Effects of Glucosinolates and Their Enzymatic Hydrolysis Products via Myrosinase on the Root-knot Nematode Meloidogyne incognita (Kofoid et White) Chitw.

Abstract

The root-knot nematode Meloidogyne incognita (Kofoid et White) Chitw. is responsible for large yield losses in several horticultural crops. Fumigation with chemicals has been efficient in fighting this soil pest, but it clearly shows a negative environmental impact. Thus, it is necessary to find an environmentally friendly alternative to control this nematode and meet the requirements imposed by world regulation to ban some chemical fumigants in the world after 2005. The glucosinolate-myrosinase system, typical of the Brassicaceae family, appears to be an important natural alternative for the control of several soilborne pests and pathogens. The aim of this study was to evaluate, in vitro, the biocidal activity of 11 glucosinolates and their degradation products on second-stage juveniles of the root-knot nematode M. incognita expressed by the nematicidal (LD(50)) and immobilization effects, after 24 and 48 h. None of the intact glucosinolates had any biological effect. After myrosinase addition, their hydrolysis products (essentially isothiocyanates) resulted in highly different biocidal activities. Among the hydrolysis products of the tested glucosinolates, 2-phenylethyl, benzyl, 4-methylthiobutyl, and prop-2-enyl isothiocyanate showed the stronger activity, with an LD(50) at concentrations of 11, 15, 21, and 34 microM, respectively. On the basis of the in vitro test results, new genotypes of Brassicaceae had been selected for high content in the roots of the glucosinolates generating the more active isothiocyanates and their agronomic performances verified in view of a full-field application as catch crop plants. With this aim, the qualitative and quantitative glucosinolate contents in the roots of these potentially nematicidal plants are also reported and discussed.

Control Potential of Brassicaceae Cover Crops as Green Manure and their Host Status for Meloidogyne javanica and Criconemoides xenoplax

“…Research has also been conducted on the efficacy of biofumigation on Meloidogyne spp. suppression (Lazzeri et al, 2004a;2004b;Riga & Collins, 2004). In future research it would be advantageous if a specific lethal concentration could be determined for the constant effective suppression of the Meloidogyne species.…”

“…(Widmer et al, 2002;Pieters, 2006). A well-documented role of green manure is the biocidal effect that it has on soilborne diseases, nematodes and weeds, which is the result of certain biologically active compounds that are released during the maceration and incorporation processes of green manures, with specific reference to Brassicaceae plants and biofumigation (Brown & Morra, 1997;Sarwar et al, 1998;Lazzeri et al, 2004a;Matthiessen & Kirkegaard, 2006). The technique, defined as biofumigation, relies on the fumigant action of volatile compounds released during biodegradation for the suppression of plant pathogens (Piedra Buena et al, 2007).…”

Effects of intraspecific variation in white cabbage (Brassica oleracea var. capitata) on soil organisms

“…Upon tissue damage, glucosinolates are degraded by the enzyme myrosinase, thereby forming toxic breakdown products such as (iso)thiocyanates (Wang et al 2009). Belowground, glucosinolates and their breakdown products are known to reduce the abundance of phytophagous organisms such as rootfeeding nematodes (Lazzeri et al 2004;Potter et al 1998;Potter et al 2000), fungi (Bressan et al 2009;Rumberger and Marschner 2003;Snapp et al 2007), and bacteria (Aires et al 2009;Bressan et al 2009;Rumberger and Marschner 2003). Aromatic glucosinolates, particularly gluconasturtiin and its breakdown product 2-phenylethyl isothiocyanate, are generally considered as the most toxic glucosinolates in plant roots (Potter et al 1998;Potter et al 2000;Rumberger and Marschner 2003;van Dam et al 2009;Vierheilig et al 2000).…”

Glucosinolates in Some Brassica Species as Sources of Bioactive Compounds Against Root Knot Nematodes.

“…Strong nematicidal activity of isothiocyanates derived from sinigrin (2-propenyl isothiocyanate) was reported in vitro on juveniles of H. schachtii after 24 hours at 0.5% concentration (Lazzeri et al, 1993). Lazzeri et al, (2004) demonstrated stronger activity of the isothiocyanate on M. incognita in vitro. Aside from plant-parasitic nematodes, sinigrin isothiocyanate showed also high biocidal activity on other soil-borne pathogens (Mayton et al, 1996) Glucosativin (4-mercaptobutyl), glucoerucin (4-methylthiobutyl) and glucoraphanin (4-methylsulfinylbutyl) are the most prominent glucosinolates within the leaf tissue of Eruca species (Pasini et al, 2011; Villatoro-Pulido et al, 2013).…”