Identification of mycorrhizal fungi from single pelotons of Dactylorhiza majalis (Orchidaceae) using single-strand conformation polymorphism and mitochondrial ribosomal large subunit DNA sequences

The mitochondrial ribosomal large subunit (Ls) DNA was used to identify the orchid mycorrhizal fungi found in roots of Dactylorhiza majalis. The gene was amplified using DNA extracted from single pelotons obtained from fresh and silica gel dried roots. Furthermore, sequencing a variety of well-chara cterized orchid isolates expanded the fungal database of the mitochondrial ribosomal LsDNA. Polymerase chain reaction product length variants present in D. majalis were sequenced and identified using the expanded database. Th ese analyses revealed two different peloton-forming fungi in samples from D . majalis, which sometimes occurred together as a single two-taxa peloton w ithin the same cortex cell. The first taxon belonged to the genus Tulasnell a and the second taxon was distantly related to Laccaria.