First report of ectomycorrhizae in Prunus serotina in the exotic range
Résumé
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.