Silver nanoparticles as a potential nematicide against Meloidogyne graminicola.

Richa Baronia,R K Walia,S P Singh,Puneet Kumar

doi:10.21307/jofnem-2020-002

Abstract

Plant-parasitic nematodes cause severe damage to the various agricultural crops, leading to economic losses for farmers. Therefore, identification and development of novel and environmentally benign nematicides is critically important. In this study, a silver nanoparticle (AgNP) formulation was synthesized, characterized, and investigated as a potential nematicide against rice root-knot nematode, Meloidogyne gramnicola, on rice (Oryza sativa). A series of lab assays (water and sand screening) and glasshouse experiments (using soilless system, autoclaved soil, and naturally infested soil) were conducted to examine the nematicidal effects of AgNP. The results from lab assays revealed 0.1 μg/ml as the minimum concentration for 100% irreversible nematode mortality after 12 hr in the water screening test. However, results from the sand screening test indicated 100% nematicidal effect of AgNP at 2 μg/ml after 24 hr of incubation. In glasshouse assays in soilless system of rice cultivation, 1 μg/ml concentration of AgNP applied directly to the trays achieved significant suppression of root gall formation. The effective dosage to kill nematodes in field soil assays was determined to be 3 μg/ml, which is lower than the value of 150 μg/ml reported in the literature. No visible adverse effect of AgNP was observed on seed germination or plant growth in all the experiments. The results indicate that AgNP has effective nematicidal activity against M. graminicola in rice.

Highlights

Rice (Oryza sativa) is a major life-sustaining crop in India and feeds more than 60% of the population
A pure culture of rice root-knot nematode, M. graminicola, maintained on a soilless system (Kumar et al, 2017) in a glasshouse at National Phytotron Facility of ICAR-IARI, New Delhi was used in this study
UV–Vis spectra of the Ag nanoparticles (AgNP) revealed a welldefined surface plasmon resonance absorption peak centered at 417 nm (Fig. 1A), which is the characteristic peak related to spherical AgNP

Summary

Introduction

Rice (Oryza sativa) is a major life-sustaining crop in India and feeds more than 60% of the population. Rice root-knot nematode, Meloidogyne graminicola, is widely distributed across diverse agro-climatic conditions in India (Salalia et al, 2017) and it has emerged as the economically most threatening plant-parasitic nematode in rice nurseries causing a yield loss of USD 350 million annually (Walia et al, 2018). Ag nanoparticles (AgNP) have shown evidence of being a potentially effective nematicide (Cromwell et al, 2014; Abdellatif et al, 2016; Hassan et al, 2016; Nassar, 2016; Taha, 2016). The first report on the bio-efficacy of AgNP on a plant-parasitic nematode was provided by Cromwell et al (2014) against root-knot nematode on bermuda grass with mixed results, the lab assays revealed promising results but field experiments were not conclusive. Its efficacy was compared with a commercial AgNP product (Silvox 500®)

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