小麦产量损失约为3亿英镑，而农作物中使用的杀菌剂的成本。更糟糕的是，真菌开始对可用于治疗的真菌产生抗性。这意味着我们需要新的方法来控制感染。为了开发控制Z. tritici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。在先前的工作中，我表明Z. tritici的一些分离株可以在叶片表面生长大约十天，然后入侵。叶片表面生长的量和持续时间在真菌分离株之间有所不同，当相同的分离株感染不同的小麦品种时。特定的小麦品种对特定的Z. tritici分离株具有抗性，然后分离株永远不会侵入叶子。但是，看来这种“无毒的”分离株可以持续在叶子表面上，甚至可以在那里繁殖，从而使新的孢子分散到更易感的小麦植物上。相比之下，大多数植物致病真菌无法在叶片表面获得足够的营养，无法生存超过24小时。因此，我想确定该叶子表面生长阶段对Z. tritici的重要性，以及它是否与真菌在引起疾病的有效性有关。我还想找出某些分离株是否比其他分离株更有可能在叶子表面花费长时间的时间，并且行为上的这种差异是否可以归因于真菌基因组的差异。其次，我的目的是确定真菌在叶片表面上使用的养分。例如，真菌可能依赖于内部脂质储物，或者利用叶子中散发出的营养或肥料等农业输入。另外，它可能能够秘密地秘密酶，这些酶从叶子等消化叶片的结构成分（例如蜡）中获得营养。真菌也可能能够利用叶片表面上的其他微生物的活性，而叶子表面秘密，或者通过损坏叶子表面而导致营养物质从叶子泄漏出来。第三，因此，我打算在田间采样小麦叶子，并使用宏基因组学研究叶片表面存在哪些微生物。然后，我将比较这些微生物群落，并注意Z. tritici在每个领域的严重影响，以寻找特定微生物的存在与促进真菌感染之间的相关性。在获得Z. tritici中叶片表面生长的这些数据之后，我打算使用它们来详细描述真菌在进入叶片之前的第一阶段感染中需要生存的东西。或者如果小麦具有抗性并且无法进入，则在叶子表面持续并繁殖。这将使我能够确定真菌所拥有的任何漏洞，我们可能能够利用以控制这种疾病。例如，如果通过肥料的存在来增强叶片表面的生长，那么可以通过相互关联肥料和杀菌剂的施用时间来提高杀菌剂的实用性。替代性，如果真菌依赖于特定的代谢途径来获得营养，那么该途径可以针对新的化学物质或其他控制形式。或者，如果真菌获得了与特定细菌共享叶子表面的大优势，那么可以通过生物控制来控制该细菌，而这种细菌可能会与竞争性细菌无法促进真菌生长，可能会间接控制真菌。

项目成果

Presence of ice-nucleating Pseudomonas on wheat leaves promotes Septoria tritici blotch disease (Zymoseptoria tritici) via a mutually beneficial interaction.

• DOI: 10.1038/s41598-020-74615-7
• 发表时间: 2020-10-20
• 期刊: Scientific reports
• 影响因子: 4.6
• 作者: Fones HN

Use of chitin:DNA ratio to assess growth form in fungal cells.

• DOI: 10.1186/s12915-024-01815-2
• 发表时间: 2024-01-17
• 期刊: BMC BIOLOGY
• 影响因子: 5.4
• 作者: Kovacs-Simon, Andrea;Fones, Helen N.
• 通讯作者: Fones, Helen N.

Biofilm formation in Zymoseptoria tritici

• DOI: 10.1101/2023.07.26.550639
• 发表时间: 2023-07-26
• 期刊: bioRxiv
• 作者: Tyzack，Tegan E.;Hacker，Christian;Fones，Helen N.
• 通讯作者: Fones，Helen N.