Screening of anti-nematode potential through inhibition of egg hatching in plant-parasitic nematode Meloidogyne javanica

Abstract

Plant-parasitic nematodes have emerged as nature’s most successful among all parasites known till today. These animals have been reported from all terrains of all ecosystems. Their capability to survive on a wide diversity of the host plants, circumvent host plant defence is a few of several of their secrets making them most successful of all known parasites. Among various groups of plant-parasitic nematodes, endo-parasitic nematodes are the most damaging one and also difficult to control. Meloidogyne sps. are commonly known as root-knot nematodes. Our inability to control them is primarily due to our poor understanding of the biology of these plant parasites. Due to the availability of the complete genome sequence of few Meloidogyne species, biotechnological interventions are used to unravel the secrets of their success. Chemical controls of these nematodes are extensively reported in the literature. Due to the environmental toxicity associated with these chemicals, and restrictions on the use of chemicals against nematodes led to screening and development of eco-friendly management strategies. The present study was conducted to screen nematotoxic properties of Neem (Azadirachta indica), Jatropha (Jatropha curcas), Kachnar (Bauhinia variegate), Bel (Aegle marmelos) and Eucalyptus (Eucalyptus globules) leaf extracts against root-knot nematode Meloidogyne javanica in vitro. The aqueous extracts were used against the hatching of the nematode eggs, movement of second stage juveniles (J2) and the viability of the J2 in increasing concentration of the bioactive compound. The eggs were treated with various concentrations of the selected extracts for different time periods ranging from 24h to 6 days. A significant inhibition of egg hatching and increase in the mortality of the nematode juvenile in few of the aqueous extracts were recorded. Reduced egg hatching and increased mortality of the nematode juveniles could be maybe the indicators of the presence of anti-nematode potential in the selected plant leaves. The results from the study can pave the way for the development of eco-friendly management strategies for plant-parasitic nematodes.

Efficacy of Leaf Extract of Piliostigma Thonningii for Control of Root-Knot Nematode (Meloidogyne javanica) on Eggplant

“…The extracts contained the phytochemicals needed to inhibit egg hatch. Also, it was evident from the study that level of toxicity of the extract decreases with increase in dilution [31,32]. The low level of egg hatch inhibition recorded in control resulted from death of the juveniles in them due to unknown reasons because they had not received any extract treatment.…”

Nematicidal Properties of Medicinal Plants against Root-Knot Nematode - A Systematic Review

“…Distilled water leaf extract of Neem (Azadirachta indica) and Bael (Aegle marmelos) shows 86.6% and 11.9% mortality of the second-stage juveniles of Meloidogyne javanica in 100% concentration in the In-vitro experimental study (Shakya & yadav, 2020). Similarly, leaf extract from five different plants viz., margosa, marigold, datura, hemp, and tobacco plant repressed the growth of Meloidogyne incognita, reduced root galling and enhanced the plant growth (Shah et al, 2018).…”

A Review of the Potency of Plant Extracts and Compounds from Key Families as an Alternative to Synthetic Nematicides: History, Efficacy, and Current Developments

“…Several other species within the family have been directly tested and utilized in the management of PPNs. Extracts from Bauhinia variegate induced significant J2 hatching inhibition and mortality of M. javanica J2s, with LC 50/96h of 24.1 mg/ml ( Shakya and Yadav, 2020 ). Piptadenia viridiflora EOs rich in benzaldehyde (98%) were significantly more toxic to M. incognita than the renown carbofuran, causing mortalities of 75–97% at application rates of 100–200 μg/ml, after 48 h. Significant reductions of 90–100% in the number of galls and eggs in tomato roots were also evident when J2s were pre-exposed to benzaldehyde prior to inoculation ( Barros et al, 2019a ).…”

“…Other species within the family are also known to produce compounds with nematicidal properties. Extracts from leaves of Jatropha curcas significantly inhibited hatching and caused mortality of M. javanica J2s (LC 50/96h = 15.62 mg/ml) ( Shakya and Yadav, 2020 ). Cassava extracts contain methyl palmitate and methyl stearate which are bioactive compounds, and when tested against M. incognita , J2 hatching, egg mass number and root-galling on Musa spp.…”