Root-knot Nematode Meloidogyne Incognita Research Articles

Development of Bio-Rational Based Management Packages Against Root Knot (Meloidogyne Incognita) Of Bottle Gourd

The efficacy of Tricho-compost alone and combination of lower dose of Furadan 5G with Tricho-compost, poultry refuse, neem oil cake and saw dust burning against root-knot nematode (Meloidogyne incognita) of bottle gourd was studied in the field laboratory of Plant Pathology Division of Bangladesh Agricultural Research Institute (BARI) during 2017 through 2019 cropping seasons. All the treatments gave appreciable reduction of gall development on roots and enhanced shoot and root growth as well as fruit yield of bottle gourd. Integration of Furadan 5G with Trichoderma based bio-fungicides. Trichocomposts, neem oil cake, and poultry refuse were the effective treatments in reducing root-knot severity and increasing plant growth and fruit yield of bottle gourd.
 Bangladesh J. Agril. Res. 46(4): 373-383, December 2021

Management of root-knot nematode (Meloidogyne incognita) and improve defensive ability of cucumber plant using Serratia marcescens, Salicylic acid and Fosthiazate (melotherin®) through adaptive processes and antioxidant capacity

Management of root-knot nematode (Meloidogyne incognita) and improve defensive ability of cucumber plant using Serratia marcescens, Salicylic acid and Fosthiazate (melotherin®) through adaptive processes and antioxidant capacity

Biocontrol of the root-knot nematode Meloidogyne incognita with Purporeocillum lilacinum and liquid bio-formulates in tomato (Solanum lycopersicum)

Root-knot nematodes (Meloidogyne spp.) cause great losses in tomato crops. An environmentally friendly for its control is the use of predatory fungi such as Purporeocillum lilacinum, which reduces its population in the soil and mitigates yield losses. Therefore, the objective of the present study was to evaluate the biocontrol efficacy of the strains of the nematophagous fungus Purporeocillum lilacinum and liquid bioformulates on the eggs of the root-knot nematode Meloidogyne incognita, and the formation of galls on the tomato root. Two native strains of Purporeocillum lilacinum H2 and H3 combined with the bioformulated Extract of Beneficial Microorganisms (EPMB®) and the root exudate stimulator Exu-Root® were tested on Meloidogyne incognita eggs and tomato plants. The results obtained indicate that the Purporeocillum lilacinum H2 and H3 strains infected the Meloidogyne incognita eggs, interrupted the development of the embryos and caused their death, which significantly reduced the presence of galls in the root of the plants. In short, the maximum biological performance was presented with the treatments H2+Exu-Root® and H3+EPMB®, which had the lowest number of galls with 19.2 and 20.3 galls per plant respectively, compared to the control that presented 88 galls in the root and the treatments where the fungus was not applied (69-85 galls). Finally, it is concluded that the results demonstrate the potential of the Purporeocillum lilacinum H2 and H3 strains as biocontrol agents against the root-knot nematode Meloidogyne incognita, and that, in combination with EPMB® and Exu-Root®, the efficacy can be increased to reduce its population.

AtSWEET1 negatively regulates plant susceptibility to root-knot nematode disease.

The root-knot nematode Meloidogyne incognita is a pathogenic pest that causes severe economic loss to agricultural production by forming a parasitic relationship with its hosts. During the development of M. incognita in the host plant roots, giant cells are formed as a nutrient sink. However, the roles of sugar transporters during the giant cells gain sugar from the plant cells are needed to improve. Meanwhile, the eventual function of sugars will eventually be exported transporters (SWEETs) in nematode-plant interactions remains unclear. In this study, the expression patterns of Arabidopsis thaliana SWEETs were examined by inoculation with M. incognita at 3 days post inoculation (dpi) (penetration stage) and 18 dpi (developing stage). We found that few AtSWEETs responded sensitively to M. incognita inoculation, with the highest induction of AtSWEET1 (AT1G21460), a glucose transporter gene. Histological analyses indicated that the β-glucuronidase (GUS) and green fluorescent protein (GFP) signals were observed specifically in the galls of AtSWEET1-GUS and AtSWEET1-GFP transgenic plant roots, suggesting that AtSWEET1 was induced specifically in the galls. Genetic studies have shown that parasitism of M. incognita was significantly affected in atsweet1 compared to wild-type and complementation plants. In addition, parasitism of M. incognita was significantly affected in atsweet10 but not in atsweet13 and atsweet14, expression of which was induced by inoculation with M. incognita. Taken together, these data prove that SWEETs play important roles in plant and nematode interactions.

Nematicidal Properties of Chitosan Nanoformulation.

Chitosan is the second most abundant bio-polymer available in the world, second only to cellulose. It is found in crustaceous shells, e.g., those of crabs, shrimps, prawns, and fungi, as well as insect exoskeletons. The use of nanoformulations for the management of pests and diseases is receiving increased interest with the advancement of nanotechnology. Here, chitosan nanospheres were obtained from chitosan using the ionic gelation technique. The nanoformulations obtained were characterized using a particle size analyzer, Fourier transform infrared spectroscopy, and a transmission electron microscope. The efficacy of chitosan nanospheres in suppressing the root-knot nematode Meloidogyne incognita was studied. The particle size of nanospheres formulated for this study was 380.2 nm, with a polydispersity index (PI) of 0.4 and Zeta potential of 45.7 or 50.9 mV at pH 5.2. The chitosan nanospheres were spherical and the particles did not agglomerate. FTIR spectra of the chitosan nanospheres peaked at 3334 cm-1, thereby indicating the stretching of the OH and NH group. In In-vitro studies, chitosan nanospheres showed significant nematicidal activity against M. incognita. Under pot culture conditions, chitosan nanospheres (1%- active compound chitosan) at 2ml/plant decreased the nematode population in roots or soil. Compared to the control, the number of galls was reduced by 83.68%, the number of egg masses by 83.85%, the number of adult females by 66.56%, and the number of second-stage juveniles by 73.20%. In a field experiment, application of chitosan nanospheres (1%) was followed by a 18.75% increase in fruit yield compared to the non-treated control.

The root-knot nematode effector MiMSP32 targets host 12-oxophytodienoate reductase 2 to regulate plant susceptibility.

To establish persistent infections in host plants, herbivorous invaders, such as root-knot nematodes, must rely on effectors for suppressing damage-induced jasmonate-dependent host defenses. However, at present, the effector mechanisms targeting the biosynthesis of biologically active jasmonates to avoid adverse host responses are unknown. Using yeast two-hybrid, in planta co-immunoprecipitation, and mutant analyses, we identified 12-oxophytodienoate reductase 2 (OPR2) as an important host target of the stylet-secreted effector MiMSP32 of the root-knot nematode Meloidogyne incognita. MiMSP32 has no informative sequence similarities with other functionally annotated genes but was selected for the discovery of novel effector mechanisms based on evidence of positive, diversifying selection. OPR2 catalyzes the conversion of a derivative of 12-oxophytodienoate to jasmonic acid (JA) and operates parallel to 12-oxophytodienoate reductase 3 (OPR3), which controls the main pathway in the biosynthesis of jasmonates. We show that MiMSP32 targets OPR2 to promote parasitism of M. incognita in host plants independent of OPR3-mediated JA biosynthesis. Artificially manipulating the conversion of the 12-oxophytodienoate by OPRs increases susceptibility to multiple unrelated plant invaders. Our study is the first to shed light on a novel effector mechanism targeting this process to regulate the susceptibility of host plants.

The effects of micronutrient-enriched media on the efficacy of Bacillus subtilis as biological control agent against Meloidogyne incognita

The root-knot nematodes Meloidogyne incognita poses a serious threat to horticultural food and plantation crops. One of the effective and efficient measures to overcome this nematode is using bacteria as a biological control agent. This study aimed to test the effectiveness of Bacillus subtilis bacteria grown on media with additional micronutrients as a biological control agent for M. incognita. The test was carried out by growing bacteria in 100 mL of nutrient broth (NB) added with FeCl2, MnCl2, and CuCl2. Each type of micronutrient was administered at concentrations of 35 ppm, 40 ppm, 45 ppm, 50 ppm, and 55 ppm. As a control, NB media was used without the addition of micronutrients. The test results showed that the best performances on bacterial growth were 55 ppm MnCl2, 45 ppm MnCl2, 40 ppm MnCl2, 40 ppm CuCl2, 50 ppm MnCl2, and 35 ppm MnCl2. These six treatments were then used in an antagonism test. A total of 150 J2 M. incognita in 4 mL of suspension was put into a petri dish with a diameter of 5 cm. After that, 1 mL of each bacterial suspension was put into a petri dish following the treatment. The mortality rate of M. incognita in each treatment was 77.5% in 55 ppm MnCl2, 74.5% in 45 ppm MnCl2, 77.25% in 40 ppm MnCl2, 73.25% in 40 ppm CuCl2, 78.75% in 50 ppm MnCl2, 79% in 35 ppm MnCl2, and 53.25% in control. The same six treatments were also used to measure the chemotaxis index of M. incognita on tomato roots. Tomato seeds of the Tantyna variety were soaked for 60 minutes in a bacterial suspension grown on micronutrient-enriched media. After seven days, the tomato seed roots were removed and placed in 5 mL 20% Pluronic F-127 Gel which had been infested with 100 J2 M. incognita. After 6 hours, the number of nematodes approaching the roots was observed. The chemotaxis index in the treatments ranged from 16% to 24%, while that in the control was 33%. This study corroborates that the addition of micronutrients MnCl2 and CuCl2 to the growth medium of B. subtilis can increase antagonistic activity against M. incognita and suppress its chemotaxis response in tomato roots soaked in the bacterial suspension.

Efficacy evaluation of Streptomyces nigrescens KA-1 against the root-knot nematode Meloidogyne incognita

The nematicidal effects of Streptomyces nigrescens KA-1 isolated from soil samples of Mt. Naejang (Korea) were evaluated against Meloidogyne incognita in vitro and in vivo (pot experiments). The culture broth of the KA-1 strain exhibited 91.3% nematicidal activity in in vitro assays, and this strain significantly reduced the number of nematodes in the soil and the number of egg masses in roots of red pepper in in vivo pot experiments. In addition, anti-nematicidal substances were isolated from the culture broth of the strain and identified as trichostatin C (1) and dehydroxytrichostatin A (2) through various spectroscopic analyses (1H, 13C NMR and MS). These compounds showed potent anti-nematicidal activity against M. incognita. Therefore, the KA-1 strain, containing these active compounds, may be used as a biocontrol agent against M. incognita.

A quantitative and qualitative assessment of sugar beet genotype resistance to root-knot nematode, Meloidogyne incognita.

Sugar beet productivity is highly constrained by the root-knot nematode (RKN) Meloidogyne incognita. Eight sugar beet genotypes were screened under greenhouse conditions for their susceptibility to M. incognita according to an adapted quantitative scheme for assignment Canto-Saenz's host suitability (resistance) designations (AQSCS). Besides, the degree of susceptibility or tolerance of the examined genotypes was recorded by the modified host-parasite index (MHPI) scale based on yield performance. In addition, single nucleotide polymorphism (SNP) was also determined. Sugar beet genotypes have been classified into four categories for their susceptibility or tolerance according to the AQSCS scale. The first category, the moderately resistant (MR) group implies only one variety named SVH 2015, which did not support nematode reproduction (RF≤1), and had less root damage (GI≈2). Second, the tolerant group (T) involving Lilly and Halawa KWS supported fairly high nematode reproduction (RF>1) with relatively plant damage (GI≤2). Whereas the susceptible (S) category involved four varieties, FARIDA, Lammia KWS, Polat, and Capella, which supported nematode reproduction factor (RF>1) with high plant damage (GI>2). The fourth category refers to the highly susceptible (HYS) varieties such as Natura KWS that showed (RF≤1) and very high plant damage (GI>2). However, the MHPI scale showed that Lammia KWS variety was shifted from the (S) category to the (T) category. Results revealed significant differences among genotypes regarding disease severity, yield production, and quality traits. The SVH 2015 variety exhibited the lowest disease index values concerning population density with 800/250 cm3 soils, RF=2, root damage/gall index (GI=1.8), gall size (GS=2.3), gall area (GA=3.7), damage index (DI=3.4), susceptibility rate (SR=2.4), and MHP index (MHPI=2.5). However, Lammia KWS showed the highest disease index values regarding population density with 8890/250 cm3 soils, RF= 22.2, GI= 4.8, and SR= 14.1. Meanwhile, Natura KWS the highest GS, GA and MHPI with 7.1, 8 and 20.9, respectively. The lowest DI was achieved by Capella (DI= 6) followed by Lammia KWS (DI= 5.9). For yield production, and quality traits, SVH 2015 exhibited the lowest reductions of sugar yields/beet's root with 11.1%. While Natura KWS had the highest reduction with 79.3%, as well as it showed the highest reduction in quality traits; including sucrose, T.S.S, and purity with 65, 27.3, and 51.9%, respectively. The amino acid alignment and prediction of the DNA sequences revealed the presence of five SNPs among all sugar beet verities.

Establishment and maintenance of DNA methylation in nematode feeding sites.

A growing body of evidence indicates that epigenetic mechanisms, particularly DNA methylation, play key regulatory roles in plant-nematode interactions. Nevertheless, the transcriptional activity of key genes mediating DNA methylation and active demethylation in the nematode feeding sites remains largely unknown. Here, we profiled the promoter activity of 12 genes involved in maintenance and de novo establishment of DNA methylation and active demethylation in the syncytia and galls induced respectively by the cyst nematode Heterodera schachtii and the root-knot nematode Meloidogyne incognita in Arabidopsis roots. The promoter activity assays revealed that expression of the CG-context methyltransferases is restricted to feeding site formation and development stages. Chromomethylase1 (CMT1), CMT2, and CMT3 and Domains Rearranged Methyltransferase2 (DRM2) and DRM3, which mediate non-CG methylation, showed similar and distinct expression patterns in the syncytia and galls at various time points. Notably, the promoters of various DNA demethylases were more active in galls as compared with the syncytia, particularly during the early stage of infection. Mutants impaired in CG or CHH methylation similarly enhanced plant susceptibility to H. schachtii and M. incognita, whereas mutants impaired in CHG methylation reduced plant susceptibility only to M. incognita. Interestingly, hypermethylated mutants defective in active DNA demethylation exhibited contrasting responses to infection by H. schachtii and M. incognita, a finding most likely associated with differential regulation of defense-related genes in these mutants upon nematode infection. Our results point to methylation-dependent mechanisms regulating plant responses to infection by cyst and root-knot nematodes.

Nematicidal activity of o-hydroxybenzaldehyde from common buckwheat methanol extract on Meloidogyne incognita.

The nematicidal activity of buckwheat (Fagopyrum esculentum Moench) on the root-knot nematode Meloidogyne incognita was tested. Dried plant methanol extract presented higher nematicidal activity than fresh plant extracts with an EC50 = 62.6 ± 26.0 and 40.8 ± 26.1 μg/ml after 48 and 72 hours of immersion, respectively. GC-MS analysis showed the presence of 17 aldehydes, with salicylaldehyde (o-hydroxybenzaldehyde) being the most abundant at 16%. Nematicidal activity of the latter refers to salicylaldehyde and other aldehydes with chemical similarities was then assessed. The most active aldehyde was o-hydroxybenzaldehyde followed by m-hydroxybenzaldehyde, p-hydroxybenzaldehyde and benzeneacetaldehyde with an EC50 of about 11.0 ± 1.0, 31.0 ± 22.0, 75.0 ± 23.0 and 168.1 ± 52.3 μg/ml after 1 day of immersion, respectively. Position 2 of the hydroxyl group in the benzene ring seems to be very important for the nematicidal activity, followed by positions 3 and 4. As a complementary experiment, synergistic activity was observed when we added o-hydroxybenzaldehyde to m-hydroxybenzaldehyde and to p-hydroxybenzaldehyde with an EC50 after 24 hours of immersion of 8.0 ± 2.5 and 6.1 ± 2.3 μg/ml, respectively. Antioxidant activity assessment showed that this latter is inversely proportional to nematicidal activity. Our results showed that F. esculentum and its major compound salicylaldehyde could be integrated into the pest management system.

Biocontrol of root-knot nematode Meloidogyne incognita in arabica coffee seedling by using fortified bacterial consortium

The damage caused by the southern root-knot nematode (Meloidogyne incognita) in coffee plants has been reported in various countries, including Indonesia. The measures to control the nematodes on coffee seedlings and fields depend on synthetic nematicides. Addressing this issue requires not only a more environmentally friendly and cheaper technology but also equal effectiveness comparable to synthetic nematicides. This study aimed to test the effectiveness of fortified bacterial consortium (FBC) involving a combination of liquid organic fertilizer (LOF), botanical pesticide, and a bacterial consortium to control M. incognita infection in Coffea arabica seedlings. The treatments in this study consisted of control, synthetic nematicide with theactive ingredient fluopyram, and various FBC concentrations ranging from 20%, 40%, 60%, 80%, and 100%. The results demonstrated that the application of 60% to 100% FBC increased plant growth. The most effective and efficient treatment for increasing plant growth was the application of 60% FBC. When compared with control plants, 60% FBC treatment resulted in 6.8% longer root, 9.5% higher plant, 5.3% heavier plant fresh weight, and 4.8% heavier root fresh weight. We also found that the application of 60% to 100% FBC increased the amount of chlorophyll in leaves. FBC application also reduced the number of nematodes in the soil up to 60.6%, the number of galls up to 286.4%, and the severity of root damage up to 118.2%. This study indicates that the application of 60% FBC is the most effective and efficient in controlling M. incognita and stimulating the growth of C. arabica seedlings. Key words: Bacillus; pseudomonas; endophyte; rhizobacteria; fluopyram.

Biocontrol Potential of Neem leaf Extract on Mortality of Meloidogyne incognita

Root-knot nematode Meloidogyne incognita is one of the widely distributed in India and most economically damaging genera in vegetable crops. Plant products are the safer alternative approaches to control root knot nematodes. An experiment was carried out in vitro to test the Neem leaf extract of aqueous, acetone and methanol extract. Different concentrations of shade-dried leaves of Neem were tested on mortality of Meloidogyne incognita juveniles. Increase in concentration and exposure period resulted in increased mortality rate of Juveniles of M. incognita. Methanol Neem leaf extract (5 ml concentration) proved to be the most effective among used aqueous, acetone and methanol neem leaf extract . After 48 hours exposure aqueous and methanol leaves extract showed 100% mortality while acetone neem leaves extract showed 100% mortality after 72 hours exposure of 5 ml concentration. Neemleaves 0.25 ml con. was the least effective among all con.

β-Aminobutyric acid induced phytotoxicity and effectiveness against nematode is stereomer-specific and dose-dependent in tomato.

β-Aminobutyric acid (BABA) induces resistance to a/biotic stress but is associated with phytotoxicity in some plant species. There are two enantiomers of BABA, the R and S enantiomers. We evaluated the phytotoxicity caused by the RS BABA (racemic mixture of R and S BABA), evaluating the dose-response effect and different modes of application on tomato. Results show that RS BABA-induced phytotoxicity in tomato is dose-dependent and stronger with foliar applications than with soil drench. We further evaluated the phytotoxicity of the two enantiomers separately and observed that BABA-induced phytotoxicity is stereomer-specific. In comparison with less phytotoxic effects induced by S BABA, R BABA induces dose-dependent and systemic phytotoxic symptoms. To investigate the possible physiological causes of this phytotoxicity, we measured levels of oxidative stress and anthocyanins and validated the findings with gene expression analyses. Our results show that high doses of RS and R BABA induce hydrogen peroxide, lipid peroxidation, and anthocyanin accumulation in tomato leaves, while this response is milder and more transient upon S BABA application. Next, we evaluated BABA induced resistance against root-knot nematode Meloidogyne incognita in tomato. BABA-induced resistance was found to be stereomer-specific and dependent on dose and mode of application. R or RS BABA multiple soil drench application at low doses induces resistance to nematodes with less phytotoxic effects. Taken together, our data provide useful knowledge on how BABA can be applied in crop production by enhancing stress tolerance and limiting phytotoxicity.

Screening of tomato genotypes against root-knot nematode (Meloidogyne incognita) under screen-house conditions

Screening of tomato genotypes against root-knot nematode (Meloidogyne incognita) under screen-house conditions

Eco-Friendly Formulations of Oil in Water Emulsion (EW) from Melia azedarach Fruit Extracts and their Nematicidal Activity against Root-Knot Nematode (Meloidogyne incognita) on Tomato Plants under Greenhouse Conditions

Eco-Friendly Formulations of Oil in Water Emulsion (EW) from Melia azedarach Fruit Extracts and their Nematicidal Activity against Root-Knot Nematode (Meloidogyne incognita) on Tomato Plants under Greenhouse Conditions

Evaluation of a prototype of soil thermal solarizer for control of gall nematode in the production of coffee seedlings

In coffee crops at Rondônia State of Brazil, there is an increase in phytonematode epidemics.Since most local coffe nurseries at Rondônia use soil as substrate for seedling production, this work aimed to test the minimum exposure time at 60 ºC to control of root-knot nematodes Meloidogyne incognita in soil by means of solar heating, using a solarizer, in an adapted version for better heating perfomance. The used solarizer prototype was built of a wooden box covered with metal sheets, thermal blankets, painted black, with aluminum pipes of 0.5 cm in diameter at the bottom of the box that circulates the water heated by the collector box. The soil was inoculated with a suspension of 1000 eggs + J2 of M. incognita per liter and placed in equipment with a capacity of 150 liters. Exposure times at a minimum temperature of 60 °C were evaluated, with 14 treatments: C1 (non-inoculated and not autoclaved), C2 (inoculated), C3 (non-inoculated and autoclaved) T0’, T15’, T30’, T45’, T60’, T180’, T360’, T720’, T1440’, T2880’ and T4320’ . The temperature was measured every 15 minutes using a skewer-type digital thermometer. The soil was removed according to the exposure time, and placed in 8-liter pots, in which clone 125 and BRS 2357 coffee seedlings, susceptible to M. incognita , were transplanted and growing in a greenhouse for 180 days. The experimental design used was DIC, with 6 replications, each seedling as na experimental unit. Reproduction factor (FR), number of eggs per plant (NOGR) and number of galls per gram of root (NGGR) were evaluated. The FR, NOGR and NGGR variables reduced with exposure time. All treatments showed an effect to control the population of M. incognita in infected soils, with 100% efficacy of pathogen eradication from the T45’ treatment, 60 minutes of exposure is recommended for the production of Coffea canephora seedlings. Taken together, thir work showed the high potential of thr solorizer to contribute in theroot-knot nematode control to seedling production. Key words: Thermal control; Meloidogyne incognita; Coffea canephora.

Chemical Composition of Different Extracts of <i>Conyza bonariensis</i>: Insecticidal and Nematicidal Activities

C. bonariensis (L.) Cronq. known as hairy fleabane was first described in Argentina but it is now widely spread through most warmer regions of Europe, Africa, Asia, the Caribbean and Central America. In this work, a chemical analysis by liquid and gas chromatography coupled with mass spectrometry of the whole plant, aerial part, flowers and roots extracts of C. bonariensis harvested in Togo (West Africa) was carried out. Two acetylenic compounds Lachnophyllum ester and limonene were identified as the main components of essential oils while Lachnophyllum and Matricaria lactones were dominant in chloroform extracts. Based on the plant chemical compositions, essential oils and chloroform extracts were tested on cowpea weevil Callosobruchus maculatus adults which are considered as one of the most cosmopolitan pests of stored beans, and on freshly hatched second-stage juveniles of root-knot nematode Meloidogyne incognita. Results showed that the whole plant essential oil demonstrated an LC50/24h value of 1.75 μL oil/L air on C. maculatus while at 3.91 μL oil/L air, it showed 100% mortality. Furthermore, the plant root chloroform extracts partitioned in diethyl ether-hexane mixture showed the strongest nematicidal activity with an LC50/72h value of 0.47 mg/mL. Our findings suggest that the widely diffused plant C. bonariensis and its acetylenic constituents could be considered as potent botanical insecticidal and nematicidal agents.

Phytochemical Analysis and Binding Interaction of Cotton Seed Cake Derived Compounds with Target Protein of Meloidogyne incognita for Nematicidal Evaluation.

The root-knot nematode Meloidogyne incognita is one of the most damaging plant-parasitic nematodes and is responsible for significant crop losses worldwide. Rising human health and environmental concerns have led to the withdrawal of commonly used chemical nematicides. There has been a tremendous demand for eco-friendly bio-nematicides with beneficial properties to the nematode hosting plants, which encourages the need for alternative nematode management practices. The current study was undertaken to determine the nematicidal potential of cotton seed cake (CSC) against second-stage juvenile (J2) hatching, J2 mortality, and J2 penetration of M. incognita in tomato plants in vitro. J2s and egg masses of M. incognita were exposed to four concentrations (250, 500, 750, and 1000 mg/L) of CSC extracts. The higher J2 mortality and inhibition of J2 hatching were found at 1000 mg/L, while the least effective result was observed at 250 mg/L of the CSC extract. The CSC extract applied with the concentrations mentioned above also showed inhibition of J2 penetration in tomato roots; 1000 mg/L showed the highest inhibition of penetration, while 250 mg/L displayed the least inhibition. Using gas chromatography-mass spectroscopy, we identified 11 compounds, out of which 9,12-Octadecadienoic acid, Hexadecanoic acid, and Tetradecanoic acid were found as major compounds. Subsequently, in silico molecular docking was conducted to confirm the nematicidal behavior of CSC based on binding interactions of the above three major compounds with the targeted protein acetylcholine esterase (AChE) of M. incognita. The values of binding free energy are -5.3, -4.5, and -4.9 kcal/mol, observed for 9,12-Octadecadienoic acid, n-Hexadecanoic acid, and Tetradecanoic acid, respectively, suggesting that 9,12-Octadecadienoic acid binds with the receptor AChE more efficiently than the other two ligands. This study indicates that CSC has nematicidal potential that can be used to control M. incognita for sustainable agriculture.

Synthetic chalcone 1-(4-Fluoro-phenyl)-3-phenyl-propenone with high nematicidal potential against the root-knot nematode Meloidogyne incognita

Synthetic chalcone 1-(4-Fluoro-phenyl)-3-phenyl-propenone with high nematicidal potential against the root-knot nematode Meloidogyne incognita