Fig. 6

Worm-killing assay of D. zeae strains towards C. elegans. a Slow-killing; b Fast-killing. Strains EC1 and MS2 were grown in LB medium at 28 °C and the C. elegans food-source E. coli OP50 (negative control) at 37 °C overnight, and 50 μL of the liquid culture was spotted onto the center of NGM (slow-killing) (a) or PGS (fast-killing) (b) agar plates and allowed to dry thoroughly. In the slow-killing assay, 50 μM of floxuridine (FudR, Sigma) was added into NG agar to inhibit hatching of nematode eggs [58]. The plates containing bacteria were incubated at 28 °C and 37 °C respectively overnight and cooled for at least 2 h at room temperature before adding 30 L4 stage or adult hermaphrodite worms. The plates were kept at 20 °C, and live worms were scored