Phylogenetic evaluation of the true-branched heterocytous cyanobacteria and description of soil dwelling Westiellopsis akinetica sp. nov.

Soil inhabiting true branching heterocytous cyanobacterium strain SNS 3 with T-type branching was collected from the campus of Banaras Hindu University, India and characterized using the polyphasic approach. Morphological observations showed the presence of akinetes (in chain), hormogonia and monocytes. Physiological characterization of strain SNS 3 showed high content of carotenoid in comparison to chlorophyll a content along with also exhibiting a higher C/N ratio in the nitrogen deficient BG110 medium. 16S rRNA gene sequencing and subsequent phylogeny indicated strong clustering of the strain SNS 3 within the Westiellopsis clade. Folded secondary structures of the ITS region showed visible differences in the D1-D1' and BoxB helix of the strain SNS 3. The polyphasic approach indicated the strain SNS 3 as a new member of the genus Westiellopsis with the name proposed being Westiellopsis akinetica sp. nov. on the basis of the International Code of Nomenclature for Algae, Fungi and Plants. Intense phylogenetic evaluation of the entire true-branched heterocytous clade indicated the need for more revisionary attempts for demarcating the sensu stricto clades along with highlighting the scope for further taxonomic revisions in the future.