Silver Nanoparticles Complexed with Bovine Submaxillary Mucin Possess Strong Antibacterial Activity and Protect against Seedling Infection

ABSTRACT A simple method for the synthesis of nanoparticles (NPs) of silver (Ag) in a matrix of bovine submaxillary mucin (BSM) was reported previously by some of the authors of this study. Based on mucin characteristics such as long-lasting stability, water solubility, and surfactant and adhesive characteristics, we hypothesized that these compounds, named BSM-Ag NPs, may possess favorable properties as potent antimicrobial agents. The goal of this study was to assess whether BSM-Ag NPs possess antibacterial activity, focusing on important plant-pathogenic bacterial strains representing both Gram-negative ( Acidovorax and Xanthomonas ) and Gram-positive ( Clavibacter ) genera. Growth inhibition and bactericidal assays, as well as electron microscopic observations, demonstrate that BSM-Ag NPs, at relatively low concentrations of silver, exert strong antimicrobial effects. Moreover, we show that treatment of melon seeds with BSM-Ag NPs effectively prevents seed-to-seedling transmission of Acidovorax citrulli , one of the most threatening pathogens of cucurbit production worldwide. Overall, our findings demonstrate strong antimicrobial activity of BSM-Ag NPs and their potential application for reducing the spread and establishment of devastating bacterial plant diseases in agriculture. IMPORTANCE Bacterial plant diseases challenge agricultural production, and the means available to manage them are limited. Importantly, many plant-pathogenic bacteria have the ability to colonize seeds, and seed-to-seedling transmission is a critical route by which bacterial plant diseases spread to new regions and countries. The significance of our study resides in the following aspects: (i) the simplicity of the method of BSM-Ag NP synthesis, (ii) the advantageous chemical properties of BSM-Ag NPs, (iii) the strong antibacterial activity of BSM-Ag NPs at relatively low concentrations of silver, and (iv) the fact that, in contrast to most studies on the effects of metal NPs on plant pathogens, the proof of concept for the novel compound is supported by in planta assays. Application of this technology is not limited to agriculture; BSM-Ag NPs potentially could be exploited as a potent antimicrobial agent in a wide range of industrial areas, including medicine, veterinary medicine, cosmetics, textiles, and household products.

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Potential Control of Potato Soft Rot Disease by the Obligate Predators Bdellovibrio and Like Organisms

Applied and Environmental Microbiology ◽

10.1128/aem.02543-19 ◽

2020 ◽

Vol 86 (6) ◽

Cited By ~ 3

Author(s):

Daniel Youdkes ◽

Yael Helman ◽

Saul Burdman ◽

Ofra Matan ◽

Edouard Jurkevitch

Keyword(s):

Plant Pathogens ◽

Soft Rot ◽

Plant Diseases ◽

Predator Population ◽

Bacterial Soft Rot ◽

Population Parameters ◽

Live Prey ◽

Content Type ◽

Wide Range

ABSTRACT Bacterial soft rot diseases caused by Pectobacterium spp. and Dickeya spp. affect a wide range of crops, including potatoes, a major food crop. As of today, farmers mostly rely on sanitary practices, water management, and plant nutrition for control. We tested the bacterial predators Bdellovibrio and like organisms (BALOs) to control potato soft rot. BALOs are small, motile predatory bacteria found in terrestrial and aquatic environments. They prey on a wide range of Gram-negative bacteria, including animal and plant pathogens. To this end, BALO strains HD100, 109J, and a ΔmerRNA derivative of HD100 were shown to efficiently prey on various rot-causing strains of Pectobacterium and Dickeya solani. BALO control of maceration caused by a highly virulent strain of Pectobacterium carotovorum subsp. brasilense was then tested in situ using a potato slice assay. All BALO strains were highly effective at reducing disease, up to complete prevention. Effectivity was concentration dependent, and BALOs applied before P. carotovorum subsp. brasilense inoculation performed significantly better than those applied after the disease-causing agent, maybe due to in situ consumption of glucose by the prey, as glucose metabolism by live prey bacteria was shown to prevent predation. Dead predators and the supernatant of BALO cultures did not significantly prevent maceration, indicating that predation was the major mechanism for the prevention of the disease. Finally, plastic resistance to predation was affected by prey and predator population parameters, suggesting that population dynamics affect prey response to predation. IMPORTANCE Bacterial soft rot diseases caused by Pectobacterium spp. and Dickeya spp. are among the most important plant diseases caused by bacteria. Among other crops, they inflict large-scale damage to potatoes. As of today, farmers have few options to control them. The bacteria Bdellovibrio and like organisms (BALOs) are obligate predators of bacteria. We tested their potential to prey on Pectobacterium spp. and Dickeya spp. and to protect potato. We show that different BALOs can prey on soft rot-causing bacteria and prevent their growth in situ, precluding tissue maceration. Dead predators and the supernatant of BALO cultures did not significantly prevent maceration, showing that the effect is due to predation. Soft rot control by the predators was concentration dependent and was higher when the predator was inoculated ahead of the prey. As residual prey remained, we investigated what determines their level and found that initial prey and predator population parameters affect prey response to predation.

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Antibacterial activity of the seeds, roots and shoots of Lotus populations

Legume Research - An International Journal ◽

10.18805/lr-408 ◽

2018 ◽

Author(s):

Gurkan Demirkol

Keyword(s):

Antibacterial Activity ◽

Ethyl Acetate ◽

Pathogenic Bacteria ◽

Plant Pathogens ◽

Plant Diseases ◽

Dilution Method ◽

Agar Dilution Method ◽

Clavibacter Michiganensis ◽

High Antibacterial Activity ◽

Agar Dilution

In this study the antibacterial activity of the ethanol, ethyl acetate and chloroform extracts from the seeds, roots and shoots of Lotus aegaeus, Lotus angustissimus, Lotus corniculatus, Lotus gebelia, Lotus palustris populations grown naturally in Turkey were investigated by using the disc diffusion and agar dilution method, against main plant pathogenic bacteria (Clavibacter michiganensis, Agrobacterium tumefaciens, Erwinia caratovora, Pseudomonas phaseolicola). According to results, the shoot ethyl acetate extract of L. aegaeus and shoot extracts of L. corniculatus against C. michiganensis and shoot extracts of all solvents of L. angustissimus against P. phaseolicola showed high antibacterial activity. This is the first report of antibacterial activity of the Lotus species against plant pathogens. In the study these stated effective extracts showed higher antibacterial effects by comparison with used chemical preservatives against sensitive bacteria. This study offers that active compounds present in Lotus species could play a big role in naturally plant preservation against plant diseases.

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Microbial antagonists against plant pathogens in Iran: A review

Open Agriculture ◽

10.1515/opag-2020-0031 ◽

2020 ◽

Vol 5 (1) ◽

pp. 404-440 ◽

Cited By ~ 1

Author(s):

Mehrdad Alizadeh ◽

Yalda Vasebi ◽

Naser Safaie

Keyword(s):

Biological Control ◽

Chemical Control ◽

Plant Disease ◽

Plant Pathogens ◽

Plant Diseases ◽

Agricultural Products ◽

Control Measures ◽

Wide Range ◽

Plant Disease Management ◽

Published Research

AbstractThe purpose of this article was to give a comprehensive review of the published research works on biological control of different fungal, bacterial, and nematode plant diseases in Iran from 1992 to 2018. Plant pathogens cause economical loss in many agricultural products in Iran. In an attempt to prevent these serious losses, chemical control measures have usually been applied to reduce diseases in farms, gardens, and greenhouses. In recent decades, using the biological control against plant diseases has been considered as a beneficial and alternative method to chemical control due to its potential in integrated plant disease management as well as the increasing yield in an eco-friendly manner. Based on the reported studies, various species of Trichoderma, Pseudomonas, and Bacillus were the most common biocontrol agents with the ability to control the wide range of plant pathogens in Iran from lab to the greenhouse and field conditions.

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Purification and Characterization of Antibacterial Activity against Phytopathogenic Bacteria in Culture Fluids from Ganoderma lucidum

Molecules ◽

10.3390/molecules26185553 ◽

2021 ◽

Vol 26 (18) ◽

pp. 5553

Author(s):

Loreto Robles-Hernández ◽

Nora A. Salas-Salazar ◽

Ana C. Gonzalez-Franco

Keyword(s):

Antibacterial Activity ◽

Ganoderma Lucidum ◽

Pathogenic Bacteria ◽

Plant Pathogens ◽

Heat Stability ◽

Limited Information ◽

Dialysis Tubing ◽

Molecular Weights ◽

Exclusion Chromatography

Previous studies of Ganoderma lucidum have focused on its medicinal applications. Limited information is available about its antibacterial activity against plant pathogens. Thus, the goal of this study was to purify and characterize the antibacterial activity against plant pathogenic bacteria from culture fluids of G. lucidum. The nature of the bioactive components was determined using heat boiling, organic solvents, dialysis tubing, gel exclusion chromatography (GEC), proteinase sensitivity, HPLC, HPLC-APCI-MS, and GC-MS. The bioactive compounds were neither lipid, based on their solubility, nor proteic in nature, based on proteinase digestion and heat stability. The putative-bioactive polysaccharides have molecular weights that range from 3500 to 4500 Daltons as determined by dialysis tubing, GEC and APCI-MS analysis. The composition of the antibacterial compounds was determined by GC-MS. This is the first report of small polysaccharides produced by G. lucidum with activity against bacterial plant pathogens.

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Effectiveness of Dunaliella salina Extracts against Bacillus subtilis and Bacterial Plant Pathogens

Pathogens ◽

10.3390/pathogens9080613 ◽

2020 ◽

Vol 9 (8) ◽

pp. 613

Author(s):

Alfredo Ambrico ◽

Mario Trupo ◽

Rosaria Magarelli ◽

Roberto Balducchi ◽

Angelo Ferraro ◽

...

Keyword(s):

Antibacterial Activity ◽

Pseudomonas Syringae ◽

Dunaliella Salina ◽

Plant Pathogens ◽

Plant Diseases ◽

Economic Losses ◽

Tomato Plants ◽

Hexane Extracts

Several bacteria pathogens are responsible for plant diseases causing significant economic losses. The antibacterial activity of Dunaliella salina microalgae extracts were investigated in vitro and in vivo. First, biomass composition was chemically characterized and subjected to extraction using polar/non-polar solvents. The highest extraction yield was obtained using chloroform:methanol (1:1 v/v) equal to 170 mg g−1 followed by ethanol (88 mg g−1) and hexane (61 mg g−1). In vitro examination of hexane extracts of Dunaliella salina demonstrated antibacterial activity against all tested bacteria. The hexane extract showed the highest amount of β-carotene with respect to the others, so it was selected for subsequent analyses. In vivo studies were also carried out using hexane extracts of D. salina against Pseudomonas syringae pv. tomato and Pectobacterium carotovorum subsp. carotovorum on young tomato plants and fruits of tomato and zucchini, respectively. The treated young tomato plants exhibited a reduction of 65.7% incidence and 77.0% severity of bacterial speck spot disease. Similarly, a reduction of soft rot symptoms was observed in treated tomato and zucchini fruits with a disease incidence of 5.3% and 12.6% with respect to 90.6% and 100%, respectively, for the positive control.

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Edible film based on Vicia faba shell gum, nano silver and Helichrysum arenarium essence

Nutrition & Food Science ◽

10.1108/nfs-04-2019-0136 ◽

2019 ◽

Vol 50 (2) ◽

pp. 280-287 ◽

Cited By ~ 1

Author(s):

Farzane Jahantigh

Keyword(s):

Antimicrobial Activity ◽

Antibacterial Activity ◽

Pathogenic Bacteria ◽

Natural Antioxidants ◽

Inhibition Zone ◽

Edible Film ◽

Composition Analysis ◽

Disk Diffusion Test ◽

Content Type ◽

The Difference

Purpose The inclusion of natural antioxidants and nanoparticles into edible coatings can improve their structure, functionality and applicability in foods. This study aims to determine the antibacterial effect of new nano-composite based on bean pod shell gum (BPSG), silver nanoparticle (SNP) and herbal essential oil (EO). Design/methodology/approach For this purpose, BPSG (4 per cent w/v), SNP (0.5-1 per cent w/v) and Helichrysum arenarium EO (1-2 per cent v/v) were mixed. After preparation the edible film, the antibacterial activity was tested on five food-borne pathogenic bacteria in two categories including two-gram positives and three-gram negatives bacteria. The EO composition was determined by GC–mass spectrometry and the antibacterial activity was tested using disk diffusion test. Findings Results showed that gram-positive bacteria were more susceptible than gram-negative bacteria. Increasing Helichrysum arenarium EO and SNP content increased antimicrobial activity of the edible film based on BPSG, so that the treatment containing 2 per cent v/v Helichrysum arenarium EO and 1 per cent w/v SNP led to the highest inhibition zone (8.1-13.1 mm) compared to treatment containing 1 per cent v/v Helichrysum arenarium EO and 0.5 per cent w/v SNP with inhibition zone range of 5.4-9.9 mm and the difference was statistically significant (p = 0.41). Also, the chemical composition analysis of the EO identified a total of 38 compounds in which a-pinene (32 per cent), 1,8-cineole (16 per cent), α-humulene (15 per cent) and ß-caryophyllene (8 per cent) were the main fractions. Other separated components accounted less than 29 per cent of the oil. Originality/value In general, SNP and Helichrysum arenarium EO improved the functional properties including the antimicrobial activity of the edible film based on BPSG, which increases the potential to be used as active packaging for fresh products.

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Antimicrobial Activity of O-Carboxymethyl Chitosan Nanofibers Containing Silver Nanoparticles Synthesized by Green Method

Journal of Nano Research ◽

10.4028/www.scientific.net/jnanor.40.136 ◽

2016 ◽

Vol 40 ◽

pp. 136-145 ◽

Cited By ~ 1

Author(s):

Metwally Ezzat ◽

Mohammed Ghanim ◽

Hassan Nageh ◽

Ahmed H. Hassanin ◽

Ahmed Abdel-Moneim

Keyword(s):

Antibacterial Activity ◽

Wound Dressing ◽

Pathogenic Bacteria ◽

Reaction Times ◽

Carboxymethyl Chitosan ◽

Diffusion Method ◽

Ag Nps ◽

High Antibacterial Activity ◽

Transmission Electron ◽

Bacteria And Fungi

New green synthesis of Ag-nanoparticles (Ag-NPs) using O-Carboxymethyl Chitosan (O-CMCs) as stabilizing agent and ascorbic acid as reducing agent was achieved. The reaction was carried out in an autoclave at a pressure of 0.12 MPa and a temperature of 120°C at varying concentrations of solution precursors and different reaction times. The size, shape and structure of Ag-NPs were measured using transmission electron microscope (TEM), X-Ray Diffraction (XRD), FT-IR and UV spectrophotometers. The Ag-NPs stabilized in O-CMCs were blended with polyvinyl alcohol (PVA) polymer solution and then electrospun to produce wound dressing nanofibers with high antibacterial activity. The morphological study of O-CMCs/ PVA/Ag-NPs nanofiber membranes was characterized using SEM. Finally, the release behavior of Ag-NPs from these nanofibers was examined and the antibacterial activity was measured against some skin pathogenic bacteria and fungi using the agar diffusion method. The newly developed membranes show a unique antibacterial activity against the tested strains and were presented as promising active wound dressing materials in medical applications.

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Biosynthesis Pathways, Transport Mechanisms and Biotechnological Applications of Fungal Siderophores

Journal of Fungi ◽

10.3390/jof8010021 ◽

2021 ◽

Vol 8 (1) ◽

pp. 21

Author(s):

Lorenzo Pecoraro ◽

Xiao Wang ◽

Dawood Shah ◽

Xiaoxuan Song ◽

Vishal Kumar ◽

...

Keyword(s):

Plant Pathogens ◽

Iron Acquisition ◽

Growth Enhancement ◽

Extracellular Medium ◽

Peptide Synthetases ◽

Hydroxamate Siderophores ◽

Low Concentrations ◽

Wide Range ◽

Essential Nutrient ◽

Abundant Element

Iron (Fe) is the fourth most abundant element on earth and represents an essential nutrient for life. As a fundamental mineral element for cell growth and development, iron is available for uptake as ferric ions, which are usually oxidized into complex oxyhydroxide polymers, insoluble under aerobic conditions. In these conditions, the bioavailability of iron is dramatically reduced. As a result, microorganisms face problems of iron acquisition, especially under low concentrations of this element. However, some microbes have evolved mechanisms for obtaining ferric irons from the extracellular medium or environment by forming small molecules often regarded as siderophores. Siderophores are high affinity iron-binding molecules produced by a repertoire of proteins found in the cytoplasm of cyanobacteria, bacteria, fungi, and plants. Common groups of siderophores include hydroxamates, catecholates, carboxylates, and hydroximates. The hydroxamate siderophores are commonly synthesized by fungi. L-ornithine is a biosynthetic precursor of siderophores, which is synthesized from multimodular large enzyme complexes through non-ribosomal peptide synthetases (NRPSs), while siderophore-Fe chelators cell wall mannoproteins (FIT1, FIT2, and FIT3) help the retention of siderophores. S. cerevisiae, for example, can express these proteins in two genetically separate systems (reductive and nonreductive) in the plasma membrane. These proteins can convert Fe (III) into Fe (II) by a ferrous-specific metalloreductase enzyme complex and flavin reductases (FREs). However, regulation of the siderophore through Fur Box protein on the DNA promoter region and its activation or repression depend primarily on the Fe availability in the external medium. Siderophores are essential due to their wide range of applications in biotechnology, medicine, bioremediation of heavy metal polluted environments, biocontrol of plant pathogens, and plant growth enhancement.

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Plant thionins: structure, biological functions and potential use in biotechnology

Vavilov Journal of Genetics and Breeding ◽

10.18699/vj18.409 ◽

2018 ◽

Vol 22 (6) ◽

pp. 667-675 ◽

Cited By ~ 1

Author(s):

T. I. Odintsova ◽

M. P. Slezina ◽

E. A. Istomina

Keyword(s):

Pathogenic Bacteria ◽

Plant Pathogens ◽

Biological Activities ◽

Three Dimensional ◽

Amino Acid Sequences ◽

Lipid Transfer ◽

Human Pathogens ◽

Candida Spp ◽

Wide Range ◽

Bacteria And Fungi

Antimicrobial peptides (AMPs) are important components of defense system in both plants and animals. They represent an ancient mechanism of innate immunity providing rapid first line of defense against pathogens. Plant AMPs are classified into several families: thionins, defensins, nonspecific lipid-transfer proteins, hevein- and knottin-type peptides, hairpinins and macrocyclic peptides (cyclotides). The review focuses on the thionin family. Thionins comprise a plant-specific AMP family that consists of short (~5 kDA) cysteine-rich peptides containing 6 or 8 cysteine residues with antimicrobial and toxic properties. Based on similarity in amino acid sequences and the arrangement of disulphide bonds, five structural classes of thionins are discriminated. The three-dimensional structures of a number of thionins were determined. The amphipathic thionin molecule resembles the Greek letter Г, in which the long arm is formed by two antiparallel α-helices, while the short one, by two parallel β-strands. The residues responsible for the antimicrobial activity of thionins were identified. Thionins are synthesized as precursor proteins consisting of a signal peptide, the mature peptide region and the C-terminal prodomain. Thionins protect plants from pathogenic bacteria and fungi acting directly on the membranes of microorganisms at micromolar concentrations, although their precise mode of action remains unclear. In addition to plant pathogens, thionins inhibit growth of a number of human pathogens and opportunistic microorganisms, such as Candida spp., Saccharomyces cerevisiae, Fusarium solani, Staphylococcus aureus and Escherichia coli. Thionins are toxic to different types of cells including mammalian cancer cell lines. Transgenic plants expressing thionin genes display enhanced resistance to pathogens. A wide range of biological activities makes thionins promising candidates for practical application in agriculture and medicine.

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De Novo Design of Antimicrobial Peptides With a Special Charge Pattern and Their Application in Combating Plant Pathogens

Frontiers in Plant Science ◽

10.3389/fpls.2021.753217 ◽

2021 ◽

Vol 12 ◽

Author(s):

Eric H. -L. Chen ◽

Cheng-Wei Weng ◽

Yi-Min Li ◽

Ming-Chin Wu ◽

Chien-Chih Yang ◽

...

Keyword(s):

Antimicrobial Activity ◽

Antimicrobial Peptides ◽

Plant Pathogens ◽

De Novo ◽

Plant Protection ◽

Acyl Chain ◽

Fatty Acyl ◽

Plant Diseases ◽

Basic Residue ◽

Wide Range

Plant diseases are important issues in agriculture, and the development of effective and environment-friendly means of disease control is crucial and highly desired. Antimicrobial peptides (AMPs) are known as potential alternatives to chemical pesticides because of their potent broad-spectrum antimicrobial activity and because they have no risk, or have only a low risk, of developing chemical-resistant pathogens. In this study, we designed a series of amphipathic helical peptides with different spatial distributions of positive charges and found that the peptides that had a special sequence pattern “BBHBBHHBBH” (“B” for basic residue and “H” for hydrophobic residue) displayed excellent bactericidal and fungicidal activities in a wide range of economically important plant pathogens. The peptides with higher helical propensity had lower antimicrobial activity. When we modified the peptides with a long acyl chain at their N-terminus, their plant protection effect improved. Our application of the fatty acyl-modified peptides on the leaves of tomato and Arabidopsis plants lessened the infection caused by Pectobacterium carotovorum subsp. carotovorum and Botrytis cinerea. Our study provides important insights on the development of more potent novel AMPs for plant protection.

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