Haloacetophenones as newly potent nematicides against Meloidogyne incognita

Acetophenones are a class of aromatic compounds frequently produced by plants as a response to a stress or as a protection reaction against parasites or herbivors. In the present research, we investigated the role of the carbonyl moiety in a series of commercially available aromatic ketones tested for their nematicidal activity against the root-knot nematode Meloidogyne incognita (Kofoid et White) Chitwood. Interestingly, we found that the presence of electron withdrawing groups onto the aromatic ring were highly efficient in inducing nematode paralysis and death (EC50/24h between 2.5 and 54.8mg/L and EC50/72h between 2.3 and 65.6mg/L, respectively). Moreover, a chlorine atom in α-position to the carbonyl functionality emerged as a key residue in improving acetophenones activity. In this paper, the nematicidal ability of a series of differently substituted acetophenones is reported and the preliminary structure-activity relationship studies are also discussed. We also performed an in vitro GC-MS metabolomics analysis on the potato cyst nematode Globodera pallida, after treatment with 2,4'-dichloroacetophenone (6) at 100mg/L for 24h. The 1-dodecanol and talose were evidenced as the main upregulated metabolites, suggesting a possible V-ATPase dysfunction.