Protistology • 14 (3), XXX–XXX (2020) |
Rozellids and aphelids: cryptic diversity and distribution in the environment |
Anna Glotova1,2 and Elena Nassonova1,2
1 Laboratory of Cytology of Unicellular Organisms, Institute of Cytology RAS, 194064 St. Petersburg, Russia
| Submitted November 4, 2019 | Accepted December 10, 2019 | Summary Opisthosporidia Karpov et al. 2014 is a paraphyletic group uniting such parasitic lineages as microsporidia, rozellids and aphelids. Together with nucleariids these organisms represent the basal holomycotan lineages, which attract an attention as an intermediate link between protists and fungi and therefor can shed light on their early evolution and phylogeny. Unlike microsporidia, aphelids and rozellids (there is no consensus in the naming of this group; several synonymous names are in use: Rozellida, Cryptomycota, Rozellomycota, Rozellosporidia) are poorly studied. Few species belonging to these groups were isolated and studied at the organismal level; the diversity is mainly known from the data of environmental sequencing. 357 sequences of small subunit rRNA gene (SSU rDNA) of rozellids and aphelids revealed through GenBank, SILVA, and PR2 databases search were analyzed, with 93% of them (331 sequences) obtained in metagenomic studies and representing environmental sequences of uncultured and non-described organisms, yet unknown to science. In the reconstructed phylogenetic trees 47 clades were identified, including 39 clades of rozellids (5 of them were revealed for the first time) and 8 clades of aphelids. The analyzed sequences were obtained from the samples collected from a huge range of ecotopes in geographically distant habitats on all continents. The majority of sequences were isolated from fresh- and wastewater. They were also found in soil, groundwater, activated sludge, ice, invertebrate guts, marine and anoxic sediments. Current results confirm that rozellids and aphelids are ubiquitous and phylogenetically diverse lineages, and their cryptic diversity and ecological impact require further exploration.
Key words: Opisthosporidia, rozellids, aphelids, metabarcoding, environmental sequences, cryptic diversity
Address for correspondence: Elena Nassonova. Laboratory of Cytology of Unicellular Organisms, Institute of Cytology RAS, Tikhoretsky ave. 4, 194064 St. Petersburg, Russia; e-mail: nosema@mail.ru |
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