Figure 5. Two mutations of OsMTP8.1 can confer Zn tolerance phenotype in yeast sensitive mutant.

(A) Yeast cell suspensions of a zrc1 or pmr1 transformed with empty vector pFL61, or with pFL61 containing wild-type OsMTP8.1 or mutated OsMTP8.1 cDNAs were pre-cultured in SD-Urea overnight. Pre-cultured cells were diluted to OD600 nm of 1.0, 10 μL of cell suspensions were spotted on SD-Urea plates supplemented with the indicated concentrations of Mn²⁺or Zn²⁺. Plates were incubated at 30 °C for 72 h. (B) Concentration of Zn in yeast cells determined in the wild-type BY4741(WT) and mutant strain zrc1 transformed with empty vector pFL61, OsMTP8.1, and two mutants of OsMTP8.1 (F75A and S132A). Yeast cells were grown in liquid SD medium supplemented with 0.5 mM ZnCl₂ at an initial OD600 = 0.1. Bars with different letters are significantly different (Tukey’s test, p < 0.01).