Co-existing ericaceous plant species in a subarctic mire community share fungal root endophytes

During the last decade, culture-independent identification tools have widened our knowledge of fungi colonizing ericaceous roots including ericoid mycorrhizal fungi. One focal interest has been to identify fungi, which simultaneously can establish ericoid and ectomycorrhiza, while knowledge about the fungal composition in roots of co-existing ericaceous plants is scarce. In the present paper, the fungal community in roots of four ericaceous plant species, Empetrum hermaphroditum, Andromeda polifolia, Vaccinium uliginosum and Vaccinium vitis-idaea which often dominate subarctic heaths and mires, was studied. From each of these plants, in each of five plots, clone libraries were established using fungal specific ITS-PCR followed by cloning, PCR–RFLP and sequencing. The clone libraries were dominated by potential ericoid mycorrhizal fungi, particularly Rhizoscyphus ericae, fungi belonging to the Sebacinales group B, and Capronia-like fungi. Additionally, the results showed that while ericaceous plant species growing within the same 15 × 15 cm blocks shared a common fungal community, plots just 2–3 m away harboured a significantly different fungal community. The possible functional implications of co-existing ericaceous plants being interlinked by a common mycelial network are discussed.