scholarly journals Effects of cell suspension and cell·free culture filtrate of Pseudomonas aeruginosa in the control of root rot-root kont disease complex of tomato (Lycopersicon esculentum Mill.)

2013 ◽  
Vol 53 (2) ◽  
pp. 47-55 ◽  
Author(s):  
I. A. Siddiqui
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Cell Suspension ◽  
Culture Filtrate ◽  
Macrophomina Phaseolina ◽  
Antagonistic Activity ◽  
Root Knot Nematode ◽  
Egg Hatching ◽  
Tomato Seedlings ◽  
Plant Growth Promoting

The plant growth-promoting rhizobacterium <i>Pseudomonas aeruginosa</i> strain IE-6 was tested for antagonistic activity towards <i>Meloidogyne javanica</i>, the root-knot nematode and soilbome root-infecting fungi viz., <i>Macrophomina phaseolina</i>, <i>Fusarium solani</i> and <i>Rhizoctonia solani</i> under laboratory and greenhouse conditions. Cell-free culture filtrate of the bacterium caused significant reduction in egg hatching of <i>M.javanica</i> and inhibited radial growth of fungi <i>in vitro</i>. Cell-free culture filtrate also caused lyses in mycelium of <i>F.solani</i>. Under greenhouse conditions, soil drenches with the aqueous cell suspension or cell-free culture resulted in a considerable reduction in nematode population densities in soil and subsequent root-knot development due to <i>M.javanica</i>. In addition to nematode control, rhizobacterium application also inhibited root-infection caused by soilborne root~infecting fungi with significant enhancement of growth of tomato seedlings.

scholarly journals Nematicidal Activity of the Essential Oil of Three Varieties of Tagetes minuta from Argentina

2017 ◽  
Vol 12 (5) ◽  
pp. 1934578X1701200
Author(s):  
Yamile Massuh ◽  
Angel Cruz-Estrada ◽  
Azucena González-Coloma ◽  
Marta S. Ojeda ◽  
Julio A. Zygadlo ◽  
...  
Keyword(s):  
Lethal Dose ◽  
Nematicidal Activity ◽  
Root Knot Nematode ◽  
Egg Hatching ◽  
Tomato Seedlings ◽  
Tagetes Minuta ◽  
In Vivo Tests ◽  
New Varieties

Essential oils composition of three Tagetes minuta varieties and a wild population (WP) from Argentina and their in vitro and in vivo nematicidal activity against root-knot nematode, Meloidogyne javanica, are described. All T. minuta EOs tested were very active against nematode juveniles (J2), but the strongest nematicidal effects were exhibited by the TmV3 variety oil, characterized by a high content of ( E)-ocimenone. High nematode egg hatching suppression (> 90%) was induced by TmV3 EO after five days of incubation. In vivo tests on tomato seedlings showed a significant reduction of infection rate of M. javanica J2 treated with TmV3 and WP oils at sub lethal dose. Therefore, EOs from chemically stable new varieties of T. minuta could be environmentally friendly nematicidal agents.

scholarly journals BIO-EFFICACY OF FUNGAL BIOAGENTS AND ITS CRUDE SECONDARY ME-TABOLITES AGAINST ROOT KNOT NEMATODE MELOIDOGYNE INCOGNITA [(KOFOID & WHITE,1919) CHITWOOD, 1949]INFESTING TOMATO (SOLANUMLYCOPERSICUM L.)

Redia ◽  
2021 ◽  
Vol 104 ◽  
pp. 37-43
Author(s):  
LAKSHMAN PRASAD ◽  
RASHID PERVEZ ◽  
SWATI GABA
Keyword(s):  
Plant Growth ◽  
In Vitro Study ◽  
Good Alternative ◽  
Root Knot Nematode ◽  
Egg Hatching ◽  
Antagonistic Microorganisms ◽  
Plant Growth Promoting Activities ◽  
Plant Growth Promoting ◽  
Growth Promoting

Tomato (Solanumlycopersicum L.) is one of the most important vegetable cropin the world. Various obstacles are existingwith this cropcultivation, among them root knot nematode,Meloidogyne incognitarecognized as a major path-ogen of tomato. The complete elimination of M. incognitafromthe soil is very difficult because of its polyphagous nature. Although,different methods are employed to manage this nematode, however, biological control has become a good alternative to the chemical nematicides. Antagonistic microorganisms are appropriate for controlling nematodes still require progressive investigation. Hence,present study on the biologicalactivity of the different concentrations of mixer of crude secondary metabolitesof the various fungal bioagents againston egg hatching, M. incognita(J2) mortal-ity in vitro as well asin planta were evaluated. Plant growth promoting activities were also recorded. Among the tested fungal bioagentsV. lecanii, F. chlamydosporum andA. niger were found promising in vitroas well asin planta studies while M. anisopliaeand A. nigerwas found promising to inhibit the egg hatchingunder in vitro study. It is concluded thatV. lecanii, F. chlamydosporum andA. nigerhave high antagonistic/nematicidalas well as good plant growth pro-motion activities. These promising fungal biocontrol agents can be considering for evaluation on a larger scale in field.

Effect of the endophytic plant growth promoting Enterobacter ludwigii EB4B on tomato growth

2020 ◽  
Vol 13 (2) ◽  
pp. 54-65 ◽  
Author(s):  
M.E.A. Bendaha ◽  
H.A. Belaouni
Keyword(s):  
Root Length ◽  
Biocontrol Agent ◽  
Growth Promotion ◽  
Dry Weight ◽  
Antagonistic Activity ◽  
Rrna Gene ◽  
Plant Growth Promoting ◽  
Enterobacter Ludwigii ◽  
Tomato Growth

SummaryThis study aims to develop a biocontrol agent against Fusarium oxysporum f.sp. radicis-lycopersici (FORL) in tomato. For this, a set of 23 bacterial endophytic isolates has been screened for their ability to inhibit in vitro the growth of FORL using the dual plate assay. Three isolates with the most sound antagonistic activity to FORL have been qualitatively screened for siderophore production, phosphates solubilization and indolic acetic acid (IAA) synthesis as growth promotion traits. Antagonistic values of the three candidates against FORL were respectively: 51.51 % (EB4B), 51.18 % (EB22K) and 41.40 % (EB2A). Based on 16S rRNA gene sequence analysis, the isolates EB4B and EB22K were closely related to Enterobacter ludwigii EN-119, while the strain EB2A has been assigned to Leclercia adecarboxylata NBRC 102595. The promotion of tomato growth has been assessed in vitro using the strains EB2A, EB4B and EB22K in presence of the phytopathogen FORL. The treatments with the selected isolates increased significantly the root length and dry weight. Best results were observed in isolate EB4B in terms of growth promotion in the absence of FORL, improving 326.60 % of the root length and 142.70 % of plant dry weight if compared with untreated controls. In the presence of FORL, the strain EB4B improved both root length (180.81 %) and plant dry weight (202.15 %). These results encourage further characterization of the observed beneficial effect of Enterobacter sp. EB4B for a possible use as biofertilizer and biocontrol agent against FORL.

Enhancement of the ability of the porcine colonic microflora to resist colonisation by Salmonella poona, in an in vitro intestinal simulation

2002 ◽  
Vol 2002 ◽  
pp. 80-80
Author(s):  
K. Hillman
Keyword(s):  
Quorum Sensing ◽  
Culture Filtrate ◽  
Pathogenic Bacteria ◽  
Intestinal Microflora ◽  
Antagonistic Activity ◽  
Simulation System ◽  
Current Experiment ◽  
Subsequent Work ◽  
Colonic Microflora

The ability of the porcine intestinal microflora to resist the establishment of pathogenic bacteria has been demonstrated previously (Hillman et al, 1994). Subsequent work has shown that certain intestinal lactobacilli react to the presence of a culture filtrate derived from a coliform pathogen by increasing their antagonistic activity towards that pathogen (Hillman and Robertson, unpublished), indicating the presence of a quorum-sensing or related mechanism. The current experiment was devised to determine whether a similar effect could be produced within the entire porcine colonic microflora, using an in vitro simulation system.

Characterization of an antifungal soil bacterium and its antagonistic activities againstFusariumspecies

2003 ◽  
Vol 49 (4) ◽  
pp. 253-262 ◽  
Author(s):  
Yiu-Kwok Chan ◽  
Wayne A McCormick ◽  
Keith A Seifert
Keyword(s):  
Bacillus Subtilis ◽  
Culture Filtrate ◽  
Fusarium Species ◽  
Hyphal Growth ◽  
Antagonistic Activity ◽  
Plant Diseases ◽  
Ear Rot ◽  
In Planta ◽  
Head Blight

Bacteria were isolated from a cultivated soil and screened for antagonistic activity against Fusarium graminearum, a predominant agent of ear rot and head blight in cereal crops. Based on its in vitro effectiveness, isolate D1/2 was selected for characterization and identified as a strain of Bacillus subtilis by phenotypic tests and comparative analysis of its 16S ribosomal RNA gene (rDNA) sequence. It inhibited the mycelial growth of a collection of common fungal phytopathogens, including eight Fusarium species, three other ascomycetes, and one basidiomycete. The cell-free culture filtrate of D1/2 at different dilutions was active against macroconidium germination and hyphal growth of F. graminearum, depending on the initial macroconidium density. It induced the formation of swollen hyphal cells in liquid cultures of this fungus grown from macroconidia. A bioassay also demonstrated that D1/2 offered in planta protection against the damping-off disease in alfalfa seedlings caused by F. graminearum, while the type strain of B. subtilis was ineffective. Hence, B. subtilis D1/2 or its culture filtrate has potential application in controlling plant diseases caused by Fusarium.Key words: antifungal activity, Bacillus subtilis, biological control, biopesticide, Fusarium species.

scholarly journals Investigating the in vitro and in vivo nematicidal performance of structurally related macrolides against the root-knot nematode, Meloidogyne incognita

2019 ◽  
Vol 12 (1) ◽  
pp. 24-37
Author(s):  
M.A. Radwan ◽  
A.S.A. Saad ◽  
H.A. Mesbah ◽  
H.S. Ibrahim ◽  
M.S. Khalil
Keyword(s):  
Meloidogyne Incognita ◽  
Root Length ◽  
Egg Mass ◽  
Root Knot Nematode ◽  
Egg Hatching ◽  
Shoot Height ◽  
Egg Masses ◽  
New Family

Summary Avermectins and spinosyns are structurally related natural products of microbial origin and belong to a new family of macrolides which are active against a vast array of invertebrate pests. In the present study, the effects of four members of macrolides; abamectin (ABM), emamectin benzoate (EMB), spinosad (SPI) and spinetoram (SPIT), on Meloidogyne incognita were investigated under in vitro and in vivo conditions. All compounds reduced egg hatching and led to high mortality of the nematode second-stage juveniles (J2). ABM showed the maximum rate of egg hatching inhibition and J2 mortality while SPIT recorded the minimum. All treatments reduced the number of galls, egg masses, eggs/egg mass in roots and J2 in the soil when compared to the control. Based on the 10 folds of the 24 h-LC50 values of J2 mortality in vitro, EMB and ABM exhibited higher percent reduction in galls (79.68 and 71.45%), egg masses (75.19 and 70.54%), eggs/egg mass (60.49 and 40.91%) and J2 in the soil (90.31 and 86.54%), respectively, compared to SPI and SPIT. Significant increase in tomato shoot height occurred in all biopesticides (10 folds) and SPIT (20 folds). SPI at 10 folds of the 24 h-LC50 values of J2 mortality in vitro, significantly increased root length while ABM at 50 folds and SPIT at 20 folds decreased root length by 5.15% and 5.88%, respectively, compared to the untreated inoculated plants. In all treatments, the dry shoot and root weights increased, compared to the untreated control. Our findings suggest that these macrolides have the ability to regulate nematode population densities and may be an alternative to classical nematicides.

scholarly journals Biological control of Ralstonia solanacearum (Smith), the causal pathogen of bacterial wilt disease by using Pantoea spp

2021 ◽  
Vol 31 (1) ◽  
Author(s):  
Kamal A. M. Abo-Elyousr ◽  
Sabry A. Hassan
Keyword(s):  
Biological Control ◽  
Cell Suspension ◽  
Disease Severity ◽  
Culture Filtrate ◽  
Bacterial Wilt ◽  
Ralstonia Solanacearum ◽  
Wilt Disease ◽  
Nucleotide Sequence Analysis ◽  
Tomato Root

Abstract Background Bacterial wilt of tomato (BWP) caused by Ralstonia solanacearum (Smith) is a very important disease. Biological control of this disease is a very important tool to protect the plant and environment from pollution of chemical control. Results Twenty isolates of genus, Pantoea were isolated from healthy tomato root. Out of 20 isolates, 2 strains, PHYTPO1 and PHYTPO2, showed highly antagonistic property to control the growth of R. solanacearum in vitro conditions. They were identified as P. agglomerans by using 16S rRNA nucleotide sequence analysis. The 2 isolates were selected to study their effect (as cell suspension or culture filtrate) on the bacterial wilt under greenhouse conditions. PHYTPO1 inhibited maximum growth reduction of R. solanacearum and formed 2.5 cm2 of inhibition zone, followed by 1.2 cm2 in PHYTOPO2 under in vitro conditions. Treating with both isolates of P. agglomerans was significantly reduced disease severity of tomato wilt disease. The disease severity was reduced to 74.1 when treated as cell suspension, while when treated as culture filtrate, it reduced the disease severity up to 69.4 than infected control. Conclusion The strains of Pantoea can be used as an ecofriendly method to control of the most economic pathogen of tomato under greenhouse conditions. Further study is needed to find an appropriate formulation and approving application of these bacteria under field conditions.

scholarly journals Bacillus velezensis as Antagonist towards Penicillium roqueforti s.l. in Silage: in vitro and in vivo Evaluation

2018 ◽  
Author(s):  
Eva Wambacq ◽  
Kris Audenaert ◽  
Monica Höfte ◽  
Sarah De Saeger ◽  
Geert Haesaert
Keyword(s):  
Cell Suspension ◽  
Antagonistic Activity ◽  
Antagonistic Effect ◽  
Corn Silage ◽  
Penicillium Roqueforti ◽  
Bacillus Velezensis ◽  
Toxigenic Fungi ◽  
The Impact

In Belgium, silages are often infected by Penicillium roqueforti sensu lato (s.l.). These toxigenic fungi are well adapted to silage conditions, and their prevention during feed-out is difficult. Bacillus velezensis strain NRRL B-23189 has been reported to inhibit P.&nbsp;roqueforti&nbsp;s.s. conidiospore germination in vitro by the production of lipopeptides. In the present study, the antagonistic effect of this B. velezensis strain towards P.&nbsp;roqueforti&nbsp;s.l. was evaluated in vitro and in vivo. In vitro, corn silage conditions were simulated, and the impact of B.&nbsp;velezensis culture supernatant or cell suspension on P.&nbsp;roqueforti&nbsp;s.l. growth, conidiospore germination and survival and roquefortine C production was evaluated. The antagonism was promising, but growth of B.&nbsp;velezensis in corn silage infusion was poor. An in vivo experiment with microsilos containing a mixture of perennial ryegrass and white clover artificially contaminated with P.&nbsp;roqueforti&nbsp;s.l. was carried out to determine if B.&nbsp;velezensis cell suspension could be used as an antagonistic silage inoculant. The B.&nbsp;velezensis cell suspension applied was unsuccessful in reducing P.&nbsp;roqueforti&nbsp;s.l. numbers at desiling after 56 days compared to no additive application. However, feed-out of the silage was not simulated, so it remains elusive whether or not B.&nbsp;velezensis exerts antagonistic activity during this phase.&nbsp;

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