Molecular phylogenetic and morphometric evaluation of Calothrix sp. N۴۲ and Scytonema sp. N۱۱

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. N۴۲ and Scytonema sp. N۱۱ 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 (۱۶S rRNA) data were used to characterize the strains in liquid suspension cultures and solid media under photoautotrophic conditions. The results of sequencing the ۱۶S rRNA fragment and phylogenetic comparison strongly indicated that, two strains fall into different phylogenetic clusters. Theywere named as Calothrix sp. N۴۲ and Scytonema sp. N۱۱ and have been registered under DDBJ, accession number KY۵۴۸۰۶۲ and KY۵۴۸۰۶۵, respectively.  

Keywords:

Calothrix sp. N۴۲ , Nostocales , phylogenetic approaches , Scytonema sp. N۱۱ , Taxonomy