This study aimed to fingerprint 36 water yam (Dioscorea alata) accessions using microsatellite markers. Ten accessions were collected in local markets from several municipalities in Brazil, eight were obtained from the 'Instituto Agronômico de Campinas' (IAC) germplasm collection and eighteen were collected directly from growers from São Paulo state. A total of nine microsatellite loci were used in the analysis. Loci revealed high polymorphism verified by elevated PIC values (0.57-0.77), and by high gene diversity and Shannon-Wiener indices (0.69 and 1.29 on average, respectively). The accessions were classified into two groups based on clustering analysis. One group contained mostly accessions from the IAC collection, including a commercial cultivar acquired in a market in the city of Cuiabá, Mato Grosso state. The second group was composed of most accessions, including those collected directly from growers and markets in São Paulo, a few accessions from the IAC collection, and an accession from Puerto Rico, named 'Florida', which is the most cultivated in Brazil. Several duplicates were identified in this study, including accessions obtained from two farmers in Mogi Guaçu and Mogi Mirim, São Paulo state. However, some of these accessions were allocated in different sub-groups, within this second group. Results suggested the hypothesis of different origins for accessions currently cultivated in Brazil. Similar accessions obtained from different municipalities revealed the commercialization of the same accessions at different locations.

The objective of the present study was to revise the recently described order Entrophosporales of the Glomeromycetes. The single family Entrophosporaceae had been divided into three genera, Entrophospora, Claroideoglomus and Albahypha, due to molecular phylogenetic or morphological analyses, but recently these three genera were combined within the type genus of the family, Entrophospora. Our new studies now suggest once more three genera, but Entrophospora and Claroideoglomus were not separated again. In the present study, we resurrected Albahypha with A. drummondii and A. furrazolae comb. nov. and established Alborhynchus gen. nov. with A. walkeri comb. nov. Morphologically, all glomoid morphs of the three genera have hyaline to white subtending hyphae with one spore wall continuous with the subtending hyphal wall. However, the genera can easily be differentiated from each other and from other glomoid species of the Glomeromycetes by the combination of the characteristics of the subtending hyphae, the staining reaction of the spore wall layers in Melzer’s reagent and phylogeny. In conclusion, the three AMF genera, currently recognized in the Entrophosporales, can unequivocally be identified by molecular phylogeny or by morphological characteristics of their spores and their subtending hyphae. An identification key distinguishes all AMF species currently attributed to Entrophosporales.

A new arbuscular mycorrhizal (AM) fungus, Microkamienskia peruviana, was detected in bait cultures for arbuscular mycorrhizal fungi established with rhizospheric soil substrates of the inka nut (Plukenetia volubilis). The field soil derived from three agricultural plantations in the Amazonia lowlands of the province Lamas, San Martin State, in Peru. The fungus was subsequently propagated in single species cultures on Sorghum sp., Brachiaria sp., Medicago sativa and P. volubilis as host plants. The new species differentiates hyaline spores regularly in spore clusters, up to 500–800 × 400–600 μm. The spores are 16–31(–36) × 13–29(–35) μm in diam, formed on cylindrical or slightly funnel-shaped hyphae, without a septum at or close to the spore base. Phylogenetically, the new fungus belongs to a new genus, named Microkamienskia, which has as type species M. perpusilla comb. nov. and to which also M. divaricata comb. nov. belongs. Both are transferred from Kamienskia to Microkamienskia in the present study. The new fungus can be identified by the ballooning semi-persistent to evanescent outer spore wall layer in PVLG-based mountants that is not known for the other species of these two genera, nor for any other glomeromycotan species of similar small spore sizes. Kamienskia and Microkamienskia species can be distinguished by their position in the phylogenetic tree and by hyaline spores, open pores at the spore bases and in the subtending hyphae, and by their spore sizes that are for Microkamienskia among the smallest spore sizes so far detected for AM fungi (15–35 μm).