Pathogenic, genetic and molecular characterization and differentiation of races in Colletotrichum truncatum from lentil

由真菌病原菌炭疽病引起的炭疽病是加拿大草原上扁豆的一种主要病害，对炭疽病的防治给扁豆生产者带来了巨大的经济损失，如使用杀菌剂、产量损失和品质差导致的种子降级。利用抗这两个已鉴定小种的品种被认为是控制该病最经济和对环境安全的方法。由于缺乏对田间病原菌多样性的了解，缺乏病原菌适应抗病品种的潜力，以及控制该真菌对小扁豆特定抗性基因(S)的毒力的因素，长期的抗性育种受到阻碍。利用已知小种特性的分离物，我们将识别毒力的分子标记，并使用这些标记来确定小扁豆田小种的分布。为此目的收集的分离株还将用于分子种群研究，以确定这种真菌是否在自然界中处于异种繁殖状态，从而可能通过有性重组发展新的小种。在两个小种杂交后代群体的帮助下，我们将进行遗传研究，以确定这种真菌的毒力遗传。将建立元宝炭疽菌的遗传连锁图谱。我们还打算通过显微镜和分子工具研究这两个小种在感病和抗病小扁豆上的感染生物学，以确定相互作用的关键点，并确定病原菌的毒力机制。在这样做的过程中，我们将从受感染的小扁豆叶片中开发一个cdna文库，这将使我们能够识别病原体中与毒力有关的基因，以及未来那些与抗性有关的基因。目标基因的潜在功能将通过基因中断的突变体来确认。该项目的结果将使行业合作伙伴与植物育种者和病理学家一起，为发展对炭疽病的持久抗性制定长期战略，并在未来利用该项目开发的技术和研究工具以有效的方式监测病原体。

Anthracnose caused by the fungal pathogen Colletotrichum truncatum is a major disease of lentil in the Canadian Prairies, control of which is costing lentil producers a significant amount of money through fungicide applications, yield loss and downgrading of seed due to poor quality. Use of cultivars resistant to the two identified races is considered to be the most economical and environmentally safe way of controlling the disease. Long-term success in resistance breeding has been hampered by a lack of knowledge of the pathogenic diversity of the fungus in the field, the potential of the pathogen to adapt to resistant cultivars, and factors that govern virulence in the fungus to specific resistance genes(s) in lentil. Using isolates with known race identity, we will identify molecular markers for virulence and use those to determine the distribution of races in lentil fields. Isolates collected for that purpose will also be used for a molecular population study to determine whether the fungus is outbreeding in nature and thus could develop new races through sexual recombination. With the help of a progeny population from a cross of the two races, we will conduct a genetic study to determine inheritance of virulence in this fungus. A genetic linkage map for Colletrotrichum truncatum will be developed. We also intend to investigate the infection biology of the two races on susceptible and resistant lentil genotypes by microscopy and with molecular tools to identify critical points in the interaction, and to determine virulence mechanisms in the pathogen. In doing so we will develop a cDNA library from infected lentil leaves that will allow us to identify genes involved in virulence in the pathogen, and in future those involved in resistance. Potential function of targeted genes will be confirmed by gene-disrupted mutants. The results of this project will allow the industry partner, together with plant breeders and pathologists, to develop a long-term strategy for the development of durable resistance to anthracnose, and to monitor the pathogen in an efficient way in future using technology and research tools developed in this project.