Objective  Role of VfNHX1 of faba bean in response to salt stress was studied.

  Methods  A Na⁺/H⁺ reverse transporter protein-encoding gene, VfNHX1, was cloned from Vicia faba L. by 3' and 5' RACE for a bioinformatics analysis, subcellular localization determination, expression under salt stress, and a preliminary verification on the function.

  Results  (1) VfNHX1 sequence was 2255 bp with a CDS coding region of 1629 bp encoding 542 amino acids. (2) As a stable transmembrane protein, VfNHX1 had 10 transmembrane regions without signal peptide and contained a typical Na-H exchanger conserved functional domain of NHX family. It was in the vacuolar membrane. (3) In the leaves, the expression of VfNHX1 under NaCl stress determined by qRT-PCR showed a trend of decreasing, then increasing, followed by decreasing with a peak reached in 12 h. In the roots, the expression declined initially and then rose significantly at 48 h (P＜0.01). (4) The presence of VfNHX1 in a yeast growth experiment indeed heightened the NaCl tolerance of the salt-sensitive yeast mutant AXT4K.

  Conclusion  VfNHX1 in V. faba L. was able to respond to salt stress and could be a functional gene to boost the salt resistance of the plant.