Abstract:The total RNA of Medicago varia xinmu-1 was extracted, the cDNA fragment amplified by RT-PCR using special primer was linked into pMD19-T vector and transformed into Escherichia coli DH5α. By sequencing the positive clone, the MvNHX1(EU375310) is 1 626 bp long. RT-PCR and real-time PCR assays showed that the level of MvNHX1 transcription was up-regulated and reached a steady higher level in the seedlings after high salinity treatment. The MvNHX1 gene was transformed into tobacco via agrobacterium mediation after the plant expression vectors pBI121-MvNHX1 was successfully constructed. The germination rate and biomass of the transgenic tobacco were taller than those of the control group under NaCl stress, indicating that the MvNHX1 can enhance the salt tolerance of transgenic tobacco.