FIGURE 2.

NaCl tolerance of AtNHX1 and shuffled AtNHXS1 gene in expressed in the Δean1–4 Δnhx1 yeast double mutant. A, second selection of shuffled AtNHX1 gene. Several yeast clones (numbered 22–36) obtained from the first screening were grown on an APG plate containing 125 mm NaCl for 4 days. B, serial dilutions (at 10⁵, 2 × 10⁴ and 4 × 10³ cells) of the yeast strains. Cells were grown on selective plates as described under “Experimental Procedures.” C, growth of the yeast strains in liquid medium. Absorbance measured at 600 nm after culturing for 96 h at 30 °C Results are the mean ± S.D. (n = 3). D and E, Na⁺ and K⁺ content of cells grown in the presence of NaCl. Intracellular Na⁺ and K⁺ contents were determined in cells grown in APG medium with 70 mm NaCl until the mid-exponential growth phase. Results are the mean ± S.D. (n = 3).