Characterization and sequence of a hydrogen/sodium anti-porter gene in the plasma membrane of the plant Kochia scoparia

Sodium efflux is one way to reducing of cytosolic sodium in plants. This prevents toxic effects of sodium on cytosol cellular processes. Sodium/hydrogen transporters in the plasma membrane (SOS1) are one of the best known proteins in this process. In this study Kochia scoparia, a halophyte dicotyledonous plant was used as a source to gene isolation. Using designed primers based on conserved regions of other plants, a gene coding sequence of approximate 3600 nucleotides and 1200 amino acids was identified and sequenced. Analysis with BLAST verified that maximum nucleotide homology of the sequence with other SOS1 proteins was 84%, and in amino acid homology 92%. Additional in silico analysis was performed to characterize the putative protein and its relation with other SOS1 proteins, which contain a hydrophilic alpha helix region as passenger fragment through plasma membrane and in contrast to this, a sequence with less alpha helix and hydrophilic properties, is as protein intracellular fragment. These results support the role of sodium efflux for resistance response to salinity in Kochia using plasma membrane transporters.