Paraglomus pernambucanum sp. nov. and Paraglomus bolivianum comb. nov., and biogeographic distribution of Paraglomus and Pacispora

Abstract

Paraglomus pernambucanum sp. nov. (Paraglomeromycetes) was found in a tropical dry forest in the semi-arid Caatinga biome of Pernambuco State (NE Brazil), in a cowpea and in two maize production sites. It was characterized by combined morphological and molecular analyses on the spores isolated from field soil samples. Another species, Pacispora boliviana (Glomeromycetes), first described only by spore morphology, had been known from another semi-arid biome in Southern America, the Gran Chaco in Bolivia. We detected this fungus now also at different locations in semi-arid to semi-humid NE Brazil. As for P. pernambucanum phylogenetic analyses were performed on nuclear ribosomal RNA gene sequences of the LSU region. For P. boliviana, the spores for these analyses originated from a trap culture inoculated with soils from the type location. The results now revealed that also P. boliviana belongs to Paraglomus. It grouped in a separate monophyletic cluster adjacent to P. pernambucanum, to P. brasilianum, P. laccatum and the type species P. occultum. Thus, P. boliviana is transferred to Paraglomus, as Paraglomus bolivianum comb. nov. Remarkably, it is the first species known in the Paraglomeromycetes with pigmented spores. Paraglomus pernambucanum and P. bolivianum have several features in common: e.g. bi-walled spores, and densely pitted surface ornamentations on the structural layer of the outer wall. Spores of the two species can be distinguished by color and the diagnostic nature of their pitted ornamentation. The current knowledge about the global distribution of Paraglomus and Pacispora species is summarized and discussed.