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

Plant Disease ◽  
2016 ◽  
Vol 100 (7) ◽  
pp. 1460-1465 ◽  
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.

scholarly journals Plant Extract Treatments Induce Resistance to Bacterial Spot by Tomato Plants for a Sustainable System

Horticulturae ◽  
2020 ◽  
Vol 6 (2) ◽  
pp. 36
Author(s):  
Kamal A. M. Abo-Elyousr ◽  
Najeeb M. Almasoudi ◽  
Ahmed W. M. Abdelmagid ◽  
Sergio R. Roberto ◽  
Khamis Youssef
Keyword(s):  
Antibacterial Activity ◽  
Plant Extracts ◽  
Integrated Management ◽  
Nerium Oleander ◽  
Bacterial Spot ◽  
Tomato Plants ◽  
Sustainable System ◽  
Pathogen Populations

The aim of this study is to assess the effect of extracts of Nerium oleander, Eucalyptus chamadulonsis and Citrullus colocynthis against bacterial spot disease of tomato and to investigate the induction of resistance by tomato (Solanum lycopersicum) in order to promote a sustainable management system. The antibacterial activity of aqueous and ethanol plant extracts was tested against Xanthomonas axonopodis pv. vesicatoria, isolate PHYXV3, in vitro and in vivo. The highest antibacterial activity in vitro was obtained with C. colocynthis, N. oleander and E. chamadulonsis, respectively. In vivo, ethanol extracts of N. oleander and E. chamadulonsis were more effective than aqueous extracts in reducing pathogen populations on tomato leaves. Under greenhouse conditions, application of the plant extracts at 15% (v/v) to tomato plants significantly reduced disease severity and increased the shoot weight of ‘Super Marmande’ tomato. In most cases, plant extracts significantly increased total phenol and salicylic acid content of tomato plants compared to either healthy or infected ones. In addition, C. colocynthis and E. chamadulonsis extracts significantly increased peroxidase activity while only E. chamadulonsis increased polyphenol oxidase after infection with the causal agent. The results indicated that the plant extracts showed promising antibacterial activity and could be considered an effective tool in integrated management programs for a sustainable system of tomato bacterial spot control.

scholarly journals Advanced Copper Composites Against Copper-Tolerant Xanthomonas perforans and Tomato Bacterial Spot

2018 ◽  
Vol 108 (2) ◽  
pp. 196-205 ◽  
Author(s):  
A. Strayer-Scherer ◽  
Y. Y. Liao ◽  
M. Young ◽  
L. Ritchie ◽  
G. E. Vallad ◽  
...  
Keyword(s):  
Disease Severity ◽  
Metallic Copper ◽  
Field Studies ◽  
Bacterial Disease ◽  
Bacterial Spot ◽  
Water Control ◽  
Xanthomonas Perforans ◽  
Bacterial Spot Disease ◽  
Copper Tolerant

Bacterial spot, caused by Xanthomonas spp., is a widespread and damaging bacterial disease of tomato (Solanum lycopersicum). For disease management, growers rely on copper bactericides, which are often ineffective due to the presence of copper-tolerant Xanthomonas strains. This study evaluated the antibacterial activity of the new copper composites core-shell copper (CS-Cu), multivalent copper (MV-Cu), and fixed quaternary ammonium copper (FQ-Cu) as potential alternatives to commercially available micron-sized copper bactericides for controlling copper-tolerant Xanthomonas perforans. In vitro, metallic copper from CS-Cu and FQ-Cu at 100 μg/ml killed the copper-tolerant X. perforans strain within 1 h of exposure. In contrast, none of the micron-sized copper rates (100 to 1,000 μg/ml) from Kocide 3000 significantly reduced copper-tolerant X. perforans populations after 48 h of exposure compared with the water control (P < 0.05). All copper-based treatments killed the copper-sensitive X. perforans strain within 1 h. Greenhouse studies demonstrated that all copper composites significantly reduced bacterial spot disease severity when compared with copper-mancozeb and water controls (P < 0.05). Although there was no significant impact on yield, copper composites significantly reduced disease severity when compared with water controls, using 80% less metallic copper in comparison with copper-mancozeb in field studies (P < 0.05). This study highlights the discovery that copper composites have the potential to manage copper-tolerant X. perforans and tomato bacterial spot.

scholarly journals Bactericidal Activity of Copper-Zinc Hybrid Nanoparticles on Copper-Tolerant Xanthomonas perforans

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Renato Carvalho ◽  
Kamil Duman ◽  
Jeffrey B. Jones ◽  
Mathews L. Paret
Keyword(s):  
Bacterial Degradation ◽  
Hybrid Nanoparticles ◽  
Bacterial Spot ◽  
Xanthomonas Perforans ◽  
Micron Size ◽  
Copper Zinc ◽  
Significant Yield ◽  
Hybrid Nanoparticle ◽  
Copper Tolerant

AbstractBacterial spot of tomato, caused by Xanthomonas perforans, X. euvesicatoria, X. vesicatoria and X. gardneri, is a major disease, contributing to significant yield losses worldwide. Over dependence of conventional copper bactericides over the last decades has led to the prevalence of copper-tolerant strains of Xanthomonas spp., making copper bactericides ineffective. Thus, there is a critical need to develop new strategies for better management of copper-tolerant Xanthomonas spp. In this study, we investigated the antimicrobial activity of a hybrid nanoparticle, copper-zinc (Cu/Zn), on copper-tolerant and sensitive strains. The hybrid nanoparticle significantly reduced bacterial growth in vitro compared to the non-treated and micron-size commercial copper controls. Tomato transplants treated with the hybrid nanoparticle had significantly reduced disease severity compared to the controls, and no phytotoxicity was observed on plants. We also studied the hybrid nanoparticle effect on the bacterial pigment xanthomonadin using Near-Infra Red Raman spectroscopy as an indicator of bacterial degradation. The hybrid nanoparticle significantly affected the ability of X. perforans in its production of xanthomonadin when compared with samples treated with micron-size copper or untreated. This study sheds new light on the potential utilization of this novel multi-site Cu/Zn hybrid nanoparticle for bacterial spot management.

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

Pathogens ◽  
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.

scholarly journals Lactobacillus plantarum Exopolysaccharides Induce Resistance against Tomato Bacterial Spot

2017 ◽  
Vol 9 (2) ◽  
pp. 162 ◽  
Author(s):  
Juliane Mendes Lemos Blainski ◽  
Argus Cezar da Rocha Neto ◽  
Caroline Luiz ◽  
Márcio José Rossi ◽  
Robson Marcelo Di Piero
Keyword(s):  
Lactobacillus Plantarum ◽  
Defense Mechanisms ◽  
Culture Medium ◽  
Defense Responses ◽  
Total Phenolic ◽  
Bacterial Spot ◽  
Tomato Plants ◽  
Induce Resistance ◽  
Severity Of The Disease

Lactic acid bacteria produce several exopolysaccharides (EPS) that may have antimicrobial action and/or induce defense responses in plants. This work aims to evaluate the potential of EPS produced by Lactobacillus plantarum in the protection of tomato plants against bacterial spot caused by Xanthomonas gardneri, as well as to predict the possible mechanisms of action. The EPS were characterized through FTIR and applied at 0; 0.5; 1.5 and 3.0 mg mL-1 in tomato plants with five expanded leaves, followed by the pathogen inoculation after 3 or 7 days. Antimicrobial activity of the biopolymer (1.5 or 10.0 mg mL-1) was evaluated in bioassay when EPS was incorporated into culture medium or embedded in antibiogram disk. The defense mechanisms i.e., total phenolic compounds and flavonoids content, phenylalanine ammonia-lyase (PAL), glutathione reductase (GR) and lipoxygenase (LOX) activities, were measured in tomato plants treated with EPS (1.5 mg mL-1), inoculated or not with X. gardneri. EPS reduced bacterial spot symptoms by up to 72.0% compared to the control. There were no direct effects of EPS on the in vitro growth of X. gardneri. The spectrophotometric profile, ascorbic and ellagic acid concentrations were change in tomato plants after EPS application, in plants challenged with the pathogen. Increases in PAL, GR and LOX activities were observed in plants treated with EPS. Thus, the application of L. plantarum exopolysaccharides can be considered as an effective alternative for controlling bacterial spot in tomato plants. This paper also discusses how these exopolysaccharides reduced the severity of the disease.

scholarly journals Antibacterial Effect Of Kaempferia Galanga L Extract On Lactobacillus Acidophilus –In Vitro

2017 ◽  
Vol 1 (01) ◽  
pp. 22
Author(s):  
Josi Saraswati ◽  
Annisa Septalita ◽  
Arini Bovita. N
Keyword(s):  
Antibacterial Activity ◽  
Lactobacillus Acidophilus ◽  
Antibacterial Effect ◽  
Inhibition Zone ◽  
Inhibition Effect ◽  
Kaempferia Galanga ◽  
Significant Difference ◽  
Agar Media ◽  
Negative Controls

Introduction: Lactobacillus acidophilus is one of the bacteria causes dental caries. The previous study has shown that Kaempferia galanga extract has a potential to inhibit the growth of Lactobacillus acidophilus.Objective: To determine the antibacterial effect of Kaempferia galanga extract to Lactobacillus acidophilus.Methods:Kaempferia galanga is extracted in 3 different solvents:dichlormethane, ethanol, and aquades. For each solvent, 0.2 μl Kaempferia galanga extractdroped into 6 mm steril paper dics. 0.1 ml Lactobacillus acidophilus inoculated on MRS agar. Each disc contains extract were impragnated into the agar media, then incubated at 370C for 24 hours, and inhibition zone measured.Results: Mean scores of Kaempferia galanga extract in 3 different solvents are: Kaempferia galanga (dichlormethane) is 1.6400; Kaempferia galanga (ethanol) is 1.7440; Kaempferia galanga extract is 1.6600; boiled Kaempferia galanga is 1.7000. Using Mann-Whitney Test, the results are: negative controls have no inhibition effect on Lactobacillus acidophilus compaired to Kaempferia galanga extract, comparation of those 4 Kaempferia galangal treatments shows no significant difference, those 4 Kaempferia galanga treatments compaired to erythromycin antibacterial effect shows significant difference, otherwise 4 Kaempferia galanga treatments compaired to penicillin shows no significant difference except Kaempferia galanga (ethanol).Conclusions: Kaempferia galanga extract can kill Lactobacillus acidophilus. Inhibition effect of Kaempferia galanga extract has no significant difference to penicillin but lower inhibition effect than erythromycin. The Kaempferia galanga extracts showed better antibacterial activity than penicillin.

Tetrandrine, a potent antifungal agent: inhibits mycelial growth and virulence of Botrytis cinerea

2020 ◽  
Author(s):  
Pingliang Li ◽  
jian zou ◽  
Yanhan Dong ◽  
jintao Jiang ◽  
Wenxing Liang ◽  
...  
Keyword(s):  
Botrytis Cinerea ◽  
Antifungal Agent ◽  
Plant Pathogens ◽  
Efflux Pump ◽  
Hyphal Growth ◽  
Tomato Plants ◽  
Low Concentrations ◽  
Grey Mold

Tetrandrine (TET) is a potent calcium channel blocker used for the treatment of hypertension and inflammation. Currently, TET is predominantly used to treat a variety of human diseases, and there is little information regarding the use of TET against plant pathogens. In this study, we explored the antifungal activity of TET on a plant pathogen, Botrytis cinerea. We show that administration of low concentrations of TET effectively inhibited hyphal growth of fungus grown on potato dextrose agarose, and decreased the virulence of B. cinerea in tomato plants. Real-time PCR revealed that the expression of drug efflux pump related genes (alcohol dehydrogenase 1, multi-drug/pheromone exporter, pleiotropic drug resistance protein 1, and synaptic vesicle transporter) were down-regulated in the presence of TET. Finally, we show that TET acts synergistically with iprodione, resulting in increased inhibition of B. cinerea both in vitro and in vivo. These results indicate that TET might act as an effective antifungal agent in reducing grey mold disease.

scholarly journals Nematicidal Activity of Monoterpenoids Against the Root-Knot Nematode Meloidogyne incognita

2010 ◽  
Vol 100 (2) ◽  
pp. 199-203 ◽  
Author(s):  
Sergio Echeverrigaray ◽  
Jucimar Zacaria ◽  
Ricardo Beltrão
Keyword(s):  
Meloidogyne Incognita ◽  
Nematicidal Activity ◽  
Root Knot Nematode ◽  
High Concentration ◽  
Tomato Plants ◽  
Pot Experiments ◽  
Low Concentrations ◽  
Dose Dependent ◽  
Dose Dependent Effect

Nematicidal activity of 22 monoterpenoids were evaluated in vitro and in pot experiments. Twenty of the twenty-two monoterpenoids significantly reduced hatching, and 11 reduced J2 mobility of the root-knot nematode Meloidogyne incognita at a concentration of 250 mg/liter. In general, compounds with hydroxyl and carbonyl groups exhibited higher nematicidal activity than other terpenoids. Borneol, carveol, citral, geraniol, and α-terpineol showed the highest nematicidal activity among the in vitro tested monoterpenoids. These compounds exhibited a dose dependent effect, and drastically reduced eggs hatching and J2 viability at low concentrations. These monoterpenoids, at 100 and 250 mg/kg concentration, diminished root galling of tomato plants in pot experiments. The results suggest that the selected monoterpenoids, and essential oils with high concentration of these compounds, are potential nematicides against Meloidogyne.

scholarly journals Silver i-motifs and their antibacterial activity

2021 ◽  
Author(s):  
Jessica Bratt
Keyword(s):  
Antibacterial Activity ◽  
Therapeutic Potential ◽  
Bacterial Load ◽  
Therapeutic Benefit ◽  
In Vivo Studies ◽  
Resistant Bacteria ◽  
Drug Resistant Bacteria ◽  
Low Concentrations

<p>The spread of antibiotic resistance and the emergence of multi-drug resistant bacteria is a major threat to public health. This study investigated a unique cytosine rich DNA structure, the i-Motif to deliver soluble Ag+ as a novel antimicrobial agent (AgiMs). AgiMs were evaluated in vitro against P. aeruginosa and A. baumannii strains. AgiMs displayed significant antibacterial activity against both P. aeruginosa and A. baumannii (median MIC: 0.875 µM and 0.75 µM, respectively) by rapid, bactericidal and concentration-dependent effect. Low concentrations of AgiMs showed efficacy against PAO1 20-h biofilms, resulting in 57% reduction in biomass (5 x MIC). A single dose of AgiMs extended survival of G. Mellonella larvae, with the therapeutic benefit paralleled in the reduction of internal bacterial load. Synergistic interactions were observed with the combination of AgiMs and tobramycin, a common antibiotic used to treat P. aeruginosa infections; indicating the potential for AgiMs to reinstate the potency of current antibiotics. This silver-based agent might be an alternative to the failing antibiotic regimes for MDR resistant infections. Further in vitro and in vivo studies are warranted to confirm the therapeutic potential. </p>

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

2019 ◽  
Vol 109 (1) ◽  
pp. 52-62 ◽  
Author(s):  
Y.-Y. Liao ◽  
A. L. Strayer-Scherer ◽  
J. White ◽  
A. Mukherjee ◽  
R. De La Torre-Roche ◽  
...  
Keyword(s):  
Antibacterial Activity ◽  
Magnesium Oxide ◽  
Untreated Control ◽  
Structural Changes ◽  
Field Experiments ◽  
Negative Impact ◽  
Metal Oxide Nanoparticles ◽  
Spectrometric Analysis ◽  
Bacterial Spot ◽  
Xanthomonas Perforans

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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