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A pantropically introduced tree is followed by symbiots due to pseudo-vertical transmission

Global trade increases plant introductions, but joint introduction of associated microbes is overlooked. We analyzed the ectomycorrhizal fungi of a Caribbean beach tree, seagrape ( Coccoloba uvifera , Polygonacaeae), introduced pantropically to stabilize coastal soils and produce edible fruits. Seagrape displays a limited symbiont diversity in the Caribbean. In five regions of introduction (Brazil, Japan, Malaysia, Réunion and Senegal), molecular barcoding showed that seagrape mostly or exclusively associates with Scleroderma species (Basidiomycota) that were hitherto only known from Caribbean seagrape stands. An unknown Scleroderma species dominates in Brazil, Japan and Malaysia, while Scleroderma bermudense exclusively occurs in Réunion and Senegal. Population genetics analysis of S. bermudense did not detect any demographic bottleneck associated with a possible founder effect, but fungal populations from regions where seagrape is introduced are little differentiated from the Caribbean ones, separated by thousands of kilometers, consistently with relatively recent introduction. Moreover, dry seagrape fruits carry Scleroderma spores, probably because, when drying on beach sand, they aggregate spores from the spore bank accumulated by semi-hypogeous Scleroderma sporocarps. Aggregated spores inoculate seedlings, and their abundance may limit the founder effect after seagrape introduction. This rare pseudo-vertical transmission of mycorrizal fungi likely contributed to efficient and repeated seagrape / Scleroderma co-introduction


Auteur(s) : Seynabou Sene, Marc André Selosse, Mathieu Forget, Josie Lambourdière, Khoudia Cisse, Abdalah Diedhiou, Elsie Rivera, Norikazu Kameyama, Kazuyide Nara
Année de publication : 2018
Revue : International Society for Microbial Ecology
Type : Article
Mise en ligne par : SYLLA El Hadj Samba Ndao