Examination of morphological characters of two arbuscular mycorrhizal fungi (AMF; phylum Glomeromycota), which produced clusters with glomoid spores in single-species cultures, suggested that they were undescribed species, one belonging to the genera Dominikia, Microdominikia or Kamienskia, and one to the genus Glomus. Phylogenetic analyses of the nuc rDNA small subunit (18S), internal transcribed spacer (ITS1-5.8S-ITS2 = ITS) and large subunit (28S) (= 18S-ITS-28S) region, of the largest subunit of RNA polymerase II (RPB1) gene, as well as of concatenated sequences of these two loci (18S-ITS-28S + RPB1) confirmed our hypotheses and proved that both fungi were new species, here described as Dominikia bonfanteae sp. nov. and Glomus atlanticum sp. nov., respectively. In nature, D. bonfanteae was found in a plant community on the shore of Kokotek pond II (Lubliniec in the Silesian Upland, Poland). Glomus atlanticum originated from the Dunes of Aguda Park (Northern Portugal). The phylogenetic position of these new species and their close family relatives within the Glomeraceae were compared and discussed depending on the sequence alignment analysed. This paper for the first time shows the phylogeny of AMF reconstructed from analyses of two concatenated unlinked loci: 18S-ITS-28S plus RPB1. The partial RPB1 gene of D. bonfanteae was amplified using newly designed primers.
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