Successful strategy for the selection of new strawberry-associated rhizobacteria antagonistic to Verticillium wilt

2000 ◽  
Vol 46 (12) ◽  
pp. 1128-1137 ◽  
Author(s):  
Gabriele Berg ◽  
Stefan Kurze ◽  
Arno Buchner ◽  
Elizabeth M Wellington ◽  
Kornelia Smalla

In order to isolate and characterize new strawberry-associated bacteria antagonistic to the soil-borne pathogenic fungus Verticillium dahliae Kleb., rhizobacterial populations from two different strawberry species, Greenish Strawberry (Fragaria viridis) and Garden Strawberry (F. × ananassa) obtained after plating onto King's B and glycerol-arginine agar, were screened for in vitro antagonism toward V. dahliae. The proportion of isolates with antifungal activity determined in in vitro assay against V. dahliae was higher for the Garden Strawberry than for the Greenish Strawberry. From 300 isolates, 20 isolates with strong antifungal activity were selected characterized by physiological profiling and molecular fingerprinting methods. Diversity among the isolates was characterized with molecular fingerprints using amplified ribosomal DNA restriction analysis (ARDRA) and the more discriminating BOX-PCR fingerprint method. The physiological profiles were well correlated with molecular fingerprinting pattern analysis. Significant reduction of Verticillium wilt by bacterial dipping bath treatment was shown in the greenhouse and in fields naturally infested by V. dahliae. The relative increase of yield ranged from 117% (Streptomyces albidoflavus S1) to 344% (Pseudomonas fluorescens P10) in greenhouse trials, and 113% (Streptomyces albidoflavus S1) to 247% (Pseudomonas fluorescens P6) in field trials. Evaluation resulted in the selection of three effective biocontrol agents (Pseudomonas fluorescens P6, P10, and Streptomyces diastatochromogenes S9) antagonistic to the Verticillium wilt pathogen.Key words: biocontrol, molecular fingerprint, antifungal properties, Pseudomonas, Streptomyces.

Biomolecules ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1728
Author(s):  
Stefany Castaldi ◽  
Marco Masi ◽  
Francisco Sautua ◽  
Alessio Cimmino ◽  
Rachele Isticato ◽  
...  

Pseudomonas fluorescens 9 and Bacillus subtilis 54, proposed as biofungicides to control Macrophomina phaseolina, a dangerous pathogen of soybean and other crops, were grown in vitro to evaluate their ability to produce metabolites with antifungal activity. The aim of the manuscript was to identify the natural compounds responsible for their antifungal activity. Only the culture filtrates of P. fluorescens 9 showed strong antifungal activity against M. phaseolina. Its organic extract contained phenazine and mesaconic acid (1 and 2), whose antifungal activity was tested against M. phaseolina, as well as Cercospora nicotianae and Colletotrichum truncatum, other pathogens of soybean; however, only compound 1 exhibited activity. The antifungal activity of compound 1 was compared to phenazine-1-carboxylic acid (PCA, 3), 2-hydroxyphenazine (2-OH P, 4), and various semisynthetic phenazine nitro derivatives in order to perform a structure–activity relationship (SAR) study. PCA and phenazine exhibited the same percentage of growth inhibition in M. phaseolina and C. truncatum, whereas PCA (3) showed lower activity against C. nicotianae than phenazine. 2-Hydroxyphenazine (4) showed no antifungal activity against M. phaseolina. The results of the SAR study showed that electron attractor (COOH and NO2) or repulsor (OH) groups significantly affect the antifungal growth, as well as their α- or β-location on the phenazine ring. Both PCA and phenazine could be proposed as biopesticides to control the soybean pathogens M. phaseolina, C. nicotianae, and C. truncatum, and these results should prompt an investigation of their large-scale production and their suitable formulation for greenhouse and field applications.


2017 ◽  
Vol 8 (2) ◽  
pp. 110-115
Author(s):  
L M. Alfin Agushara Bena ◽  
Achmad . ◽  
Syamsul Falah

Invasion of Botryodiplodia theobromae as a dieback fungus on jabon merah (Anthocephalus macrophyllus) seedlings is a crucial issues. This pathogenic fungus needs to be controlled precisely. Phytochemical compounds of plant material is one alternative fungicides. Crude extracts of picung (Pangium edule) leaf in water and methanol solvent known to have antifungal potential. However, its activity against B. theobromae need to be revealed. In vitro assay aimed to measuring antifungal activity of water and methanol extracts of picung leaf on controlling growth of B. theobromae pathogenic fungus. Hot water extraction and maceration in methanol was conducted to obtain crude extract materials. In-vitro antifungal assay of water and methanol extracts of picung leaf was conducted by food poisoning method on Potato Dextrose Agar media. The results showed that water and methanol extracts of pangi leaf be able to suppress the growth of B. theobromae on the first day of observation, with the highest antifungal index reached 100% at concentration of 25mg/mL and 50mg/mL, respectively. This indicates that water and methanol extracts of picung leaf have antifungal activity. Generally, there was a trend of decrease in antifungal index over time.Key words: antifungal activity, Botryodiplodia theobromae, jabon merah, picung


Author(s):  
Mahmoud A. Al-Sha'er ◽  
Mutasem O. Taha

Introduction: Tyrosine threonine kinase (TTK1) is a key regulator of chromosome segregation. TTK targeting received recent concern for the enhancement of possible anticancer therapies. Objective: In this regard we employed our well-known method of QSAR-guided selection of best crystallographic pharmacophore(s) to discover considerable binding interactions that anchore inhibitors into TTK1 binding site. Method:Sixtyone TTK1 crystallographic complexes were used to extract 315 pharmacophore hypotheses. QSAR modeling was subsequently used to choose a single crystallographic pharmacophore that when combined with other physicochemical descriptors elucidates bioactivity discrepancy within a list of 55 miscellaneous inhibitors. Results: The best QSAR model was robust and predictive (r2(55) = 0.75, r2LOO = 0.72 , r2press against external testing list of 12 compounds = 0.67), Standard error of estimate (training set) (S)= 0.63 , Standard error of estimate (testing set)(Stest) = 0.62. The resulting pharmacophore and QSAR models were used to scan the National Cancer Institute (NCI) database for new TTK1 inhibitors. Conclusion: Five hits confirmed significant TTK1 inhibitory profiles with IC50 values ranging between 11.7 and 76.6 micM.


2018 ◽  
Author(s):  
Maria-Dimitra Tsolakidou ◽  
Ioannis A. Stringlis ◽  
Natalia Fanega-Sleziak ◽  
Stella Papageorgiou ◽  
Antria Tsalakou ◽  
...  

AbstractComposts represent a sustainable way to suppress diseases and improve plant growth. Identification of compost-derived microbial communities enriched in the rhizosphere of plants and characterization of their traits, could facilitate the design of microbial synthetic communities (SynComs) that upon soil inoculation could yield consistent beneficial effects towards plants. Here, we characterized a collection of compost-derived bacteria, previously isolated from tomato rhizosphere, forin vitroantifungal activity against soil-borne fungal pathogens and for their potential to change growth parameters inArabidopsis. We further assessed root-competitive traits in the dominant rhizospheric genusBacillus. Certain isolated rhizobacteria displayed antifungal activity against the tested pathogens and affected growth ofArabidopsis, and Bacilli members possessed several enzymatic activities. Subsequently, we designed two SynComs with different composition and tested their effect onArabidopsisand tomato growth and health. SynCom1, consisting of different bacterial genera, displayed negative effect onArabidopsis in vitro, but promoted tomato growth in pots. SynCom2, consisting of Bacilli, didn’t affectArabidopsisgrowth, enhanced tomato growth and suppressed Fusarium wilt symptoms. Overall, we found selection of compost-derived microbes with beneficial properties in the rhizosphere of tomato plants, and observed that application of SynComs on poor substrates can yield reproducible plant phenotypes.


2008 ◽  
Vol 14 (S3) ◽  
pp. 148-149 ◽  
Author(s):  
M. Zuzarte ◽  
A.M. Dinis ◽  
C. Cavaleiro ◽  
J. Canhoto ◽  
L. Salgueiro

The selection of native Lavandula species and their economic exploitation have increased in the last few years. Micropropagation techniques have been used as an alternative for vegetative propagation allowing the multiplication of selected genotypes and chemotypes. Our previous studies showed that the essential oils of Lavandula pedunculata have an important antifungal activity against dermatophyte strains. Therefore, a new line of investigation concerning the in vitro culture of this species is justified. In the present study we compare the morphology of the leaf trichomes and the chemical composition of their essential oils in both field-growing and in vitro propagated plants.


2019 ◽  
Vol 132 ◽  
pp. 132-141 ◽  
Author(s):  
Julia Riede ◽  
Ken-Ichi Umehara ◽  
Patrick Schweigler ◽  
Felix Huth ◽  
Hilmar Schiller ◽  
...  

2020 ◽  
Vol 150 ◽  
pp. 02003 ◽  
Author(s):  
Azeddin El Barnossi ◽  
Fatimazahrae Moussaid ◽  
Abdelilah Iraqi Housseini

Candida albicans an opportunistic pathogenic fungus causes many infections in humans. Whereas Aspergillus niger is a fungus that can produce ochratoxins, a group of extremely dangerous secondary metabolites that are classified as potentially carcinogenic to humans and also causing deterioration in grapes, strawberries, etc. The purpose of the current study is to isolate, purify, identify and characterize new microorganisms associated with solid green household waste for the control of C. albicans and A. niger. The antifungal activity of bacterial isolates was carried out in vitro by the agar plug diffusion method, the disk and well diffusion method. The isolate that showed promising activity has been identified by those macroscopic, microscopic and biochemical characteristics. The results obtained in the course of this study showed the isolation of an isolate named Gn-A11-18, which was shown to have significant inhibitory activity with a 42.66% inhibition percentage against A. niger and a 44.66 mm inhibition diameter against C. albicans compared to the controls. The identification of Gn-A11-18 isolate has shown that this isolate belongs to the genus Bacillus with a similarity to Bacillus subtilis and Bacillus tequilensis. In the light of the results of this study, we can suggest that the bioactive compound of Bacillus sp. Gn-A11-18 could become a biological alternate that could have an important role to fight against C. albicans and A. niger.


2018 ◽  
Vol 19 (11) ◽  
pp. 3449 ◽  
Author(s):  
Eugene Rogozhin ◽  
Artur Zalevsky ◽  
Alexander Mikov ◽  
Alexey Smirnov ◽  
Tsezi Egorov

Herein, we describe a modified form of the antimicrobial hairpin-like peptide EcAMP1, isolated from barnyard grass (E. crusgalli) seeds, which is structurally characterized by a combination of high-pressure liquid chromatography, mass spectrometry, and automated Edman sequencing. This derivate has a single amino acid substitution (Pro19Hyp) in the second α-helical region of the molecule, which is critical for the formation of the hydrophobic core and the secondary structure elements. Comparing the antifungal activity of these two peptides, we found that the modified EcAMP1-Hyp had a significantly weaker activity towards the most-sensitive plant pathogenic fungus Fusarium solani. Molecular dynamics simulations and in vitro binding to the commercial polysaccharides allowed us to conclude that the Pro-19 residue is important for binding to carbohydrates located in the spore cell wall and it chiefly exhibits a fungistatic action representing the hyphal growth inhibition. These data are novel and significant for understanding a role of α-hairpinins in plant immunity.


2006 ◽  
Vol 73 (4) ◽  
pp. 1320-1331 ◽  
Author(s):  
Alka Rao ◽  
Geeta Ram ◽  
Adesh Kumar Saini ◽  
Reena Vohra ◽  
Krishan Kumar ◽  
...  

ABSTRACT Recent advances in nonrational and part-rational approaches to de novo peptide/protein design have shown increasing potential for development of novel peptides and proteins of therapeutic use. We demonstrated earlier the usefulness of one such approach recently developed by us, called “codon shuffling,” in creating stand-alone de novo protein libraries from which bioactive proteins could be isolated. Here, we report the synthesis and selection of codon-shuffled de novo proteins that bind to a selected Mycobacterium tuberculosis protein target, the histone-like protein HupB, believed to be essential for mycobacterial growth. Using a versatile bacterial two-hybrid system that entailed utilization of HupB and various codon-shuffled protein libraries as bait and prey, respectively, we were able to identify proteins that bound strongly to HupB. The observed interaction was also confirmed using an in vitro assay. One of the protein binders was expressed in Mycobacterium smegmatis and was shown to appreciably affect growth in the exponential phase, a period wherein HupB is selectively expressed. Furthermore, the transcription profile of hupB gene showed a significant reduction in the transcript quantity in mycobacterial strains expressing the protein binder. Electron microscopy of the affected mycobacteria elaborated on the extent of cell damage and hinted towards a cell division malfunction. It is our belief that a closer inspection of the obtained de novo proteins may bring about the generation of small-molecule analogs, peptidomimetics, or indeed the proteins themselves as realistic leads for drug candidates. Furthermore, our strategy is adaptable for large-scale targeting of the essential protein pool of Mycobacterium tuberculosis and other pathogens.


2021 ◽  
Vol 21 (no 1) ◽  
Author(s):  
Ruchi Vyas ◽  
Kanika Sharma

In the present study, in-vitro antifungal activity of various elicitors and binders were evaluated against Alternaria alternata, causative agent of early blight disease in Tomato. Antifungal activities were assayed by poison food technique. Among all elicitors and binders best optimum activity was observed for castor oil cake and cow dung 63.06% and 60 .95% respectively against Alternaria alternata. On the basis of results obtained, best active elicitor i.e., castor oil cake and binder cow dung can be used to develop the plant extract-based bio-formulation for effective control of leaf blight disease of Tomato in an eco-friendly manner.


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