A new genus, Desertispora, and a new species, Diversispora sabulosa, in the family Diversisporaceae (order Diversisporales, subphylum Glomeromycotina)

Three new species of arbuscular mycorrhizal fungi (Glomeromycota) and Acaulospora gedanensis revised

Studies of the morphology and the 45S nuc rDNA phylogeny of three potentially undescribed arbuscular mycorrhizal fungi (phylum Glomeromycota) grown in cultures showed that one of these fungi is a new species of the genus Diversispora in the family Diversisporaceae; the other two fungi are new Scutellospora species in Scutellosporaceae. Diversispora vistulana sp. nov. came from maritime sand dunes of the Vistula Spit in northern Poland, and S. graeca sp. nov. and S. intraundulata sp. nov. originally inhabited the Mediterranean dunes of the Peloponnese Peninsula, Greece. In addition, the morphological description of spores of Acaulospora gedanensis, originally described in 1988, was emended based on newly found specimens, and the so far unknown phylogeny of this species was determined. The phylogenetic analyses of 45S sequences placed this species among Acaulospora species with atypical phenotypic and histochemical features of components of the two inner germinal walls.

A new order, Entrophosporales, and three new Entrophospora species in Glomeromycota

As a result of phylogenomic, phylogenetic, and morphological analyses of members of the genus Claroideoglomus, four potential new glomoid spore-producing species and Entrophospora infrequens, a new order, Entrophosporales, with one family, Entrophosporaceae (=Claroideoglomeraceae), was erected in the phylum Glomeromycota. The phylogenomic analyses recovered the Entrophosporales as sister to a clade formed by Diversisporales and Glomeraceae. The strongly conserved entrophosporoid morph of E. infrequens, provided with a newly designated epitype, was shown to represent a group of cryptic species with the potential to produce different glomoid morphs. Of the four potential new species, three enriched the Entrophosporales as new Entrophospora species, E. argentinensis, E. glacialis, and E. furrazolae, which originated from Argentina, Sweden, Oman, and Poland. The fourth fungus appeared to be a glomoid morph of the E. infrequens epitype. The physical association of the E. infrequens entrophosporoid and glomoid morphs was reported and illustrated here for the first time. The phylogenetic analyses, using nuc rDNA and rpb1 concatenated sequences, confirmed the previous conclusion that the genus Albahypha in the family Entrophosporaceae sensu Oehl et al. is an unsupported taxon. Finally, the descriptions of the Glomerales, Entrophosporaceae, and Entrophospora were emended and new nomenclatural combinations were introduced.

Three new species of arbuscular mycorrhizal fungi of the genus Diversispora from maritime dunes of Poland

Three new species of arbuscular mycorrhizal fungi of the genus Diversispora (phylum Glomeromycota) were described based on their morphology and molecular phylogeny. The phylogeny was inferred from the analyses of the partial 45S rDNA sequences (18S-ITS-28S) and the largest subunit of RNA polymerase II (rpb1) gene. These species were associated in the field with plants colonizing maritime sand dunes of the Baltic Sea in Poland and formed mycorrhiza in single-species cultures.

Sieverdingia gen. nov., S. tortuosa comb. nov., and Diversispora peloponnesiaca sp. nov. in the Diversisporaceae (Glomeromycota)

Phylogenetic analyses of 18S–ITS–28S nuc rDNA sequences indicated that the arbuscular mycorrhizal fungus originally described asGlomus tortuosumand later transferred to the genusCorymbiglomusrepresents a separate, previously unrecognized clade at the rank of genus in the family Diversisporaceae (order Diversisporales, phylum Glomeromycota). The analyses located the clade between clades representing the generaDesertisporaandRedeckera. Consequently, a new genus,Sieverdingia, was erected, withS. tortuosacomb. nov. The unique morphological feature ofS. tortuosais the formation of glomoid-like spores with a single-layered spore wall covered with a hyphal mantle. Importantly, the erection ofSieverdingiaclarified the definition ofCorymbiglomus, which currently consists of three species producing glomoid-like spores with one, three- to four-layered spore wall. The features of the innermost layer, which is hyaline, laminate, flexible to semi-flexible, indicate that it is a synapomorphy ofCorymbiglomus. The definitions ofCorymbiglomusand its species were emended. Moreover, the distribution ofS. tortuosaand the three species ofCorymbiglomuswas discussed based on own studies, literature data, and molecular sequences deposited in public databases. We concluded that the distribution ofS. tortuosaandC. globiferumknown in environmental studies based on their partial 28S nuc rDNA sequences only may be understated because the main molecular characteristics distinguishing these species reside outside the 28S region. Finally, we described a new species in the genusDiversisporaoriginating from Mediterranean dunes of the Peloponnese peninsula, Greece. The same phylogenetic analyses mentioned above indicated that the closest relative of the new species, producing dark-coloured spores, isD. clara, whose spores are creamy white at most.

Rhizoglomus dalpeae, R. maiae, and R. silesianum, new species

We examined three arbuscular mycorrhizal fungi (AMF; phylum Glomeromycota) producing glomoid spores. The mode of formation and morphology of these spores suggested that they represent undescribed species in the genus Rhizoglomus of the family Glomeraceae. Subsequent morphological studies of the spores and molecular phylogenetic analyses of sequences of the nuc rDNA small subunit (18S), internal transcribed spacer (ITS1-5.8S-ITS2 = ITS), and large subunit (28S) region (= 18S-ITS-28S) confirmed the suggestion and indicated that the fungi strongly differ from all previously described Rhizoglomus species with known DNA barcodes. Consequently, the fungi were described here as new species: R. dalpeae, R. maiae, and R. silesianum. Two of these species lived hypogeously in the field in habitats subjected to strong environmental stresses. Rhizoglomus dalpeae originated from an inselberg located within Guineo-Sudanian transition savanna zone in Benin, West Africa, where the temperature of the inselberg rock during a 5-mo drought ranges from 40 to 60 C. Rhizoglomus silesianum originated from a coal mine spoil heap in Poland, whose substrate is extremely poor in nutrients, has unfavorable texture, and may heat up to 50 C. By contrast, R. maiae was found in more favorable habitat conditions. It produced an epigeous cluster of spores among shrubs growing in a tropical humid reserve in Brazil. Moreover, the compatibility of phylogenies of species of the family Glomeraceae reconstructed from analyses of sequences of 18S-ITS-28S and the largest subunit of RNA polymerase II (RPB1) gene was discussed.