scholarly journals Effects of the Endophytic Bacteria Bacillus cereus BCM2 on Tomato Root Exudates and Meloidogyne incognita Infection

Plant Disease ◽  
2019 ◽  
Vol 103 (7) ◽  
pp. 1551-1558 ◽  
Author(s):  
Xia Li ◽  
Hai-Jing Hu ◽  
Jing-Yu Li ◽  
Cong Wang ◽  
Shuang-Lin Chen ◽  
...  
Keyword(s):  
Bacillus Cereus ◽  
Root Exudates ◽  
Meloidogyne Incognita ◽  
Endophytic Bacteria ◽  
Root Exudate ◽  
Tomato Root ◽  
Second Stage ◽  
Tomato Roots ◽  
Meloidogyne Spp ◽  
Root Tissues

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.

Influence of the mutualistic endophyte Fusarium oxysporum 162 on Meloidogyne incognita attraction and invasion

Nematology ◽  
2007 ◽  
Vol 9 (6) ◽  
pp. 771-776 ◽  
Author(s):  
Richard Sikora ◽  
Abd El-Fattah Dababat
Keyword(s):  
Fusarium Oxysporum ◽  
Root Exudates ◽  
Meloidogyne Incognita ◽  
Repellent Activity ◽  
Choice Test ◽  
Root Knot Nematode ◽  
Tomato Root ◽  
Tomato Roots

AbstractThe non-pathogenic endophytic Fusarium oxysporum strain 162 (FO162) has been selected for its capacity to reduce root-knot nematode galling on tomato. The objectives of this study were to investigate the influence of this fungus on invasion of tomato roots by Meloidogyne incognita. The number of M. incognita that invaded roots of plants treated with FO162 was significantly lower (reductions of 36.0-55.9%) than in the non-treated controls in linked twin-pot chambers. The results demonstrated that colonisation of the roots by FO162 affects the number of M. incognita that penetrate the roots. The results of a choice test in the absence of a plant indicated that the tomato root exudates collected from plants colonised by FO162 are either less attractive or they exude substances that have repellent activity toward M. incognita juveniles.

scholarly journals Endophytic Bacillus cereus Effectively Controls Meloidogyne incognita on Tomato Plants Through Rapid Rhizosphere Occupation and Repellent Action

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 ◽  
...  
Keyword(s):  
Bacillus Cereus ◽  
Meloidogyne Incognita ◽  
Endophytic Bacteria ◽  
Laser Scanning ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Egg Mass ◽  
Root Knot Nematodes ◽  
Tomato Roots ◽  
Repellent Action

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.

scholarly journals Τhe Nematicidal Potential of Bioactive Streptomyces Strains Isolated from Greek Rhizosphere Soils Tested on Arabidopsis Plants of Varying Susceptibility to Meloidogyne spp.

Plants ◽  
2020 ◽  
Vol 9 (6) ◽  
pp. 699
Author(s):  
Christianna Meidani ◽  
Alexandros Savvidis ◽  
Evaggelia Lampropoulou ◽  
Aggeliki Sagia ◽  
Efstathios Katsifas ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Arabidopsis Thaliana ◽  
Meloidogyne Incognita ◽  
Meloidogyne Javanica ◽  
Wild Type ◽  
Biological Cycle ◽  
Second Stage ◽  
Cycle Arrest ◽  
Meloidogyne Spp ◽  
Culture Supernatants

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.

In vitro studies on the behaviour of second-stage juveniles of Heterodera schachtii (Nematoda: Heteroderidae) in response to host plant root exudates

Parasitology ◽  
1991 ◽  
Vol 103 (1) ◽  
pp. 149-155 ◽  
Author(s):  
F. Grundler ◽  
L. Schnibbe ◽  
U. Wyss
Keyword(s):  
Root Exudates ◽  
Root Exudate ◽  
Plant Root ◽  
Time Lapse ◽  
Heterodera Schachtii ◽  
Second Stage ◽  
Video Recordings ◽  
Aseptic Conditions ◽  
Agarose Layer

The behaviour of Heterodera schachtii second-stage juveniles in response to mustard (Sinapis alba) rooxudates was observed and analysed under aseptic conditions in a standardized bioassay. Aggregation of juveniles on an agarose layer occurred within less than 30 min in the area where root exudates had been applied and persisted for several hours. Analysis of time-lapse video recordings showed that the aggregation did not result from a directed orientation of the juvenile towards the root exudate. This was supported by an orientation assay using single juveniles. Aggregated juveniles showed pre-infection exploratory behaviour, including stylet thrusting and head-end bending, while staying at rest for several minutes.

Comparison of host recognition, invasion, development and reproduction of Meloidogyne graminicola and M. incognita on rice and tomato

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
Keyword(s):  
Meloidogyne Incognita ◽  
Host Recognition ◽  
Cortical Region ◽  
Root Knot Nematode ◽  
Root Tips ◽  
Root Knot Nematodes ◽  
Tomato Plants ◽  
Meloidogyne Graminicola ◽  
Second Stage ◽  
Tomato Roots

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.

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
Keyword(s):  
Root Exudates ◽  
Meloidogyne Incognita ◽  
Solid Phase ◽  
Dilution Effect ◽  
Salivary Secretion ◽  
Rice Root ◽  
Second Stage ◽  
Nematode Penetration ◽  
Plant Compounds ◽  
Motility Inhibition

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.

scholarly journals Effects of Tomato Root Exudates on Meloidogyne incognita

PLoS ONE ◽  
2016 ◽  
Vol 11 (4) ◽  
pp. e0154675 ◽  
Author(s):  
Guodong Yang ◽  
Baoli Zhou ◽  
Xinyu Zhang ◽  
Zijun Zhang ◽  
Yuanyuan Wu ◽  
...  
Keyword(s):  
Root Exudates ◽  
Meloidogyne Incognita ◽  
Tomato Root

Nematicidal and ovicidal activities of Dryobalanops aromatica and Mentha haplocalyx var. piperascens-derived materials and their formulations against Meloidogyne incognita second-stage juveniles and eggs

Nematology ◽  
2014 ◽  
Vol 16 (2) ◽  
pp. 193-200 ◽  
Author(s):  
Soon-Il Kim ◽  
Jae-Kook Lee ◽  
Young-Eun Na ◽  
Seong Tak Yoon ◽  
Young Ju Oh
Keyword(s):  
Population Density ◽  
Meloidogyne Incognita ◽  
Nematicidal Activity ◽  
Active Ingredients ◽  
Methanol Extracts ◽  
Emulsifiable Concentrate ◽  
Second Stage ◽  
Tomato Roots ◽  
Nematode Population Density ◽  
Main Components

Nematicidal and hatching inhibition activities (HIA) of the methanol extracts from Dryobalanops aromatica (DA) and Mentha haplocalyx var. piperascens (MH), their constituents, and emulsified concentrate and granule formulations containing the methanol extracts as active ingredients, were compared with those of commercial nematicides, cadusafos and fosthiazate, against Meloidogyne incognita second-stage juveniles (J2) and eggs using well plate, container and pot assays. In a well plate assay with J2, DA applied at 500, 250 and 125 ppm resulted in 100, 95 and 55% mortality, respectively, while MH showed 80% mortality even at the lower concentration of 63 ppm. MH gave stronger HIA than DA at 1000 and 500 ppm. In addition, α-pinene, camphor, borneol and p-menthole, which are the main components of DA and MH extracts, showed strong nematicidal properties and HIA. In particular, the nematicidal activity of p-menthole among them was the highest and its HIA was also stronger than that of cadusafos and fosthiazate. In a container test using emulsifiable concentrate (EC) and granule (G) formulations containing 50 and 30% DA and MH, respectively, EC of D. aromatica showed a stronger LC50 value (0.203 μl (g soil)−1) than G formulation (0.935 mg (g soil)−1). However, their effects were fewer than MH formulations. The lethality of EC and G formulations containing MH was comparable to that of fosthiazate soluble concentrate and granule formulations. In another test using pots containing soils naturally infected by M. incognita, these plant formulations significantly inhibited the nematode-population density judging from the number of galls that formed on tested tomato roots after 8 weeks. These results suggest that DA and MH methanol extracts, as well as their constituents, might be useful as management agents against M. incognita.

scholarly journals Temperature Effects on Resistance to Meloidogyne spp. in Excised Tomato Roots

HortScience ◽  
1996 ◽  
Vol 31 (1) ◽  
pp. 147-149 ◽  
Author(s):  
Aref A. Abdul-Baki ◽  
Sanaa A. Haroon ◽  
David J. Chitwood
Keyword(s):  
Meloidogyne Incognita ◽  
Temperature Effects ◽  
Nematode Species ◽  
Dominant Allele ◽  
Resistance Level ◽  
Root Explants ◽  
Tomato Roots ◽  
Soil Temperatures ◽  
Meloidogyne Spp

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.

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