The role of two component signalling in the regulation of stress responses and virulence in the fungal phytopathogen, Zymoseptoria tritici

两种成分信号在真菌植物病原体小麦发酵斑孢菌应激反应和毒力调节中的作用

• 批准号: 2306777
• 金额: --
• 依托单位: Newcastle University
• 依托单位国家: 英国
• 项目类别: Studentship
• 财政年份: 2019
• 资助国家: 英国
• 起止时间: 2019 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=studentship-2306777
• 关键词: role; two; component; signalling; regulation

The fungal pathogen Zymoseptoria tritici is the causative agent of Septoria tritici blotch (STB), a disease that represents a major threat to wheat production and food security worldwide. Recently, the development of a range of molecular tools for Z. tritici has provided an opportunity to decipher the pathways that regulate its pathogenicity and inform new strategies for its control. The identification of such strategies is important due to the increasing incidence of fungicide resistant strains which threaten sustainable agriculture and food production. The ability to mount effective responses to host-imposed environmental stresses has been shown to be an important virulence attribute in a variety of plant and human fungal pathogens. Central to these responses are evolutionarily conserved stress activated MAP kinase (SAPK) pathways. In Z. tritici deletion of the Hog1 SAP kinase results in sensitivity to a range of environmental stresses and loss of virulence. However, the genes controlled by the SAPK pathway and the mechanisms by which is regulated have yet to be determined. Importantly, fungi are distinct as they use 'two component' phosphorelay systems to sense and transmit specific stress signals to SAPK modules. The prototypical fungal two component system was characterised in the budding yeast, S. cerevisiae and consists of a histidine kinase Sln1, a phosphorelay protein Ypd1 and a fungal-specific response regulator protein Ssk1. Analysis of the Z. tritici genome sequence has revealed that there are multiple genes encoding histidine kinases but single homologues of Ypd1 and Ssk1. Therefore, the aim of this project is to determine the role of ZtYpd1 and ZtSsk1 in the stress response and virulence of Z. tritici. Using methodology that is already established in the lab, strains carrying deletions in these genes will be constructed. Based on analyses of model fungi, it would be predicted that loss of ZtYpd1 would result in constitutive SAPK activation whereas loss of ZtSsk1 would prevent SAPK activation in response to specific signals. Therefore, these knockout strains will allow the effect of perturbing two component signalling on stress resistance to be determined. SAPK pathway activation (ZtHog1 phosphorylation) will monitored in order to identify which stress signals are relayed via the two component system and transcript profiling will be employed to reveal the impact of ZtYpd1 and ZtSsk1 on stress-responsive gene expression. Ultimately, wheat infection assays using the knockout strains will be used to assess the contribution of the two component system to the virulence of Z. tritici.

真菌病原菌三孢发酵壳针孢菌（Zymoseptoria triacetylum）是三孢壳针孢菌斑点病（STB）的病原体，该疾病代表对全世界小麦生产和粮食安全的主要威胁。近年来，针对Z.霍乱弧菌提供了一个机会，可以破译调节其致病性的途径，并为控制霍乱弧菌提供新的战略。由于杀真菌剂抗性菌株的发生率不断增加，威胁到可持续农业和粮食生产，因此确定此类战略非常重要。对宿主施加的环境胁迫进行有效反应的能力已被证明是多种植物和人类真菌病原体的重要毒力属性。这些反应的核心是进化上保守的应激激活MAP激酶（SAPK）途径。在Z. Hog1SAP激酶的三碱基缺失导致对一系列环境胁迫的敏感性和毒力的丧失。然而，由SAPK途径控制的基因及其调节机制尚未确定。重要的是，真菌是不同的，因为它们使用“双组分”磷酸化系统来感知和传递特定的应激信号到SAPK模块。在芽殖酵母S.酿酒酵母中的一种，由组氨酸激酶Sln 1、磷酸化蛋白Ypd 1和真菌特异性反应调节蛋白Ssk 1组成。分析了Z. trips基因组序列显示，有多个基因编码组氨酸激酶，但Ypd1和Ssk1的单一同源物。因此，本研究的目的是确定ZtYpd1和ZtSsk1在Z.三个月。使用已经在实验室中建立的方法，将构建在这些基因中携带缺失的菌株。基于对模式真菌的分析，可以预测ZtYpd1的缺失将导致组成型SAPK激活，而ZtSsk1的缺失将阻止响应于特定信号的SAPK激活。因此，这些敲除菌株将允许确定干扰双组分信号传导对胁迫抗性的影响。将监测SAPK途径活化（ZtHog1磷酸化）以鉴定哪些应激信号通过双组分系统传递，并将采用转录谱分析来揭示ZtYpd1和ZtSsk1对应激应答基因表达的影响。最后，利用基因敲除菌株进行小麦感染试验，将用于评估双组分系统对Z.三个月。