Polyphasic characterization of 10 selected ecologically relevant filamentous cyanobacterial strains from the South Shetland Islands, Maritime Antarctica
The evolutionary relationships of 10 Antarctic cyanobacterial strains of the order Oscillatoriales isolated from King George
and Deception Islands, South Shetland Islands were studied by a polyphasic approach (morphology, 16S rRNA and internal
transcribed spacer sequences). The studied taxa are characteristic of coastal Antarctic biotopes, where they form distinct
populations and ecologically delimited communities. They were isolated from terrestrial habitats: microbial mats in
seepages; crusts on soil, rocks, bones and mosses; mud, sometimes close to bird colonies; and from guano. Based on major
phenotypic features, the strains were divided into four distinct morphotypes: Leptolyngbya borchgrevinkii (A), Leptolyngbya
frigida (B), Microcoleus sp. (C) and Wilmottia murrayi (D). This morphological identification was in agreement with the
phylogenetic relationships. For the first time, the 16S rRNA gene sequence of a strain corresponding to the L. borchgrevinkii
morphotype was determined. Morphotype B is most related to sequences assigned to L. frigida isolated from microbial mats
of coastal lakes in East Antarctica. Morphotype C belongs to a cluster including strains with morphotypes corresponding to
Microcoleus attenuatus, Microcoleus favosus and Microcoleus sp., which are from Antarctica and other continents. Morphotype
D is grouped with sequences assigned to W. murrayi mostly isolated from Antarctica.Biodiversity of Antarctic cyanobacteri