Molecular phylogenetic and morphometric evaluation of Calothrix sp. N42 and Scytonema sp. N11

The taxonomy of cyanobacteria has been substantially modified in the last few decades, particularly after application of modern ultra structural and molecular methods. The present research, therefore, aimed to investigate, through a polyphasic approach, the differences in morphological and genotypic features of two cyanobacteria strains isolated from different agricultural and freshwaters areas in Kermanshah province (W Iran). In fact, identification and taxonomy of both Calothrix sp. N42 and Scytonema sp. N11 was problematic and confusing. Challenges arose when the two strains seemed to be Calothrix, because of early unbranched filaments, narrow cells and ending by heterocysts. Along with the progression of growth, branching arise. Therefore, molecular analysis was made and morphometric and genetic (16S rRNA) data were used to characterize the strains in liquid suspension cultures and solid media under photoautotrophic conditions. The results of sequencing the 16S rRNA fragment and phylogenetic comparison strongly indicated that, two strains fall into different phylogenetic clusters. They were named as Calothrix sp. N42 and Scytonema sp. N11 and have been registered under DDBJ, accession number KY548062 and KY548065, respectively.