Ash dieback (ADB) caused by the pathogen Hymenoscyphus fraxineus is the cause of massive mortality of Fraxinus spp. in Europe. The aim of this work was to check for the presence of the molecular marker for ADB tolerance in mapped healthy-looking F. excelsior trees, and to compare its occurrence in trees exhibiting severe ADB symptoms. Monitoring of 135 healthy-looking F. excelsior on the island of Gotland, Sweden, showed that after 3-4 years 99.3% of these trees had 0%-10% crown damage, thus remaining in a similar health condition as when first mapped. After 5-6 years, 94.7% of these trees had 0%-10% crown damage. Molecular analysis of leaf tissues from 40 of those showed the presence of the molecular marker in 34 (85.0%) trees, while it was absent in 6 (15.0%) trees. Analysis of leaf tissues from 40 severely ADB-diseased trees showed the presence of the molecular marker in 17 (42.5%) trees, but its absence in 23 (57.5%) trees (p < .0001). The results demonstrated that monitoring of healthy-looking F. excelsior is a simple and straightforward approach for the selection of presumably ADB-tolerant ash for future breeding. The cDNA-based molecular marker revealed moderate capacity on its own to discriminate between presumably ADB-tolerant and susceptible F. excelsior genotypes.

中文翻译：

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识别耐灰枯病的白蜡木：视野监测与分子标记

由病原体 Hymenoscyphus fraxineus 引起的灰枯萎病 (ADB) 是导致水曲霉大量死亡的原因。在欧洲。这项工作的目的是检查在映射的看起来健康的 F. excelsior 树木中是否存在 ADB 耐受性的分子标记，并比较其在表现出严重 ADB 症状的树木中的发生情况。对瑞典哥特兰岛上 135 株外观健康的精益松树的监测表明，在 3-4 年后，这些树木中有 99.3% 的树冠受损 ​​0%-10%，因此保持与首次绘制地图时相似的健康状况。5-6 年后，这些树木中 94.7% 的树冠受损率为 0%-10%。对其中 40 株叶组织的分子分析表明，在 34 株（85.0%）树木中存在分子标记，而在 6 株（15.0%）树木中不存在。对 40 棵严重亚行病树的叶组织的分析表明，在 17 棵 (42.5%) 树中存在分子标记，但在 23 棵 (57.5%) 树中不存在 (p < .0001)。结果表明，监测看起来健康的 F. excelsior 是一种简单而直接的方法，可以为未来育种选择可能耐受 ADB 的灰分。基于 cDNA 的分子标记本身显示出中等能力来区分可能耐受 ADB 和易感的 F. excelsior 基因型。