scholarly journals Evaluating the biocontrol potential of Canadian strain Bacillus velezensis 1B-23 via its surfactin production at various pHs and temperatures

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Michelle S. M. Li ◽  
David A. Piccoli ◽  
Tim McDowell ◽  
Jacqueline MacDonald ◽  
Justin Renaud ◽  
...  
Keyword(s):  
Fungal Pathogens ◽  
Plant Pathogens ◽  
Control Plant ◽  
Bacterial Disease ◽  
Bacterial Strains ◽  
Bacillus Velezensis ◽  
Fungal Strains ◽  
Biocontrol Potential ◽  
Surfactin Production

Abstract Background Microorganisms, including Bacillus species are used to help control plant pathogens, thereby reducing reliance on synthetic pesticides in agriculture. Bacillus velezensis strain 1B-23 has been shown to reduce symptoms of bacterial disease caused by Clavibacter michiganensis subsp. michiganensis in greenhouse-grown tomatoes, with in vitro studies implicating the lipopeptide surfactin as a key antimicrobial. While surfactin is known to be effective against many bacterial pathogens, it is inhibitory to a smaller proportion of fungi which nonetheless cause the majority of crop diseases. In addition, knowledge of optimal conditions for surfactin production in B. velezensis is lacking. Results Here, B. velezensis 1B-23 was shown to inhibit in vitro growth of 10 fungal strains including Candida albicans, Cochliobolus carbonum, Cryptococcus neoformans, Cylindrocarpon destructans Fusarium oxysporum, Fusarium solani, Monilinia fructicola, and Rhizoctonia solani, as well as two strains of C. michiganensis michiganensis. Three of the fungal strains (C. carbonum, C. neoformans, and M. fructicola) and the bacterial strains were also inhibited by purified surfactin (surfactin C, or [Leu7] surfactin C15) from B. velezensis 1B-23. Optimal surfactin production occurred in vitro at a relatively low temperature (16 °C) and a slightly acidic pH of 6.0. In addition to surfactin, B. velenzensis also produced macrolactins, cyclic dipeptides and minor amounts of iturins which could be responsible for the bioactivity against fungal strains which were not inhibited by purified surfactin C. Conclusions Our study indicates that B. velezensis 1B-23 has potential as a biocontrol agent against both bacterial and fungal pathogens, and may be particularly useful in slightly acidic soils of cooler climates.

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.

Morphological and molecular based identification of Antifungal bacillus licheniformis

2017 ◽  
Vol 17 (1) ◽  
pp. 31-35
Author(s):  
B Oyuntogtokh ◽  
M Byambasuren
Keyword(s):  
Bacillus Licheniformis ◽  
Fungal Pathogens ◽  
Crop Production ◽  
Plant Pathogens ◽  
Control Plant ◽  
Plant Diseases ◽  
Bacillus Species ◽  
Bacterial Strains ◽  
Fusarium Spp ◽  
Bacterial Cultures

At present, plant diseases caused by soil borne plant pathogens have major constraints on crop production. Which include genera Fusarium spp, Phytophtora spp, Sclerotinia and Altenaria. Due to this reason, chemical fungicides are routinely used to control plant disease, which is also true in Mongolian case. However, use of these chemicals has caused various problems including environmental pollution with consequence of toxicity to human health also resistance of some pathogens to these fungicides are present. Fortunately, an alternative method to reduce the effect of these plant pathogens is the use of antagonist microorganisms. Therefore, some species of the genus Bacillus are recognized as one of the most effective biological control agent.Our research was focused to isolate Bacillus licheniformis, with antifungal potential, from indigenous sources. In the current study, 28 bacterial cultures were isolated from soil and fermented mare’s milk also named as koumiss. Isolated bacterial cultures were identified according to simplified key for the tentative identification of typical strain of Bacillus species. As a result 8 strains were positive and further screened for antifungal activity against Fusarium spp and Alternaria solani. Out of these 8 strains 5 strains are selected based on their high effectiveness against fungal pathogens and for further confirmation Polymerase Chain reaction run for effective bacterial strains using specific primers B.Lich-f and B.Lich-r. 

scholarly journals The Use of Essential Oils from Thyme, Sage and Peppermint against Colletotrichum acutatum

Plants ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 114
Author(s):  
Armina Morkeliūnė ◽  
Neringa Rasiukevičiūtė ◽  
Lina Šernaitė ◽  
Alma Valiuškaitė
Keyword(s):  
Essential Oils ◽  
Fungal Pathogens ◽  
Control Plant ◽  
Antimicrobial Activities ◽  
Plant Diseases ◽  
Colletotrichum Acutatum ◽  
Low Toxicity ◽  
Colletotrichum Spp ◽  
Biological Protection

The Colletotrichum spp. is a significant strawberry pathogen causing yield losses of up to 50%. The most common method to control plant diseases is through the use of chemical fungicides. The findings of plants antimicrobial activities, low toxicity, and biodegradability of essential oils (EO), make them suitable for biological protection against fungal pathogens. The aim is to evaluate the inhibition of Colletotrichum acutatum by thyme, sage, and peppermint EO in vitro on detached strawberry leaves and determine EO chemical composition. Our results revealed that the dominant compound of thyme was thymol 41.35%, peppermint: menthone 44.56%, sage: α,β-thujone 34.45%, and camphor: 20.46%. Thyme EO inhibited C. acutatum completely above 200 μL L−1 concentration in vitro. Peppermint and sage EO reduced mycelial growth of C. acutatum. In addition, in vitro, results are promising for biological control. The detached strawberry leaves experiments showed that disease reduction 4 days after inoculation was 15.8% at 1000 μL L−1 of peppermint EO and 5.3% at 800 μL L−1 of thyme compared with control. Our findings could potentially help to manage C. acutatum; however, the detached strawberry leaves assay showed that EO efficacy was relatively low on tested concentrations and should be increased.

scholarly journals The Potential of Rhizoctonia-Like Fungi for the Biological Protection of Cereals against Fungal Pathogens

Plants ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 349
Author(s):  
Dominik Bleša ◽  
Pavel Matušinský ◽  
Romana Sedmíková ◽  
Milan Baláž
Keyword(s):  
Biological Control ◽  
Fungal Pathogens ◽  
Plant Pathogens ◽  
Higher Plants ◽  
Fusarium Culmorum ◽  
Suppressive Effect ◽  
Plant Production ◽  
Shoot Biomass ◽  
Organic Substrates

The use of biological control is becoming a common practice in plant production. One overlooked group of organisms potentially suitable for biological control are Rhizoctonia-like (Rh-like) fungi. Some of them are capable of forming endophytic associations with a large group of higher plants as well as mycorrhizal symbioses. Various benefits of endophytic associations were proved, including amelioration of devastating effects of pathogens such as Fusarium culmorum. The advantage of Rh-like endophytes over strictly biotrophic mycorrhizal organisms is the possibility of their cultivation on organic substrates, which makes their use more suitable for production. We focused on abilities of five Rh-like fungi isolated from orchid mycorrhizas, endophytic fungi Serendipita indica, Microdochium bolleyi and pathogenic Ceratobasidium cereale to inhibit the growth of pathogenic F. culmorum or Pyrenophora teres in vitro. We also analysed their suppressive effect on wheat infection by F. culmorum in a growth chamber, as well as an effect on barley under field conditions. Some of the Rh-like fungi affected the growth of plant pathogens in vitro, then the interaction with plants was tested. Beneficial effect was especially noted in the pot experiments, where wheat plants were negatively influenced by F. culmorum. Inoculation with S. indica caused higher dry shoot biomass in comparison to plants treated with fungicide. Prospective for future work are the effects of these endophytes on plant signalling pathways, factors affecting the level of colonization and surviving of infectious particles.

scholarly journals PRODUCTION AND FUNGICIDAL ACTIVITY ASSESMENT OF WOOD-WASTE LIQUID SMOKE

2020 ◽  
Vol 8 (10) ◽  
pp. 285-291
Author(s):  
Budy Rahmat ◽  
Dedi Natawijaya ◽  
Endang Surahman
Keyword(s):  
Plant Pathogens ◽  
Pathogenic Fungus ◽  
Block Design ◽  
Control Plant ◽  
Wood Waste ◽  
In Vitro Test ◽  
In Vivo Test ◽  
Liquid Smoke

Liquid smoke is known to contain compounds that can control plant disease pathogens. This study aims to produce wood-waste liquid smoke and determine its effectiveness as a fungicide on plant pathogens. This research was conducted in two experimental stages, namely: (i) in vitro test as a preliminary test of the effectiveness of teak waste liquid smoke at concentrations of 0, 0.5, 1, 1.5, 2, and 2.5%; and (ii) in vivo test was arranged in randomized block design consisting of seven levels of liquid smoke concentration, namely 0, 1, 2, 3, 4, 5, and 6%, each of which was repeated four times. The results showed that the pyrolysis of 1 kg of wood waste was produced with the proportions of liquid smoke, charcoal and tar, respectively: 312 mL, 31 g, 367 g and the uncondensed gases. Treatment of liquid smoke in the in vivo test showed that a concentration of 1 to 2.5% liquid smoke was able to suppress the growth of the pathogenic fungus Sclerotium rolfsii 100%. The treatment of liquid smoke in the in vivo test showed an effect on inhibition of the growth diameter of fungal colonies, suppressing the disease occurance, and suppressing the lesion diameter.

scholarly journals The Potential Antibacterial and Antifungal Activities of Wood Treated with Withania somnifera Fruit Extract, and the Phenolic, Caffeine, and Flavonoid Composition of the Extract According to HPLC

Processes ◽  
2020 ◽  
Vol 8 (1) ◽  
pp. 113 ◽  
Author(s):  
Mervat EL-Hefny ◽  
Mohamed Z. M. Salem ◽  
Said I. Behiry ◽  
Hayssam M. Ali
Keyword(s):  
Withania Somnifera ◽  
Plant Pathogens ◽  
Fusarium Culmorum ◽  
Acetone Extract ◽  
Melia Azedarach ◽  
Bacterial Strains ◽  
Fruit Extract ◽  
Pseudomonas Cichorii ◽  
Antibacterial And Antifungal Activities

In the present study, Melia azedarach wood blocks treated with different acetone extract concentrations from Withania somnifera fruits are assessed for their antibacterial and anti-fungal activities. Wood blocks of M. azedarach treated with W. somnifera fruit extract at concentrations of 0, 1, 2, and 3% are evaluated for in vitro antimicrobial activity against five genbank accessioned bacterial strains—Agrobacterium tumefaciens, Dickeya solani, Erwinia amylovora, Pseudomonas cichorii, and Serratia pylumthica—and two fungi, namely, Fusarium culmorum and Rhizoctonia solani. Through HPLC analysis we find that the most abundant quantified phenolic and flavonoid compounds of acetone extract (mg/100 g) are salicylic acid (9.49), vanillic acid (4.78), rutin (4702.58), and myricetin (1386.62). Wood treated with the extract at 2% and 3% show no growth of A. tumefaciens, E. amylovora, and P. cichorii. Use of the extract at 3% causes inhibition of fungal mycelia of F. culmorum and R. solani by 84.07% and 67.03%, respectively. In conclusion, potent antifungal and antibacterial activity against plant pathogens is found when an acetone extract of W. somnifera fruits is applied to wood samples.

scholarly journals Constituents and antimicrobial activity of the essential oils of six Himalayan Nepeta species

2010 ◽  
Vol 75 (6) ◽  
pp. 739-747 ◽  
Author(s):  
Dinesh Bisht ◽  
Rajendra Padalia ◽  
Lalit Singh ◽  
Veena Pande ◽  
Priyanka Lal ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Essential Oil ◽  
Essential Oils ◽  
Antagonistic Activity ◽  
Significant Activity ◽  
Variable Degree ◽  
Bacterial Strains ◽  
Fungal Strains ◽  
Microbial Strains

The essential oils from six Himalayan Nepeta species, viz. Nepeta leucophylla Benth., Nepeta discolor Royle ex Benth., Nepeta govaniana Benth., Nepeta clarkei Hook f., Nepeta elliptica Royle ex Benth. and Nepeta erecta Benth., were tested for their in vitro antimicrobial activity against six pathogenic bacterial and two fungal strains. The results showed that Pseudomonas aeruginosa was the most sensitive strain tested to the essential oils of Nepeta species. The essential oils of N. elliptica and N. erecta exhibited the highest activity against P. aeruginosa, followed by the essential oils of N. leucophylla and N. clarkei. The essential oils from N. elliptica and N. erecta were also found to be very effective against Serratia marcescens; while the essential oil from N. leucophylla displayed significant activity against Proteus vulgaris and Staphylococcus aureus. Other bacterial strains displayed variable degree of susceptibility against one or more of the tested essential oils. The essential oil from N. leucophylla also showed the highest antifungal activity against both tested fungal strains, viz. Candida albicans and Trichophyton rubrum, followed by the essential oils from N. clarkei, N. govaniana and N. erecta. Iridodial derivatives, viz. iridodial ?-monoenol acetate (25.4 %), dihydroiridodial diacetate (18.2 %) and iridodial dienol diacetate (7.8 %) were identified as the major constituents of N. leucophylla, while the essential oils from N. elliptica and N. erecta were dominated by (7R)-trans, trans nepetalactone (83.4 %) and isoiridomyrmecin (66.7 %), respectively. The essential oil of N. discolor was characterized by 1,8-cineole (25.5 %) and ?-caryophyllene (18.6 %), while N. clarkei was dominated by ?-sesquiphellandrene (22.0 %) and germacrene D (13.0 %). Isoiridomyrmecin (35.2 %) and pregeijerene (20.7 %) were identified as the major constituents of N. govaniana. In general the Nepeta species containing constituents with an iridoid or lactone skeleton were found to have the greater antagonistic activity against most of the microbial strains as compared to those containing regular terpene constituents.

scholarly journals Comparison of Two Commercial Recirculated Aquacultural Systems and Their Microbial Potential in Plant Disease Suppression

2021 ◽  
Author(s):  
Sammar Khalil ◽  
Preeti Panda ◽  
Farideh Ghadamgahi ◽  
AnnaKarin Rosberg ◽  
Ramesh R Vetukuri
Keyword(s):  
Plant Growth ◽  
Fish Species ◽  
Plant Pathogens ◽  
Extracellular Enzymes ◽  
Production Systems ◽  
Sampling Site ◽  
Disease Suppression ◽  
Bacterial Strains ◽  
Promising Tool

Aquaponics are food production systems advocated for food security and health. Their sustainability from a nutritional and plant health perspective is, however, a significant challenge. Recirculated aquaculture systems (RAS) form a major part of aquaponic systems but knowledge about their potential to benefit plant growth and suppress their pathogens is limited. The current study tested if the diversity and function of microbial communities in two commercial RAS were specific to the fish species used (Tilapia or Clarias) and sampling site (fish tanks and wastewaters), and whether they confer benefits to plants and have in vitro antagonistic potential towards plant pathogens. Microbial diversity and composition was found to be dependent on fish species and sample site. The Tilapia RAS hosted higher bacterial diversity than the Clarias RAS; but the latter hosted higher fungal diversity. Both Tilapia and Clarias RAS hosted bacterial and fungal communities that promoted plant growth, inhibited plant pathogens and encouraged biodegradation. The production of extracellular enzymes, related to nutrient availability and pathogen control, by bacterial strains isolated from the Tilapia and Clarias systems, makes them a promising tool in aquaponics and in their system design.

scholarly journals A Novel Rhizospheric Bacterium, Bacillus Velezensis NKMV-3 as a Biocontrol Agent against Alternaria Leaf Blight in Tomato

2021 ◽  
Author(s):  
Vignesh Murthy ◽  
VedhaHari BodethalaNarayanan ◽  
MubarakAli Davoodbasha ◽  
MadhanShankar ShankarRamakrishanan
Keyword(s):  
Early Blight ◽  
Plant Pathogens ◽  
Alternaria Solani ◽  
Inhibitory Effect ◽  
Rrna Gene ◽  
Bacillus Velezensis ◽  
Bacterium Bacillus ◽  
Blight Disease ◽  
Molecular Sequencing

Abstract A novel strain of Bacillus isolated from rhizosphere has shown to be excellent biocontrol agents against various plant pathogens. In this study, a first report of a Bacillus strain NKMV-3 which effectively controlling Alternaria solani, which cause the Early Blight disease in tomato. Based on the cultural and molecular sequencing of 16S rRNA gene sequence, the identity of the strain was confirmed as Bacillus velezensis NKMV-3. The presence of the lipopeptide which are antibiotic synthesis genes namely Iturin C, Surfactin A, Fengycin B and D were confirmed through gene amplification. In addition, lipopetides was also confirmed through liquid chromatography. The extract showed inhibitory effect against A.solani in-vitro and detached tomato leaf assays. Bacillus velezensis strain NKMV-3 based formulations may provide an effective solution in controlling early blight disease in tomato and other crops.

scholarly journals Lactococcosis a Re-Emerging Disease in Aquaculture: Disease Significant and Phytotherapy

2021 ◽  
Vol 8 (9) ◽  
pp. 181
Author(s):  
Mehdi Soltani ◽  
Bernardo Baldisserotto ◽  
Seyed Pezhman Hosseini Shekarabi ◽  
Shafigh Shafiei ◽  
Masoumeh Bashiri
Keyword(s):  
Antibacterial Activity ◽  
Essential Oils ◽  
Medicinal Herbs ◽  
In Vitro Assays ◽  
Bacterial Disease ◽  
Bacterial Strains ◽  
Immune Parameters ◽  
Aquaculture Industry

Lactococcosis, particularly that caused by Lactococcus garvieae, is a major re-emerging bacterial disease seriously affecting the sustainability of aquaculture industry. Medicinal herbs and plants do not have very much in vitro antagonism and in vivo disease resistance towards lactococcosis agents in aquaculture. Most in vitro studies with herbal extractives were performed against L. garvieae with no strong antibacterial activity, but essential oils, especially those that contain thymol or carvacrol, are more effective. The differences exhibited by the bacteriostatic and bactericidal functions for a specific extractive in different studies could be due to different bacterial strains or parts of chemotypes of the same plant. Despite essential oils being shown to have the best anti-L. garvieae activity in in vitro assays, the in vivo bioassays required further study. The extracts tested under in vivo conditions presented moderate efficacy, causing a decrease in mortality in infected animals, probably because they improved immune parameters before challenging tests. This review addressed the efficacy of medicinal herbs to lactococcosis and discussed the presented gaps.

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