Abstract: A plasma membrane Na⁺/H⁺ antiporter gene ( LgSOS1, GenBank accession No.EU780458) has been separated from halophyte Limonium gmelinii by RT-PCR and RACE. The LgSOS1 cDNA is 3 910 bp long including 5′untranslated region of 79 bp, 3′untranslated region of 376 bp with PolyA, and an open reading frame of 3 455 bp encoding a protein of 1 151 amino acids with a predicted molecular mass of 126 kD. Bymultiple sequence alignment analysis of amino acids, it has been shown that the identities n amino acids to plasma membrane Na⁺/H⁺ antiporters gene of LgSOS1 is 69.02% , and 64.42% ,
61.96% , 60.12% , and 59.62% of Mesembryanthemum crystallinum, Populus euphratica, Lycopersicon esculentum, Thellungiella halophila and Arabidopsis thaliana, respectively. TM pred prediction showed LgSOS1 has 12 transmembrane domains. Phylogenetic analysis indicates that LgSOS1 is more related to plasma membrane-type Na⁺/H⁺ antiporter, compared with vacuolar-type Na⁺/H⁺ antiporter, to which it is less related

Key words: Limonium gmelinii (Willd. ) Kuntze, plasma membrane Na⁺/H⁺ antiporter gene(SOS1), cDNA cloning, sequence analysis