Phylogenetic relationship of Arthrospira, Phormidium and Spirulina strains from Kenyan and Indian waterbodies

Morphological and genetic diversity of cultured cynobacterial strains of species of the genera , Spirulina and Phormidium from two geographically different regions and (Kenyan saline-alkaline lakes and Indian freshwater bodies) were investigated. Light observations were used to determine morphological diversity of the . Three independent molecular techniques, sequencing of 16S rRNA gene, transcribed spacer region between 16S and 23S rDNA (ITS) and the phycocyanin (PC-IGS) were conducted for the examination of phylogenetic relationship. Despite in morphology and habitats the Kenyan and Indian Arthrospira strains belong to same cluster in phylogenetic trees of the 16S rDNA (AY575923-AY575932) or PC-IGS (AY575937-AY575946). The DNA similarity in both methods was 100%. In the ITS tree, the Indian Arthrospira strains PD1998/pus (AY575930) and PD2002/ana (AY575932) form own sub-cluster. The Phormidium strain AB2002/07 (AY575933) from Lake Nakuru, is included in the Arthrospira cluster in the ITS tree and very closely related in the 16S PC-IGS trees. Based on 16S rDNA and PC-IGS phylogeny the sequences of the Spirulina form a separate cluster distinct from the Arthrospira cluster. The Kenyan and Indian subsalsa strains show a considerable genetic variability as similarities in 16S rRNA sequence is 91.5% only. Molecular characterizations of cyanobacterial strains in the study demonstrate that several distinct morphotypes may be genetically similar and versa.