Nematicidal assay on extracts from PA-treated plants
Extracts for nematicidal assays were prepared in the same manner as for UPLC-MS/MS profiling. Briefly, ground tissue was extracted with 5 ml methanol g-1 tissue (30 minutes, RT), after which the extract was filtered, dried in a rotary evaporator (35°C), dissolved in 0.5 ml water g-1 tissue and defatted with cyclohexane. A two-fold dilution series (from 2:1 to 1:8 mass-to-solvent ratio) was prepared, and ±100 M. incognita J2s were incubated in 600 µl diluted extract. Nematode motility was evaluated after 4, 24 and 48 h. Four biological replicates, each consisting of 5-6 tomato plants, were used per treatment.