FIG 2.

Antofine phenocopies the rrd2 mutation in F. graminearum by suppressing rapamycin toxicity. (A) Growth of the F. graminearum RRD2 mutant (Fgrrd2) is insensitive to rapamycin inhibition. Growth inhibition of wild-type (Fg Wt) or RRD2 mutant (Fg rrd2) F. graminearum spores coincubated with 10 and 20 ng/ml of rapamycin was monitored by absorbance at 600 nm (ABS₆₀₀). (B) Growth inhibition of wild-type F. graminearum by rapamycin is suppressed by antofine (A₅₀ and A₁₀₀). Growth (optical density at 600 nm [OD₆₀₀]) of wild-type F. graminearum spores was monitored in the presence of rapamycin at concentrations of 20 or 50 ng/ml (R₂₀ and R₅₀) alone or in combination with 50 or 100 μg/ml of antofine (A₅₀ and A₁₀₀). (C) Overexpression of RRD2 suppresses antofine toxicity. The mycelial growth of wild-type (Fg), FgRRD2 mutant (Fg rrd2), and overexpressor of RRD2 (Fg rrd2:OEFg RRD2) F. graminearum strains was monitored by absorbance at 600 nm (ABS₆₀₀) in the absence (−) and in the presence of 50 and 100 ng/ml of antofine (A₅₀ and A₁₀₀). Values represent the average from three technical replicates with standard deviation. Results are representative of four independent biological replicates.