sskA and sakA are essential for conidial viability at 37°C. (A) Quantification of the percentage of viable conidia at 25°C and 37°C. Statistical significance using an unpaired t test and 95% confidence interval is indicated by asterisks as follows: *, P < 0.05; ***, P < 0.0001. (B) Conidial suspensions of the wild-type, ΔsskA, ΔsakA, ΔmpkA, and ΔmpkB strains were dropped onto plates containing synthetic dextrose (SD) plus (NH4)2SO4 and 0.5 M, 1 M, or 1.5 M sorbitol and incubated for 5 days at 37°C.