identification of the nitrate assimilation related genes in the novel Bacillus megaterium NCT-2 accounts for its ability to use nitrate as its only source of nitrogen

Bacillus megaterium NCT-2 is a novel bacterium that can utilize nitrate as its only nitrogen source for growth. The nitrate assimilation related genes that are involved in this process would be expected to be crucial. However, little is known about the genomic background of this bacterium, let alone the sequences of the nitrate assimilation related genes. In order to further investigate the nitrate assimilation function of the NCT-2, genome sequencing was performed. After obtaining the fine map of the NCT-2 genome, which was submitted to the NCBI GenBank (AHTF00000000), the sequences of the nitrate assimilation related genes (the nitrate reductase electron transfer subunit nasB and the nitrate reductase catalytic subunit nasC, the nitrite reductase [NAD(P)H] large subunit nasD and the nitrite reductase [NAD(P)H] small subunit nasE, and the glutamine synthetase glnA) were identified. Multiple alignments were performed to find out the sequence identities of the nitrate assimilation related genes to that of their similar species. Through KEGG signaling mapping search, the nitrate assimilation related genes were revealed to be located in the nitrogen metabolism signaling pathway. The putative 3D protein structures of these genes were modeled by SWISS MODEL, and shown to be highly similar to the nitrate assimilation related genes in the PDB database. Finally, the sequence validity of the nitrate assimilation related genes was verified by PCR with specifically designed primers.