Small Molecule Nematicides Screening Assay: A Medium Throughput Method to Screen Potential Nematicides Against Ditylenchus dipsaci

Plant-parasitic nematodes such as Ditylenchus dipsaci are microscopic worms. The living worms exhibit sinusoidal movements through muscle contractions, and their motility is an important determinant of their health in culture conditions.

Exposure to nematicides - chemical toxicants, can interfere with key biological processes, affecting the mobility of these cultured nematodes, leading to their death.

To screen small-molecule nematicides, take a distilled water-containing, multi-well plate. Using a clean pinning tool, transfer the potential small molecular nematicides from the chemical stock plate to the assay plate to ensure a transfer of consistent amounts of molecules into each well.

Dispense an equal number of nematodes to each well of the plate. Seal the plates while maintaining moist conditions to support nematode survival and mobility. Incubate the plate with mild agitation to prevent worms from settling.

During incubation, various toxic small molecules act on worms and kill them, while non-toxic ones have no impact. Observe the plate under a dissecting microscope to identify the wells with a non-motile worm population.

Supplement the assay plates with sodium hydroxide solution - end-point chemical stimulant. This triggers the movement of any resting worms and differentiates them from dead ones.

The presence of non-motile worms after sodium hydroxide treatment in some wells confirms the efficacy of corresponding small molecules as nematicides.