scholarly journals Observations on a Novel Bacterial Pathogen of Root-Knot Nematodes (Meloidogyne spp.)

Pathogens ◽  
2021 ◽  
Vol 10 (10) ◽  
pp. 1226
Author(s):  
Aurelio Ciancio
Keyword(s):  
Light Microscopy ◽  
Bacterial Pathogen ◽  
Pathogenic Bacterium ◽  
Root Knot Nematodes ◽  
Gram Negative ◽  
Second Stage ◽  
Host Body ◽  
Pure Cultures ◽  
Meloidogyne Spp ◽  
Brown Color

A novel Gram-negative pathogenic bacterium (BN) was discovered in second-stage juveniles (J2) of root-knot nematodes (RKN, Meloidogyne spp.). Mature bacteria showed a peculiar rod morphology characterized by four cells sequentially joined at septa. Mature rods measured 4–5 × 0.5–0.6 μm and were characterized by the emptying and tapering of both apical cells. The data showed an electron-dense external matrix forming a coating capsule involved in host attachment. The rods were not motile and packed in parallel inside the J2 body. After J2 penetration by adhering, germinating cells, the bacterium proliferated until the host body content was completely digested, producing a lethal disease. Parasitized hosts were recognized using light microscopy by a pale creamy-brown color assumed at parasitism completion. At death, the whole nematode body was filled with cells and only a few sclerotized esophageal structures (i.e., stylet, median bulb) remained visible. The BN cells were quickly released at host body rupture, suggesting that J2 infection occurs through passive adhesion of cells dispersed in soil. The bacterium appeared fastidious, as attempts to obtain pure cultures on common nutritive media failed.

scholarly journals Reproduction of Meloidogyne enterolobii in lettuce cultivars of the American group

2015 ◽  
Vol 33 (2) ◽  
pp. 147-150
Author(s):  
Érika CSS Correia ◽  
Norberto Silva ◽  
Marylia GS Costa ◽  
Silvia RS Wilcken
Keyword(s):  
Reproductive Potential ◽  
Egg Mass ◽  
Root Knot Nematodes ◽  
Second Stage ◽  
American Group ◽  
Meloidogyne Enterolobii ◽  
Meloidogyne Spp ◽  
Gall Index ◽  
Summer Time ◽  
Reproduction Factor

Lettuce is the main vegetable cultivated in Brazil, in volume and in marketed value. There are ranges of diseases which may affect lettuce crops, including those caused by root-knot nematodes (Meloidogyne spp.). We evaluated the reproductive potential of Meloidogyne enterolobii in 22 lettuce cultivars. The plants were inoculated with 5,000 eggs and eventuals second stage juveniles of nematode per pot, two days after the transplanting. 'Rutgers' tomato was used as standard for inoculum viability of M. enterolobii. We evaluated, 60 days after inoculation, the gall index, egg mass index and reproduction factor (RF). The 'Ithaca', 'Raider Plus', 'RS-1397', 'L-104', 'Challenge', 'IP-11', 'Classic', 'Salinas 88', 'Vanguard 75', 'Calona' and 'Desert Queen' were resistant to M. enterolobii with RF varying from 0.22 to 0.9, and the cultivars Lady Winterset, Robinson, Sonoma, Raider, Lucy Brown, Bnondaga, Summer Time, Taina, Sundevil and L-109 were susceptible to this nematode, with RF ranging from 1.06 to 5.73.

scholarly journals Variations in the level of resistance to root-knot nematodes (Meloidogyne spp.) infestation among ten cowpeas (Vigna unguiculata L. Walp.) genotypes

2019 ◽  
Vol 54 (2) ◽  
pp. 68-78
Author(s):  
F. Kankam ◽  
E. N.K. Sowley ◽  
J. Adomako ◽  
A. Boateng
Keyword(s):  
Vigna Unguiculata ◽  
Root Knot Nematode ◽  
Root Knot Nematodes ◽  
Second Stage ◽  
Randomized Design ◽  
Significant Difference ◽  
Environmentally Safe ◽  
Meloidogyne Spp ◽  
The University ◽  
Moderately Resistant

The cultivation of cowpea (Vigna unguiculata L. Walp.) cultivars that are tolerant to root-knot nematode attack is among the environmentally safe approach to managing the root-knot nematode menace in cultivated crops. In this study, the tolerance of 10 cowpea genotypes to root-knot nematodes infestation was evaluated in a pot experiment conducted in a Screenhouse, at the University for Development Studies, Nyankpala Campus. The experiment was laid out in a completely randomized design with three replications. The number of second stage juveniles (J2) per 250 cm3 of soil sample were counted while the severity of root-knot nematode damage (root galls) was assessed. The reproduction index (RI) was used to classify the varieties as resistant or susceptible. There was a significant difference (P < 0.05) in the number of second stage juveniles of root-knot nematode (RKN), galling index and RI among the genotypes tested. The study revealed that cowpea genotypes SARI 1-4-90, Padi tuya, Songotra, IT99K-1122, Sanzi and Apagbaala were moderately resistant whereas cowpea genotypes IT86D-610, Zaayura, SARI 5-5-5 and IT07K-299-6 were slightly resistant. Thus, the six moderately resistant cowpea genotypes were suggested to be used as a source of resistance to RKN in future breeding works.

scholarly journals Observations on the Influence of Temperature Of Second Stage Juveniles (Meloidogyne Spp.) in the Absence of the Host Plant

2018 ◽  
Vol 1 (1) ◽  
pp. 17-21
Author(s):  
Leonard Boroș ◽  
Tatiana Eugenia Șesan ◽  
Ionela Dobrin ◽  
Beatrice Iacomi
Keyword(s):  
Host Plants ◽  
Adult Stage ◽  
Specific Area ◽  
Biological Cycle ◽  
Root Knot Nematodes ◽  
Excessive Heat ◽  
Second Stage ◽  
Different Temperatures ◽  
Triggering Factor ◽  
Meloidogyne Spp

Abstract The knowledge of root-knot nematodes behavior in different habitats and especially the knowledge of their reaction to major ecologic factors (humidity, temperature) are important for the assessment of pathogen potential in a specific area, being at the same time an important criterion for understanding the behavior towards host plants. The temperature is the most important factor, not just in the development of the entire biological cycle of root-knot nematodes, but at the same time it also affects their distribution, spread and survival under thermic stress conditions (excessive heat or cold). Alongside with the water and oxygen, the temperature is the triggering factor of hatching and running all stages until the adult stage. The articles aims to determine the survival of juveniles stages for Meloidogyne species, in the absence of host plants, and by exposing second stage juveniles to different temperatures. The juveniles survival and mobility decreases quite much at relative low temperatures (4°C and 10°C). Forward movements, mobility, hatching and lifetime were accentuated at higher temperatures (20°C) for a few weeks, so that after a period to decrease drastically (in 10 and 12 week) for the species considered for the study.

scholarly journals Ketahanan Tujuh Varietas Tomat terhadap Nematoda Puru Akar (Meloidogyne spp.)

2019 ◽  
Vol 3 (2) ◽  
pp. 61
Author(s):  
Lilis Irmawatie ◽  
Raden Rubi Robana ◽  
Nuraidah Nuraidah
Keyword(s):  
Plant Height ◽  
Fruit Weight ◽  
Lower Number ◽  
Annual Plant ◽  
Root Knot Nematodes ◽  
High Vitamin ◽  
Second Stage ◽  
Final Population ◽  
Meloidogyne Spp ◽  
Wet Weight

<p>Tomato is an annual plant that has high vitamin content and it was widely used by the general people and industry. At present the productivity is still low. One of the causes is the attack of <em>Meloidogyne. </em>The objective of this research was to test resistance of several tomatoe varieties to root knot nematodes (<em>Meloidogyne</em> spp.). Seven tomato varieties had been tested for resistance to <em>Meloidogyne</em>. Plants that were 45 days after planting in a <em>polybag</em> containing 5 kg of soil were infested with second stage larvae (L2). The parameters observed were plant height, number of knots, final population, fruit weight and canopy wet weight and root wet weight. The results showed that none of the tomatoe varieties tested were resistant to <em>Meloidogyne</em>. But there were differences in responses to the <em>Meloidogyne </em>attack including the Ratna variety and Diamond variety showing the lower number of knot and the final population <em>Meloidogyne</em>.</p>

Genetic diversity of Meloidogyne spp. parasitising potato in Brazil and aggressiveness of M. javanica populations on susceptible cultivars

Nematology ◽  
2017 ◽  
Vol 19 (1) ◽  
pp. 69-80 ◽  
Author(s):  
Israel L. Medina ◽  
Cesar B. Gomes ◽  
Valdir R. Correa ◽  
Vanessa S. Mattos ◽  
Philippe Castagnone-Sereno ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Rapd Markers ◽  
Potato Production ◽  
Potato Cultivars ◽  
Root Knot Nematode ◽  
Root Knot Nematodes ◽  
Nematode Reproduction ◽  
Meloidogyne Spp ◽  
Prevalent Species ◽  
Reproduction Factor

Root-knot nematodes (Meloidogyne spp.) significantly impact potato production worldwide and in Brazil they are considered one of the most important group of nematodes affecting potatoes. The objectives of this study were to survey Meloidogyne spp. associated with potatoes in Brazil, determine their genetic diversity and assess the aggressiveness of M. javanica on two susceptible potato cultivars. Fifty-seven root-knot nematode populations were identified using esterase phenotyping, including Meloidogyne javanica, M. incognita, M. arenaria and M. ethiopica. Overall, root-knot nematodes were present in ca 43% of sampled sites, in which M. javanica was the most prevalent species, and the phenotypes Est J3, J2a and J2 occurred in 91.2, 6.7 and 2.1% of the positive samples, respectively. Other species, such as M. incognita, M. arenaria and M. ethiopica, were found less frequently and occurred at rates of 6.4, 4.3 and 2.1% of the samples, respectively. Sometimes, M. javanica was found in mixtures with other root-knot nematodes in ca 10.6% of sites containing Meloidogyne. After confirming the identification of 17 isolates of M. javanica and one isolate each of M. incognita, M. arenaria and M. ethiopica by SCAR markers, the populations were used to infer their genetic diversity using RAPD markers. Results revealed low intraspecifc genetic diversity among isolates (13.9%) for M. javanica. Similarly, M. javanica sub-populations (J2a) clustered together (81% of bootstrap), indicating subtle variation from typical J3 populations. The aggressiveness of four populations of M. javanica from different Brazilian states on two susceptible potato cultivars was tested under glasshouse conditions. Results indicated differences in aggressiveness among these populations and showed that potato disease was proportional to nematode reproduction factor.

Host plant response of Eumusa and Australimusa bananas (Musa spp.) to migratory endoparasitic and root-knot nematodes

Nematology ◽  
2000 ◽  
Vol 2 (8) ◽  
pp. 907-916 ◽  
Author(s):  
Ngo Thi Xuyen ◽  
Raf Verlinden ◽  
Ruth Stoffelen ◽  
Dirk De Waele ◽  
Rony Swennen
Keyword(s):  
Host Plant ◽  
Papua New Guinea ◽  
Loamy Sand ◽  
Plant Responses ◽  
Radopholus Similis ◽  
Root Knot Nematodes ◽  
Musa Spp ◽  
Pratylenchus Coffeae ◽  
Meloidogyne Spp

AbstractTwenty-five banana varieties of section Eumusa (AA-group) and seven of the section Australimusa (Fe'i-group) from Papua New Guinea were evaluated for resistance to Radopholus similis, Pratylenchus coffeae and Meloidogyne spp. The host plant responses were compared with the susceptible reference cvs Grande Naine and Cavendish 901. In vitro propagated plants were transferred to the glasshouse in loamy sand and inoculated with approximately 1000 migratory endoparasitic nematodes at 4 weeks after planting. Reproduction of R. similis and P.coffeae in the roots was determined at 8 or 10 weeks, respectively, after inoculation. Reproduction of Meloidogyne spp. was determined 8 weeks after inoculation with 3300 to 5000 eggs. No resistance to R. similis was found in the diploid varieties. The Fe'i variety Rimina and possibly Menei were resistant to R. similis. All varieties tested were susceptible to P.coffeae and Meloidogyne spp. Tests de résistance de bananiers Eumusa et Australimusa (Musa spp.) envers les nématodes endoparasites migrateurs et galligènes - Vingt-cinq variétés de bananier de la section Eumusa (groupe AA) et sept de la section Australimusa (group Fe'i) provenant de Papouasie-Nouvelle Guinée ont été testées pour leur résistance envers Radopholus similis, Pratylenchus coffeae et Meloidogyne spp. Les résponses de ces variétés ont été comparées à celles des cultivars sensibles de référence Grande Naine et Cavendish 901. Des vitroplants ont été mis en place en serre sur un sol argilo-sableux et inoculés 4 semaines après plantation avec environ 1000 R. similis ou P.coffeae dont la reproduction a été déterminée 8 et 10 semaines, respectivement, après inoculation. La reproduction de Meloidogyne spp. l'a été 8 semaines après inoculation avec 3300 à 5000 oeufs. Aucune résistance à R. similis n'a été observée chez les variétés diploïdes. Les variétés du groupe Fe'i Rimina et Menei se sont montrées résistantes à R. similis, avec un certain doute dans le cas de la dernière. Toutes les variétés testées sont sensibles à P.coffeae et Meloidogyne spp.

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.

2017 ◽  
Vol 63 ◽  
pp. 96-104 ◽  
Author(s):  
José Thalles Jocelino Gomes de Lacerda ◽  
Rodrigo Rodrigues e Lacerda ◽  
Nilson Antonio Assunção ◽  
Alexandre Keiji Tashima ◽  
Maria Aparecida Juliano ◽  
...  
Keyword(s):  
Ceratitis Capitata ◽  
Abelmoschus Esculentus ◽  
Toxic Effects ◽  
Root Knot Nematodes ◽  
Meloidogyne Spp ◽  
Kunitz Type
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