scholarly journals Testing Methods Affecting the Antagonistic Ability of  Pseudomonas Biocontrol Strains

2002 ◽  
Vol 51 (1-2) ◽  
pp. 107-114 ◽  
Author(s):  
I. Jevcsák ◽  
Bálint Oldal ◽  
L. Ködöböcz ◽  
Keyword(s):  
Rhizoctonia Solani ◽  
Fusarium Solani ◽  
Fungal Pathogens ◽  
Culture Media ◽  
Colony Growth ◽  
Antagonistic Effect ◽  
Bacterial Strains ◽  
Testing Methods ◽  
Selection Of

The antagonistic effect of thirteen Pseudomonas aeruginosa and thirteen strains of other Pseudomonas species was studied on the soil-borne phytopathogenic Rhizoctonia solani and Fusarium solani fungi.  The inhibition of pathogen colony growth was tested with two different in vitro techniques using the same type of culture media. In case of the spread slant technique the antagonists induced a significantly stronger inhibition on the growth of pathogens than in case of spot transfer. Among the 26 investigated Pseudomonas strains, P. aeruginosa strains were generally more effective against the fungal pathogens. Rhizoctonia solani proved to be affected to a greater extent by the bacterial strains studied than the Fusarium solani representative. The possibility of in vitro strain selection of biocontrol microbes is being further discussed .

Relationship between in vitro growth inhibition of pathogens and suppression of preemergence damping-off and postemergence root rot of white bean seedlings in the greenhouse by bacteria

1994 ◽  
Vol 40 (2) ◽  
pp. 113-119 ◽  
Author(s):  
M. S. Reddy ◽  
R. K. Hynes ◽  
G. Lazarovits
Keyword(s):  
Rhizoctonia Solani ◽  
Disease Severity ◽  
Fusarium Solani ◽  
Root Rot ◽  
Culture Media ◽  
Pythium Ultimum ◽  
Damping Off ◽  
Bacterial Strains ◽  
White Bean

One hundred and twenty diverse bacterial strains were screened under greenhouse conditions for their ability to protect white bean seedlings from preemergence damping-off caused by Pythium ultimum and Rhizoctonia solani and postemergence root rot by Fusarium solani f.sp. phaseoli. Preemergence mortality or root rot increased with an increase in the inoculum concentration of fungal isolates. For further testing, 200 propagules/g soil of P. ultimum, 3 propagules/g soil of R. solani, and log 3 conidia/g vermiculite of F. solani f.sp. phaseoli were used, as these rates provided an optimal level (approximately 50%) of disease severity. Bacterial strains suspended in sterile distilled water were added to pathogen-amended soil or vermiculite at log 7 colony-forming units/g soil or vermiculite prior to seeding. Final healthy stand and root rot were recorded 4 weeks after planting. Nine bacterial strains on P. ultimum, five on R. solani, and nine on F. solani f.sp. phaseoli provided significant (P = 0.05) suppression of disease severity compared with the nonbacterized control. Bacterial strains were also tested in vitro against the mycelial growth of the fungi on solid and liquid media. There was no relationship between the ability of bacterial strains to inhibit fungal vegetative growth on solid culture media and their ability to suppress pathogen activity in the greenhouse, but, for a few strains, the reduction in disease was linked to reduced growth of the pathogens in liquid media.Key words: White bean, damping-off, root rot, Pythium ultimum, Rhizoctonia solani, Fusarium solani f.sp. phaseoli.

scholarly journals Trichoderma species as Biocontrol Agent against Soil Borne Fungal Pathogens

2017 ◽  
Vol 5 (1) ◽  
pp. 39-45 ◽  
Author(s):  
Srijana Bastakoti ◽  
Shiva Belbase ◽  
Shrinkhala Manandhar ◽  
Charu Arjyal
Keyword(s):  
Rhizoctonia Solani ◽  
Fusarium Solani ◽  
Fungal Pathogens ◽  
Plant Pathogens ◽  
Biocontrol Agent ◽  
Sclerotium Rolfsii ◽  
Dual Culture ◽  
Trichoderma Species ◽  
Biocontrol Efficacy

Soil borne pathogenic fungi are of major concern in agriculture which significantly decreases the plant yield. Chemically controlled plant imposes environmental threats potentially dangerous to humans as well as other animals. Thus, application of biological methods in plant disease control is more effective alternative technique. This study was carried out to isolate Trichoderma species from soil sample and to assess its in vitro biocontrol efficacy against fungal pathogens viz. Sclerotium rolfsii, Sclerotionia sclerotiorum, Fusarium solani and Rhizoctonia solani. Biocontrol efficacy testing of isolates against different fungal pathogens was performed by dual culture technique.In this study, 5 different Trichoderma species were isolated from 26 various soil samples and were tested against four fungal soil-borne pathogens. Inhibition percentage of radial growth of Sclerotium rolfsii by three of the Trichoderma isolates was found to be 100%; about 62% and 68% of maximum inhibition was observed against Rhizoctonia solani and Fusarium solani respectively whereas Sclerotionia sclerotiorum was inhibited maximum up to 23%. This in vitro study revealed that although Trichoderma species plays an important role in controlling all type of soil borne fungal plant pathogens, however, isolates as biocontrol agent against Sclerotium rolfsii was found to be more efficient in comparison to other pathogens.Nepal Journal of Biotechnology. Dec. 2017 Vol. 5, No. 1: 39-49

In vitro evaluation of the effect of nicotine, cotinine, and caffeine on oral microorganisms

2008 ◽  
Vol 54 (6) ◽  
pp. 501-508 ◽  
Author(s):  
Karina Cogo ◽  
Michelle Franz Montan ◽  
Cristiane de Cássia Bergamaschi ◽  
Eduardo D. Andrade ◽  
Pedro Luiz Rosalen ◽  
...  
Keyword(s):  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
High Performance ◽  
Culture Media ◽  
Bacterial Species ◽  
In Vitro Study ◽  
Bacterial Strains ◽  
Planktonic Cells ◽  
Susceptibility Tests

The aim of this in vitro study was to evaluate the effects of nicotine, cotinine, and caffeine on the viability of some oral bacterial species. It also evaluated the ability of these bacteria to metabolize those substances. Single-species biofilms of Streptococcus gordonii , Porphyromonas gingivalis , or Fusobacterium nucleatum and dual-species biofilms of S. gordonii – F. nucleatum and F. nucleatum – P. gingivalis were grown on hydroxyapatite discs. Seven species were studied as planktonic cells, including Streptococcus oralis , Streptococcus mitis , Propionibacterium acnes , Actinomyces naeslundii , and the species mentioned above. The viability of planktonic cells and biofilms was analyzed by susceptibility tests and time-kill assays, respectively, against different concentrations of nicotine, cotinine, and caffeine. High-performance liquid chromatography was performed to quantify nicotine, cotinine, and caffeine concentrations in the culture media after the assays. Susceptibility tests and viability assays showed that nicotine, cotinine, and caffeine cannot reduce or stimulate bacterial growth. High-performance liquid chromatography results showed that nicotine, cotinine, and caffeine concentrations were not altered after bacteria exposure. These findings indicate that nicotine, cotinine, and caffeine, in the concentrations used, cannot affect significantly the growth of these oral bacterial strains. Moreover, these species do not seem to metabolize these substances.

scholarly journals Anti-fungal activities of constituents from Uvaria scheffleri and Artabotrys brachypetalus

2006 ◽  
Vol 51 (1) ◽  
pp. 79-86 ◽  
Author(s):  
A.C. Odebode ◽  
S.A. Jonker ◽  
C.C. Joseph ◽  
S.W. Wachira
Keyword(s):  
Fusarium Solani ◽  
Radial Growth ◽  
Fungal Pathogens ◽  
Dry Weight ◽  
Stem Bark ◽  
Inhibitory Effect ◽  
In Vitro Bioassay ◽  
Botryodiplodia Theobromae ◽  
Anti Fungal

The anti-fungal activity of schefflone, a mixture of dimmer, 3,5 dimethoxy carvacrol and annonaceous acetogenin, extracted from stem-bark and root of Uvaria scheffleri and Artabotrys bruchypetalus against Fusarium solani, Botryodiplodia theobromae, Asperillus niger and Aspergillus flavus was determined. An in-vitro bioassay showed that the minimum inhibitory effect of the compounds to the fungal pathogens occurred at 200 ppm in both radial growth and mycelia dry weight measurements. Acetogenin from A brachypetalus had a very strong anti-fungal effect on all the test fungi. The effects of the compounds were more pronounced on F solani than on the other. The bioassay methods also play a significant role in the sensitivity of the samples on the pathogens. .

scholarly journals Rhizosphere-enriched microbes as a pool to design synthetic communities for reproducible beneficial outputs

2018 ◽  
Author(s):  
Maria-Dimitra Tsolakidou ◽  
Ioannis A. Stringlis ◽  
Natalia Fanega-Sleziak ◽  
Stella Papageorgiou ◽  
Antria Tsalakou ◽  
...  
Keyword(s):  
Antifungal Activity ◽  
Fungal Pathogens ◽  
Growth Parameters ◽  
Tomato Plants ◽  
Beneficial Effects ◽  
Negative Effect ◽  
Tomato Growth ◽  
Selection Of

AbstractComposts represent a sustainable way to suppress diseases and improve plant growth. Identification of compost-derived microbial communities enriched in the rhizosphere of plants and characterization of their traits, could facilitate the design of microbial synthetic communities (SynComs) that upon soil inoculation could yield consistent beneficial effects towards plants. Here, we characterized a collection of compost-derived bacteria, previously isolated from tomato rhizosphere, forin vitroantifungal activity against soil-borne fungal pathogens and for their potential to change growth parameters inArabidopsis. We further assessed root-competitive traits in the dominant rhizospheric genusBacillus. Certain isolated rhizobacteria displayed antifungal activity against the tested pathogens and affected growth ofArabidopsis, and Bacilli members possessed several enzymatic activities. Subsequently, we designed two SynComs with different composition and tested their effect onArabidopsisand tomato growth and health. SynCom1, consisting of different bacterial genera, displayed negative effect onArabidopsis in vitro, but promoted tomato growth in pots. SynCom2, consisting of Bacilli, didn’t affectArabidopsisgrowth, enhanced tomato growth and suppressed Fusarium wilt symptoms. Overall, we found selection of compost-derived microbes with beneficial properties in the rhizosphere of tomato plants, and observed that application of SynComs on poor substrates can yield reproducible plant phenotypes.

In vitro antimicrobial and preliminary phytochemical screening of some Samburu Anti‐diarrhoeal medicinal plants ‐ Kenya

2012 ◽  
Vol 2 (5) ◽  
pp. 217-226
Author(s):  
E. O. Omwenga ◽  
P. O. Okemo ◽  
P. K. Mbugua
Keyword(s):  
Antimicrobial Activity ◽  
Medicinal Plants ◽  
Fungal Pathogens ◽  
Antimicrobial Effect ◽  
Significant Activity ◽  
Bacterial Strains ◽  
Fungal Strains ◽  
Local Isolate ◽  
Agar Disc

The antimicrobial effect of some selected Samburu medicinal plants was evaluated on bacterial strains like Staphylococcus aureus ‐ ATCC 20591, Bacillus subtillis ‐ Local isolate, Salmonella typhi‐ATCC 2202, Escherichia coli‐STD. 25922 and Pseudomonas aeroginosa ‐ ATCC 25852 and fungal strains like Candida albicans ATCC EK138, Aspergillus niger ATCC 16404, Aspergillusflavus‐Local isolate, Fusarium lateritium‐Local isolate, and Penicillium spp.‐ local isolate. Methanol was used as solvent for the extraction from the selected medicinal plants used by the Samburu community. The in vitro antimicrobial activity was performed by agar disc diffusion and micro‐dilution technique. The most susceptible Gram‐positive bacterium was S. aureus, while the most susceptible Gram‐negative bacterium was P. aeroginosa. The extracts of Gomphocarpus fruticosus (L) W.T. Aiton showed less activity against the bacterial strains investigated. The most active antibacterial plants were Euphorbia scarlatica S. Carter, and Euclea divinoram Hiern. Incidentally most of the extracts were inactive against the fungal strains with only a few proving to be slightly active against the C. albicans i.e. Loranthus acaciae Zucc., Kedrostis pseudogijef (Gilg) C. Jeffrey, Euclea divinoram Hiern. and Croton macrostachyus (A. Rich). Benths. The significant antimicrobial activity of active extracts was compared with the standard antimicrobials, cefrodoxima, amoxicillin and fluconazole. The MICs of the most active plants ranged from 18.75mg/ml to 37.50mg/ml. The MBCs ranged between 18.75mg/ml to75mg/ml. These results were significant at P< 0.01. The findings show that most of the medicinal plants used by the Samburu community have some significant activity on the bacterial but not fungal pathogens known to cause diarrhoea.

ISOLATION, IDENTIFICATION AND CHARACTERIZATION OF BACTERIAL ANTAGONISTS OF THE DRAGON FRUIT FUNGAL PATHOGEN Neoscytalidium dimidiatum

2021 ◽  
Vol 44 (02) ◽  
Author(s):  
NGUYEN NGOC AN ◽  
HUA HUYNH MINH THAO ◽  
HO NGUYEN HOANG YEN ◽  
NGUYEN THI DIEU HANH ◽  
NGUYEN LE HIEN HOA ◽  
...  
Keyword(s):  
Fungal Pathogens ◽  
Pathogenic Fungi ◽  
Fungal Spore ◽  
Stem Canker ◽  
Antagonistic Effect ◽  
Fruit Rot ◽  
Economic Losses ◽  
Neoscytalidium Dimidiatum ◽  
Dragon Fruit

Dragon fruit or pitahaya (Hylocereus spp.) are famous for their nutrient-rich favourable taste, which brings high economic value to subtropical and tropical countries. However, dragon fruit cultivation all over the world is threatened by fungal pathogens and among them, Neoscytalidium dimidiatum has recently been shown to be responsible for stem canker and fruit rot which cause big economic losses. In order to find an environmentally friendly way to control this pathogen, five out of sixty-nine bacterial isolates used in a screening test for antifungal activity were selected. All five strains appeared to be aerobic Gram positive spore forming bacteria suggesting that they all belong to the Bacillus genus. Cell-free culture supernatants of these strains were found to strongly inhibit both fungal spore germination and mycelia growth in vitro for at least 5 days. The strain D19 which possessed the highest antagonistic effect was further identified to be Bacillus amyloliquefaciens, a well-known species shown to have antifungal effect against several other pathogenic fungi. Thus, the results of this study opened a new promising perspective to prevent Neoscytalidium dimidiatum infection during cultivation of dragon fruit.

Control of damping-off caused by Rhizoctonia solani and Fusarium solani using olive mill waste water and some of its indigenous bacterial strains

2008 ◽  
Vol 27 (2) ◽  
pp. 189-197 ◽  
Author(s):  
Thabèt Yangui ◽  
Ali Rhouma ◽  
Mohamed Ali Triki ◽  
Kamel Gargouri ◽  
Jalel Bouzid
Keyword(s):  
Waste Water ◽  
Rhizoctonia Solani ◽  
Fusarium Solani ◽  
Damping Off ◽  
Bacterial Strains ◽  
Olive Mill Waste ◽  
Olive Mill Waste Water ◽  
Mill Waste ◽  
Olive Mill

scholarly journals Selection of Promising Lactobacilli Antagonistic to Campylobacter Jejuni

2019 ◽  
Vol 9 (1) ◽  
pp. 3983-3986
Keyword(s):  
Lactobacillus Plantarum ◽  
Campylobacter Jejuni ◽  
New Technologies ◽  
Lactobacillus Reuteri ◽  
Antagonistic Activity ◽  
Bacterial Strains ◽  
Opportunistic Bacteria ◽  
Wide Range ◽  
Selection Of

This article reflects the results of a study on the selection of promising lactobacilli antagonistic to Campilobacter jejuni, a strain that is the most common and more pathogenic for humans, carried out as part of a project to scientifically substantiate the use of new technologies in poultry feeding using special probiotic strains that increase productivity and obtaining poultry products of improved quality with the properties of functional food products. During the study, strains of lactic acid bacteria were obtained. The cultivation of strains of Lactobacillus crispatus, Lactobacillus gasseri, Lactobacillus fermentum, Lactobacillus reuteri, Lactobacillus plantarum, Lactobacillus plantarum was carried out on liquid and agarized nutrient media MRS at 370С for 24 hours. In vitro antagonistic studies were performed using the two-way antagonistic method on a wide range of indicator crops. Since there is evidence of a specific mechanism for the manifestation of the antagonistic activity of lactobacilli to gram-negative and gram-positive bacteria, we used test strains of both groups of bacteria. The antagonistic activity of the studied cultures against pathogenic and opportunistic bacteria was determined by the zone of growth inhibition of indicator strains around the colonies of individual strains of lactobacilli and their consortium (in mm). Priority clinical isolates isolated from birds with intestinal infections were used as indicator cultures: Proteus vulgaris, Escherichia coli, Salmonella typhimurium, Staphylococcus aureus, Campylobacter jejuni and Campylobacter jejuni ATCC strains 33560. During the study, most bacterial strains of the genus Lactobacillus were highly antagonistic its activity against indicator strains. The most sensitive to the inhibitory effect of lactobacilli were E. coli, Campylobacter jejuni, S. typhimurium and P. vulgaris. The research results showed that the strain L.plantarum ATCC 8014 exhibits a more pronounced antagonistic activity than other strains of lactobacilli.

scholarly journals Antagonismo de Trichoderma harzianum contra la fusariosis del garbanzo y su efecto biofertilizante

2020 ◽  
Vol 11 (5) ◽  
pp. 1135-1147
Author(s):  
Talina Olivia Martínez-Martínez ◽  
Brenda Zulema Guerrero-Aguilar ◽  
Víctor Pecina-Quintero ◽  
Enrique González-Pérez ◽  
Juan Gabriel Angeles-Núñez
Keyword(s):  
Rhizoctonia Solani ◽  
Fusarium Oxysporum ◽  
Trichoderma Harzianum ◽  
Fusarium Solani ◽  
Baja California ◽  
Sclerotium Rolfsii ◽  
Macrophomina Phaseolina

El garbanzo es una leguminosa, que se cultiva en dos regiones de México principalmente, noroeste (Sonora, Sinaloa y Baja california) y la región de El Bajío (Guanajuato, Michoacán y Jalisco); sin embargo, cada año la producción del cultivo está comprometida con la fusariosis vascular, una de las principales enfermedades que afectan al cultivo y que está asociada al complejo fúngico Fusarium oxysporum, Fusarium solani, Rhizoctonia solani, Macrophomina phaseolina y Sclerotium rolfsii. Una alternativa de control biológico es la aplicación de Trichoderma, la que además tiene un efecto indirecto en la nutrición de la planta. El objetivo de este estudio fue determinar el antagonismo in vitro de dos cepas de Trichoderma harzianum (T1 y T2) y su efecto como biofertilizante. Se realizaron confrontaciones in vitro contra cepas de las razas de Fusariumoxysporum f. sp. ciceris (Foc 0, 1B/C, 5 y 6), Fusarium solani, Macrophomina phaseolina (MSonora y M-GTO) y Sclerotium rolfsii. Se evaluó el efecto de T2 como biofertilizante (TB) midiendo las variables: número de flores, vainas, altura de la planta, diámetro del tallo, longitud de la raíz y rendimiento de grano. Las dos cepas de T. harzianum mostraron antagonismo en diferente escala contra los patógenos. Adicionalmente, con el tratamiento donde se aplicó T. harzianum (TB) se presentaron incrementos en el número de flores (30%), vainas (24%), altura (3%), diámetro de las plantas (3.5%), así como la longitud de la raíz (13%) y rendimiento del grano (23%).

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