Kosawang Chatchai, Amby Daniel Buchvaldt, Bussaban Boonsom, McKinney Lea Vig, Xu Jing, Kjær Erik D, Collinge David B, Nielsen Lene Rostgaard
Department of Geosciences and Natural Resource Management, University of Copenhagen, Denmark.
Department of Geosciences and Natural Resource Management, University of Copenhagen, Denmark; Department of Plant and Environmental Sciences, Copenhagen Plant Science Centre, University of Copenhagen, Denmark.
Fungal Biol. 2018 Feb-Mar;122(2-3):110-120. doi: 10.1016/j.funbio.2017.11.002. Epub 2017 Nov 20.
Ash dieback, caused by the fungus Hymenoscyphus fraxineus, has threatened ash trees in Europe for more than two decades. However, little is known of how endophytic communities affect the pathogen, and no effective disease management tools are available. While European ash (Fraxinus excelsior) is severely affected by the disease, other more distantly related ash species do not seem to be affected. We hypothesise that fungal endophytic communities of tolerant ash species can protect the species against ash dieback, and that selected endophytes have potential as biocontrol agents. These hypotheses were tested by isolating members of the fungal communities of five tolerant ash species, and identifying them using ITS regions. Candidate endophytes were tested by an in vitro antagonistic assay with H.fraxineus. From a total of 196 isolates we identified 9 fungal orders, 15 families, and 40 species. Fungi in orders Pleosporales, such as Boeremia exigua and Diaporthe spp., and Hypocreales (e.g., Fusarium sp.), were recovered in most communities, suggesting they are common taxa. The in vitro antagonistic assay revealed five species with high antagonistic activity against H. fraxineus. These endophytes were identified based on ITS region as Sclerostagonospora sp., Setomelanomma holmii, Epicoccum nigrum, B. exigua and Fusarium sp. Three of these taxa have been described previously as antagonists of plant pathogenic microbes, and are of interest for future studies of their potential as biological control agents against ash dieback, especially for valuable ash trees in parks and urban areas.
由真菌 Hymenoscyphus fraxineus 引起的白蜡树枯梢病已经威胁欧洲的白蜡树二十多年了。然而，关于内生菌群落如何影响这种病原体我们知之甚少，并且没有有效的病害管理工具。虽然欧洲白蜡树（Fraxinus excelsior）受到这种病害的严重影响，但其他亲缘关系较远的白蜡树种似乎并未受到影响。我们推测，耐受白蜡树种的真菌内生菌群落可以保护这些树种免受白蜡树枯梢病的侵害，并且某些选定的内生菌有作为生物防治剂的潜力。通过分离五种耐受白蜡树种的真菌群落成员并利用 ITS 区域对其进行鉴定来检验这些假设。候选内生菌通过与 Hymenoscyphus fraxineus 的体外拮抗试验进行测试。从总共 196 个分离物中，我们鉴定出 9 个真菌目、15 个科和 40 个物种。在大多数群落中都发现了 Pleosporales 目中的真菌，如 Boeremia exigua 和 Diaporthe spp.，以及 Hypocreales 目（如 Fusarium sp.），这表明它们是常见类群。体外拮抗试验揭示了五种对 Hymenoscyphus fraxineus 具有高拮抗活性的物种。这些内生菌根据 ITS 区域被鉴定为 Sclerostagonospora sp.、Setomelanomma holmii、Epicoccum nigrum、Boeremia exigua 和 Fusarium sp.。这些类群中的三个之前已被描述为植物病原微生物的拮抗剂，并且对于它们作为防治白蜡树枯梢病生物防治剂的潜力的未来研究具有重要意义，特别是对于公园和城市地区的珍贵白蜡树。
