Abstract：The plant Na+/H+ antiporter(NHX) adjusts the pH and Na+ balance，reducing the salt-stress damage to the plant. A full length cDNA from Moso bamboo(Phyllostachys pubescens)，designated PpNHX1(GenBank accession No.GU295174), was isolated by RT-PCR and RACE according to the homologous region of plant Na+/H+ antiporter genes. The sequence with 2 290 bp in length, contained an open reading frame of 1 635 bp which encoded a predicted polypeptide of 545 amino acids. The amino acid sequence of PpNHX1 was about 88% and 89% identical to the NHX1s from Oryza sativa and Phragmites communis, respectively. PpNHX1 protein shared high homologies with other reported Na+/H+ antiporter. Phylogenetic analysis showed that PpNHX1 shared the same group with vacuolar-type Na+/H+ antiporter, and distinguished from plasma membrane-type Na+/H+ antiporter. RT-PCR results revealed that PpNHX1 expression under 200 mm/L NaCl stress was continuously enhanced in the roots, stems and leaf of Moso bamboo under different NaCl stress time, and after 1 h of treatment the expression of PpNHX1 in the root was higher than that of leaf and stems, but after 4 h the expression of PpNHX1 in leaf was the highest. Therefore, we can infer that the expression of PpNHX1 has a close relation with the ability of salt tolerance of Moso bamboo.
