Abstract:The NtNHX13 gene was successfully isolated by homologous cloning from cultivated tobacco. The CDS length of NtNHX13 was 1 617 bp, and it was predicted to encode a 538amino acid protein. The theoretical isoelectric point of NtNHX13 protein was 8.67, and the molecular weight was 59.34 kD. The bioinformation analysis of NtNHX13 showed that it belonged to membrane protein containing 11 transmembrane regions,and had a conserved amiloride bindingsite specific to NHX protein. The phylogenetic tree analysis showed that NtNHX13 shared the same group with NHX from chicory and chrysanthemum. Tissuespecific expression analysis indicated that NtNHX13 was ubiquitously expressed in roots, stems, leaves and flowers, whereas had the highest level in leaves. The expression of NtNHX13 was upregulated after salt treatment, indicating that it was involved in salt stress response. The expression of NtNHX13 was upregulated in the early stage of topping, which was consistent with the increase of potassium content in this stage. Therefore, it was speculated that NtNHX13 could transport potassium ions from cytoplasm to vacuole.