Phylogeny of DHODH and F901318 susceptibility. (A) Class 2 DHODH sequences from fungi and selected other organisms. (B) Zygomycete DHODH phylogeny. Branch support values expressed as a percentage are indicated in red. The scale bar corresponds to the branch length for an expected number of 0.3 and 0.6 substitution per site in A and B, respectively. Antifungal susceptibility testing of F901318 against the species indicated was carried out according to CLSI protocol M38-A2. For the fungi with a score, at least five different strains were tested, except for the following organisms: A. lentulus, n = 4; F. solani, n = 3; F. oxysporum, n = 2; S. apiospermum, n = 2; and P. variotti, n = 3. For S. prolificans, three different strains were tested, all giving an MIC of ≤0.06 µg/mL, but no DHODH sequence could be obtained for phylogenetic analysis. MIC scoring: +++, MIC ≤0.06 µg/mL; ++, MIC = 0.125–0.5 µg/mL; +, MIC = 1–2 µg/mL; −, MIC >32 µg/mL.