Effect of small lipophilic molecules in tomato and rice root exudates on the behaviour of Meloidogyne incognita and M. graminicola

Nematology ◽  
2012 ◽  
Vol 14 (3) ◽  
pp. 309-320 ◽  
Author(s):  
Tushar K. Dutta ◽  
Stephen J. Powers ◽  
Hari S. Gaur ◽  
Michael Birkett ◽  
Rosane H.C. Curtis

Plant chemicals in the rhizosphere originating from root exudates or sites of previous nematode penetration can influence nematode behaviour, and a number of plant compounds, some present in root exudates, have been shown either to attract nematodes to the roots, or to result in repellence, motility inhibition, or even death. The present work was conducted to isolate small lipophilic molecules (SLMs) emitted by root exudates of Solanum lycopersicum and Oryza sativa to investigate their effect on root-knot nematodes. SLMs extracted, through solid phase extraction, from hydroponically collected root exudates of 40 tomato and rice plants had an inhibitory impact on the motility of second-stage juveniles of Meloidogyne incognita and M. graminicola and showed a nematotoxic or nematostatic (upon dilution) effect on both species. The semiochemicals present in the SLMs induced a very small, albeit statistically significant, effect on stylet thrusting. A small quantity of salivary secretion around the stylet tip and a significant decrease in nematode head movement were observed. The semiochemicals negatively influenced behaviour of M. incognita and M. graminicola by strongly affecting their mobility. Therefore, it is proposed that SLMs present in both tomato and rice root exudates play important roles during the interaction of Meloidogyne spp. with their host plant, and that they might exert a repellent, or allellopathic, effect on these nematodes.

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.


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


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

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.


1994 ◽  
Vol 35 (3) ◽  
pp. 768-771 ◽  
Author(s):  
M.L. Bouillant ◽  
C. Jacoud ◽  
I. Zanella ◽  
J. Favre-Bonvin ◽  
R. Bally
Keyword(s):  

Nematology ◽  
2000 ◽  
Vol 2 (2) ◽  
pp. 191-199 ◽  
Author(s):  
Hari Gaur ◽  
Jack Beane ◽  
Roland Perry

Abstract The root-knot nematode, Meloidogyne triticoryzae, produces three kinds of unhatched second stage juveniles (J2): i) those that hatch freely in water, ii) those that require stimulus from rice root diffusate (RRD), and iii) those that do not hatch even in the presence of RRD. The proportion of these three types varies with generation, with the final generation produced on senescing plants having a large proportion of unhatched J2 of the third type, which is likely to equate with diapause. Dilution of RRD reduced its hatching activity and there is no evidence of the presence of inhibitors in the diffusate. The hatching response of M. triticoryzae may be modified additionally by the growing conditions: submergence of infected plants may have delayed hatch, possibly by causing anoxybiosis in unhatched J2, and thereby delayed the appearance of the second and third generations of the nematodes. Le nématode Meloidogyne triticoryzae produit trois types de juvéniles de 2ème stade (J2) non encore éclos: i) ceux qui éclosent d’eux-même dans l’eau; ii) ceux qui requièrent le stimulus produit par le diffusat radiculaire de riz (RRD); enfin iii) ceux qui n’éclosent pas même en présence de RRD. La proportion de ces trois types varie avec la génération du nématode, la dernière génération, produite sur un hôte sénescent, contenant une grande proportion de J2 non éclos de type 3, ce fait représentant l’équivalent d’une diapause. La dilution du RRD diminue l’éclosion et aucune évidence d’inhibiteurs n’a été relevée dans le diffusat. Chez M. triticoryzae l’éclosion peut de plus être modifiée par les conditions de croissance de l’hôte; ainsi la submersion des plants infestés peut retarder l’éclosion, l’anoxybiose ainsi induite affectant vraisemblablement les J2 non éclos et retardant de ce fait l’apparition des deuxième et troisième générations du nématode.


Sign in / Sign up

Export Citation Format

Share Document