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

Plant Disease ◽  
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.

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 Photocatalysis: Effect of Light-Activated Nanoscale Formulations of TiO2 on Xanthomonas perforans and Control of Bacterial Spot of Tomato

2013 ◽  
Vol 103 (3) ◽  
pp. 228-236 ◽  
Author(s):  
Mathews L. Paret ◽  
Gary E. Vallad ◽  
Devron R. Averett ◽  
Jeffrey B. Jones ◽  
Stephen M. Olson
Keyword(s):  
Reactive Oxygen Species ◽  
Photocatalytic Activity ◽  
Disease Incidence ◽  
Reactive Oxygen ◽  
Field Trials ◽  
Molecular Structures ◽  
Oxygen Species ◽  
Bacterial Spot ◽  
Xanthomonas Perforans

Protection of crops from bacterial diseases presents a continuing challenge, mandating the development of novel agents and approaches. Photocatalysis is a process where chemically reactive oxygen species are catalytically generated by certain minerals in the presence of light. These reactive oxygen species have the capacity to destroy organic molecular structures critical to pathogen viability. In this study, the antibacterial potential of photocatalytic nanoscale titanium dioxide (TiO2), nanoscale TiO2 doped (incorporation of other materials into the structure of TiO2) with silver (TiO2/Ag), and nanoscale TiO2 doped with zinc (TiO2/Zn; AgriTitan) was evaluated against Xanthomonas perforans, the causal agent for bacterial spot disease of tomato. In vitro experiments on photocatalytic activity and dose dependency were conducted on glass cover slips coated with the nanoscale formulations by adding a known population of X. perforans strain Xp-F7 and illuminating the cover slips under a visible light source. TiO2/Ag and TiO2/Zn had high photocatalytic activity against X. perforans within 10 min of exposure to 3 × 104 lux. Greenhouse studies on naturally and artificially infected transplants treated with TiO2/Zn at ≈500 to 800 ppm significantly reduced bacterial spot severity compared with untreated and copper control. Protection was similar to the grower standard, copper + mancozeb. The use of TiO2/Zn at ≈500 to 800 ppm significantly reduced disease incidence in three of the four trials compared with untreated and copper control, and was comparable to or better than the grower standard. The treatments did not cause any adverse effects on tomato yield in any of the field trials.

scholarly journals 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 ◽  
2012 ◽  
Vol 96 (2) ◽  
pp. 221-227 ◽  
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.

Impact of the biofungicide tetramycin on the development of Fusarium head blight, grain yield and deoxynivalenol accumulation in wheat

2020 ◽  
Vol 13 (2) ◽  
pp. 235-246
Author(s):  
W.Q. Shi ◽  
L.B. Xiang ◽  
D.Z. Yu ◽  
S.J. Gong ◽  
L.J. Yang
Keyword(s):  
Fusarium Head Blight ◽  
Fusarium Graminearum ◽  
Spore Germination ◽  
Field Experiments ◽  
Synergistic Effects ◽  
Field Trials ◽  
Head Blight ◽  
Mycelium Growth ◽  
Key Aspects

Fusarium graminearum causes Fusarium head blight (FHB), a devastating disease that leads to extensive yield and quality loss in wheat and barley production. Integrated pest management (IPM) is required to control this disease and biofungicides, such as tetramycin, could be a novel addition to IPM strategies. The current study investigated in vitro tetramycin toxicity in Fusarium graminearum and evaluated its effectiveness for the control of Fusarium head blight FHB. Tetramycin was shown to affect three key aspects of Fusarium pathogenicity: spore germination, mycelium growth and deoxynivalenol (DON) production. The in vitro results indicated that tetramycin had strong inhibitory activity on the mycelial growth and spore germination. Field trials indicated that tetramycin treatment resulted in a significant reduction in both the FHB disease index and the level of DON accumulation. The reduced DON content in harvested grain was correlated with the amount of Tri5 mRNA determined by qRT-PCR. Synergistic effects between tetramycin and metconazole, in both the in vitro and field experiments were found. Tetramycin could provide an alternative option to control FHB.

scholarly journals Development and Evaluation of Thermosensitive Hydrogels with Binary Mixture of Scutellariae baicalensis radix Extract and Chitosan for Periodontal Diseases Treatment

2021 ◽  
Vol 22 (21) ◽  
pp. 11319
Author(s):  
Justyna Chanaj-Kaczmarek ◽  
Tomasz Osmałek ◽  
Emilia Szymańska ◽  
Katarzyna Winnicka ◽  
Tomasz M. Karpiński ◽  
...  
Keyword(s):  
Binary Mixture ◽  
Synergistic Effects ◽  
Periodontal Diseases ◽  
Antibacterial Properties ◽  
Poloxamer 407 ◽  
Cellulose Derivatives ◽  
Novel Approach ◽  
Thermosensitive Hydrogels ◽  
Scutellariae Baicalensis

Scutellaria baicalensis root displays anti-inflammatory and antibacterial properties due to the presence of flavonoids, particularly baicalin, baicalein, and wogonin. Our work aimed at developing thermosensitive hydrogels containing a binary mixture of S. baicalensis radix lyophilized extract and chitosan as a novel approach for periodontal diseases treatment. Two types of chitosan were employed in preliminary studies on binary mixtures with S. baicalensis radix lyophilized extract standardized for baicalin, baicalein, and wogonin. Thermosensitive hydrogels were prepared of poloxamer 407, alginate sodium, and cellulose derivatives and evaluated in terms of rheological and mucoadhesive behavior. The presence of chitosan altered the release profile of active compounds but did not affect their in vitro permeation behavior in PAMPA assay. The synergistic effects of S. baicalensis radix lyophilized extract and chitosan toward ferrous ion-chelating activity, inhibition of hyaluronidase, and pathogen growth were observed. The thermosensitive gelling system showed shear-thinning properties, gelation temperature between 25 and 27 °C, and favorable mucoadhesiveness in contact with porcine buccal mucosa, which was enhanced in the presence of binary mixture of S. baicalensis radix extract and chitosan. The release tests showed that baicalin and baicalein were liberated in a prolonged manner with a fast onset from hydrogel formulations.

Synergistic Effects of Silver Nanoparticles with Ethanolic Extract of Eucalyptus globules on Standard Pathogenic Bacteria in Vitro

2020 ◽  
Author(s):  
Abolfazl Jafari Sales ◽  
Afsoon Shariat
Keyword(s):  
Silver Nanoparticles ◽  
Pathogenic Bacteria ◽  
Synergistic Effects ◽  
Antibacterial Properties ◽  
Ethanolic Extract ◽  
Soxhlet Method ◽  
Eucalyptus Plant ◽  
Eucalyptus Globules

Introduction: Nowadays, with the increase of resistance due to overuse of synthetic chemical antibiotics, it seems necessary to find alternative drugs. The aim of this study was to compare the effects of silver nanoparticles and Eucalyptus globules (eucalyptus) ethanolic extract on standard bacteria of Staphylococcus aureus, Bacillus cereus, Pseudomonas aeruginosa and Escherichia coli. Material and Methods: In this experimental study, aerial parts of Eucalyptus plant were collected from Marand city and identified as Eucalyptus plant by botanists of Islamic Azad University, Ahar Branch. In this study, eucalyptus ethanolic extract was prepared by Soxhlet method and the antibacterial effects of eucalyptus extract at concentrations of 20, 30, 50 and 400 mg / ml and silver nanoparticles at concentrations of 10, 20, 40 and 80 μg / ml with agar well diffusion methods and tubular dilution were investigated. Results: The results showed that the ethanolic extract of Eucalyptus had more antibacterial properties compared to silver nanoparticles. Eucalyptus extract and silver nanoparticles had a greater effect on gram-positive bacteria. The effect of the combination of eucalyptus extract and silver nanoparticles was much greater than the effect of either. Conclusion: The results showed that silver nanoparticles in combination with eucalyptus extract have good antimicrobial activity against pathogenic bacteria. Therefore, this extract along with silver nanoparticles can be a good option for future studies in vivo to prepare antibacterial drugs.

scholarly journals Fungicide Seed Treatment Effects on Seedling Damping-off of Pumpkin Caused by Phytophthora capsici

Plant Disease ◽  
2003 ◽  
Vol 87 (1) ◽  
pp. 63-68 ◽  
Author(s):  
M. Babadoost ◽  
S. Z. Islam
Keyword(s):  
Seed Germination ◽  
Untreated Control ◽  
Mycelial Growth ◽  
Seed Treatment ◽  
Culture Medium ◽  
Phytophthora Capsici ◽  
Field Trials ◽  
Seedling Vigor ◽  
Damping Off

Apron XL LS (mefenoxam) and Allegiance FL (metalaxyl) were highly inhibitory to growth of mycelium of Phytophthora capsici in vitro. Effective dose (ED50) of mefenoxam and metalaxyl for 50% inhibition of mycelial growth, for all five isolates of P. capsici tested, was 0.98 and 0.99 μg a.i./ml of culture medium, respectively. For mefenoxam at 200 μg a.i./ml, sporangium and zoospore germination were reduced by 92 and 96%, respectively, and 21 and 24%, respectively, for metalaxyl. In greenhouse studies, seed treatment with mefenoxam (0.42 ml of Apron XL LS/kg of seed) and metalaxyl (0.98 ml of Allegiance FL/kg of seed) significantly reduced pre- and post-emergence damping-off of seedlings caused by P. capsici in three pumpkin cultivars (Dickinson, Hybrid-401, and Hybrid-698) tested. Thirty-one days after seeding, at inoculum levels of 0, 90, 600, 1,400, and 4,000 CFU/g of soil, the average seedling stands for mefenoxam treatment were 98.4, 93.8, 88.3, 77.8, and 64.8%; for metalaxyl, 99.1, 85.3, 85.8, 73.5, and 59.3; and for the untreated control, 97.5, 55.2, 45.7, 37.0, and 22.9%, respectively. In field trials, the average seedling stands 35 days after seeding were 76.7, 74.7, and 44.9% for mefenoxam, metalaxyl, and untreated control, respectively. Seed treatment with mefenoxam or metalaxyl did not have any significant effect on either seed germination or seedling vigor.

scholarly journals Flupropanate in vitro pasture species susceptibilities

2015 ◽  
Vol 68 ◽  
pp. 105-111
Author(s):  
S.L. Lamoureaux ◽  
G.W. Bourd?t ◽  
A.D.L. Noble ◽  
C.A. Dowsett
Keyword(s):  
New Zealand ◽  
Field Trial ◽  
Untreated Control ◽  
Field Trials ◽  
Lipid Biosynthesis ◽  
Selective Control ◽  
Linear Regressions

Flupropanate a soilactive herbicide that inhibits lipid biosynthesis has become available in New Zealand for the selective control of the stipoid grasses Nassella neesiana and N trichotoma in pasture In commercial spray operations and field trials the selectivity of the herbicide has been extremely variable As a first step towards identifying pasture species that could be safely sown following application of the herbicide the in vitro doseresponse of 33 species and cultivars (grasses and dicotyledons) was determined Ranking the cultivars based on the slopes of linear regressions fitted to their radicle lengths (relative to untreated control) against the logarithm of flupropanate dose suggested that ryegrass and Nassella spp are among the most sensitive whilst plantain chicory and some legumes including lucerne are relatively tolerant The rankings from this study will be subjected to validation in a field trial using a subset of the species

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