Three new arbuscular mycorrhizal Diversispora species in Glomeromycota

Abstract

Morphological observations of spores and mycorrhizal structures of three arbuscular mycorrhizal fungi (Glomeromycota) prompted, and subsequent phylogenetic analyses of SSU–ITS–LSU nrDNA sequences confirmed, that they are undescribed species of the genus Diversispora. Morphologically, the first species, here named D. varaderana, is most distinguished by its relatively small (≤90 μm diam when globose) and yellow-coloured spores with a simple spore wall consisting of two layers, of which layer 1, forming the spore surface, is short-lived and usually completely sloughed in most spores. The distinctive features of the second species, D. peridiata, are the occasional formation of spores in clusters and peridium-like hyphae covering the clusters and single spores, and especially the permanent and relatively thick spore wall layer 1, which is the only coloured component of the two-layered spore wall of the yellow-coloured and relatively small spores (≤100 μm diam). The third species, D. slowinskiensis, is most characterized by its spore wall layer 1 that is the only coloured component of the three-layered spore wall and frequently is covered with blister-like swellings. All the three species were grown in single-species cultures established from spores extracted from trap cultures inoculated with rhizosphere soils of plants growing in maritime sand dunes: D. varaderana from those located near Varadero on the Hicacos Peninsula, Cuba, and the two others from those of the Slowinski National Park, northern Poland.