Sebacinales are common mycorrhizal associates of Ericaceae

Authors

  • Marc-André Selosse,

    1. Centre d’Ecologie Fonctionnelle et Evolutive (CNRS, UMR 5175), Equipe coévolution, 1919 Route de Mende, 34293 Montpellier cedex 5, France;
    2. These authors contributed equally to this work.
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  • Sabrina Setaro,

    1. Botanisches Institut, Universität Tübingen, Auf der Morgenstelle 1, D-72076 Tübingen, Germany;
    2. These authors contributed equally to this work.
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  • Florent Glatard,

    1. Centre d’Ecologie Fonctionnelle et Evolutive (CNRS, UMR 5175), Equipe coévolution, 1919 Route de Mende, 34293 Montpellier cedex 5, France;
    2. These authors contributed equally to this work.
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  • Franck Richard,

    1. Centre d’Ecologie Fonctionnelle et Evolutive (CNRS, UMR 5175), Equipe coévolution, 1919 Route de Mende, 34293 Montpellier cedex 5, France;
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  • Carlos Urcelay,

    1. Instituto Multidisciplinario de Biologia Vegetal and FCEFyN, Universidad Nacional de Cordoba, CONICET, CC 495, 5000 Cordoba, Argentina;
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  • Michael Weiß

    1. Botanisches Institut, Universität Tübingen, Auf der Morgenstelle 1, D-72076 Tübingen, Germany;
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Author for correspondence: Marc-André Selosse Tel: +33 467 61 32 31 Fax: +33 467 41 21 38 Email: ma.selosse@wanadoo.fr

Summary

  • • Previous reports of sequences of Sebacinales (basal Hymenomycetes) from ericoid mycorrhizas raised the question as to whether Sebacinales are common mycorrhizal associates of Ericaceae, which are usually considered to associate with ascomycetes.
  • • Here, we sampled 239 mycorrhizas from 36 ericoid mycorrhizal species across the world (Vaccinioideae and Ericoideae) and 361 mycorrhizas from four species of basal Ericaceae lineages (Arbutoideae and Monotropoideae) that do not form ericoid mycorrhizas, but ectendomycorrhizas. Sebacinales were detected using sebacinoidspecific primers for nuclear 28S ribosomal DNA, and some samples were investigated by transmission electron microscopy (TEM).
  • • Diverging Sebacinales sequences were recovered from 76 ericoid mycorrhizas, all belonging to Sebacinales clade B. Indeed, some intracellular hyphal coils had ultrastructural TEM features expected for Sebacinales, and occurred in living cells. Sebacinales belonging to clade A were found on 13 investigated roots of the basal Ericaceae, and TEM revealed typical ectendomycorrhizal structures.
  • • Basal Ericaceae lineages thus form ectendomycorrhizas with clade A Sebacinales, a clade that also harbours ectomycorrhizal fungi. This further supports the proposition that Ericaceae ectendomycorrhizas involve ectomycorrhizal fungal taxa. When ericoid mycorrhizas evolved secondarily in Ericaceae, a shift of mycobionts occurred to ascomycetes and clade B Sebacinales, hitherto not described as ericoid mycorrhizal fungi.

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