Isolation and characterization of plasma membrane Na+/H+ antiporter genes from salt-sensitive and salt-tolerant reed plants

We isolated cDNAs for Na+/H+ antiporter genes (PhaNHA1s) from salt-sensitive and salt-tolerant reed plants. A phylogenetic analysis and localization analysis using yeast strains expressing PhaNHA1-GFP protein showed that PhaNHA1s were plasma membrane Na+/H+ antiporters. Yeast strains expressing PhaNHA1 from salt-tolerant reed plants (PhaNHA1-n) grew well than yeast strains expressing PhaNHA1 from salt-sensitive reed plants (PhaNHA1-u) in the presence of 100 mM NaCl. Furthermore, Na+ contents of yeast cells expressing PhaNHA1-n were less than half of those of yeast cells expressing PhaNHA1-u. These results suggest that PhaNHA1-n is more efficient at excluding Na+ from the cells than PhaNHA1-u.