Exploring effectors in Puccinia striiformis f. sp. tritici and identifying new sources of host resistance

农作物病原菌危害全球粮食生产，条锈菌对粮食安全具有重要意义。小麦条锈病（Stripe/Yellow Rust）的病原菌小麦条锈病（Pst）是加拿大和全世界最具破坏性的小麦病原体之一。真菌夏孢子通过反复的感染循环在小麦上无性繁殖，并且在有利的环境中可以引起疾病流行;这种多环疾病循环可以在单个易感小麦植物上产生无数的夏孢子，并且单个作物田地中的孢子数量可以是难以想象的。在这种情况下，即使是最低的随机突变率加上宿主选择压力也会在种群中产生新的变异/种族。Pst的生理小种或毒力表型在携带已知条锈病抗性基因（Yr基因）的小麦基因型上表征，并且通过我们过去的研究，我们已经表征了加拿大西部的>35个Pst小种。小麦-Pst致病系统遵循经典的基因对基因关系;为了成功感染小麦并克服部署的Yr基因，Pst使用了一系列武器，其中最重要的是“效应子”或“Avr基因”，然后被小麦中的免疫受体感知以赋予抗性。鉴定和表征的Pst效应，这导致在小麦Yr基因的毒性，是我的研究计划的两个长期目标之一。我们已经广泛的特点PST人口从加拿大西部的毒力表型和遗传谱系（使用分子标记和全基因组测序），并产生了巨大的基因组资源。对于锈病防治来说，鉴定Avr效应子是成功的一半，另一半是增强小麦免疫系统。小麦及其近缘种的抗条锈性鉴定、遗传鉴定（定位、精细定位、克隆、功能鉴定）以及通过为小麦育种者产生预育种种质来利用抗性是我研究计划的另一个主要目标。为此，我们已经确定了几个加入（栽培，野生，和地方品种）的小麦抗性，并克隆了两个新的Yr基因（未发表）从野生小麦面板。短期目标是利用现有的基因组资源，产生更多的基因组数据，从其他国家的加拿大和选定的Pst种族，以确定Avr基因对应于我们克隆的Yr基因和克隆新的Yr基因从野生小麦和沃特金斯地方品种使用尖端的基因克隆技术命名为AgRenSeq。了解小麦中新Yr基因的效应生物学和克隆将使我们能够为农民（在加拿大和全球）培育更好的小麦品种抗性，因为该项目将提供有关Pst使用的“武器”和病原体进化潜力的知识。该项目将培养学生（在一个多样化的实验室小组），使他们成为自信的科学家，在学术界建立自己的研究项目，或成为行业领导者。

Crop pathogens jeopardize global food production and Puccinia striiformis f. sp. tritici (Pst), the cause of stripe/yellow rust, is one of the most devastating wheat pathogens in Canada and worldwide. Fungal urediniospores are reproduced asexually on wheat via repeated cycles of infections and in conducive environments can cause disease epidemic; this polycyclic disease cycle can produce zillions of urediniospores on a single susceptible wheat plant and the number of spores in a single crop field can be unimaginable. In such scenarios, even the lowest rate of random mutation coupled with host selection pressure can give rise to new variants/races in the population. Physiologic races or virulence phenotypes of Pst are characterized on wheat genotypes carrying known stripe rust resistance genes (Yr genes) and through our past research we have characterized >35 Pst races in western Canada. The wheat-Pst pathosystem follows the classical gene-for-gene relationship; to successfully infect wheat and overcome deployed Yr genes, Pst uses a cocktail of weapons and the most important of those is 'effectors' or 'Avr genes' which are then perceived by immune receptors in wheat to confer resistance. Identification and characterization of Pst effectors, which results in virulence on wheat Yr genes, is one of the two long-term goals of my research program. We have extensively characterized Pst population from western Canada for virulence phenotypes and genetic lineages (using molecular markers and whole-genome sequencing) and have generated enormous genomic resources. For rust management, identification of Avr effectors is half the battle, the other half of the battle is to strengthen wheat immune system. Identification of stripe rust resistance in wheat & wheat relatives, genetic characterization (mapping, fine-mapping, cloning, functional characterization) and utilization of the resistance by generating pre-breeding germ plasm for wheat breeders is the other major goal of my research program. To this end, we have identified several accessions (cultivated, wild, and landraces) of wheat with resistance and have cloned two novel Yr genes (unpublished) from wild wheat panel. The short-term objectives are to utilize available genomic resources, generate more genomic data on Canadian and selected Pst races from other countries to identify Avr genes corresponding to our cloned Yr genes and clone novel Yr genes from wild wheat and Watkins landraces using cutting-edge gene cloning technology named AgRenSeq. Understanding effector biology and cloning of new Yr genes in wheat will enable us breed for better resistance in wheat varieties for farmers (in Canada and globally) because the project will deliver knowledge about the 'weapons' used by Pst and evolutionary potential of the pathogen. The project will train students (in a diverse lab group) to prepare them to become confident scientists & build their own research programs in academia or become leaders in industry.