Exploring resistance mechanisms in the S. musiva - Populus interaction

在过去几十年中，世界对木材和纤维等森林产品的需求有所增加，而可用于帮助满足这些需求的相应土地面积却减少了。因此，森林公司已经开始探索人工林，以此作为抵消可用土地减少的一种手段，同时保持稳定的纤维生产。速生杂交杨树种植园一直是加拿大各地的选择物种。然而，这些树种的种植增加往往伴随着病虫害暴发的增加。特别令人感兴趣的是一种名为溃疡病的疾病。虽然这种疾病侵染叶片，引起叶斑和木质组织，导致溃烂，但大多数重要的经济损失是由于木质组织的溃烂造成的。显然需要进行研究，重点研究杨树-黄腐病病原菌相互作用的基本和应用方面，以及对加拿大杂交杨树种植园的潜在短期和长期成功的明确影响。我们建议进行多项研究，以更好地了解白三叶与杨树的相互作用，减少对杨树人工林的损害，从而提高纤维生产的质量和数量。在我们的研究中，我们将(1)进行范围广泛的病原菌遗传分析，并用不同的病原菌菌株人工接种杂交杨树。这将提供整个范围内病原菌群体遗传学的描述，然后可以与病原菌的病情严重程度进行比较，(2)描述病原菌进入寄主组织并引起疾病的方式，以及(3)通过比较抗病和感病树在暴露于不同的病原菌品系后产生的防御化学物质来研究杨树所使用的抗性机制。我们预计，该项目的成果将对更广泛的杨树病害管理社区和加拿大更有针对性的黑杨病原菌调查者和杨树种植者社区有用，以及由此产生的信息将支持旨在减少黑杨溃烂病损失的纤维管理策略的开发。

Over the last several decades world demand for forest products such as timber and fiber have increased and the corresponding land area available to help meet these demands has decreased. As a result forest companies have begun to explore plantation forestry as a means of offsetting the reduction in land available while maintain a steady fiber production. Plantations of fast growing hybrid poplar have been the species of choice across Canada. However, the increased plantation of these tree species is often accompanied by an increased insect and disease outbreaks. Of particular interest is a disease called Septoria canker pathogen. While this disease infects leaves, causing leaf spots, and woody tissue, causing cankers, the majority of the economically important damage is a result of cankers on woody tissues. Studies focusing on both fundamental and applied aspects of poplar-Septoria pathogen interaction in combination with clear impacts on the potential short- and long- term success of hybrid poplar plantations in Canada are clearly needed. We propose multiple studies to develop a better understanding of Septoria-poplar interactions and reduce damage to poplar plantations, and thus improve quality and quantity of fiber production. In our studies, we will (1) investigate a range-wide genetic analysis of the Septoria pathogen and artificially inoculate hybrid poplars with different strains of the pathogen. This will provide a description of the pathogen population genetics across its range, which can then be compared with disease severity of the pathogen, (2) describe the mode by which the Septoria pathogen enters into host tissue and causes disease, and (3) examine the resistance mechanism employed by poplar trees by comparing the defensive chemicals produced by resistant and susceptible trees after exposure to different strains of the pathogen. We expect that the outcome of this project will be useful to a broader community involved in poplar disease management and a more targeted community of Septoria pathogen investigators and poplar growers in Canada, as well as the resulting information will support the development of fiber management strategies that are aimed at reducing losses due to Septoria canker.