Root-knot Nematodes Meloidogyne Spp Research Articles

Nematicidal effectiveness of propolis against the root-knot nematode Meloidogyne spp.

Nematicidal effectiveness of propolis against the root-knot nematode Meloidogyne spp.

Laboratory Evaluation of Efficiency of some Normal and Nano Amino Acids in Hatching Eggs and Vitality of J2 Second Instar Juveniles in Root-knot Nematode Meloidogyne spp.

Tomato affected by several pathogenic factors, including root-knot nematodes (Meloidogyne spp.). This research was conducted to evaluate the efficacy of three amino acid Arginine, Serine, and Leucine, in their normal and Nano forms, at three different concentrations (10, 20, 30 ppm). The evaluation was performed under laboratory conditions to assess their effectiveness in inhibiting egg hatching and the viability Second stage Juveniles (J2) of the targeted nematode species. The laboratory results demonstrated the efficiency of all treatments in reducing the percentage of unhatched eggs, particularly at higher concentrations. The Nano-form of the three amino acids at a concentration of 30 ppm exhibited the highest efficacy compared to the normal form and showed significant superiority over the control treatment. After 72 hours, the percentage of unhatched eggs for Arginine, Serine, and Leucine Nano-amino acids was (21.00, 31.33, and 30.67), respectively, with a kill rate of (79%, 68.88%, and 69.33%) compared to the control treatment, which recorded 75% unhatched eggs and a kill rate of 25%. The impact of these treatments on the viability Second stage juveniles(J2) also varied significantly with different concentrations, showing a dose-dependent effect over time and significant differences compared to the control group. The highest concentration of 3000 ppm was the most effective, resulting in the highest kill rate for Arginine, Serine, and Leucine Nano-amino acids, which reached (95.27%, 90.27%, 88.89%), respectively, compared to the control treatment, which had a kill rate of 48.60%.

Molecular and Environmental Triggering Factors of Pathogenicity of Fusarium oxysporum and F. solani Isolates Involved in the Coffee Corky-Root Disease.

Coffee corky-root disease causes serious damages to coffee crop and is linked to combined infection of Fusarium spp. and root-knot nematodes Meloidogyne spp. In this study, 70 Fusarium isolates were collected from both roots of healthy coffee plants and with corky-root disease symptoms. A phylogenetic analysis, and the detection of pathogenicity SIX genes and toxigenicity Fum genes was performed for 59 F. oxysporum and 11 F. solani isolates. Based on the molecular characterization, seven F. oxysporum and three F. solani isolates were assessed for their pathogenicity on coffee seedlings under optimal watering and water stress miming root-knot nematode effect on plants. Our results revealed that a drastic increment of plant colonization capacity and pathogenicity on coffee plants of some Fusarium isolates was caused by water stress. The pathogenicity on coffee of F. solani linked to coffee corky-root disease and the presence of SIX genes in this species were demonstrated for the first time. Our study provides evidence for understanding the pathogenic basis of F. oxysporum and F. solani isolates on coffee and revealed the presence of SIX and Fum genes as one of their pathogenicity-related mechanisms. We also highlight the relevance of chlorophyll, a fluorescence as an early and high-throughput phenotyping tool in Fusarium pathogenicity studies on coffee.

Evaluation of some plant species for their resistance against root-knot nematode Meloidogyne spp.

Evaluation of some plant species for their resistance against root-knot nematode Meloidogyne spp.

Evaluation the efficiency of some controlling methods on olive seedlings infected with root-knot nematodes Meloidogyne spp.

The study was aimed to evaluate different controlling methods and agents including the nematicide Rugby, the bio-agents Trichoderma.harzianum and Trichoderma.atroviride, compost of poultry manure, cows and sheep dung. These agents were compared for their effect on nematode populations and plant growth parameters of olive infected plant. The results revealed that Rugby was the most effective treatment that decreased all measured criteria of nematode infection including gall number / 2 g root, Female number / 2 g root, number of egg masses/2g root and number of males and juveniles/100g soil which recorded 0.33/2g root, 0.33/2g root, 0.33/2g root, 0.00/100g soil respectively. The highest values of some plant growth parameters including plant height, root length, number of branches/plant and leaf area/plant were gained from treated with the poultry manure treatment that resulted in 32.66cm2, 34.00cm2, 22.88g, 7,00 branch/plant and 5.37cm2 respectively. Among all treatments compost of poultry manure, cow dung and sheep dung had increased biochemical indicators of plant health such as percentage of nitrogen content (1.93, 1.93, 1.89)% portion content(12.07, 12.07, 11.8)% and chlorophyll a, b and total chlorophyll content (0.604, 0.503, 0.488), (0.302, 0.258, 0.244), (0.906, 0.671, 0.732) mg/g fresh weight respectively.

Identificación y distribución de especies de Meloidogyne en Baja California Sur, México

La agricultura en Baja California Sur presenta un grave problema debido al daño provocado por el nematodo agallador Meloidogyne spp. La incidencia de daños provocados por este tipo de patógenos es alta, sin embargo, actualmente no se conoce su distribución ni las especies presentes en la entidad. Tomando en cuenta que esta información es clave en las estrategias para el manejo de dicho fitonemátodo, el objetivo del presente estudio fue identificar mediante caracteres morfológicos y métodos moleculares, las especies de Meloidogyne presentes en los cultivos muestreados, asi como su distribución en el estado. Durante el ciclo agrícola 2017-2018, se realizaron muestreos de suelo y raíces de plantas con síntoma de marchitez y amarillamiento en los diferentes cultivos de cuatro municipios de la entidad. A partir de raíces colectadas, se extrajeron 50 hembras de Meloidogyne spp. de los cultivos muestreados, las cuales, se identificaron mediante caracterización morfológica de patrones perineales. Posteriormente se extrajo ADN genómico de dichas hembras y se amplificaron genes específicos reportados en la bibliografía para diferentes especies. Los resultados obtenidos muestran que las especies identificadas corresponden a Meloidogyne incognita y Meloidogyne enterelobii, donde la incidencia de las poblaciones fue 30% y 70% respectivamente. De las dos especies identificadas M. enterelobii fue la que predominó en las áreas agrícolas de Baja California Sur. Mientras que M. incognita solo se encontró en dos municipios. Esta información será útil en la implementación eficaz de medidas de control contra las diferentes especies de Meloidogyne en el Estado.

New insights into lectin from Abelmoschus esculentus seeds as a Kunitz-type inhibitor and its toxic effects on Ceratitis capitata and root-knot nematodes Meloidogyne spp.

Plants produce lectins to confer resistance to pathogens through specific carbohydrate binding. The classification of lectins based only ligands can sometimes obscure other functions intrinsic to its structure. In this work, we characterized Abelmoschus esculentus lectin (AEL) on the basis of structural insights and reported its toxic effects on the Mediterranean fruit fly Ceratitis capitata and root-knot nematodes Meloidogyne incognita and Meloidogyne javanica. LC–MS/MS analysis followed by SPIDER searches and de novo sequencing indicated AEL as a Kunitz-type protease inhibitor homologous to the 21-kDa seed protein of Theobroma cacao, an endopeptidase inhibitor. AEL inhibited the activities of trypsin (Ki = 3.3 nM), chymotrypsin (Ki = 8.3 nM), and papain (Ki = 0.5 μM) but not cathepsin D. Insecticidal activity was evaluated in the first, second, and third instar larvae and pupae, in which AEL (2000 μg/mL) was more effective on the pupal stage, showing more toxicity than the organophosphates malathion and dimethoate. AEL (500 μg/mL) inhibited the hatching of second-stage juveniles in both nematode species, with greater inhibition occurring in M. incognita. The Kunitz-type serine/cysteine protease inhibitor activities of AEL and its pest control effects may provide a novel understanding of its mechanisms in the plant immune system and their biotechnological applications.

Efectividad biológica del nematicida oxamyl en el control de Meloidogyne spp. en tomate Solanum lycopersicum

El nemátodo agallador de raíces Meloidogyne spp., es una plaga de gran importancia económica en todo el mundo; se reportan pérdidas de la producción mundial sobre todo en productos horto-frutícolas por causa de este nemátodo en aproximadamente 115 mil millones de dólares anuales por lo general los productores no detectan el problema antes de la siembra; el estudio busca la efectividad biológica de un nematicida a diferentes dosis para el control de Meloidogyne spp. en tomate. El experimento se estableció en el municipio de Tamiahua, Veracruz, usando un diseño de bloques completos al azar, con 5 tratamientos y 4 repeticiones, evaluando los siguientes productos: Nematicida Vydate L® a dosis de 0.75 lts/ ha-1, 1.0 lts/ ha-1 y 2.0 lts/ ha-1, el nematicida Nemator ® a dosis de 1.0 kg/ ha-1, y un testigo absoluto; realizando 3 aplicaciones al cultivo, estas se llevaron a cabo al momento del trasplante, a los 20 días después del trasplante (ddt), a los 40 y 60 ddt, respectivamente. El Nematicida Nemator® a dosis de 1.0 kg/ ha-1controla satisfactoriamente el agallamiento en tomate causado por Meloidogyne spp. al igual que Vydate L® a dosis de 2.0 lts/ ha-1, además este último, presenta buen control contra insectos chupadores, en el testigo se encontró presencia de pulgón Myzus persicae, comparado con el resto de los tratamientos. En base al análisis de los resultados, se recomienda tratamiento en plántula debido a que mejora la asimilación y existe ahorro de productos.

Investigation of Culture Filtrate of Endophytic Fungi Nigrospora Sp. Isolate Rs 10 in Different Concentrations towards Root-knot Nematode Meloidogyne Spp.

One of the modes of action of endophytic fungi against plant pathogens e.g. plant parasitic nematode, is the production of toxic culture filtrate. Experiments were conducted to investigate the antagonistic effects of different concentrations of the culture filtrate produced by the endophytic fungi Nigrospora sp. isolate RS 10 against the root knot nematode Meloidogyne spp. Nigrospora sp. isolate RS 10 was isolated from the healthy root of a sengon plant ( Paraserianthes falcataria ). Three different concentrations of the culture filtrate were investigated using in vitro bioassays against the motile juvenile stage 2 of the root knot nematode Meloidogyne spp. Inactivation and mortality were recorded after 1, 3 and 24 hrs of exposure to culture filtrates. The mortality of the root-knot nematode Meloidogyne -J2 after 24 hrs exposure to the culture filtrate was confirmed by rinsing with sterile distilled water that demonstrated the effects of the culture filtrate treatment were irreversible, as nematodes did not recover. Nematode mortality rates after 1 to 24 hr exposure periods ranged from 80 % to 100 %. The effects of the culture filtrates on root-knot nematode Meloidogyne -J2 increased with increasing culture filtrate concentration.

First Report of Meloidogyne incognita Infecting Corn in Western Spain.

During the 2009 to 2010 corn-growing (Zea mays L. cv. Alexandria) seasons, severely stunted and yellowing corn plants in several commercial fields at Aldearrubia (Salamanca Province) were observed in western Spain. The disease incidence ranged from 80 to 100%. Early symptoms consisted of severely reduced growth of the plants coupled with extensive leaf yellowing. Occurrence of the disease was estimated to cause near complete loss of the crop yields since the corn produced in affected fields was unmarketable. Disease surveys revealed high parasitism in the main and feeder roots and a large soil population of the root-knot nematode Meloidogyne spp. The nematode population was extracted and quantified from soil and root samples according to Barker (1). It was identified as the southern root-knot nematode M. incognita race 1, by female perineal pattern, host-differential test, and multiplex PCR using forward primers H-18S, CF-ITS, I-ITS, and reverse primer HCFI-28S (3,4). ITS products cloned and assayed using the ABI PRISM 3100 Genetic Analyzer (Applied Biosystems, Salamanca, Spain) were subjected to a database search using BLAST (National Centre for Biotechnology Information) to confirm the identification. These sequences exhibited 99.0% similarity with that of an M. incognita isolate from France (GenBank Accession No. AF402309.1). M. incognita was found in 80% of soil samples collected from the areas where the disease was observed and 83.5% of root samples with nematode population densities ranging from 26 to 269 eggs and second-stage juveniles (J2s) per 100 cm3 of soil and 234 to 1,634 eggs and J2s per 5 g of fresh roots. In glasshouse proofs of pathogenicity, a mix of 1,500 eggs and J2s of these populations of M. incognita were inoculated in 20-cm-diameter pots with 10 replicates with a single pregerminated seed of corn cv. Alexandria as host plant; another 10 replicates without inoculation were established as control plants. After 6 weeks, all plants inoculated were severely stunted and yellowing; infected roots showed galls on root tips and secondary feeder roots. Galling of root tips that cause stubby root symptoms prevented further root growth into deeper soil layers and induced proliferation of secondary roots, which confirmed the nematodes' pathogenicity. The severe infections in roots of corn plants suggest that parasitism of corn roots by the root-knot nematode must contribute to stunting, yellowing, and decline of corn, reducing yield by restricting access to water and nutrients that are needed for plant growth and development, and can result in the death of younger plants as previously reported (2). To our knowledge, this is the first report of M. incognita infecting corn in Spain.

Varietal response of sunflower Helianthus annus (L) to root-knot nematode Meloidogyne spp and other field pathogens

Varietal response of sunflower Helianthus annus (L) to root-knot nematode Meloidogyne spp and other field pathogens