The control of root-knot nematodes (Meloidogyne spp.) by Pseudomonas oryzihabitans and its immunological detection on tomato roots

Nematology ◽  
2007 ◽  
Vol 9 (3) ◽  
pp. 363-370 ◽  
Author(s):  
Keith Davies ◽  
Ioannis Vagelas ◽  
Simon Gowen ◽  
Barbara Pembroke

AbstractPseudomonas oryzihabitans, a bacterium associated with the entomopathogenic nematode Steinernema abbasi, was evaluated for its potential to colonise roots and thereby control a field population of root-knot nematodes. Immunological techniques were developed to detect root colonisation of P. oryzihabitans on tomato roots using a specific polyclonal antibody raised against vegetative bacterial cells. In vitro, bacterial cell filtrates were also shown significantly to inhibit juveniles hatching. In a glasshouse pot experiment, there were 22 and 82% fewer females in roots of plants treated with suspensions containing 103 and 106 cells ml−1 of P. oryzihabitans, respectively. In addition, there were significantly fewer egg masses produced; however, the numbers of eggs per egg mass did not differ significantly. The relationship between root colonisation and nematode control is discussed.

Nematology ◽  
2000 ◽  
Vol 2 (8) ◽  
pp. 907-916 ◽  
Author(s):  
Ngo Thi Xuyen ◽  
Raf Verlinden ◽  
Ruth Stoffelen ◽  
Dirk De Waele ◽  
Rony Swennen

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.


2015 ◽  
Vol 33 (2) ◽  
pp. 147-150
Author(s):  
Érika CSS Correia ◽  
Norberto Silva ◽  
Marylia GS Costa ◽  
Silvia RS Wilcken

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.


2008 ◽  
Vol 21 (9) ◽  
pp. 1205-1214 ◽  
Author(s):  
Kishor K. Bhattarai ◽  
Qi-Guang Xie ◽  
Sophie Mantelin ◽  
Usha Bishnoi ◽  
Thomas Girke ◽  
...  

Responses of resistant (Mi-1/Mi-1) and susceptible (mi-1/ mi-1) tomato (Solanum lycopersicum) to root-knot nematodes (RKNs; Meloidogyne spp.) infection were monitored using cDNA microarrays, and the roles of salicylic acid (SA) and jasmonic acid (JA) defense signaling were evaluated in these interactions. Array analysis was used to compare transcript profiles in incompatible and compatible interactions of tomato roots 24 h after RKN infestation. The jai1 and def1 tomato mutant, altered in JA signaling, and tomato transgenic line NahG, altered in SA signaling, in the presence or absence of the RKN resistance gene Mi-1, were evaluated. The array analysis identified 1,497 and 750 genes differentially regulated in the incompatible and compatible interactions, respectively. Of the differentially regulated genes, 37% were specific to the incompatible interactions. NahG affected neither Mi-1 resistance nor basal defenses to RKNs. However, jai1 reduced tomato susceptibility to RKNs while not affecting Mi-1 resistance. In contrast, the def1 mutant did not affect RKN susceptibility. These results indicate that JA-dependent signaling does not play a role in Mi-1-mediated defense; however, an intact JA signaling pathway is required for tomato susceptibility to RKNs. In addition, low levels of SA might be sufficient for basal and Mi-1 resistance to RKNs.


2020 ◽  
Vol 38 (3) ◽  
pp. 239-245
Author(s):  
Jadir B Pinheiro ◽  
Giovani Olegário da Silva ◽  
Danielle Biscaia ◽  
Amanda G Macedo ◽  
Fábio A Suinaga

ABSTRACT Genetic resistance is the most suitable mechanism to control root-knot nematodes in lettuce. However, information about the resistance levels of currently used lettuce cultivars is scarce in the literature. Thus, the objective of this research was to characterize lettuce cultivars for resistance to root-knot nematodes Meloidogyne incognita (Mi) and M. javanica (Mj), aiming the identification of resistance sources for breeding, and to transfer information to the productive sector. We evaluated 97 lettuce genotypes in tree trials. In the first one (preliminary assessment), 92 lettuce genotypes were inoculated simultaneously with M. incognita race 1 and M. javanica species, 17 days after sowing. The gall index (GI) was evaluated 41 days after inoculation. In the second trial nine genotypes, selected from the first trial, were evaluated; and in the third trial, two new cultivars from Embrapa were evaluated. In the last two trials, the nematode species were inoculated separately, and the egg mass index (EMI), number of eggs per gram of roots (NEGR) and reproduction factor (RF) were also evaluated. In both trials, the lettuce cultivars Salinas 88 and Grand Rapids were used as resistant controls, as well as cultivar Irene as the susceptible control. The data were submitted to analysis of variance and treatments means grouping by Scott-Knott´s test. The crisp leaf cultivars presented a higher degree of resistance to the root-knot nematodes compared to the smooth leaf type cultivars. Cultivars Vera and Amanda present resistance to M. incognita, and Vanda to M. javanica. ‘Salinas 88’ present resistance mainly to M. javanica; while cultivar Mônica and the Embrapa cultivars BRS Leila and BRS Mediterrânea are resistant to both nematode species.


Plant Disease ◽  
2017 ◽  
Vol 101 (3) ◽  
pp. 448-455 ◽  
Author(s):  
Hai-Jing Hu ◽  
Ya-Li Chen ◽  
Yu-Fang Wang ◽  
Yun-Yun Tang ◽  
Shuang-Lin Chen ◽  
...  

Root-knot nematodes (Meloidogyne spp.), which cause severe global agricultural losses, can establish a special niche in the root vascular cylinder of crops, making them difficult to control. Endophytic bacteria have great potential as biocontrol organisms against Meloidogyne incognita. Three endophytic bacteria were isolated from plant tissues and showed high nematicidal activity against M. incognita second-stage juveniles (J2) in vitro. The gyrB gene sequence amplification results indicated that the three isolates were Bacillus cereus BCM2, B. cereus SZ5, and B. altitudinis CCM7. The isolates colonized tomato roots rapidly and stably during the colonization dynamic experiment. Three pot experiments were designed to determine the potential of three endophytic bacterial isolates on control of root-knot nematodes. The results showed that the preinoculated B. cereus BCM2 experiment significantly reduced gall and egg mass indexes. The inhibition ratio of gall and egg mass was up to 81.2 and 75.6% on tomato roots and significantly enhanced shoot length and fresh weight. The other two experiments with inoculated endophytic bacteria and M. incognita at the same time or after morbidity had lower inhibition ratios compared with the preinoculated endophytic bacteria experiment. The confocal laser-scanning microscopy method was used to further study the possible mechanism of endophytic bacteria in the biocontrol process. The results showed the localization pattern of the endophytic bacteria B. cereus BCM2-(str′)-pBCgfp-1 in tomato root tissues. Root tissue colonized by endophytic bacteria repelled M. incognita J2 infection compared with the untreated control in a repellence experiment. We isolated an endophytic B. cereus strain that stably colonized tomato and controlled M. incognita effectively. This strain has potential for plant growth promotion, successful ecological niche occupation, and M. incognita J2 repellent action induction. It plays an important role in endophytic bacteria against root-knot nematodes.


HortScience ◽  
1996 ◽  
Vol 31 (1) ◽  
pp. 147-149 ◽  
Author(s):  
Aref A. Abdul-Baki ◽  
Sanaa A. Haroon ◽  
David J. Chitwood

Resistance to root-knot nematodes (Meloidogyne spp.) in tomato (Lycopersicon esculentum Mill.) plants has been reported to break down at soil temperatures >28C. We evaluated in vitro root explants of tomato heterozygous (Mimi), homozygous (MiMi) at the Mi locus, or lacking the Mi-1 gene for resistance to Meloidogyne incognita (Kofoid & White) Chitwood and Meloidogyne arenaria (Neal) Chitwood at 28, 31, 34, and 37C. Genotypes Ace-55 UF and Rutgers, lacking the dominant allele, were susceptible to M. incognita and M. arenaria at all temperatures. Genotypes possessing the dominant allele (heterozygous or homozygous) were equally resistant to both nematode species. The resistance level in these genotypes was maintained fully at 31C, partially maintained at 34C, and lost at 37C. Resistance in the heat-tolerant Mi-heterozygous accession CLN 475-BC1F2-265-4-19 was not different from that of the heat-sensitive genotypes. As temperature increased, the genotypes differed in their sensitivity to resistance conferred by the Mi-1 locus.


Nematology ◽  
2006 ◽  
Vol 8 (6) ◽  
pp. 895-902 ◽  
Author(s):  
Wim Wesemael ◽  
Roland Perry ◽  
Maurice Moens

AbstractThe root-knot nematodes, Meloidogyne chitwoodi and M. fallax, cause severe damage to economically important crops and, in 1998, both species were listed as quarantine pests in Europe. Comparative studies were made on the effects of root diffusates and host age on the in vitro hatching of M. chitwoodi and M. fallax. There is a marked contrast in the hatching response of the two species. Hatching of second-stage juveniles (J2) of M. chitwoodi produced on young plants did not require host root diffusate stimulus, whereas at the end of the plant growing season, egg masses contained a percentage of unhatched J2 that require host root diffusate to cause hatch. This form of obligate quiescence at the end of the host growing season was not found in M. fallax. This species hatched well in water and did not require hatch stimulation from root diffusate, irrespective of the age of the plant on which the egg masses were produced. The number of eggs per egg mass for M. fallax collected on senescing plants was significantly greater than the number of eggs per egg mass for M. chitwoodi. The number of eggs per egg mass of M. chitwoodi decreased with plant age. The results are discussed in the context of the differing survival strategies of the two species.


Plants ◽  
2020 ◽  
Vol 9 (11) ◽  
pp. 1546
Author(s):  
Trifone D’Addabbo ◽  
Maria Pia Argentieri ◽  
Sebastiano Laquale ◽  
Vincenzo Candido ◽  
Pinarosa Avato

In this study, the relationship between nematicidal activity and chemical composition of ten essential oils (EOs) from different plant species was investigated both in in vitro assays on juveniles (J2) and eggs of the root-knot nematode Meloidogyne incognita and in experiments on tomato in soil infested by M. incognita. Nematode J2 were exposed for 4, 8 or 24 h to 0.78–100 μg mL−1 concentrations of each EO, whereas 24, 48 or 96 h exposures to 250, 500 and 1000 μg mL−1 solutions were tested on M. incognita egg masses. Treatments with 50, 100 or 200 μg kg soil rates of each EO were applied in the experiment on potted tomato. The highest nematicidal potential resulted for the C. verum EO, as highly toxic to both M. incognitaJ2 and eggs and strongly suppressive on nematode multiplication on tomato roots. The infestation of M. incognita on tomato roots was also strongly reduced by the EOs from E. citriodora and S. aromaticum, both highly toxic to M. incognitaJ2 but less active on nematode eggs. Adversely, R. graveolens EO strongly inhibited the egg hatch but was limitedly toxic to the infective J2. Chemical composition of the EOs was determined by GC-FID and GC-MS. The ten EOs showed a very different chemical composition in terms of major phytochemicals, with one or two dominant components totally amounting up to 85%. The structure–activity relationship based on the main phytochemicals identified in the assayed EOs and their nematicidal effects on M. incognita was also discussed. Results from this study confirmed that the selection of suitable EO raw materials can lead to the formulation on new effective nematicidal products.


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