Dominikia bernensis, a new arbuscular mycorrhizal fungus from a Swiss no-till farming site, and D. aurea, D. compressa and D. indica, three new combinations in Dominikia

摘要

A new arbuscular mycorrhizal (AM) fungus was isolated in Rubigen (canton Bern, Switzerland) from an agricultural field subjected to no-till farming. It was also cultivated in AM fungal trap cultures established for this field site, and in a monosporic pot culture using Hieracium pilosella as host plant. Phylogenetically, it clusters within species of the recently described genus Dominikia (Glomeraceae). The new fungus forms bright yellow to golden-yellow, hi-layered spores, (19-)25-43(-52) x (19-)25-42(-46) mu m in size, formed either singly, in small spore clusters, or in non-organized sporocarps with (8-)15-85 up to 125-300 spores per sporocarp. Spores of the fungus, named Dominikia bernensis, can be distinguished from all other glomeromycotan fungal species by the combination of size and color, and the characteristics of their pigmented subtending hyphae (SH) that usually form a short pore channel and wall thickening at the spore base, which continue for less than 3-7 mu m in the SH. According to our phylogenetic analyses, three other AM fungal species, Glomus aureum, Glomus compressum and Glomus indicum cluster within the Dominikia clade, and accordingly they are recombined in the latter genus as D. aurea, D. compressa and D. indica. We conclude that Dominikia spp. do not only form colorless to very pale colored spores, but also bright yellow to golden yellow spores of small spore sizes.