Root colonization by four closely related genotypes of the ectomycorrhizal basidiomycete Laccaria bicolor (Maire) Orton – comparative studies using electron microscopy

Authors

  • KEN K. Y. WONG,

    1. Centre de Recherche en Biologie Forestière, Facultè de Foresterie et de Gèomatique, Université Laval, Sainte-Foy (Qué), Canada G1K 7P4
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    • *

      Present address: Biotechnology Research Institute, 6100 ave. Royalmount, Montréal (Qué), Canada H4P 2R2.

  • DIANE MONTPETIT,

    1. Centre de Recherche en Biologie Forestière, Facultè de Foresterie et de Gèomatique, Université Laval, Sainte-Foy (Qué), Canada G1K 7P4
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    • Present address: Centre de Recherche et de Dévéloppement sur les Aliments, 3600 ouest boul. Casavant, St-Hyacinthe (Qué.), Canada J2S 8E3.

  • YVES PICHÉ,

    Corresponding author
    1. Centre de Recherche en Biologie Forestière, Facultè de Foresterie et de Gèomatique, Université Laval, Sainte-Foy (Qué), Canada G1K 7P4
      ‡To whom reprint requests should be addressed.
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  • JIYU LEI

    1. Centre de Recherche en Biologie Forestière, Facultè de Foresterie et de Gèomatique, Université Laval, Sainte-Foy (Qué), Canada G1K 7P4
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‡To whom reprint requests should be addressed.

SUMMARY

Electron microscopy was used to compare four closely related genotypes of Laccaria bicolor (Maire) Orton (the two sib-monokaryons m4 and m10 having been crossed twice to give the two dikaryons d1 and d2) which showed substantially different ectomycorrhizal structures on roots of Pinus banksiana Lamb. All four strains incorporated into mucilage on long roots but only the most compatible strain dl formed thick mantles with closely packed hyphae at surfaces of both long and short roots. At the inner Hartig net found in short roots, hyphae of dl showed a highly convoluted morphology whereas other strains formed roundish hyphal cross sections. The rare Hartig nets formed by m4 occasionally showed highly distorted root cell walls adjacent to hyphae. The occurrence of extracellular glycofibrils during initial hypha-root contact was rare for all four fungal strains whereas substantial tannin-like deposits were frequently found in root cortical cells.

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