scholarly journals Nuclear receptor nhr-48 is required for pathogenicity of the second stage (J2) of the plant parasite Meloidogyne incognita

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Chao-Jun Lu ◽  
Bao-Yu Tian ◽  
Yi Cao ◽  
Cheng-Gang Zou ◽  
Ke-Qin Zhang



2018 ◽  
Vol 7 (2) ◽  
pp. 141-145
Author(s):  
Gulwaiz Akhter ◽  
◽  
Tabreiz Ahmad Khan ◽  

Aqueous leaf extracts were utilized to assess the nematicidal or nematostatic property on second stage juvenile of Meloidogyne incognita. The juvenile were incubate at various concentration of leaf extract viz., 250, 500, 1000 and 2000 ppm. Corrected mortality using Abbot’s formula was recorded after 12, 24 and 48 hours respectively. Correlation coefficient (Pearson) was checked to explain the association between percentages mortality of juvenile with extract concentrations. Linear regression was used to denote concentration and rank dependent outcome of four aqueous plant leaves extracts on the second stage juvenile (J2) mortality. All leaf extracts were found to be nematicidal or nematostatic in property. Maximum juvenile mortality rate was recorded in Xanthium strumarium throughout the incubation period as followed by Acalypha indica, Argemone mexicana and Colocasia gigantean. Concentration depended effect of X. strumarium and C. gigantean proved maximum and minimum level when analyzed by values of regression and correlation. Aqueous leaves extracts of these aforementioned weeds give us an idea about nematicidal properties and therefore may be used as biopesticide in future



2020 ◽  
Vol 3 (2) ◽  
pp. 21-31
Author(s):  
Sudeep Subedi ◽  
Bihani Thapa ◽  
Jiban Shrestha

Root-knot nematode (RKN) Meloidogyne incognita stands out among the most harmful polyphagous endoparasite causing serious harm to plants, and distributed all over the globe. RKN causes reduced growth, quality and yield along with reduced resistance of the host against biotic and abiotic stresses. Infective second stage juvenile enters host roots with the help of the stylet and becomes sedentary getting into the vascular cylinder. Dramatic changes occur in host cells, making a specialized feeding site, induced by the secretion of effector protein by RKN. M. incognita can be controlled by nematicides, biocontrol agents, botanicals essential oils and growing resistant cultivars. Nematicides are no longer allowed to use in many parts of the world because of environmental hazards and toxicity to humans and other organisms. Researchers are concentrating on searching suitable alternatives to nematicides for effective management of M. incognita. This review mainly tries to explain the biology of M. incognita and different management options recommended in recent years. However, an effective and economical management of M. incognita remains an immense challenge.



Plants ◽  
2020 ◽  
Vol 9 (6) ◽  
pp. 699
Author(s):  
Christianna Meidani ◽  
Alexandros Savvidis ◽  
Evaggelia Lampropoulou ◽  
Aggeliki Sagia ◽  
Efstathios Katsifas ◽  
...  

A total of 461 indigenous Streptomycetes strains recovered from various Greek rhizosphere habitats were tested for their bioactivity. All isolates were examined for their ability to suppress the growth of 12 specific target microorganisms. Twenty-six were found to exert antimicrobial activity and were screened for potential nematicidal action. S. monomycini ATHUBA 220, S. colombiensis ATHUBA 438, S. colombiensis ATHUBA 431, and S. youssoufensis ATHUBA 546 were proved to have a nematicidal effect and thus were further sequenced. Batch culture supernatants and solvent extracts were assessed for paralysis on Meloidogyne javanica and Meloidogyne incognita second-stage juveniles (J2). The solvent extracts of S. monomycini ATHUBA 220 and S. colombiensis ATHUBA 438 had the highest paralysis rates, so these Streptomycetes strains were further on tested for nematodes’ biological cycle arrest on two Arabidopsis thaliana plants; the wild type (Col-0) and the katanin mutant fra2, which is susceptible to M. incognita. Interestingly, S. monomycini ATHUBA 220 and S. colombiensis ATHUBA 438 were able to negatively affect the M. incognita biological cycle in Col-0 and fra2 respectively, and increased growth in Col-0 upon M. incognita infection. However, they were ineffective against M. javanica. Fra2 plants were also proved susceptible to M. javanica infestation, with a reduced growth upon treatments with the Streptomyces strains. The nematicidal action and the plant-growth modulating abilities of the selected Streptomycetes strains are discussed.



Plant Disease ◽  
2019 ◽  
Vol 103 (7) ◽  
pp. 1551-1558 ◽  
Author(s):  
Xia Li ◽  
Hai-Jing Hu ◽  
Jing-Yu Li ◽  
Cong Wang ◽  
Shuang-Lin Chen ◽  
...  

Root-knot nematodes (Meloidogyne spp.) cause serious crop losses worldwide. The colonization of tomato roots by endophytic bacteria Bacillus cereus BCM2 can greatly reduce Meloidogyne incognita damage, and tomato roots carrying BCM2 were repellent to M. incognita second-stage juveniles (J2). Here, the effects of BCM2 colonization on the composition of tomato root exudates was evaluated and potential mechanisms for BCM2-mediated M. incognita control explored using a linked twin-pot assay and GC-MS. On water agar plates, J2 preferentially avoided filter paper treated with tomato root exudates (organic phase only) from plants inoculated with BCM2, visiting these 67.1% less than controls. In a linked twin-pot assay, BCM2 treatment resulted in a 42.0% reduction in the number of nematodes in the soil, a 43.3% reduction in the number of galls and a 47.7% decrease in the density of M. incognita in root tissues. Analysis of root exudate composition revealed that BCM2 inoculation increased the number of components in exudates. Among these, 2,4-di-tert-butylphenol, 3,3-dimethyloctane, and n-tridecane secretions markedly increased. In repellency trials on water agar plates, J2 avoided 2,4-di-tert-butylphenol, n-tridecane, and 3,3-dimethyloctane at concentrations of 4 mmol/liter. In a linked twin-pot assay, inoculation with 2,4-di-tert-butylphenol or 3,3-dimethyloctane reduced the number of nematodes in the soil (by 54.9 and 70.6%, respectively), the number of galls (by 53.7 and 52.4%), and the number of M. incognita in root tissues (by 67.5 and 36.3%). BCM2 colonization in tomato roots affected the composition of root exudates, increasing the secretion of substances that appear to be repellent, thus decreasing M. incognita J2 infection of roots.



Nematology ◽  
2003 ◽  
Vol 5 (2) ◽  
pp. 213-217 ◽  
Author(s):  
Jean-Baptiste Laffaire ◽  
Marie-Noëlle Rosso ◽  
Stéphanie Jaubert ◽  
Pierre Abad

AbstractA new cDNA, named Mi-ace-2, encoding an acetylcholinesterase, was isolated from Meloidogyne incognita. The full-length cDNA, carrying the trans-spliced SL1 leader sequence, was 2122 bp long with an open reading frame of 2058 bp. The predicted protein shared 32.3% identity with the previously identified MI ACHE and 49.1% identity with the C. elegans ACE-2. The conserved motifs involved in the catalytic triad, the choline binding site and 11 aromatic residues lining the catalytic gorge were present in the MI-ACE-2 deduced protein. RT-PCR analysis showed that Mi-ace-2 is transcribed in second stage juveniles before and after hatching, in females and in males. Phylogenetic analysis showed that MI-ACE-2 and ACE-2 were clustered in a distinct group closely related to the acetylcholinesterases secreted by animal-parasitic nematodes.



Nematology ◽  
2011 ◽  
Vol 13 (5) ◽  
pp. 509-520 ◽  
Author(s):  
Tushar K. Dutta ◽  
Stephen J. Powers ◽  
Brian R. Kerry ◽  
Hari S. Gaur ◽  
Rosane H.C. Curtis

AbstractThe rice root-knot nematode Meloidogyne graminicola normally infects rice, wheat and several other graminaceous plants. Meloidogyne incognita is a serious pest of dicotyledonous crops, although it can infect and reproduce on some cereals. This paper demonstrates and compares host recognition, development and reproduction of these two species of root-knot nematodes on rice and tomato plants. Attraction bioassays in pluronic gel clearly showed that M. incognita preferred tomato roots to rice or mustard roots, whilst M. graminicola was more attracted towards rice compared with tomato or mustard roots. Based on the attraction data from this study, it can be hypothesised that either: i) the blend of attractants and repellents are different in good and poor hosts; or ii) relatively long-range attractants, together with shorter-range repellents, might affect nematode movement patterns. Some host specific attractants might also be involved. Meloidogyne incognita was able to invade and develop to adult female but did not produce eggs in rice roots. By contrast, M. graminicola developed and reproduced faster on both rice and tomato plants compared with M. incognita. Nevertheless, second-stage juveniles of both these root-knot nematodes showed a similar pattern of distribution inside the roots, preferring to accumulate at the root tips of rice or in the vascular cylinder and cortical region of tomato.



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