Integrative genomic and genetic analysis of nonhost resistance across Triticeae species - TritNONHOST (PPR-CROP)

在自然环境中，植物经常接触到可能导致疾病的微生物。然而，每种植物只是非常有限数量的病原体的宿主。在进化过程中，植物和潜在的病原体经历了一场军备竞赛，建立或避免了成功的感染，最终导致了今天已知的寄主-病原体的相互作用。植物进一步进化了抗性(R)基因，以克服这些寄主病原体的某些分离物。传统的植物育种策略利用这些R基因来培育抗病作物品种。然而，随着新的致病小种病原菌种群的增加，携带R基因的品种在商业上释放后，抗性往往会迅速克服，导致R基因的保护作用丧失。另一方面，大多数植物对大多数病原体都有抵抗力。这种现象称为非寄主抗性。然而，我们对这种非寄主抗性背后的生物学机制知之甚少。因此，非寄主抗性是一种持久的抗性形式，非适应病原菌还没有进化出能够克服的形式。这项提案中的工作涉及植物中负责这种非寄主抗性的生物过程和遗传途径。这项工作对小麦和大麦在接种寄主和非寄主病原体后发生的基因表达模式的重新编程进行了全球检测。研究了引起白粉病、锈病和稻瘟病的三种具有重要经济和生态意义的病原体。在小麦和大麦与这些病原菌的相互作用中，涉及寄主和非寄主抗性的基因和生物学途径将被识别。在每种谷类作物中，负责非寄主抗性的重要基因和途径将被识别，并进一步描述它们的功能。该项目的成果将使我们对谷物中非寄主抗性的生物学有一个新的理解。这将为植物育种行业提供实现对主要病原体的可持续抗性所需的知识和工具。最终目的是将非寄主抗性的遗传成分从一种谷类作物转移到另一种谷类作物，以实现对适应病原菌的“非寄主”抗性。

Within the natural environment plants are constantly exposed to micro-organisms which have the potential to cause disease. However, each plant species is a host to only a very limited number of pathogens. During evolution the plant and the potential pathogen have undergone an arms race, establishing or avoiding successful infection, which finally resulted in the host-pathogen interactions known today. Plants have further evolved resistance (R) genes to over come certain isolates of these host-pathogens. Traditional plant breeding strategies have used these R-genes to develop resistant crop cultivars. However, after commercial release of the R-gene carrying cultivars the resistance is often rapidly overcome, following the increase in the pathogen populations of novel virulent races, resulting in the loss of the protective effect of the R-genes. On the other hand, most plants are resistant to most pathogens. This phenomenon is referred to as nonhost resistance. However, we know very little about the biological mechanisms operating behind this nonhost resistance. Nonhost resistance therefore presents as a durable form of resistance that the non-adapted pathogen has not evolved to over come. The work in this proposal addresses the biological processes and genetic pathways operating in the plant that are responsible for this nonhost resistance. This work undertakes a global examination of the reprogramming of the gene expression patterns that occur in wheat and barley following inoculation with host and nonhost pathogens. Three economically and ecologically important pathogens are examined that cause the diseases of powdery mildew, rust and blast. The genes and biological pathways involved in host and nonhost resistance in each of the wheat and barley interactions with these pathogens will be identified. Significant genes and pathways responsible for nonhost resistance in each cereal crop will be identified and their function further characterised. The outputs from this project will provide us with a new level of understanding of the biology of nonhost resistance in cereals. This will provide the plant breeding industry with the knowledge and tools required to achieve sustainable resistance to major pathogens. The ultimate aim is to transfer the genetic components of nonhost resistance from one cereal to the other to achieve 'nonhost-like' resistance to the adapted pathogen.