The evolved strains acquired cross-tolerance for isobutanol. Shown are growth curves of different strains with standard deviations (n = 3). (A) GLY3 (closed squares), trm2 (closed circles), tam44 (open triangles), and tam45 (open diamonds) were grown in nutrient-rich medium with 1.75 or 2% (vol/vol) isobutanol. (B) GLY3 (closed squares), GLY3dr1 (closed circles), GLY3dfy (open triangles), GLY3dr1G (open diamonds), GLY3dr1O (open circles), and GLY3dr1OG (crosses) were grown in nutrient-rich medium with 1.75% (vol/vol) isobutanol.