Characterization of Dryas octopetala ectomycorrhizas from limestone karst vegetation, western Ireland

Abstract

The principal ectomycorrhizas of Dryas octopetala L. from a treeless grass-heath in the Burren, western Ireland, were characterized using morphotyping and molecular methods (PCR-RFLP analysis of ITS-rDNA and sequencing of the ITS region). Twenty-one distinct morphotypes are described. Six of these (Cortinarius atrovirens Kalchbr., Cortinarius caesiocanescens (Mos.) Kühn. & Romagn., Cortinarius calochrous (Mos.) Nezd., Cortinarius odorifer Britz., Cortinarius mussivus Fr., and Tricholoma myomyces (Scop.) Quél.) were distinguished by tracing rhizomorph connections between mycorrhizas and basidiomes. The ectomycorrhizas of Cenococcum geophilum Fr., Craterellus lutescens (Pers.:Fr.) Fr., and Hebeloma sinapizans (Paulet:Fr.) Gill were identified based on molecular and morphological evidence. The ectomycorrhizas of Cortinarius brunneus (Pers.:Fr.) Fr., Cortinarius infractus (Pers.:Fr.) Fr., Hydnum repandum L., and Hebeloma circinans Quél. were distinguished provisionally, because they were consistently found in soil core samples containing basidiomes of a particular fungal species. The provisional identification of Lactarius sanguifluus (Paulet) Fr., and Russula delica Fr. ectomycorrhizas was also based on anatomical evidence, particularly the presence of lacticifers and cystidia, respectively. Six morphotypes could not be assigned to a specific fungal taxon and, therefore, were named "Dryadirhiza" + a characterizing epithet (D. aerea, D. cerina, D. fulgens, D. nigra, D. rugosa, and D. truncata). It is concluded that Dryas octopetala forms ectomycorrhizal associations in the Burren with woodland fungal species.Key words: ectomycorrhizas, Dryas octopetala, morphotyping, ITS-RFLP, mountain avens.