Integrated transcriptome and genetic analysis of early events determining tissue susceptibility in the Claviceps purpurea - wheat interaction

对安全和营养的小麦的需求一如既往地重要。本项目的目的是了解产生生物碱的植物病原菌Clavicep Purpurea与其寄主六倍体小麦之间的相互作用。克氏杆菌在感染花后，在小麦粒的位置形成了一种称为麦角的真菌实体。麦角含有高水平的剧毒生物碱，在摄入时对人类和动物构成危险，因此对进入人类食物链的小麦零容忍水平，并严格允许出售谷物作为饲料。近年来，在种子场中发现的麦角虫数量一直在增加，这推动了这项研究的需要。为了了解感染过程中相互作用的基本生物学，我们将从受感染的小麦花的一组非常特定的组织中提取并测量相对丰度的表达基因，在一段时间内识别Clavicep感染的关键阶段和未受感染的对照。在授粉过程中，克氏杆菌菌丝通过小麦花中生长的花粉管相同的组织生长，所以我们建议在分析中包括花粉与花的相互作用。我们将确定一组对花粉和/或菌丝生长有上调和下调调控的基因，并将确定与感知和反应有关的共同信号。没有任何化学物质可以用来防御克氏杆菌的感染，因此必须在任何长期可持续的控制策略中利用对这种病原体的自然抵抗力。在英国的一个小麦品种中已经鉴定出部分抗性，在硬粒小麦中也发现了近完全抗性的来源，我们打算定位与这些性状有关的基因，并将它们与其表达在时间和空间上似乎与抗性表达相关的基因的位置进行比较。通过使用基因修饰来增加或减少特定候选基因的表达，将获得更多支持或反对感兴趣基因在决定抗性中的假定作用的证据。

The need for safe and nutritious wheat is as important as ever. The aim of this project is to gain an understanding of the interaction between the alkaloid producing plant pathogen Claviceps purpurea and its host hexaploid wheat. Claviceps forms a fungal body called an ergot in the place of a wheat grain following infection of the flower. Ergots contain high levels of extremely toxic alkaloids and pose a risk to humans and animals when ingested hence a zero tolerance level for wheat entering the human food chain and strict levels allowed for sale of grain for feed. Levels of ergots found in seed lots have been increasing over recent years which is driving the need for this research. In order to understand the fundamental biology of the interaction during the infection process, we will extract and measure relative abundance of the expressed genes from a set of very specific tissues of the infected wheat flower over a time course that identifies the key stages of Claviceps infection along with an uninfected control. Claviceps hyphae grow through the same tissues of the wheat flower as the growing pollen tube during pollination so we propose to include the pollen-flower interactions in the analysis. We will identify set of genes that are up and down regulated in response to either pollen and or hyphal growth and will identify common signals involved in perception and response. There is no chemical that can be deployed to defend against infection by Claviceps, so natural resistance to this pathogen must be exploited in any long-term sustainable control strategy. Partial resistance has been identified for a UK wheat variety and there is also source of near complete resistance identified in durum wheat, and we intend to locate the genes conferring these traits and to compare their location with those of genes whose expression appears to correlate in time and space with the expression of resistance. Additional evidence for or against the putative role of genes of interest in determining resistance will be gained by using genetic modification to increase or decrease expression of specific candidates.