The ability of freshwater filamentous sulfur bacteria from the family Beggiatoaceae to assimilate molecular nitrogen: molecular detection and expression of nifH - the marker gene of nitrogen fixation

Abstract

The purpose of this work was to prove the ability of three representatives from the family Beggiatoaceae -Beggiatoa leptomitiformis D-401 and D-402 and “Thioflexothrix psekupsii” gen. nov., sp. nov. – for nitrogen fixation with the help of nitrogenase complex. We used the next methods to achieve this purpose: the cultivation of bacteria on nutrient media with nitrogen and without it, RNA extraction with the help of sorbent microcolumns, reverse transcription, qPCR and genome annotation with the help of an automatical annotator RAST. It was shown that bacteria were able to sustain five passages on the nutrient medium without nitrogen, the whole set of genes of nitrogenase complex was present in the analyzed genomes and there was a significant increase in the expression of the gene nifH in all three strains after cultivation on the medium without nitrogen. All of it demonstrate the ability of the investigated bacteria for molecular nitrogen fixation.