فعالية المکافحة الحيوية للبکتيريا Bacillus subtilis ضد الفطريات Fusarium oxysporum f. sp. lycopersici, F.solani, Rizhoctonia solani  في المختبر والمشتل EFFECTIVENESS OF BIOLOGICAL CONTROL BY BACILLUS SUBTILIS AGAINST THE PLANT PATHOGENIC FUNGI FUSARIUM OXYSPORUM F. SP. LYCOPERSICI, F.SOLANI, RIZHOCTONIA SOLANI IN VITRO AND NURSERY

For farmers the use of agrochemicals is the preferred method to control pests and diseases. Considering the market demand for biological control products, the encapsulation could be a competent alternative to current commercial formulations for cellular viability and controlled release. The purpose of this study was to use ionic gelation with sodium alginate, starch and maltodextrin to immobilize Bacillus subtilis and to evaluate the biocontrol effect against Fusarium oxysporum f. sp. lycopersici in vitro. The matrix with a concentration of 2% sodium alginate, 1% starch, and 1% maltodextrin is a suitable method for cellular viability and biological control activity against Fusarium oxysporum f. sp. lycopersici, with a reduction of mycelial growth of 49.6% and a survival rate for Bacillus subtilis of 98.05% (p less than 0.0001).The use of immobilized bacteria as biological control agents are sustainable and effective bio-inputs that could be used at industrial scale and benefit the tomato crops against attack by Fusarium oxysporum f. sp. lycopersici.

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A pair of effectors encoded on a conditionally dispensable chromosome of Fusarium oxysporum suppress host-specific immunity

Communications Biology ◽

10.1038/s42003-021-02245-4 ◽

2021 ◽

Vol 4 (1) ◽

Author(s):

Yu Ayukawa ◽

Shuta Asai ◽

Pamela Gan ◽

Ayako Tsushima ◽

Yasunori Ichihashi ◽

...

Keyword(s):

Arabidopsis Thaliana ◽

Fusarium Oxysporum ◽

Host Specificity ◽

Pathogenic Fungi ◽

Plant Pathogenic Fungi ◽

Effector Genes ◽

Dispensable Chromosome ◽

Genes Encoding ◽

Insight Into

AbstractMany plant pathogenic fungi contain conditionally dispensable (CD) chromosomes that are associated with virulence, but not growth in vitro. Virulence-associated CD chromosomes carry genes encoding effectors and/or host-specific toxin biosynthesis enzymes that may contribute to determining host specificity. Fusarium oxysporum causes devastating diseases of more than 100 plant species. Among a large number of host-specific forms, F. oxysporum f. sp. conglutinans (Focn) can infect Brassicaceae plants including Arabidopsis (Arabidopsis thaliana) and cabbage. Here we show that Focn has multiple CD chromosomes. We identified specific CD chromosomes that are required for virulence on Arabidopsis, cabbage, or both, and describe a pair of effectors encoded on one of the CD chromosomes that is required for suppression of Arabidopsis-specific phytoalexin-based immunity. The effector pair is highly conserved in F. oxysporum isolates capable of infecting Arabidopsis, but not of other plants. This study provides insight into how host specificity of F. oxysporum may be determined by a pair of effector genes on a transmissible CD chromosome.

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A pair of effectors encoded on a conditionally dispensable chromosome of Fusarium oxysporum suppress host-specific immunity

10.1101/2020.10.06.329052 ◽

2020 ◽

Author(s):

Yu Ayukawa ◽

Shuta Asai ◽

Pamela Gan ◽

Ayako Tsushima ◽

Yasunori Ichihashi ◽

...

Keyword(s):

Fusarium Oxysporum ◽

Host Specificity ◽

Pathogenic Fungi ◽

Plant Pathogenic Fungi ◽

Effector Genes ◽

Dispensable Chromosome ◽

Genes Encoding ◽

Atypical Feature ◽

Insight Into

AbstractMany plant pathogenic fungi contain conditionally dispensable (CD) chromosomes that are associated with virulence, but not growth in vitro. Virulence-associated CD chromosomes carry genes encoding effectors and/or host-specific toxin biosynthesis enzymes that may contribute significantly to determining host specificity. Fusarium oxysporum causes devastating diseases of more than 100 plant species. Among a large number of host-specific forms, F. oxysporum f. sp. conglutinans (Focn) can infect Brassicaceae plants including Arabidopsis and cabbage. Here we show that Focn has multiple CD chromosomes involved in virulence but also in vegetative growth, which is an atypical feature of CD chromosomes. We identified specific CD chromosomes that are required for virulence on Arabidopsis, cabbage, or both, and describe a pair of effectors encoded on one of the CD chromosomes that is required for suppression of Arabidopsis-specific phytoalexin-based immunity. The effector pair is highly conserved in F. oxysporum isolates capable of infecting Arabidopsis, but not of other plants. This study provides insight into how host specificity of F. oxysporum may be determined by a pair of effector genes on a transmissible CD chromosome.

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Improved Production of Two Anti-Candida Lipopeptide Homologues Co- Produced by the Wild-Type Bacillus subtilis RLID 12.1 under Optimized Conditions

Current Pharmaceutical Biotechnology ◽

10.2174/1389201020666191205115008 ◽

2020 ◽

Vol 21 (5) ◽

pp. 438-450

Author(s):

Ramya Ramchandran ◽

Swetha Ramesh ◽

Anviksha A ◽

RamLal Thakur ◽

Arunaloke Chakrabarti ◽

...

Keyword(s):

Bacillus Subtilis ◽

Pathogenic Fungi ◽

Fold Increase ◽

Production Yield ◽

Yield Enhancement ◽

Bioactive Metabolites ◽

Candida Auris ◽

Media Formulation ◽

Static Conditions

Background:: Antifungal cyclic lipopeptides, bioactive metabolites produced by many species of the genus Bacillus, are promising alternatives to synthetic fungicides and antibiotics for the biocontrol of human pathogenic fungi. In a previous study, the co- production of five antifungal lipopeptides homologues (designated as AF1, AF2, AF3, AF4 and AF5) by the producer strain Bacillus subtilis RLID 12.1 using unoptimized medium was reported; though the two homologues AF3 and AF5 differed by 14 Da and in fatty acid chain length were found effective in antifungal action, the production/ yield rate of these two lipopeptides determined by High-Performance Liquid Chromatography was less in the unoptimized media. Methods:: In this study, the production/yield enhancement of the two compounds AF3 and AF5 was specifically targeted. Following the statistical optimization (Plackett-Burman and Box-Behnken designs) of media formulation, temperature and growth conditions, the production of AF3 and AF5 was improved by about 25.8- and 7.4-folds, respectively under static conditions. Results:: To boost the production of these two homologous lipopeptides in the optimized media, heat-inactivated Candida albicans cells were used as a supplement resulting in 34- and 14-fold increase of AF3 and AF5, respectively. Four clinical Candida auris isolates had AF3 and AF5 MICs (100 % inhibition) ranging between 4 and 16 μg/ml indicating the lipopeptide’s clinical potential. To determine the in vitro pharmacodynamic potential of AF3 and AF5, time-kill assays were conducted which showed that AF3 (at 4X and 8X concentrations) at 48h exhibited mean log reductions of 2.31 and 3.14 CFU/ml of C. albicans SC 5314, respectively whereas AF5 at 8X concentration showed a mean log reduction of 2.14 CFU/ml. Conclusion:: With the increasing threat of multidrug-resistant yeasts and fungi, these antifungal lipopeptides produced by optimized method promise to aid in the development of novel antifungal that targets disease-causing fungi with improved efficacy.

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Antibiotic and Biosurfactant Properties of Cyclic Lipopeptides Produced by Fluorescent Pseudomonas spp. from the Sugar Beet Rhizosphere

Applied and Environmental Microbiology ◽

10.1128/aem.68.7.3416-3423.2002 ◽

2002 ◽

Vol 68 (7) ◽

pp. 3416-3423 ◽

Cited By ~ 133

Author(s):

T. H. Nielsen ◽

D. Sørensen ◽

C. Tobiasen ◽

J. B. Andersen ◽

C. Christophersen ◽

...

Keyword(s):

Amino Acids ◽

Biological Control ◽

Cyclic Peptide ◽

Agricultural Soils ◽

Pathogenic Fungi ◽

Growth Media ◽

Single Strain ◽

Cyclic Lipopeptides ◽

Peptide Moiety

ABSTRACT Cyclic lipopeptides (CLPs) with antibiotic and biosurfactant properties are produced by a number of soil bacteria, including fluorescent Pseudomonas spp. To provide new and efficient strains for the biological control of root-pathogenic fungi in agricultural crops, we isolated approximately 600 fluorescent Pseudomonas spp. from two different agricultural soils by using three different growth media. CLP production was observed in a large proportion of the strains (approximately 60%) inhabiting the sandy soil, compared to a low proportion (approximately 6%) in the loamy soil. Chemical structure analysis revealed that all CLPs could be clustered into two major groups, each consisting of four subgroups. The two major groups varied primarily in the number of amino acids in the cyclic peptide moiety, while each of the subgroups could be differentiated by substitutions of specific amino acids in the peptide moiety. Production of specific CLPs could be affiliated with Pseudomonas fluorescens strain groups belonging to biotype I, V, or VI. In vitro analysis using both purified CLPs and whole-cell P. fluorescens preparations demonstrated that all CLPs exhibited strong biosurfactant properties and that some also had antibiotic properties towards root-pathogenic microfungi. The CLP-producing P. fluorescens strains provide a useful resource for selection of biological control agents, whether a single strain or a consortium of strains was used to maximize the synergistic effect of multiple antagonistic traits in the inoculum.

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Diffusible and volatile compounds produced by an antagonistic Bacillus subtilis strain cause structural deformations in pathogenic fungi in vitro

Microbiological Research ◽

10.1016/j.micres.2004.09.013 ◽

2005 ◽

Vol 160 (1) ◽

pp. 75-81 ◽

Cited By ~ 141

Author(s):

Bhaskar Chaurasia ◽

Anita Pandey ◽

Lok Man S. Palni ◽

Pankaj Trivedi ◽

Bhavesh Kumar ◽

...

Keyword(s):

Bacillus Subtilis ◽

Volatile Compounds ◽

Pathogenic Fungi ◽

Subtilis Strain ◽

Structural Deformations

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Hevein-Like Antimicrobial Peptides Wamps: Structure–Function Relationship in Antifungal Activity and Sensitization of Plant Pathogenic Fungi to Tebuconazole by WAMP-2-Derived Peptides

International Journal of Molecular Sciences ◽

10.3390/ijms21217912 ◽

2020 ◽

Vol 21 (21) ◽

pp. 7912 ◽

Cited By ~ 3

Author(s):

Tatyana Odintsova ◽

Larisa Shcherbakova ◽

Marina Slezina ◽

Tatyana Pasechnik ◽

Bakhyt Kartabaeva ◽

...

Keyword(s):

Antifungal Activity ◽

Antimicrobial Peptides ◽

Structure Function ◽

Spore Germination ◽

Pathogenic Fungi ◽

Plant Pathogenic Fungi ◽

Fungal Cell ◽

Structure Function Relationship ◽

Function Relationship

Hevein-like antimicrobial peptides (AMPs) comprise a family of plant AMPs with antifungal activity, which harbor a chitin-binding site involved in interactions with chitin of fungal cell walls. However, the mode of action of hevein-like AMPs remains poorly understood. This work reports the structure–function relationship in WAMPs—hevein-like AMPs found in wheat (Triticum kiharae Dorof. et Migush.) and later in other Poaceae species. The effect of WAMP homologues differing at position 34 and the antifungal activity of peptide fragments derived from the central, N- and C-terminal regions of one of the WAMPs, namely WAMP-2, on spore germination of different plant pathogenic fungi were studied. Additionally, the ability of WAMP-2-derived peptides to potentiate the fungicidal effect of tebuconazole, one of the triazole fungicides, towards five cereal-damaging fungi was explored in vitro by co-application of WAMP-2 fragments with Folicur® EC 250 (25% tebuconazole). The antifungal activity of WAMP homologues and WAMP-2-derived peptides varied depending on the fungus, suggesting multiple modes of action for WAMPs against diverse pathogens. Folicur® combined with the WAMP-2 fragments inhibited the spore germination at a much greater level than the fungicide alone, and the type of interactions was either synergistic or additive, depending on the target fungus and concentration combinations of the compounds. The combinations, which resulted in synergism and drastically enhanced the sensitivity to tebuconazole, were revealed for all five fungi by a checkerboard assay. The ability to synergistically interact with a fungicide and exacerbate the sensitivity of plant pathogenic fungi to a commercial antifungal agent is a novel and previously uninvestigated property of hevein-like AMPs.

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Antifungal activity in vitro of propolis solutions from Argentina against two plant pathogenic fungi: Didymella bryoniae and Rhizotocnia solani

Journal of Apicultural Research ◽

10.3896/ibra.1.53.4.08 ◽

2014 ◽

Vol 53 (4) ◽

pp. 438-440

Author(s):

Liliana Gallez ◽

Mirta Kiehr ◽

Leticia Fernández ◽

Rolf Delhey ◽

Débora Stikar

Keyword(s):

Antifungal Activity ◽

Pathogenic Fungi ◽

Plant Pathogenic Fungi ◽

Didymella Bryoniae

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Antifungal Activity of Silver Ions and Nanoparticles on Phytopathogenic Fungi

Plant Disease ◽

10.1094/pdis-93-10-1037 ◽

2009 ◽

Vol 93 (10) ◽

pp. 1037-1043 ◽

Cited By ~ 322

Author(s):

Young-Ki Jo ◽

Byung H. Kim ◽

Geunhwa Jung

Keyword(s):

Antifungal Activity ◽

Colony Formation ◽

Magnaporthe Grisea ◽

Silver Ions ◽

Pathogenic Fungi ◽

Chloride Ions ◽

Plant Diseases ◽

Plant Pathogenic Fungi ◽

In Planta

Silver in ionic or nanoparticle forms has a high antimicrobial activity and is therefore widely used for various sterilization purposes including materials of medical devices and water sanitization. There have been relatively few studies on the applicability of silver to control plant diseases. Various forms of silver ions and nanoparticles were tested in the current study to examine the antifungal activity on two plant-pathogenic fungi, Bipolaris sorokiniana and Magnaporthe grisea. In vitro petri dish assays indicated that silver ions and nanoparticles had a significant effect on the colony formation of these two pathogens. Effective concentrations of the silver compounds inhibiting colony formation by 50% (EC50) were higher for B. sorokiniana than for M. grisea. The inhibitory effect on colony formation significantly diminished after silver cations were neutralized with chloride ions. Growth chamber inoculation assays further confirmed that both ionic and nanoparticle silver significantly reduced these two fungal diseases on perennial ryegrass (Lolium perenne). Particularly, silver ions and nanoparticles effectively reduced disease severity with an application at 3 h before spore inoculation, but their efficacy significantly diminished when applied at 24 h after inoculation. The in vitro and in planta evaluations of silver indicated that both silver ions and nanoparticles influence colony formation of spores and disease progress of plant-pathogenic fungi. In planta efficacy of silver ions and nanoparticles is much greater with preventative application, which may promote the direct contact of silver with spores and germ tubes, and inhibit their viability.

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Activity of Armillarisin B in vitro against Plant Pathogenic Fungi

Zeitschrift für Naturforschung C ◽

10.1515/znc-2009-11-1206 ◽

2009 ◽

Vol 64 (11-12) ◽

pp. 790-792 ◽

Cited By ~ 2

Author(s):

Jin-Wen Shen ◽

Bing-Ji Ma ◽

Wen Li ◽

Hai-You Yu ◽

Ting-Ting Wu ◽

...

Keyword(s):

Antifungal Activity ◽

Methanolic Extract ◽

Pathogenic Fungi ◽

2D Nmr ◽

Spectroscopic Studies ◽

Gibberella Zeae ◽

Plant Pathogenic Fungi ◽

Fruiting Bodies ◽

Bioassay Guided Fractionation

The methanolic extract of the fruiting bodies of the mushroom Armillariella tabescens was found to show antifungal activity against Gibberella zeae. The active compound was isolated from the fruiting bodies of A. tabescens by bioassay-guided fractionation of the extract and identifi ed as armillarisin B. Armillarisin B eventually corresponds to 2-hydroxy-2- phenylpropanediamide and its structure was confi rmed on the basis of spectroscopic studies including 2D NMR experiments.

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