First observation of genus Komarkiella in Iranian saline soils.

Cyanobacteria are key elements of saline soils, particularly in the formation of vast surface crusts in arid regions and mine spoil wastes. These microorganisms are also abundant in areas that subjected to periodic wetting and submergence. In fact, sheaths or mucilage and its component polysaccharides have important effects in improving soil structure in saline environments. In our current research, we studied a nitrogen-fixing cyanobacterium obtained from saline soils in Golestan Province, Iran. We used a polyphasic analysis, combing both morphological and molecular techniques. Phylogenetic analysis was performed via the complete sequence of the 16S rRNA gene, along with 16S-23S internal transcribed spacer (ITS) secondary structures Further determinants were investigate using the sequences of the nifD, psbA, and rbcL genes. The isolates were assigned to the genus Komarekiella on the basis of 16S rRNA phylogenetic analysis with 98.80 to 100% similarity to other species of this genus. The 16S-23S ITS fold structures of the D1-D1', Box-B, and V2 helical regions distinguished the isolates from known Komarekiella species. Futuremore, ITS p-distances between the studied strain and related taxa revealed that the Komarekiella sp. isolate 1400 shared an ITS sequence similarity of 98.20 to 98.47% with the Komarekiella atlantica species. These results increase our knowledge of the biodiversity and characterisation of the heterocystous genus Komarekiella in the saline soils of Iran, isolated for the first time from this type of environment.