Nano-Magnesium Oxide: A Novel Bactericide Against Copper-Tolerant Xanthomonas perforans Causing Tomato Bacterial Spot

Bacterial spot caused by Xanthomonas perforans causes significant damage on tomato in Florida. Due to the presence of copper (Cu)-tolerant X. perforans strains, Cu bactericides are not effective in disease management. Hence, there is a critical need to find alternatives for Cu. Antibacterial activity of magnesium oxide (Nano-MgO), and other metal oxide nanoparticles, were evaluated against a Cu-tolerant and -sensitive X. perforans strain. In vitro experiments demonstrated high antibacterial activity of Nano-MgO against both strains compared with the commercial Cu. The minimum inhibitory concentration of Nano-MgO is 25 µg/ml and the minimum bactericidal concentration is 100 µg/ml against a Cu-tolerant X. perforans strain after 4 h of exposure. Structural changes in the bacterial membrane following exposure to Nano-MgO treatments compared with the controls were observed using transmission electron microscopy. In two greenhouse experiments with a Cu-tolerant strain, bacterial spot severity was significantly reduced by Nano-MgO at 200 µg/ml compared with Cu-ethylene bis-dithiocarbamate (grower standard), and the untreated control (P = 0.05). In three field experiments, Nano-MgO at 200 µg/ml significantly reduced disease severity with no negative impact on yield compared with the untreated control. Inductively coupled plasma mass spectrometric analysis of the fruit confirmed that Nano-MgO application did not lead to the accumulation of Mg, Cu, Ca, K, Mn, P, and S. This study is the first to demonstrate the potential of Nano-MgO against bacterial spot of tomato.

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Particle-size dependent bactericidal activity of magnesium oxide against Xanthomonas perforans and bacterial spot of tomato

Scientific Reports ◽

10.1038/s41598-019-54717-7 ◽

2019 ◽

Vol 9 (1) ◽

Cited By ~ 4

Author(s):

Y. Y. Liao ◽

A. Strayer-Scherer ◽

J. C. White ◽

R. De La Torre-Roche ◽

L. Ritchie ◽

...

Keyword(s):

Particle Size ◽

Magnesium Oxide ◽

Bactericidal Activity ◽

Inductively Coupled Plasma ◽

Field Experiments ◽

Optical Emission ◽

Bacterial Spot ◽

Inductively Coupled ◽

Xanthomonas Perforans

AbstractBacterial spot, caused by Xanthomonas spp., is a highly destructive disease of tomatoes worldwide. Copper (Cu) bactericides are often ineffective due to the presence of Cu-tolerant strains. Magnesium oxide (MgO) is an effective alternative to Cu bactericides against Xanthomonas spp. However, the effects of particle size on bactericidal activity and fruit elemental levels are unknown. In this study, nano (20 nm) and micron (0.3 and 0.6 µm) size MgO particles were compared for efficacy. Nano MgO had significantly greater in vitro bactericidal activity against Cu-tolerant X. perforans than micron MgO at 25–50 µg/ml. In field experiments nano and micron MgO applied at 200 and 1,000 µg/ml were evaluated for disease control. Nano MgO at 200 µg/ml was the only treatment that consistently reduced disease severity compared to the untreated control. Inductively Coupled Plasma Optical Emission Spectroscopy revealed that nano MgO applications did not significantly alter Mg, Cu, Ca, K, Mn, P and S accumulation compared to fruits from the untreated plots. We demonstrated that although both nano MgO and micron MgO had bactericidal activity against Cu-tolerant strains in vitro, only nano MgO was effective in bacterial spot disease management under field conditions.

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Low Concentrations of a Silver-Based Nanocomposite to Manage Bacterial Spot of Tomato in the Greenhouse

Plant Disease ◽

10.1094/pdis-05-15-0580-re ◽

2016 ◽

Vol 100 (7) ◽

pp. 1460-1465 ◽

Cited By ~ 45

Author(s):

A. Strayer ◽

I. Ocsoy ◽

W. Tan ◽

J. B. Jones ◽

M. L. Paret

Keyword(s):

Antibacterial Activity ◽

Bacterial Cells ◽

Bacterial Spot ◽

Management Options ◽

Tomato Plants ◽

Xanthomonas Perforans ◽

Low Concentrations ◽

Negative Controls ◽

Copper Tolerant

Bacterial spot, caused by four Xanthomonas spp., is one of the most damaging diseases of tomato worldwide. Due to limited disease management options, growers rely heavily on copper-based bactericides, which are often ineffective due to the presence of copper-resistant Xanthomonas strains. This study was undertaken to characterize the antibacterial activity of a silver-based nanocomposite, Ag-dsDNA-GO, and its potential as an alternative to copper. Ag-dsDNA-GO at rates as low as 10 μg/ml killed all bacterial cells of copper-tolerant and -sensitive Xanthomonas perforans strains in suspensions containing approximately 103 CFU/ml within 15 min of exposure in vitro, whereas equivalent rates of copper (10, 25, and 50 μg/ml) were unable to significantly reduce populations compared with the untreated control after 24 h of exposure (P = 0.05). All copper concentrations killed the copper-sensitive X. perforans strain but required exposure for ≥1 h. Ag-dsDNA-GO also exhibited antibacterial activity against copper-tolerant X. vesicatoria, X. euvesicatoria, and X. gardneri strains. In greenhouse studies, tomato plants treated with Ag-dsDNA-GO at either 75 or 100 μg/ml prior to artificial inoculation significantly reduced disease severity when compared with copper-mancozeb and negative controls (P = 0.05). This study highlights the potential of Ag-dsDNA-GO as an alternative to copper in tomato transplant production.

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Suppression of the Bacterial Spot Pathogen Xanthomonas euvesicatoria on Tomato Leaves by an Attenuated Mutant of Xanthomonas perforans

Applied and Environmental Microbiology ◽

10.1128/aem.02399-08 ◽

2009 ◽

Vol 75 (10) ◽

pp. 3323-3330 ◽

Cited By ~ 26

Author(s):

A. P. Hert ◽

M. Marutani ◽

M. T. Momol ◽

P. D. Roberts ◽

S. M. Olson ◽

...

Keyword(s):

Biological Control ◽

Plant Pathogen ◽

Tomato Plant ◽

Plant Pathogens ◽

Field Experiments ◽

Biological Control Agent ◽

Leaf Tissue ◽

Wild Type ◽

Bacterial Spot ◽

Xanthomonas Perforans

ABSTRACT A bacteriocin-producing strain of the bacterial spot of tomato plant pathogen, Xanthomonas perforans, with attenuated pathogenicity was deployed for biocontrol of a bacteriocin-sensitive strain of the genetically closely related bacterial spot of tomato plant pathogen, X. euvesicatoria. The attenuated mutant (91-118ΔopgHΔbcnB) of X. perforans was tested in leaf tissue and shown to significantly inhibit internal populations of the wild-type X. euvesicatoria strain although significantly less than the wild-type 91-118 strain, whereas in a phyllosphere inhibition assay, the mutant strain reduced epiphytic populations comparably to 91-118. Thus, the attenuated mutant limited the sensitive bacterium more efficiently on the leaf surface than inside the leaf. In field experiments, weekly application of 91-118ΔopgHΔbcnB significantly reduced X. euvesicatoria populations compared to the growers’ standard control (copper hydroxide and mancozeb applied weekly and acibenzolar-S-methyl applied every 2 weeks). The biological control agent, 91-118ΔopgHΔbcnB, applied every 2 weeks also significantly reduced X. euvesicatoria populations in one season but was not significantly different from the growers’ standard control. Potentially, attenuated pathogenic strains could be deployed as biological control agents in order to improve disease control of foliar plant pathogens.

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Management of Tomato Bacterial Spot in the Field by Foliar Applications of Bacteriophages and SAR Inducers

Plant Disease ◽

10.1094/pdis.2004.88.7.736 ◽

2004 ◽

Vol 88 (7) ◽

pp. 736-740 ◽

Cited By ~ 95

Author(s):

A. Obradovic ◽

J. B. Jones ◽

M. T. Momol ◽

B. Balogh ◽

S. M. Olson

Keyword(s):

Disease Control ◽

Untreated Control ◽

Field Experiments ◽

Total Yield ◽

Copper Hydroxide ◽

Bacterial Spot ◽

Central Florida ◽

Harpin Protein ◽

Marketable Fruit ◽

Control Application

Various combinations of the harpin protein, acibenzolar-S-methyl, and bacteriophages were compared for controlling tomato bacterial spot in field experiments. Harpin protein and aciben-zolar-S-methyl were applied every 14 days beginning twice before transplanting and then an additional four applications throughout the season. Formulated bacteriophages were applied prior to inoculation followed by twice a week at dusk. A standard bactericide treatment, consisting of copper hydroxide plus mancozeb, was applied once prior to inoculation and then every 7 days, while untreated plants served as an untreated control. Experiments were conducted in north and central Florida fields during fall 2001, spring 2002, and fall 2002. In three consecutive seasons, acibenzolar-S-methyl applied in combination with bacteriophage or bacteriophage and harpin significantly reduced bacterial spot compared with the other treatments. However, it did not significantly affect the total yield compared with the standard or untreated control. Application of host-specific bacteriophages was effective against the bacterial spot pathogen in all three experiments, providing better disease control than copper-mancozeb or untreated control. When results of the disease severity assessments or harvested yield from the bacteriophage-treated plots were grouped and compared with the results of the corresponding nonbacteriophage group, the former provided significantly better disease control and yield of total marketable fruit.

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Effect of Application Frequency and Reduced Rates of Acibenzolar-S-Methyl on the Field Efficacy of Induced Resistance Against Bacterial Spot on Tomato

Plant Disease ◽

10.1094/pdis-03-11-0183 ◽

2012 ◽

Vol 96 (2) ◽

pp. 221-227 ◽

Cited By ~ 46

Author(s):

Cheng-Hua Huang ◽

Gary E. Vallad ◽

Shouan Zhang ◽

Amin Wen ◽

Botond Balogh ◽

...

Keyword(s):

Disease Severity ◽

Untreated Control ◽

Systemic Acquired Resistance ◽

Field Experiments ◽

Acquired Resistance ◽

Foliar Spray ◽

Field Trials ◽

Plant Diseases ◽

Bacterial Spot ◽

Field Efficacy

Acibenzolar-S-methyl (ASM), a plant activator known to induce systemic acquired resistance, has demonstrated an ability to manage a number of plant diseases, including bacterial spot on tomato caused by four distinct Xanthomonas spp. The aim of this study was to evaluate application rate and frequency of ASM in order to optimize field efficacy against bacterial spot in Florida, while minimizing its impact on marketable yields. ASM was applied biweekly (once every 2 weeks) as a foliar spray at a constant concentration of 12.9, 64.5, and 129 μM throughout four field experiments during 2007–08. A standard copper program and an untreated control were also included. Overall, biweekly applications of ASM did not significantly reduce disease development or the final disease severity of bacterial spot compared with the copper-mancozeb standard or the untreated control. Only one experiment showed a significant reduction in the final disease severity on plants treated with ASM at 129 μM compared with the untreated control. Three additional field trials conducted during 2009–10 to evaluate the effects of weekly and biweekly applications of ASM at concentrations of 30.3 to 200 μM found that weekly applications provided significantly better disease control than biweekly applications. The tomato yields were not statistically improved with the use of ASM relative to the untreated control and standard copper program. Weekly ASM applications at rates as low as 75 μM (equivalent to 1.58 g a.i./ha in 100 liters of water or 0.21 oz. a.i./acre in 100 gallons of water) to 200 μM (equivalent to 4.20 g a.i./ha in 100 liters of water or 0.56 oz. a.i./acre in 100 gallons of water) were statistically equivalent in managing bacterial spot of tomato without significantly reducing yield compared with the untreated control.

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Evaluation of a Small-Molecule Compound, N-Acetylcysteine, for the Management of Bacterial Spot of Tomato Caused by Copper-Resistant Xanthomonas perforans

Plant Disease ◽

10.1094/pdis-05-20-0928-re ◽

2021 ◽

Vol 105 (1) ◽

pp. 108-113

Author(s):

Kang Qiao ◽

Qingchun Liu ◽

Ye Xia ◽

Shouan Zhang

Keyword(s):

Disease Severity ◽

Small Molecule ◽

Untreated Control ◽

Synergistic Effects ◽

Antibacterial Properties ◽

Field Trials ◽

Copper Resistance ◽

Bacterial Spot ◽

Xanthomonas Perforans

Bacterial spot caused by Xanthomonas spp. is one of the major diseases in tomato. Xanthomonas perforans is the main pathogen of bacterial spot on tomato in Florida. Currently, application of copper fungicides is the primary measure used to manage this disease. However, the development of copper resistance in X. perforans and accumulation of copper in the environment are major concerns for excessive use of copper-based products in agriculture. Due to its antibacterial properties and low environmental impact, N-acetylcysteine (NAC), a small molecule commonly used in medicine for human bacterial diseases, has been studied in agriculture for the control of plant bacterial pathogens, including X. citri and Xylella fastidiosa. This study evaluated the effect of NAC alone and in combination with copper on a copper-resistant X. perforans strain in vitro and its ability to control bacterial spot of tomato under greenhouse and field conditions. In vitro, the minimum inhibitory concentration of NAC against the X. perforans strain was 2,048 mg liter−1. NAC increased sensitivity of the copper-resistant X. perforans to copper in vitro when application of NAC was followed by copper application after 6 h. In greenhouse assays, NAC applied alone or in combination with copper significantly (P < 0.05) reduced the disease severity of bacterial spot on tomato compared with the untreated control. NAC at 100 mg liter−1 + copper at 300 mg liter−1 consistently exhibited synergistic effects against bacterial spot. In the field trials, NAC at 1,000 mg liter−1 + copper at 150 mg liter−1 significantly reduced disease severity compared with the untreated control. Results from this study demonstrated that NAC significantly reduced the disease severity of bacterial spot of tomato and enhanced the efficacy of copper against copper-resistant X. perforans, indicating that NAC could be applied for the effective management of bacterial spot of tomato.

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Antibacterial activity of magnesium oxide nanoparticles prepared by Calcination method

International Journal of Pharmaceutical Quality Assurance ◽

10.25258/ijpqa.10.3.25 ◽

2019 ◽

Vol 10 (03) ◽

Author(s):

Elaf Ayad Kadhem ◽

Miaad Hamzah Zghair ◽

Sarah , Hussam H. Tizkam, Shoeb Alahmad Salih Mahdi ◽

Hussam H. Tizkam ◽

Shoeb Alahmad

Keyword(s):

Antibacterial Activity ◽

Magnesium Oxide ◽

Diffusion Method ◽

Oxide Nanoparticles ◽

Gram Negative Bacteria ◽

Gram Positive ◽

Gram Negative ◽

Gram Positive Bacteria ◽

Magnesium Oxide Nanoparticles ◽

Agar Disc

magnesium oxide nanoparticles (MgO NPs) were prepared by simple wet chemical method using different calcination temperatures. The prepared NPs were characterized by Electrostatic Discharge (ESD), Scanning Electron Microscope (SEM) and X-ray Diffraction (XRD). It demonstrates sharp intensive peak with the increase of crystallinty and increase of the size with varying morphologies with respect to increase of calcination temperature. Antibacterial studies were done on gram negative bacteria (E.coli) and gram positive bacteria (S.aureus) by agar disc diffusion method. The zones of inhibitions were found larger for gram positive bacteria than gram negative bacteria, this mean, antibacterial MgO NPs activity more active on gram positive bacteria than gram negative bacteria because of the structural differences. It was found that antibacterial activity of MgO NPs was found it has directly proportional with their concentration.

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An insight into the Mechanism of Antibacterial activity by Magnesium oxide nanoparticles

Journal of Materials Chemistry B ◽

10.1039/d1tb00875g ◽

2021 ◽

Author(s):

Proma Bhattacharya ◽

Aishee Dey ◽

Sudarsan Neogi

Keyword(s):

Antibacterial Activity ◽

Magnesium Oxide ◽

Oxide Nanoparticles ◽

Antibacterial Efficacy ◽

Magnesium Oxide Nanoparticles ◽

Insight Into

The exact mechanism behind the antibacterial efficacy of nanoparticles remain unexplored till date. This study is aimed at shedding light on the mechanism adopted by magnesium oxide nanoparticles prepared in...

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Green Synthesis of Zinc Oxide Nanoparticles: Fortification for Rice Grain Yield and Nutrients Uptake Enhancement

Molecules ◽

10.3390/molecules26030584 ◽

2021 ◽

Vol 26 (3) ◽

pp. 584

Author(s):

Omnia M. Elshayb ◽

Khaled Y. Farroh ◽

Heba E. Amin ◽

Ayman M. Atta

Keyword(s):

Zinc Oxide ◽

Grain Yield ◽

Field Experiments ◽

Metal Oxide Nanoparticles ◽

Foliar Spray ◽

Yield Component ◽

Oxide Nanoparticles ◽

Rice Grain ◽

Zno Nps ◽

Agriculture Sector

Applications of metal oxide nanoparticles in the agriculture sector are being extensively included as the materials are considered superior. In the present work, zinc oxide nanoparticle (ZnO NPs), with a developing fertilizer, is applied in the fortification of rice grain yield and nutrient uptake enhancement. To evaluate the role of ZnO NP, two field experiments were conducted during the 2018 and 2019 seasons. ZnO NPs were small, nearly spherical, and their sizes equal to 31.4 nm, as proved via the dynamic light scattering technique. ZnO NPs were applied as a fertilizer in different concentrations, varying between 20 and 60 mg/L as a foliar spray. The mixture of ZnSO4 and ZnO NP40 ameliorated yield component and nutrients (N, K, and Zn) uptake was enhanced compared to traditional ZnSO4 treatment. Nevertheless, the uptake of the phosphorous element (P) was adversely affected by the treatment of ZnO NPs. Thus, treatment via utilizing ZnO NPs as a foliar with a very small amount (40 ppm) with of basal ZnSO4 led to a good improvement in agronomic and physiological features; eventually, higher yield and nutrient-enriched rice grain were obtained.

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