Purpose

Prunus serotina is a tree species native to north America which successfully invades European temperate forests. In the native range, it forms arbuscular mycorrhizae (AM), but few data are available in the exotic range. We thus investigated root-fungi interactions in several deciduous forests of northern France.

Methods

We sampled P. serotina roots in six sites with contrasted soil, canopy composition and invasion history conditions. We combined macroscopic and microscopic observations of coloured root sections with molecular analyses to document the type and identity of mycorrhizae.

Results

We evidenced characteristic structures of ectomycorrhizae (ECM) (mantles and Hartig nets) in the same roots as AM-like structures. Molecular analyses retrieved several native and exotic ECM fungal species, in particular Piloderma fallax and Xerocomellus macmurphyi. ECM species richness was the highest in sites with the longest history of invasion.

Conclusions

P. serotina is proven a dual-mycorrhizal species in the exotic range, forming both AM and ECM. This may enable it to exploit a large range of soil resources, but also to connect to the common mycorrhizal network of ECM-dominated European temperate forest, according to the “enhanced mutualism hypothesis”, thereby explaining its successful invasion.

中文翻译：

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异域李属 serotina 外生菌根的首次报道

目的

Prunus serotina是一种原产于北美的树种，已成功入侵欧洲温带森林。在本地范围内，它形成丛枝菌根 (AM)，但在外来范围内的数据很少。因此，我们调查了法国北部几个落叶林中的根真菌相互作用。

方法

我们在具有对比土壤、冠层组成和入侵历史条件的六个地点对P. serotina根进行了采样。我们将彩色根切片的宏观和微观观察与分子分析相结合，以记录菌根的类型和特性。

结果

我们在与 AM 样结构相同的根中证明了外生菌根 (ECM)（地幔和 Hartig 网）的特征结构。分子分析检索了几种本地和外来的 ECM 真菌物种，特别是Piloderma fallax和Xerocomellus macmurphyi。ECM 物种丰富度在入侵历史最长的地点最高。

结论

P. serotina被证明是外来范围内的双菌根物种，形成 AM 和 ECM。这可能使其能够利用大范围的土壤资源，而且根据“增强互惠假说”，还可以连接到以 ECM 为主的欧洲温带森林的共同菌根网络，从而解释其成功入侵。