FIGURE 3.

Complementation by NtZIP4B cDNA of yeast mutants defective in metal uptake on selective media. Yeast cells: DY1457, Δzrt1zrt2 (defective in Zn uptake) were transformed with empty vectors pAG426 as a control, or with vectors carrying tobacco gene NtZIP4B with the stop codon pAG426-ZIP4B-STOP (pAG426-ZIP4B). Yeast cultures were adjusted to an OD600 of 0.2 and 5 μl of serial dilutions (from left to right in each panel) was spotted on SC-URA medium containing 2% (w/v) galactose solidified with 2% agar, supplemented with EGTA (A), CdCl₂ (B) or 0.2 mM Zn (control). The plates were incubated for 3–6 days at 30°C. The images are representative of three independent experiments taken after 5 days of growth (A) and 3 days of growth (B).