Fig. 2
Hrk1 and Pma1 functions in acetate tolerance. a Cell growth of K. phaffii wild-type GS115 (WT), Δhrk1, Δhrk1-HRK1 and GS-HRK1 under YND medium supplemented with 30 mM acetate (medium pH 4.5). b The extracellular pH of GS115, GS-HRK1, GS-PMA1 and GS-HRK1/PMA1 in YND medium with initial acetate concentration of 30 mM (medium pH 4.5). #Significant at P < 0.05 for GS-PMA1&GS115 and GS-HRK1/PMA1&GS115 at 46 and 58 h, n = 6 for each strain. c K. phaffii phenotypes of wild-type GS115 (WT), HRK1 overexpression strain (GS-HRK1) and PMA1 overexpression strain (GS-PMA1). Cells were spotted on YPD agar plates with acetate of 0, 30 and 40 mM (medium pH 4.5) at three concentrations (OD600 = 0.1, 0.01 and 0.001). d ATPase activity of GS115 and Δhrk cultivated for 4 h in YND medium (pH 4.5) with different conditions. D, 1% (w/v) glucose; A, 30 mM acetate; D + A, 1% (w/v) glucose and 30 mM acetate. Difference of ATPase activity between Δhrk1 and GS115 was not significant (N.S.)