Cloning Of Na~+/H~+ Antiporter Gene From Bruguiera Gymnorrhiza(L.)LAM

Plant salt stress is mainly caused by Na+. The Na+/H+ antiporters catalyze the exchange of Na+ for H+ across the membrane, and they play an important role in the mechanisms of plant salt tolerance.The cloning, expression and function study of the Na+/H+antiporter is of great importance for the study of plnat salt resistant mechanism and the breeding of salt resistant plant.In order to isolate the full length cDNA of Na+/H+ antiporter gene from the Bruguiera gymnorhiza, RT-PCR and RACE were carried out, and a pair of degenerate primers were designed according the Na+/H+ antiporter homologous gene region of other plants. The genes obtained were named BgNHX1 and BgSOS1. BgNHX1 cDNA(2130bp) included a 332bp 5’UTR, a 172bp 3’UTR, a 1626bp open reading frame encoding a 541-amino-acid polypeptide which was 83%、83%、84%、80%、80%、81%、81%、78% to sequences of Ricinus communis、Populus trichocarpa、Populus euphratica、Citrus reticulata、Glycine max、Gossypium hirsutum、Vitis vinifera、Arabidopsis thaliana in amino acid homology respectively. The deduced amino acid sequence included the conserved amiloride binding sites of LFFIYLLPPI.BgSOS1 cDNA (3703bp) included a 116bp 5’UTR, a 125bp 3’UTR, a 3462bp open reading frame encoding a 1153-amino-acid polypeptide which was 77%、75%、75%、73%、69%、67%、68%、64% to sequences of Populus trichocarpa、Ricinus communis、Populus euphratica、Vitis vinifera、Zygophyllum xanthoxylum、Chenopodium quinoa、Solanum lycopersicum、Oryza sativa in amino acid homology respectively.To amplify the ORF sequence of BgSOS1, Primers were designed according to the full length cDNA sequence of BgSOS1.And the BgSOS1 ORF was used for the constructing of the plant expression vector pCAMBIA1302-BgSOS1. The resultant plasmid pCAMBIA1302-BgSOS1 was transferred into Agrobacterium tumefaciens (EHA105). The BgSOS1 gene was transferred into tobacco. PCR analysis showed that BgSOS1 gene was integrated into tobacco genome.