Electron deficient alkynes as powerful tools against root-knot nematode Meloidogyne incognita. Nemaaticidal activity and investigation on the mode of action.

The present study reports on the powerful nematicidal activity of a series of electron-deficient alkynes against theroot-knot nematode Meloidogyne incognita (Kofoid and White) Chitwood. Interestingly, we found that the conjugation of electronwithdrawing carbonyl groups to an alkyne triple bond was extremely proficient in inducing nematode paralysis and death. Inparticular, dimethylacetylenedicarboxylate (10), 3-butyn-2-one (1), and methyl propiolate (4), with EC50/48 h of 1.54 ± 0.16, 2.38 ±0.31, and 2.83 ± 0.28 mg/L, respectively, were shown to be the best tested compounds. Earlier studies reported on the ability ofalkynoic esters and alkynones to induce a chemoselective cysteine modification of unprotected peptides. Thus, also following ourprevious findings on the impairment of vacuolar-type proton translocating ATPase functionality by activated carbonyl derivatives, wespeculate that the formation of a vinyl sulfide linkage might be responsible for the nematicidal activity of the presented electrondeficient alkynes.