Chemoreception of botanical nematicides byMeloidogyne incognitaandCaenorhabditis elegans

Abstract

Plant-parasitic nematodes, such as Meloidogyne incognita, cause serious damage to various agricultural crops worldwide, and their control necessitates environmentally safe measures. We have studied the effects of plant secondary metabolites on M. incognita locomotion, as it is an important factor affecting host inoculation inside the soil. We compared the effects to the respective behavioral responses of the model saprophytic nematode Caenorhabditis elegans. The tested botanical nematicides, all reported to be active against Meloidogyne sp. in our previous works, are small molecular weight molecules (acids, alcohols, aldehydes, and ketones). Here, we specifically report on the attractant or repellent properties of trans-anethole, (E,E)-2,4-decadienal, (E)-2-decenal, fosthiazate, and 2-undecanone. The treatments for both nematode species were made at sublethal concentration levels, namely, 1 mM (<EC), and the chemical controls used for the experiments were the commercial nematicides fosthiazate and oxamyl. According to our results, trans-anethole, decenal, and oxamyl attract C. elegans, while 2-undecanone strongly attracts M. incognita. These findings can be of use in the development of nematicidal formulations, contributing to the disruption of nematode chemotaxis to root systems.

Nematicidal Amendments and Soil Remediation

“…Most importantly, these secondary metabolites form complexes that often act at multiple or novel target sites, thus reducing the likelihood of pest development of resistance [76,77]. Different natural molecules may affect directly nematode biology and behavior [71,78] but also interfere with respect to nematodes and other soil microfauna interaction, although this relationship needs extensive research.…”

A Chemosensory GPCR as a Potential Target to Control the Root-Knot Nematode Meloidogyne incognita Parasitism in Plants

“…The data obtained in the present study show that some of the tested compounds affect mostly or only the penetration rates most probably due to muscle contraction/behavioral disruption [96,97]. These results suggest that some of these substances, although not affecting mortality, may change the nematode behavior and its sigmosoidal crawling [96].…”

Nematicidal Effect of Methyl Palmitate and Methyl Stearate against Meloidogyne incognita in Bananas

“…Chemotaxis assays were conducted as described previously, with some modifications. , At the bottom of the 9 cm Petri dishes, two circles with a diameter of 2 cm were drawn 1 cm from the center, and 15 mL of 1.0% agar was added to the Petri dishes. Methyl palmitate and methyl stearate (Sigma-Aldrich) were diluted with methanol to 1.0, 2.0, 4.0, 8.0, and 16.0 mM and stored at 4 °C.…”