FIG. 6.

Deletion of tol1⁺ gene leads to sulfite auxotrophy. (A) Δtol1 cells (Δtol1) and Δtol1 cells carrying pDB248[tol1⁺] (Δtol1+ptol1⁺) or pDB248[HAL2] (Δtol1+pHAL2) were streaked onto each plate containing YPAD plus 16 mM sodium sulfite (+Sulfite) or YPAD (−Sulfite) and incubated at 33°C for 4 days. (B) Δtol1 cells carrying pDB248[tol1⁺] (Δtol1+ptol1⁺) or pREP81[tol1⁺] (Δtol1+pREPtol1⁺) were streaked onto each plate containing EMM (EMM), EMM plus 4 μM thiamine (+Thiamine), EMM plus 16 mM sodium sulfite (+Sulfite), EMM plus 4 μM thiamine and 16 mM sodium sulfite (+Thiamine +Sulfite), or EMM plus 4 μM thiamine and cysteine (30 μg/ml) (+Thiamine +Cysteine). The plates were incubated at 33°C for 4 days. Each EMM plate was supplemented with adenine sulfate (20 μg/ml).