Fig. 4.

TbHKT1 suppresses K⁺ uptake deficiency in yeast and in E. coli. (A) The plasmid containing TbHKT1 allows the E. coli K⁺ uptake-deficient quadruple mutant LB2003 to grow in medium containing 2 mM K⁺; the empty plasmid does not. (B) Expression of TbHKT1 in the S. cerevisiae Δtrk1 Δtrk2 double null mutant CY162 permits growth on 1 mM K⁺. The effect is not dependent on Na⁺. Cells were spotted in triplicates, in a dilution series from optical density at 600 nm (OD₆₀₀) of 1 to OD₆₀₀ of 10⁻³.