scholarly journals A Metabolomic Study of Epichloë Endophytes for Screening Antifungal Metabolites

Metabolites ◽  
2022 ◽  
Vol 12 (1) ◽  
pp. 37
Author(s):  
Krishni Fernando ◽  
Priyanka Reddy ◽  
Kathryn M. Guthridge ◽  
German C. Spangenberg ◽  
Simone J. Rochfort
Keyword(s):  
Phytopathogenic Fungi ◽  
Bioactive Metabolites ◽  
Symbiotic Association ◽  
In Planta ◽  
Vitro Assay ◽  
Antifungal Metabolites ◽  
Bioassay Guided Fractionation ◽  
Toxic Alkaloids ◽  
Epichloë Endophytes

Epichloë endophytes, fungal endosymbionts of Pooidae grasses, are commonly utilized in forage and turf industries because they produce beneficial metabolites that enhance resistance against environmental stressors such as insect feeding and disease caused by phytopathogen infection. In pastoral agriculture, phytopathogenic diseases impact both pasture quality and animal production. Recently, bioactive endophyte strains have been reported to secrete compounds that significantly inhibit the growth of phytopathogenic fungi in vitro. A screen of previously described Epichloë-produced antifeedant and toxic alkaloids determined that the antifungal bioactivity observed is not due to the production of these known metabolites, and so there is a need for methods to identify new bioactive metabolites. The process described here is applicable more generally for the identification of antifungals in new endophytes. This study aims to characterize the fungicidal potential of novel, ‘animal friendly’ Epichloë endophyte strains NEA12 and NEA23 that exhibit strong antifungal activity using an in vitro assay. Bioassay-guided fractionation, followed by metabolite analysis, identified 61 metabolites that, either singly or in combination, are responsible for the observed bioactivity. Analysis of the perennial ryegrass-endophyte symbiota confirmed that NEA12 and NEA23 produce the prospective antifungal metabolites in symbiotic association and thus are candidates for compounds that promote disease resistance in planta. The “known unknown” suite of antifungal metabolites identified in this study are potential biomarkers for the selection of strains that enhance pasture and turf production through better disease control.

Role of chitinase and β-1,3-glucanase activities produced by a fluorescent pseudomonad and in vitro inhibition of Phytophthora capsici and Rhizoctonia solani

2007 ◽  
Vol 53 (2) ◽  
pp. 207-212 ◽  
Author(s):  
Naveen Kumar Arora ◽  
Min Jeong Kim ◽  
Sun Chul Kang ◽  
Dinesh Kumar Maheshwari
Keyword(s):  
Rhizoctonia Solani ◽  
Phytophthora Capsici ◽  
Phytopathogenic Fungi ◽  
Culture Technique ◽  
Dual Culture ◽  
Fluorescent Pseudomonad ◽  
Antifungal Metabolites ◽  
Fluorescent Pseudomonas

A study was conducted to investigate the possibility of involvement of chitinase and β-1,3-glucanase of an antagonistic fluorescent Pseudomonas in growth suppression of phytopathogenic fungi, Phytophthora capsici and Rhizoctonia solani . Fluorescent Pseudomonas isolates GRC3 and GRC4 were screened for their antifungal potential against phytopathogenic fungi by using dual culture technique both on solid and liquid media. The percent inhibition was calculated. Various parameters were monitored for optimization of enzyme activities by fluorescent Pseudomonas GRC3. The involvement of chitinases, β-1,3-glucanases, and antifungal metabolites of nonenzymatic nature was correlated with the inhibition of P. capsici and R. solani. The results provide evidence for antibiosis as a mechanism for antagonism. The study also confirms that multiple mechanisms are involved in suppressing phytopathogens as evidenced by the involvement of chitinase and β-1,3-glucanase in inhibition of R. solani but not P. capsici by isolate GRC3.

scholarly journals Generation of strong casein kinase 1 inhibitor of Arabidopsis thaliana

2019 ◽  
Author(s):  
Ami N Saito ◽  
Hiromi Matsuo ◽  
Keiko Kuwata ◽  
Azusa Ono ◽  
Toshinori Kinoshita ◽  
...  
Keyword(s):  
Bromine Atom ◽  
Casein Kinase ◽  
In Planta ◽  
Vitro Assay ◽  
Casein Kinase 1 ◽  
Yeast Fungi ◽  
Genes Encoding ◽  
Period Lengthening

AbstractCasein kinase 1 (CK1) is an evolutionarily conserved protein kinase among eukaryotes. Studies on yeast, fungi, and animals have revealed that CK1 plays roles in divergent biological processes. By contrast, the collective knowledge regarding the biological roles of plant CK1 lags was behind those of animal CK1. One of reasons for this is that plants have more multiple genes encoding CK1 than animals. To accelerate the research for plant CK1, a strong CK1 inhibitor that efficiently inhibits multiple members of CK1 proteins in vivo (in planta) is required. Here, we report a novel strong CK1 inhibitor of Arabidopsis (AMI-331). Using a circadian period-lengthening activity as estimation of the CK1 inhibitor effect in vivo, we performed a structure-activity relationship (SAR) study of PHA767491 (1,5,6,7-tetrahydro-2-(4-pyridinyl)-4H-pyrrolo[3,2-c]pyridin-4-one hydrochloride), a potent CK1 inhibitor of Arabidopsis, and found that PHA767491 analogues bearing a propargyl group at the pyrrole nitrogen atom (AMI-212) or a bromine atom at the pyrrole C3 position (AMI-23) enhance the period-lengthening activity. The period lengthening activity of a hybrid molecule of AMI-212 and AMI-23 (AMI-331) is about 100-fold stronger than that of PHA767491. An in vitro assay indicated a strong inhibitory activity of CK1 kinase by AMI-331. Also, affinity proteomics using an AMI-331 probe showed that targets of AMI-331 are mostly CK1 proteins. As such, AMI-331 is a strong potent CK1 inhibitor that shows promise in the research of CK1 in plants.

scholarly journals The Effect of Various pH Medium on the Secondary Metabollites Production from Trichoderma harzianum T10 to Control Damping Off on Cucumber Seedlings

2020 ◽  
Vol 3 (2) ◽  
pp. 65
Author(s):  
Nur Chalimah ◽  
Loekas Soesanto ◽  
Woro Sri Suharti
Keyword(s):  
Secondary Metabolites ◽  
Trichoderma Harzianum ◽  
Disease Incidence ◽  
In Vitro Assay ◽  
Cucumber Seedling ◽  
Damping Off ◽  
In Planta ◽  
Vitro Assay ◽  
Cucumber Seedlings

Damping-off is one of the main diseases in cucumber seedlings caused by Pythium sp. Secondary metabolites of Trichoderma harzianum T10 can conduct the control of the disease. The pH of the medium influences the production of secondary metabolites. The research aimed to determine the effective pH medium on production of T. harzianum T10 secondary metabolites, and the effect of the T. harzianum T10 secondary metabolites application in damping-off disease control also to the growth of cucumber seedling. The research was consist of two steps; 1) in vitro assay with various pH levels 5; 3; 3.5; 4; 4.5; 5.5; 6; 6.5; and 7, 2) In planta treatments consisted of control, fungicide (Mancozeb), secondary metabolites in pH 5 and 5.5 with the concentration of 5, 10 and 15% each. The research showed that: 1) the effective pH medium for the production of T. harzianum T10 secondary metabolites was 5 and 5.5. 2) application of the T. harzianum T10 secondary metabolites on pH 5 and 5.5 with a concentration of 5, 10, and 15% could decrease the disease incidence and support cucumber seedling growth.

scholarly journals Chromatographic profiles of antifungal exo- and endometabolites of Bacillus velezensis

2021 ◽  
Vol 2(26) ◽  
pp. 191-199
Author(s):  
T.M. Sidorova ◽  
◽  
A.M. Asaturova ◽  
V.V. Allakhverdyan ◽  
◽  
...  
Keyword(s):  
Antifungal Activity ◽  
Fusarium Oxysporum ◽  
Phytopathogenic Fungi ◽  
Antagonistic Activity ◽  
Active Metabolites ◽  
Fungicidal Action ◽  
Antifungal Metabolites ◽  
Alternaria Sp ◽  
Tlc Analysis

The antifungal activity of the Bacillus bacteria is based on their ability to produce metabolites. Therefore, when selecting a strain that produces an effective biofungicide, it is necessary to assess the metabolism of bacteria. The aim of this work is to isolate exo- and endometabolites of the promising B. velezensis BZR 336g and B. velezensis BZR 517 strains and assess their antifungal activity. Studies were carried out in 2020–2021. The object of the study is a liquid culture of the B. velezensis BZR 336g and B. velezensis BZR 517 strains. Methods of liquid extraction, ascending thin layer chromatography (TLC), bioautography with a test-culture of Fusarium oxysporum var. orthoceras and Alternaria sp. fungi were used to analyze metabolites. The ability of the strains to accumulate a complex of active metabolites showing antifungal effect from fungistatic to fungicidal action was revealed. On the bioautogram of exometabolites, we found two most pronounced zones (Rf 0.18 and 0.29) of Fusarium oxysporum var. orthoceras BZR P1 growth inhibition (fungicide). Zones with Rf 0.58 for B. velezensis BZR 336g and Rf 0.70 for B. velezensis BZR 517 correspond to the test fungus growth retardation (fungistatic). Significant suppression of Alternaria sp. BZR P8 growth was also observed in two zones (Rf 0.18 and 0.29). The use of surfactin, iturin A, fengycin (Sigma-Aldrich®) in the TLC analysis made it possible to detect similar lipopeptides in the composition of metabolite complexes produced by the studied bacteria. It should be noted that the studied strains differed both in their ability to produce metabolites of different structure (can be found when analyzing chromatograms under ultraviolet light) and in their effect on phytopathogenic fungi in vitro. This may indicate possible differences in the mechanism of antagonistic activity of bacteria against phytopathogenic fungi. Thus, B. velezensis BZR 336g and B. velezensis BZR 517 produce a significant set of antifungal metabolites and can be used as strains to produce effective biofungicides.

ASSESSMENT OF SOME ABIOTIC FACTORS ON MICROBIAL BIOPRODUCTS USEFUL IN BIOCONTROL OF PHYTOPATHOGENS

2016 ◽  
Vol 5 (3) ◽  
pp. 799-803
Author(s):  
Sergiu Fendrihan ◽  
Sorina Dinu ◽  
Oana Alina Sicuia ◽  
Florica Constantinescu
Keyword(s):  
Abiotic Factors ◽  
Fungal Growth ◽  
Phytopathogenic Fungi ◽  
Antagonistic Activity ◽  
Antagonistic Effect ◽  
Limiting Factors ◽  
Multiplication Rate ◽  
Antifungal Metabolites ◽  
Ph Conditions

The environmental factors may influence the growth of microorganisms, by favoring their growth or slowing their multiplication rate and the synthesis of different metabolites. Parameters such as temperature, aeration, nutrients, pH or tolerance to NaCl can become limiting factors for microorganisms survival. Bacillus subtilis and related species can grow in variable pH conditions, maintaining the cytoplasmically pH in a relatively close range, stable to the synthesis of proteins and nucleic acids.The aim of this work was to assess the influence of some abiotic factors on the biocontrol activity of microbial bioproducts, based on beneficial strains from Bacillus sp.. The bioproducts were tested in vitro against soil borne fungi at different temperatures and pH conditions. The results showed that the antagonistic activity of the biopreparates, tested at 27°C and 25°C, against phytopathogenic fungi released antifungal metabolites which inhibited the fungal growth. Also, when different pH values were analyzed, the results reflected that at pH 5.5 and pH 8.5 the bioproducts maintained the same antagonistic effect as in the control variant (pH 7.0).

scholarly journals Baseline Sensitivity of Pyraclostrobin and Toxicity of SHAM to Sclerotinia sclerotiorum

Plant Disease ◽  
2015 ◽  
Vol 99 (2) ◽  
pp. 267-273 ◽  
Author(s):  
Hong-Jie Liang ◽  
Ya-Li Di ◽  
Jin-Li Li ◽  
Hong You ◽  
Fu-Xing Zhu
Keyword(s):  
Sclerotinia Sclerotiorum ◽  
Mycelial Growth ◽  
Inhibitory Effect ◽  
Oxidase Inhibitor ◽  
Cross Resistance ◽  
In Planta ◽  
Baseline Sensitivity ◽  
Vitro Assay ◽  
Quinone Outside Inhibitor

Sclerotinia sclerotiorum is a cosmopolitan plant pathogen notable for its wide host range. The quinone outside inhibitor (QoI) fungicide pyraclostrobin has not been registered for control of S. sclerotiorum in China. In this study, baseline sensitivity of pyraclostrobin was established based on effective concentration for 50% inhibition of mycelial growth (EC50) values of 153 isolates of S. sclerotiorum collected from five provinces of China and toxicity of alternative oxidase inhibitor salicylhydroxamic acid (SHAM) to S. sclerotiorum was determined. Results showed that the frequency distribution of EC50 values of the 153 isolates was unimodal but with a right-hand tail. The mean EC50 value was 0.1027 μg/ml and the range of EC50 values was 0.0124 to 0.6324 μg/ml. Applied as a preventive fungicide in pot experiments, pyraclostrobin at 5, 15, and 45 μg/ml provided control efficacies of 61, 77, and 100%, respectively. There was no positive cross-resistance between pyraclostrobin and carbendazim or dimethachlon. EC50 values for SHAM against four isolates of S. sclerotiorum were 44.4, 51.8, 54.4, and 68.7 μg/ml. SHAM at 20 μg/ml could significantly increase not only the inhibitory effect of pyraclostrobin on mycelial growth on potato dextrose agar media but also the control efficacy in planta. These results indicated that SHAM should not be added into artificial media in in vitro assay of S. sclerotiorum sensitivity to pyraclostrobin. This has broad implications for assay of sensitivity of fungal pathogen to QoI fungicides.

scholarly journals Screening and Isolation of a Novel Polyene-Producing Streptomyces Strain Inhibiting Phytopathogenic Fungi in the Soil Environment

2021 ◽  
Vol 9 ◽  
Author(s):  
Heung-Soon Park ◽  
Hee-Ju Nah ◽  
Seung-Hoon Kang ◽  
Si-Sun Choi ◽  
Eung-Soo Kim
Keyword(s):  
Genome Mining ◽  
Biosynthetic Gene Cluster ◽  
Phytopathogenic Fungi ◽  
Bioactive Metabolites ◽  
Target Compound ◽  
Soil Environment ◽  
Soil Isolate ◽  
Linear Polyene ◽  
Polyene Compound

Microbial-based eco-friendly biological substances are needed to protect crops from phytopathogenic fungi and replace toxic chemical fungicides that cause serious environmental issues. This study screened for soil antifungal Streptomyces strains, which produce rich, diverse, and valuable bioactive metabolites in the soil environment. Bioassay-based antifungal screening of approximately 2,400 Streptomyces strains led to the isolation of 149 strains as tentative antifungal producers. One Streptomyces strain showing the most potent antifungal activities against Candida albicans and Fusarium oxysporum was identified as a putative anti-phytopathogenic soil isolate that is highly homologous to Streptomyces rubrisoli (named S. rubrisoli Inha 501). An in vitro antifungal assay, pot-test, and field-test against various phytopathogenic fungi confirmed that S. rubrisoli Inha 501 is a potential novel phytopathogenic fungicide producer to protect various crops in the soil environment. Whole-genome sequencing of S. rubrisoli Inha 501 and an anti-SMASH genome mining approach revealed an approximately 150-kb polyene biosynthetic gene cluster (BGC) in the chromosome. The target compound isolation and its BGC analysis confirmed that the giant linear polyene compound exhibiting the anti-phytopathogenic activity in S. rubrisoli Inha 501 was highly homologous to the previously reported compound, neotetrafibricin A. These results suggest that a bioassay-based screening of a novel antifungal Streptomyces strain followed by its genome mining for target compound BGC characterization would be an efficient approach to isolating a novel candidate phytopathogenic fungicide that can protect crops in the soil environment.

scholarly journals Effect of agitation rate on the production of antifungal metabolites by Streptomyces hygroscopicus in a lab-scale bioreactor

2017 ◽  
pp. 231-244 ◽  
Author(s):  
Ivana Mitrovic ◽  
Jovana Grahovac ◽  
Jelena Dodic ◽  
Mila Grahovac ◽  
Sinisa Dodic ◽  
...  
Keyword(s):  
Inhibition Zone ◽  
Phytopathogenic Fungi ◽  
Plant Diseases ◽  
Streptomyces Hygroscopicus ◽  
Agitation Rate ◽  
Promising Alternative ◽  
Potato Dextrose Agar Medium ◽  
Antifungal Metabolites ◽  
Apple Fruits

The application of antifungal compounds produced by microorganisms in the control of plant diseases caused by phytopathogenic fungi is a promising alternative to synthetic pesticides. Among phytopathogenic fungi, Alternaria alternata and Fusarium avenaceum are significant pathogens responsible for the storage rot of apple fruits. During storage, transport and marketing A. alternata and F. avenaceum can cause significant losses of apple fruits and their control is of great importance for the producers and consumers. In the present study, the effects of agitation rate on the production of antifungal methabolite( s) by Streptomyces hygroscopicus in a 3-L lab-scale bioreactor (Biostat? Aplus, Sartorius AG, Germany) against two isolates of A. alternata and two isolates of F. avenaceum were investigated. The cultivation of S. hygroscopicus was carried out at 27?C with agitation rates of 100 rpm and 200 rpm during 7 days. The aim was to analyze the bioprocess parameters of biofungicide production in a medium containing glycerol as a carbon source, and examine the effect of agitation rate on the production of antifungal metabolite(s). The in vitro antifungal activity of the produced metabolites against fungi from the genera Alternaria and Fusarium grown on potato dextrose agar medium was determined every 24 h using wells technique. In the experiments conducted in the bioreactor at different stirring speeds, it was found that the maximum production of antifungal metabolites occurred after 96 hours of cultivation. A higher consumption of nutrients and a larger inhibition zone diameter was registered in the experiment with an agitation rate of 200 rpm.

scholarly journals Broad-spectrum inhibition of Phytophthora infestans by root endophytes

2017 ◽  
Author(s):  
Sophie de Vries ◽  
Janina K. von Dahlen ◽  
Anika Schnake ◽  
Sarah Ginschel ◽  
Barbara Schulz ◽  
...  
Keyword(s):  
Phytophthora Infestans ◽  
Broad Spectrum ◽  
Biocontrol Agent ◽  
Agar Medium ◽  
Fungal Endophytes ◽  
Effective Control ◽  
Bioactive Metabolites ◽  
List Type ◽  
In Planta

SummaryPhytophthora infestans (Phy. infestans) is a devastating pathogen of tomato and potato. It readily overcomes resistance genes and applied agrochemicals. Fungal endophytes provide a largely unexplored avenue of control against Phy. infestans. Not only do endophytes produce a wide array of bioactive metabolites, they may also directly compete with and defeat pathogens in planta.Twelve isolates of fungal endophytes from different plant species were tested in vitro for their production of metabolites with anti-Phy. infestans activity. Four well-performing isolates were evaluated for their ability to suppress nine isolates of Phy. infestans on agar medium and in planta.Two endophytes reliably inhibited all Phy. infestans isolates on agar medium, of which Phoma eupatorii isolate 8082 was the most promising. It nearly abolished infection by Phy. infestans in planta.Here we present a biocontrol agent, which can inhibit a broad-spectrum of Phy. infestans isolates. Such broadly acting inhibition is ideal, because it allows for effective control of genetically diverse pathogen isolates and may slow the adaptation of Phy. infestans.

scholarly journals From Strain Characterization to Field Authorization: Highlights on Bacillus velezensis Strain B25 Beneficial Properties for Plants and Its Activities on Phytopathogenic Fungi

2021 ◽  
Vol 9 (9) ◽  
pp. 1924
Author(s):  
Pierre Joly ◽  
Alexandra Calteau ◽  
Aurélie Wauquier ◽  
Rémi Dumas ◽  
Mylène Beuvin ◽  
...  
Keyword(s):  
Plant Growth ◽  
Crop Yields ◽  
Antibiotic Resistance Genes ◽  
Pathogenic Fungi ◽  
Phytopathogenic Fungi ◽  
In Planta ◽  
Bacillus Velezensis ◽  
Plant Growth Promoting ◽  
Growth Promoting

Agriculture is in need of alternative products to conventional phytopharmaceutical treatments from chemical industry. One solution is the use of natural microorganisms with beneficial properties to ensure crop yields and plant health. In the present study, we focused our analyses on a bacterium referred as strain B25 and belonging to the species Bacillus velezensis (synonym B. amyloliquefaciens subsp. plantarum or B. methylotrophicus), a promising plant growth promoting rhizobacterium (PGPR) and an inhibitor of pathogenic fungi inducing crops diseases. B25 strain activities were investigated. Its genes are well preserved, with their majority being common with other Bacillus spp. strains and responsible for the biosynthesis of secondary metabolites known to be involved in biocontrol and plant growth-promoting activities. No antibiotic resistance genes were found in the B25 strain plasmid. In vitro and in planta tests were conducted to confirm these PGPR and biocontrol properties, showing its efficiency against 13 different pathogenic fungi through antibiosis mechanism. B25 strain also showed good capacities to quickly colonize its environment, to solubilize phosphorus and to produce siderophores and little amounts of auxin-type phytohormones (around 13,051 µg/mL after 32 h). All these findings combined to the fact that B25 demonstrated good properties for industrialization of the production and an environmental-friendly profile, led to its commercialization under market authorization since 2018 in several biostimulant preparations and opened its potential use as a biocontrol agent.

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