GlcCer C9-methylation is relevant for A. nidulans growth. The ΔsmtA niiA::smtB conditional double mutant exhibits impaired growth under niiA-repressing conditions. (A) Relative smtB mRNA levels in WT, ΔsmtA and ΔsmtA niiA::smtB strains grown for 16 h at 37 °C in the presence of niiA-inducer (10 mM sodium nitrate, black bars) or niiA-repressor agents (50 mM ammonium tartrate, grey bars). (B) Conidial suspensions of WT and ΔsmtA, ΔsmtB, ΔsmtA niiA::smtB mutants were point inoculated in MM containing nitrate or tartrate and uracil, uridine, pyridoxine. After 2 days of growth at 37 °C, images were taken, and (C) the colony diameter was measured. The results are the average of 3 replicates ± SEM; ***p < 0.001.