Nematode-Induced Trap Formation Assay

For analysis of trap formation induced by nematodes, conidia harvested from 7-day-old CMY cultures were resuspended to 1 × 10⁵ conidia per ml in sterile water. A fifty microliter conidial suspension of the WT and mutants was inoculated on separate WA plates and incubated at 28°C for 2 days (Xie et al., 2019 (link)). Arthrobotrys oligospora mycelia and ΔAolatg4 mutants were added to ~200 nematodes on each plate. Trap formation was observed at the time intervals, 12, 24, and 36 h under a light microscopy (Olympus, Tokyo, Japan). Staining with 0.1% Calcofluor White (CFW, Sigma-Aldrich, United States) was carried out to observe trap formation induced by nematodes (Xie et al., 2020 (link)). Trap production and nematode death rate were quantified as the total number of traps and nematodes present per unit area of the plates in WT and ΔAolatg4 mutants.