New insights into the mycorrhizal Rhizoscyphus ericae aggregate: spatial structure and co-colonization of ectomycorrhizal and ericoid roots

Authors

  • Gwen-Aëlle Grelet,

    1. Institute of Biological and Environmental Sciences, University of Aberdeen, Aberdeen, AB24 3UU, UK
    2. The Macaulay Land Use Research Institute, Craigiebuckler, Aberdeen, AB15 8QH, UK
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  • David Johnson,

    1. Institute of Biological and Environmental Sciences, University of Aberdeen, Aberdeen, AB24 3UU, UK
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  • Trude Vrålstad,

    1. Department of Biology, University of Oslo, Box 1066, Blindern, N–0316 Oslo, Norway
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  • Ian J. Alexander,

    1. Institute of Biological and Environmental Sciences, University of Aberdeen, Aberdeen, AB24 3UU, UK
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  • Ian C. Anderson

    1. The Macaulay Land Use Research Institute, Craigiebuckler, Aberdeen, AB15 8QH, UK
    2. Centre for Plants and the Environment, University of Western Sydney, Locked Bag 1797, Penrith South DC, NSW 1797, Australia
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Author for correspondence:
Gwen-Aëlle Grelet
Tel: +64 3 3219999
Email: g.grelet@abdn.ac.uk

Summary

  • Fungi in the Rhizoscyphus ericae aggregate have been recovered from the roots of co-occurring ericaceous shrubs and ectomycorrhizal trees. However, to date, there is no evidence that the same individual genotypes colonize both hosts, and no information on the extent of the mycelial networks that might form.
  • Using spatially explicit core sampling, we isolated fungi from neighbouring Pinus sylvestris (ectomycorrhizal) and Vaccinium vitis-idaea (ericoid mycorrhizal) roots and applied intersimple sequence repeat (ISSR) typing to assess the occurrence and extent of shared genets.
  • Most isolates were identified as Meliniomyces variabilis, and isolates with identical ISSR profiles were obtained from neighbouring ericoid and ectomycorrhizal roots on a number of occasions. However, genet sizes were small (< 13 cm), and several genets were found in a single soil core. Genetic relatedness was independent of spatial separation at the scales investigated (< 43 m) and M. variabilis populations from sites 20 km apart were genetically indistinguishable.
  • We conclude that individual genets of M. variabilis can simultaneously colonize Scots pine and Vaccinium roots, but there is no evidence for the formation of large mycelial networks. Our data also suggest significant genotypic overlap between widely separated populations of this ubiquitous root-associated fungus.

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