Hymenoscyphus fraxineus, the causal agent of common ash dieback, possesses a low level of genetic diversity in Europe. The introduction of novel strains of this fungus must be prevented, due to the possible emergence of new virulence alleles, which could result in the infestation of the small proportion of hitherto resistant or tolerant ash trees. More comprehensive knowledge of the host spectrum of H. fraxineus is necessary for preventing further introductions. It is possible that H. fraxineus manifests itself in hosts beyond the genus Fraxinus, though this proposition has received little attention thus far. Two in vitro experiments were set up to investigate whether privet (Ligustrum vulgare) could serve as a host: germination rate of fresh H. fraxineus ascospores and colony growth of H. fraxineus were tested on agar media containing leaf extracts of privet, common ash (Fraxinus excelsior) and manna ash (Fraxinus ornus). Two different media with leaf extracts were tested, one with high (60%) and one with low (12%) extract content. Barely any significant differences were recorded in the case of the media with low extract content. Significant effects occurred only at the higher extract content level: germination was completely inhibited on the privet medium. Mycelial growth on the privet medium was slower than on both the common ash and manna ash media and, in addition, one of the three H. fraxineus strains was completely inhibited. These observations indicate the presence of inhibitors in privet. It is therefore unlikely to be a suitable host for H. fraxineus.

中文翻译：

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女贞叶提取物抑制曲霉菌的孢子萌发和菌丝生长

灰灰斑病的病原体Hymenoscyphus fraxineus在欧洲的遗传多样性水平较低。由于可能会出现新的毒力等位基因，因此必须防止引入这种真菌的新菌株，这可能会导致少量的迄今具有抗药性或耐性的灰树受到侵害。为了防止进一步引入，必须对水曲霉宿主光谱有更全面的了解。尽管迄今为止，这种主张很少受到关注，但弗雷克斯菌可能出现在Fraxinus属以外的宿主中。建立了两个体外实验来研究女贞子（女贞）可以作为宿主：新鲜发芽率H. fraxineus子囊孢子和的集落生长H. fraxineus在含有女贞的叶提取物琼脂培养基，普通灰（测试欧洲白蜡树）和甘露灰（白蜡ornus）。测试了两种不同的含叶提取物的培养基，一种具有高含量（60％），一种具有低含量（12％）。对于提取物含量低的培养基，几乎记录不到任何显着差异。仅在较高的提取物含量水平下才会产生重大影响：在女贞培养基上完全抑制了发芽。女贞培养基上的菌丝体生长比普通灰烬和甘露灰烬培养基慢，此外，三种水曲霉菌之一菌株被完全抑制。这些观察结果表明在女贞中存在抑制剂。因此，不太可能是适合于H. fraxineus的宿主。