US Forest Service, Northern Research Station, 359 Main Rd, Delaware, OH, 43015, USA.
Proteome Sci. 2013 Jan 14;11(1):2. doi: 10.1186/1477-5956-11-2.
Beech bark disease is an insect-fungus complex that damages and often kills American beech trees and has major ecological and economic impacts on forests of the northeastern United States and southeastern Canadian forests. The disease begins when exotic beech scale insects feed on the bark of trees, and is followed by infection of damaged bark tissues by one of the Neonectria species of fungi. Proteomic analysis was conducted of beech bark proteins from diseased trees and healthy trees in areas heavily infested with beech bark disease. All of the diseased trees had signs of Neonectria infection such as cankers or fruiting bodies. In previous tests reported elsewhere, all of the diseased trees were demonstrated to be susceptible to the scale insect and all of the healthy trees were demonstrated to be resistant to the scale insect. Sixteen trees were sampled from eight geographically isolated stands, the sample consisting of 10 healthy (scale-resistant) and 6 diseased/infested (scale-susceptible) trees.
Proteins were extracted from each tree and analysed in triplicate by isoelectric focusing followed by denaturing gel electrophoresis. Gels were stained and protein spots identified and intensity quantified, then a statistical model was fit to identify significant differences between trees. A subset of BBD differential proteins were analysed by mass spectrometry and matched to known protein sequences for identification. Identified proteins had homology to stress, insect, and pathogen related proteins in other plant systems. Protein spots significantly different in diseased and healthy trees having no stand or disease-by-stand interaction effects were identified.
Further study of these proteins should help to understand processes critical to resistance to beech bark disease and to develop biomarkers for use in tree breeding programs and for the selection of resistant trees prior to or in early stages of BBD development in stands. Early identification of resistant trees (prior to the full disease development in an area) will allow forest management through the removal of susceptible trees and their root-sprouts prior to the onset of disease, allowing management and mitigation of costs, economic impact, and impacts on ecological systems and services.
山毛榉树皮病是一种由昆虫和真菌组成的复合病症，会损害山毛榉树，甚至导致其死亡，对美国东北部和加拿大东南部森林的生态和经济都有重大影响。该病症始于外来山毛榉扁虱蚕食树皮，接着是被一种 Neonectria 真菌属的真菌感染受损的树皮组织。对严重感染山毛榉树皮病的地区中健康和患病山毛榉的树皮蛋白进行了蛋白质组学分析。所有患病树木都有 Neonectria 感染的迹象，如溃疡或子实体。在其他地方报告的先前测试中，所有患病树木都表现出对扁虱的易感性，而所有健康树木都表现出对扁虱的抗性。从 8 个地理位置孤立的林中采集了 16 棵树，样本由 10 棵健康（抗扁虱）和 6 棵患病/感染（易感扁虱）的树木组成。
从每棵树中提取蛋白质，通过等电聚焦进行三次重复分析，然后进行变性凝胶电泳。对凝胶进行染色，鉴定蛋白质斑点并对其强度进行量化，然后拟合统计模型以确定树木之间的显著差异。通过质谱分析对 BBD 差异蛋白的一部分进行分析，并与其他植物系统中已知的蛋白质序列进行匹配以进行鉴定。鉴定出的蛋白质与其他植物系统中与应激、昆虫和病原体相关的蛋白质具有同源性。在无林分或林分间无疾病相互作用效应的患病和健康树木之间，鉴定出差异显著的蛋白质斑点。
进一步研究这些蛋白质应有助于了解对山毛榉树皮病的抗性至关重要的过程，并开发用于树木选育计划的生物标志物，以及在林分中 BBD 发展的早期或早期阶段选择抗性树木。在该地区全面发病之前，对抗性树木进行早期鉴定，可通过在疾病发作前移除易感树木及其根蘖，进行森林管理，从而控制和减轻成本、经济影响以及对生态系统和服务的影响。
