[Transformation of Astragalus melilotoides Pall with AtNHX1 gene and the expression of salinity tolerance of transformants].

Using RT-PCR method, the open reading frame (ORF) of AtNHX1-cDNA, encoding the vacuolar Na+/H+ antiportor, was cloned from Arabidopsis thaliana seedlings pretreated with 100 mmol/L NaCl for 24h. This ORF was inserted between CaMV35S promoter, a Omega fragment of TMV RNA 5'UTR and NOS polyA terminator in the T-DNA region of a binary expression vector pNT (Fig1). The recombinant plasmid, designated as pNT-AtNHX1, was then transformed into Agrobacterium tumefaciens LBA4404.