Molecular diversity and phylogenetic affinities of symbiotic root-associated ascomycetes of the Helotiales in burnt and metal polluted habitats

Authors

  • Trude Vrålstad,

    Corresponding author
    1. Ascomycete Research group, Oslo, Norway (ARON), Division of Botany and Plant Physiology, Department of Biology, University of Oslo, PO Box 1045 Blindern, N-0316 Oslo, Norway
      Author for correspondence: Trude Vrålstad Tel: +47 22 85 46 63 Fax: +47 22 85 46 64 Email: trudevr@ulrik.uio.no
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  • Elin Myhre,

    1. Ascomycete Research group, Oslo, Norway (ARON), Division of Botany and Plant Physiology, Department of Biology, University of Oslo, PO Box 1045 Blindern, N-0316 Oslo, Norway
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  • Trond Schumacher

    1. Ascomycete Research group, Oslo, Norway (ARON), Division of Botany and Plant Physiology, Department of Biology, University of Oslo, PO Box 1045 Blindern, N-0316 Oslo, Norway
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Author for correspondence: Trude Vrålstad Tel: +47 22 85 46 63 Fax: +47 22 85 46 64 Email: trudevr@ulrik.uio.no

Summary

  • • The diversity and phylogenetic affinities of symbiotic root-associated ascomycetes of the Helotiales are reported here based on ITS1–5.8S-ITS2 (internal transcribed spacer, ITS) nrDNA sequences.
  • • Mycobionts were obtained from roots of ericoid plants and grasses and from Piceirhiza bicolorata ectomycorrhizas (pbECM) on conifers and hardwoods, predominantly in burnt and metal-polluted habitats. The mycobionts were sequenced through the ITS and compared with sequences of known helotialean taxa.
  • • We recognized 132 fungal ITS-sequences with affinity to the Helotiales, of which 75% (54 different ITS-genotypes) grouped within the Hymenoscyphus ericae aggregate including Phialophora finlandia. This aggregate showed stronger affinity to members of the Hyaloscyphaceae and Dermateaceae than to Hymenoscyphus fructigenus (genus-type species; Helotiaceae). Most of the pbECM mycobionts grouped with P. finlandia, although some grouped with H. ericae. Two genotypes co-occurred in ericoid and ectomycorrhizal roots.
  • • The H. ericae aggregate may be referable to a generic unit, and includes a diverse group of closely related, more or less darkly pigmented, root-associated ascomycetes where the borders between intra- and interspecific ITS-sequence variation, as well as different mycorrhizal and nonmycorrhizal root-symbioses, remains unclear.

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