Pantanalinema gen. nov. and Alkalinema gen. nov.: novel pseudanabaenacean genera (Cyanobacteria) isolated from saline-alkaline lakes
Résumé
The genus Leptolyngbya Anagnostidis & Komárek (1988) was described from a set of strains identified as "LPP-group B". The morphology within this group is not particularly informative and underestimates the group's genetic diversity. In the present study, two new pseudanabaenacean genera related to Leptolyngbya morphotypes, Pantanalinema gen. nov. and Alkalinema gen. nov., are described under the provisions of the International Code of Nomenclature for algae, fungi, and plants, based on a polyphasic approach. Pantanalinema gen. nov. has sheaths and trichomes with slight gliding motility, which distinguish this genus from Alkalinema gen. nov., that possesses trichomes arranged in an ornate (interwoven) pattern. Pantanalinema and Alkalinema 16S rRNA gene sequences exhibited low identity compared to each other (≤ 91.6 %) and compared to other sequences from known pseudanabaenacean genera (≤ 94.3 and 93.7 %, respectively). In a phylogenetic reconstruction, six Pantanalinema and four Alkalinema sequences formed two separate and robust clades (99 % of bootstrap value), with the genera Oculatella and Phormidesmis, respectively, as the closest related groups. Intergenic spacer (ITS) sequences and secondary structures of Pantanalinema and Alkalinema did not correspond to any previous descriptions. The Pantanalinema and Alkalinema strains were able to survive and produce biomass at a range of pH values (4-11) and were also able to alter the culture medium to pH values ranging from 8.40-9.9. These data indicate that cyanobacterial communities in underexplored environments, such as the Pantanal wetlands, are promising sources of novel taxa.
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