The Na+/H+ antiport genes namedTaNHX1andTaNHX2were cloned by screening a salt_stressed wheat cDNA library using rice Na+/H+ antiport cDNA fragment as the probe. Sequencing analysis showed thatTaNHX1was 2 029 bp in length and contained a complete ORF of 1 638 bp. TheTaNHX1encodes a polypeptide of 546 amino acids with a transmembrane domain DIFFIYLLPPI.TaNHX2was 1 693 bp in length consisting of a partial ORF followed by a 3′_UTR of 808 bp. The amino acid sequence of these two genes were about 70% identical to the known NHX genes from rice, Arabidopsis and Atriplex. A RT_PCR assay showed that the level ofTaNHX1transcripts was increased and reached a steady higher level in the seedlings after 3 h treatment with 400 mmol/L NaCl.
