Ecology and biogeography of the ‘marine Geitlerinema’ cluster and a description of Sodalinema orleanskyi sp. nov., Sodalinema gerasimenkoae sp. nov., Sodalinema stali sp. nov. and Baaleninema simplex gen. et sp. nov. (Oscillatoriales, Cyanobacteria)

Abstract

Filamentous cyanobacteria belonging to the ‘marine Geitlerinema’ cluster are spread worldwide in saline environments and considered to play an important ecological role. However, the taxonomy of this group remains unclear. Here, we analyzed the phylogeny, ecology and biogeography of the ‘marine Geitlerinema’ cluster representatives and revealed two subclusters: 1) an ‘oceanic’ subcluster containing PCC7105 clade and BBD clade with free-living and pathogenic strains distributed in Atlantic, Indian and Pacific Ocean-related localities, and 2) a Sodalinema subcluster containing free-living strains from marine, hypersaline, saline-alkaline and soda lake habitats from the Eurasian and African continents. Polyphasic analysis using genetic and phenotypic criteria demonstrated that these two groups represent separate genera. Representatives of Sodalinema subcluster were phylogenetically attributed to the genus Sodalinema. Our data expand the ecological and geographical distribution of this genus. We emended the description of the genus Sodalinema and proposed three new species differing in phylogenetic, geographic and ecological criteria: Sodalinema orleanskyi sp. nov., Sodalinema gerasimenkoae sp. nov. and Sodalinema stali sp. nov. Additionally, a new genus and species Baaleninema simplex gen. et sp. nov. was discribed within the PCC7105 clade. By this, we put in order the current confusion of the ‘marine Geitlerinema’ group and highlight its ecological diversity.

Zarconia navalis gen. nov., sp. nov., Romeriopsis navalis gen. nov., sp. nov. and Romeriopsis marina sp. nov., isolated from inter- and subtidal environments from northern Portugal

“…This particular phylogenetic placement of O. princeps/strain CCALA 1115 has been already noticed by other studies, including Suda et al [37], Komárek et al [31]. The monophyletic subclade containing 'Phormidium' (=Sodalinema stali) GI08AO and Baaleninema simplex PCC7105 strains was recently described [25]. These are currently the closest known genera to Zarconia and to the 'L.…”

“…[31]. The monophyletic subclade containing ‘ Phormidium ’ (= Sodalinema stali ) GI08AO and Baaleninema simplex PCC7105 strains was recently described [25]. These are currently the closest known genera to Zarconia and to the ‘ L.…”

“…Phylogenies were reconstructed aligning the 16S rRNA gene sequences from Zarconia and Romeriopsis along with those from their best blast hit results as retrieved from GenBank and from a set of selected cyanobacterial strains, including reference strains covering the cyanobacterial diversity particularly from different Oscillatoriales and Synechococcales families. Reference strains were retrieved from CyanoType [15] and from newer taxonomic literature [5,6,24,25]. The total alignment length had 83 sequences and 1721 nucleotide positions with 927 informative sites.…”

“…Both phylogenies confirm Romeriopsis as a monophyletic clade (ML=100, BI=1) in the family Leptolyngbyaceae (Synechococcales) [31], being more closely related to Alkalinema Vaz et al The new genus Zarconia is also monophyletic, with strong phylogenetic support (ML=100, BI=1), and is clustered with Lyngbya cf. confervoides (ML=97, BI=1), 'Phormidium' (=Sodalinema stali) GI08AO and Baaleninema clades [25] in the Oscillatoriales. In these phylogenetic trees, the order Synechococcales presents well-supported monophyletic families.…”

“…1), is 95%. The similarity between Zarconia and the clade comprising 'Phormidium' (=Sodalinema stali) GI08AO and Baaleninema simplex PCC 7105 is of 94%, two strains belonging to recently erected marine genera [25].…”