scholarly journals Maple Bark Biochar Affects Rhizoctonia solani Metabolism and Increases Damping-Off Severity

2015 ◽  
Vol 105 (10) ◽  
pp. 1334-1346 ◽  
Author(s):  
Tanya R. Copley ◽  
Konstantinos A. Aliferis ◽  
Suha Jabaji
Keyword(s):  
Rhizoctonia Solani ◽  
Plant Species ◽  
Plant Pathogens ◽  
Plant Diseases ◽  
Mass Spectrometry Analysis ◽  
Gas Chromatography Mass Spectrometry ◽  
Primary Metabolism ◽  
Damping Off ◽  
Biochar Amendment

Many studies have investigated the effect of biochar on plant yield, nutrient uptake, and soil microbial populations; however, little work has been done on its effect on soilborne plant diseases. To determine the effect of maple bark biochar on Rhizoctonia damping-off, 11 plant species were grown in a soilless potting substrate amended with different concentrations of biochar and inoculated or not with Rhizoctonia solani anastomosis group 4. Additionally, the effect of biochar amendment on R. solani growth and metabolism in vitro was evaluated. Increasing concentrations of maple bark biochar increased Rhizoctonia damping-off of all 11 plant species. Using multivariate analyses, we observed positive correlations between biochar amendments, disease severity and incidence, abundance of culturable bacterial communities, and physicochemical parameters. Additionally, biochar amendment significantly increased R. solani growth and hyphal extension in vitro, and altered its primary metabolism, notably the mannitol and tricarboxylic acid cycles and the glycolysis pathway. One or several organic compounds present in the biochar, as identified by gas chromatography-mass spectrometry analysis, may be metabolized by R. solani. Taken together, these results indicate that future studies on biochar should focus on the effect of its use as an amendment on soilborne plant pathogens before applying it to soils.

scholarly journals Phytotoxicity of Essential Oils on Selected Weeds: Potential Hazard on Food Crops

Plants ◽  
2018 ◽  
Vol 7 (4) ◽  
pp. 79 ◽  
Author(s):  
María Ibáñez ◽  
María Blázquez
Keyword(s):  
Seed Germination ◽  
Essential Oil ◽  
Essential Oils ◽  
Mass Spectrometry Analysis ◽  
Gas Chromatography Mass Spectrometry ◽  
Food Crops ◽  
Potential Hazard ◽  
Spectrometry Analysis

The chemical composition of winter savory, peppermint, and anise essential oils, and in vitro and in vivo phytotoxic activity against weeds (Portulaca oleracea, Lolium multiflorum, and Echinochloa crus-galli) and food crops (maize, rice, and tomato), have been studied. Sixty-four compounds accounting for between 97.67–99.66% of the total essential oils were identified by Gas Chromatography-Mass Spectrometry analysis. Winter savory with carvacrol (43.34%) and thymol (23.20%) as the main compounds produced a total inhibitory effect against the seed germination of tested weed. Menthol (48.23%), menthone (23.33%), and iso-menthone (16.33%) from peppermint only showed total seed germination inhibition on L. multiflorum, whereas no significant effects were observed with trans-anethole (99.46%) from anise at all concentrations (0.125–1 µL/mL). Low doses of peppermint essential oil could be used as a sustainable alternative to synthetic agrochemicals to control L. multiflorum. The results corroborate that in vivo assays with a commercial emulsifiable concentrate need higher doses of the essential oils to reproduce previous in vitro trials. The higher in vivo phytotoxicity of winter savory essential oil constitutes an eco-friendly and less pernicious alternative to weed control. It is possible to achieve a greater in vivo phytotoxicity if less active essential oil like peppermint is included with other active excipients.

scholarly journals Sensitivity of Rhizoctonia solani AG-2-2 from Sugar Beet to Fungicides

Plant Disease ◽  
2016 ◽  
Vol 100 (12) ◽  
pp. 2427-2433 ◽  
Author(s):  
Sahar Arabiat ◽  
Mohamed F. R. Khan
Keyword(s):  
Sugar Beet ◽  
Rhizoctonia Solani ◽  
Root Rot ◽  
The United States ◽  
Damping Off ◽  
Growth Assay ◽  
The Mean ◽  
Crown And Root Rot ◽  
Mean Concentration

Rhizoctonia damping-off and crown and root rot caused by Rhizoctonia solani are major diseases of sugar beet (Beta vulgaris L.) worldwide, and growers in the United States rely on fungicides for disease management. Sensitivity of R. solani to fungicides was evaluated in vitro using a mycelial radial growth assay and by evaluating disease severity on R. solani AG 2-2 inoculated plants treated with fungicides in the greenhouse. The mean concentration that caused 50% mycelial growth inhibition (EC50) values for baseline isolates (collected before the fungicides were registered for sugar beet) were 49.7, 97.1, 0.3, 0.2, and 0.9 μg ml−1 and for nonbaseline isolates (collected after registration and use of fungicides) were 296.1, 341.7, 0.9, 0.2, and 0.6 μg ml−1 for azoxystrobin, trifloxystrobin, pyraclostrobin, penthiopyrad, and prothioconazole, respectively. The mean EC50 values of azoxystrobin, trifloxystrobin, and pyraclostrobin significantly increased in the nonbaseline isolates compared with baseline isolates, with a resistant factor of 6.0, 3.5, and 3.0, respectively. Frequency of isolates with EC50 values >10 μg ml−1 for azoxystrobin and trifloxystrobin increased from 25% in baseline isolates to 80% in nonbaseline isolates. Although sensitivity of nonbaseline isolates of R. solani to quinone outside inhibitors decreased, these fungicides at labeled rates were still effective at controlling the pathogen under greenhouse conditions.

scholarly journals Pathogenicity and Volatile Nematicidal Metabolites from Duddingtonia flagrans against Meloidogyne incognita

2021 ◽  
Vol 9 (11) ◽  
pp. 2268
Author(s):  
Xiaoyu Mei ◽  
Xin Wang ◽  
Guohong Li
Keyword(s):  
Meloidogyne Incognita ◽  
Plant Pathogens ◽  
Plant Root ◽  
Nematicidal Activity ◽  
Mass Spectrometry Analysis ◽  
Gas Chromatography Mass Spectrometry ◽  
Egg Mass ◽  
Duddingtonia Flagrans ◽  
Egg Hatching ◽  
Root Knot Nematodes

Plant parasitic nematodes, especially parasitic root-knot nematodes, are one of the most destructive plant pathogens worldwide. The control of plant root-knot nematodes is extremely challenging. Duddingtonia flagrans is a type of nematode-trapping fungi (NTF), which produces three-dimensional adhesive networks to trap nematodes. In this study, the pathogenicity and volatile organic compounds (VOCs) of the NTF D. flagrans against the plant root-knot nematode, Meloidogyne incognita, were investigated. The predatory process of D. flagrans trapping M. incognita was observed using scanning electron microscopy. Gas chromatography-mass spectrometry analysis of the VOCs from D. flagrans led to the identification of 52 metabolites, of which 11 main compounds were tested individually for their activity against M. incognita. Three compounds, cyclohexanamine, cyclohexanone, and cyclohexanol, were toxic to M. incognita. Furthermore, these three VOCs inhibited egg hatching of M. incognita. Cyclohexanamine showed the highest nematicidal activity, which can cause 97.93% mortality of M. incognita at 8.71 µM within 12 h. The number of hatched juveniles per egg mass after 3 days was just 8.44 when treated with 26.14 µM cyclohexanamine. This study is the first to demonstrate the nematicidal activity of VOCs produced by D. flagrans against M. incognita, which indicates that D. flagrans has the potential to biocontrol plant root-knot nematodes.

scholarly journals Effect of Fungal Metabolites and Amendments on Mycelial Growth of Rhizoctonia Solani

2010 ◽  
Vol 50 (1) ◽  
pp. 93-97 ◽  
Author(s):  
Keyword(s):  
Rhizoctonia Solani ◽  
Culture Filtrate ◽  
Mycelial Growth ◽  
Plant Pathogens ◽  
Organic Amendment ◽  
Test Organism ◽  
Suppressive Effect ◽  
Fungal Metabolites ◽  
Castor Cake

Effect of Fungal Metabolites and Amendments on Mycelial Growth ofRhizoctonia SolaniA shift towards organic farming suggests amalgamation of organic resources against soil borne plant pathogens. The influence of metabolites of most ubiquitousAspergillusspp., organic amendment extracts and their combined effect withTrichoderma virenswere evaluatedin vitroagainstRhizoctonia solani.The minimum (36.1 mm) growth was attained byR. solaniin co-culture withA. niger.The maximum (42.3 mm) inhibition of mycelial growth of the test organism was observed with culture filtrate ofA. ochraceousfollowed byA. niger, A. fumigatus, A. flavusandA. terreus.Among organic amendment extractants, castor cake exhibited an additive effect on the growth ofT. virens, however, the maximum (41.8 mm) suppressive effect onR. solaniwas observed with vermicompost. With the advance in time, the effect of organic amendment extracts increased markedly. Inhibition potential of culture filtrate mixturte ofA. niger+T. virensandA. ochraceous+T. virensagainstR. solaniwas significantly higher in comparison to the other combinations.

scholarly journals Synergistic Antifungal Activity of Graphene Oxide and Fungicides against Fusarium Head Blight In Vitro and In Vivo

Nanomaterials ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 2393
Author(s):  
Xiuping Wang ◽  
Fei Peng ◽  
Caihong Cheng ◽  
Lina Chen ◽  
Xuejuan Shi ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Plant Pathogens ◽  
Antimicrobial Agents ◽  
Plant Protection ◽  
Disease Incidence ◽  
Agricultural Science ◽  
Plant Diseases ◽  
Synergistic Activity

Plant pathogens constantly develop resistance to antimicrobial agents, and this poses great challenges to plant protection. Therefore, there is a pressing need to search for new antimicrobials. The combined use of antimicrobial agents with different antifungal mechanisms has been recognized as a promising approach to manage plant diseases. Graphene oxide (GO) is a newly emerging and highly promising antimicrobial agent against various plant pathogens in agricultural science. In this study, the inhibitory activity of GO combined with fungicides (Mancozeb, Cyproconazol and Difenoconazole) against Fusarium graminearum was investigated in vivo and in vitro. The results revealed that the combination of GO and fungicides has significant synergistic inhibitory effects on the mycelial growth, mycelial biomass and spore germination of F. graminearum relative to single fungicides. The magnitude of synergy was found to depend on the ratio of GO and fungicide in the composite. In field tests, GO–fungicides could significantly reduce the disease incidence and disease severity, exhibiting a significantly improved control efficacy on F. graminearum. The strong synergistic activity of GO with existing fungicides demonstrates the great application potential of GO in pest 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 Chemical Composition and Biological Activities of Essential Oils of Pinus patula

2011 ◽  
Vol 6 (10) ◽  
pp. 1934578X1100601 ◽  
Author(s):  
Ismail Amri ◽  
Hamrouni Lamia ◽  
Samia Gargouri ◽  
Mohsen Hanana ◽  
Mariem Mahfoudhi ◽  
...  
Keyword(s):  
Gas Chromatography ◽  
Essential Oils ◽  
Biological Activities ◽  
Pathogenic Fungi ◽  
Plant Diseases ◽  
Gas Chromatography Mass Spectrometry ◽  
Pinus Patula ◽  
Flame Ionization ◽  
Total Oil

Essential oils isolated from needles of Pinus patula by hydrodistillation were analyzed by gas chromatography-flame ionization detection (GC-FID) and gas chromatography mass spectrometry (GC-MS). Thirty-eight compounds were identified, representing 98.3% of the total oil. The oil was rich in monoterpene hydrocarbons (62.4%), particularly α-pinene (35.2%) and β-phellandrene (19.5%). The in vitro antifungal assay showed that P. patula oil significantly inhibited the growth of 9 plant pathogenic fungi. The oil, when tested on Sinapis arvensis, Lolium rigidum, Phalaris canariensis and Trifolium campestre, completely inhibited seed germination and seedling growth of all species. Our preliminary results showed that P. patula essential oil could be valorized for the control of weeds and fungal plant diseases.

scholarly journals GAS CHROMATOGRAPHY-MASS SPECTROMETRY ANALYSIS AND IN VITRO ANTIMICROBIAL SCREENING OF WEDELIA GLAUCA (ORTEGA) O. HOFFM. EX HICKEN

2017 ◽  
Vol 10 (11) ◽  
pp. 109
Author(s):  
Krishnavignesh L Krishnavignesh ◽  
Mahalakshmipriya A ◽  
Ramesh M
Keyword(s):  
Mass Spectrometry ◽  
Gas Chromatography ◽  
Antimicrobial Activity ◽  
Mass Spectrometry Analysis ◽  
Gas Chromatography Mass Spectrometry ◽  
Diffusion Method ◽  
Spectrometry Analysis ◽  
Chromatography Mass Spectrometry ◽  
Ms Analysis

  Objective: Continued resistance toward the antibiotics urges us to explore newer antibiotics. Plants are being the safer source of antibiotics with lesser or no side effects. This study was designed to study the presence of phytochemical constituents and antibacterial activity of leaf and flower extracts of Wedelia glauca against urinary tract infection causing pathogens.Methods: The plant leaves were extracted with five different solvents based on the polarity. The extraction was done using soxhalation. Antimicrobial activity was determined by agar well diffusion method for both the sample and standard. The acetone plant extract was subjected to gas chromatography-mass spectrometry (GC-MS) analysis for screening phytoconstituents.Results: Preliminary phytochemical screening revealed the presence of diverse phytoconstituents in the plant. The different extracts exhibited a considerable antimicrobial potential. Among the solvents used acetone extract showed comparably better antimicrobial activity with 100% of inhibition rate with the maximum zone of inhibition of 1.6±0.77 mm against Staphylococcus sp. and Aspergillus sp. at the concentration of 5 mg. GC-MS analysis provided 8 major peaks which revealed the existence of a variety of bioactive compounds which may attribute to the efficacy of the plant.Conclusion: W. glauca leaf and flower extracts displayed a broad spectrum of antibacterial and antifungal activity and can be considered as a potential source of newer antibiotic compounds.

scholarly journals Staphylococcus saprophyticus L-38 produces volatile 3,3-dimethyl-1,2-epoxybutane with strong inhibitory activity against Aspergillus flavus germination and aflatoxin production

2020 ◽  
Vol 13 (2) ◽  
pp. 247-258 ◽  
Author(s):  
A.D. Gong ◽  
G.J. Sun ◽  
Z.Y. Zhao ◽  
Y.C. Liao ◽  
J.B. Zhang
Keyword(s):  
Food Safety ◽  
Antifungal Activity ◽  
Aspergillus Flavus ◽  
Plant Pathogens ◽  
Aflatoxin Production ◽  
Gas Chromatography Mass Spectrometry ◽  
Total Peak Area ◽  
Staphylococcus Saprophyticus

Controlling proliferation and aflatoxin production by Aspergillus flavus is a pressing challenge for global food safety and security. Marine bacterium Staphylococcus saprophyticus strain L-38 showed excellent antifungal activity toward A. flavus in vitro and in vivo. In sealed, non-contact confrontation assays, L-38 completely inhibited conidial germination and mycelial growth of A. flavus through the production of volatile organic compounds (VOCs). Gas chromatography-mass spectrometry identified 3,3-dimethyl-1,2-epoxybutane (3-DE) as the most abundant VOC (32.61% of total peak area, 78% matching). Exposure of A. flavus cultures to synthetic 3-DE similarly demonstrated strong inhibition of growth. Moreover, culture of L-38 in a sealed chamber with maize or peanuts artificially inoculated with A. flavus, at high water activity, resulted in significant inhibition of A. flavus germination and aflatoxin biosynthesis. Scanning electron microscopy of these samples revealed severe damage to conidial cells and hyphae compared to samples not exposed to L-38. L-38 also showed broad and effective antifungal activity toward eight other phytopathogenic fungi including Aspergillus niger, Fusarium verticillioides, Fusarium graminearum, Sclerotinia sclerotiorum, Rhizoctonia solani, Alternaria alternata, Monilinia fructicola, and Botrytis cinerea. This work introduces S. saprophyticus L-38 as a potential biocontrol agent and demonstrates the efficacy of the volatile 3-DE in the control of A. flavus and other destructive plant pathogens for post-harvest food safety.

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