Chemoreception of Meloidogyne incognita and Caenorhabditis elegans on botanical nematicidals

Plant-parasitic nematodes cause serious damage to various agricultural crops worldwide, and their control necessitates environmentally safe measures. Plant secondary metabolites of botanical origin are tested here-in to study their effect in Meloidogyne incognita locomotion, being this an important factor affecting host inoculation inside the soil. We compare the effect to the respective behavioral responses of the model organism Caenorhabditis elegans. The tested botanical nematicidals, all reported of activity against Meloidogyne sp. in our previous works, belong to different chemical groups of small molecular weight molecules encompassing acids, alcohols, aldehydes and ketones. Specifically we report on the attractant or repellent properties of trans-anethole, (E,E)-2,4-decadienal, (E)-2-decenal, fostiazate, and 2-undecanone. The treatments for both nematode species were made at sublethal concentration levels, namely 1mM (<EC50), and the chemical control used for the experiment was the commercial nematicide fosthiazate and oxamyl. According to our results, trans-anethole, decenal, and oxamyl act as C. elegans attractants. 2-undecanone strongly attracts M. incognita. These findings can be of use in the development of nematicidal formulates, contributing to the disruption of nematode chemotaxis to root systems.