Molecular characterization of the poplar-rust interaction

由于它们的生命周期长，树木已经发展出独特的防御机制，使它们能够长期生存。森林害虫可对树木生长和生存、木材产量和质量以及野生动物栖息地产生不利影响，造成直接或间接的经济和环境损失。事实上，害虫的重要性及其对森林（天然和人工林）的负面影响主要被低估了。最近，农业和森林产品国际贸易的增加也促进了昆虫和疾病的流动。全球气候变化也可能增加虫害爆发的发生和严重程度。由于缺乏明确定义的生物系统，对森林树种中宿主-病原体相互作用的研究一直受到限制。然而，杨树与锈病的相互作用已经有了相对较好的记录。杨树具有遗传资源丰富、生长早期快、克隆繁殖容易、转化方法常规等优点，已成为基因组学研究的模式树种（http://www.ornl.gov/sci/ipgc/）。它的基因组序列最近也完成了。此外，一组相关微生物的基因组正在测序，包括第一个树木病原体，Melampsora杨树锈病。在过去的几年里，我们已经开发了防御反应中诱导的基因组合，并且最近在杨树锈病病理系统中产生了相容和不相容的宿主-病原体相互作用的cDNA文库。我们正计划利用这一专业知识，利用独特的杨树锈病相互作用系统进行功能和进化分析。这将使我们能够识别这些对比相互作用的基因和表达谱特征，并识别可能在宿主-病原体识别中必不可少的基因。

With their long life cycle, trees have developed distinct defense mechanisms allowing their long term survival. Forest pests can have adverse effects on tree growth and survival, yield and quality of wood, as well as wildlife habitat, resulting in either direct or indirect economic and environmental losses. In fact, the importance of pests and their negative impacts on forests (natural and planted) has been mainly understated. More recently, insect and disease movement has also been facilitated by the increased international trade of agricultural and forest products. Global climate change could also increase the occurrence and severity of pest outbreaks. The study of host-pathogen interactions in forest tree species has been limited primarily due to the lack of clearly defined biological systems. However, poplar-rust interactions have been relatively well documented. Poplar has become the model tree species for genomics research due to its extensive genetic resources, rapid early growth, ease of clonal propagation, and routine transformation protocols ( http://www.ornl.gov/sci/ipgc/). The sequence of its genome has also been recently completed. In addition, genomes of a cortege of associated microorganisms are being sequenced including the first tree pathogen, Melampsora poplar rust. During the last few years of this proposal we have developed a portfolio of genes induced during the defense response and have recently produced cDNA libraries of compatible and incompatible host-pathogen interactions in the poplar-rust pathosystem. We are planning to build upon this expertise to target functional and evolutionary analyses taking advantage of unique poplar-rust interaction systems. This will allow us to identify genes and expression profiles characteristic of these contrasting interactions and to identify genes that may be essential in host-pathogen recognition.