scholarly journals Isolation of a New Mexican Strain ofBacillus subtiliswith Antifungal and Antibacterial Activities

2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
M. G. L. Basurto-Cadena ◽  
M. Vázquez-Arista ◽  
J. García-Jiménez ◽  
R. Salcedo-Hernández ◽  
D. K. Bideshi ◽  
...  

Although several strains ofB. subtiliswith antifungal activity have been isolated worldwide, to date there are no published reports regarding the isolation of a nativeB. subtilisstrain from strawberry plants in Mexico. A native bacterium (Bacillus subtilis21) demonstratedin vitroantagonistic activity against different plant pathogenic fungi. Under greenhouse conditions, it was shown that plants infected withRhizoctonia solaniandFusarium verticillioidesand treated withB. subtilis21 produced augment in the number of leaves per plant and an increment in the length of healthy leaves in comparison with untreated plants. In addition,B. subtilis21 showed activity against pathogenic bacteria. Secreted proteins byB. subtilis21 were studied, detecting the presence of proteases and bacteriocin-like inhibitor substances that could be implicated in its antagonistic activity. Chitinases and zwittermicin production could not be detected. Then,B. subtilis21 could potentially be used to control phytopathogenic fungi that infect strawberry plants.

2020 ◽  
Vol 30 (1) ◽  
Author(s):  
Zahaed Evangelista-Martínez ◽  
Erika Anahí Contreras-Leal ◽  
Luis Fernando Corona-Pedraza ◽  
Élida Gastélum-Martínez

Abstract Background Fungi are one of the microorganisms that cause most damage to fruits worldwide, affecting their quality and consumption. Chemical controls with pesticides are used to diminish postharvest losses of fruits. However, biological control with microorganisms or natural compounds is an increasing alternative to protect fruits and vegetables. In this study, the antifungal effect of Streptomyces sp. CACIS-1.5CA on phytopathogenic fungi that cause postharvest tropical fruit rot was investigated. Main body Antagonistic activity was evaluated in vitro by the dual confrontation over fungal isolates obtained from grape, mango, tomato, habanero pepper, papaya, sweet orange, and banana. The results showed that antagonistic activity of the isolate CACIS-1.5CA was similar to the commercial strain Streptomyces lydicus WYEC 108 against the pathogenic fungi Colletotrichum sp., Alternaria sp., Aspergillus sp., Botrytis sp., Rhizoctonia sp., and Rhizopus sp. with percentages ranging from 30 to 63%. The bioactive extract obtained from CACIS-1.5 showed a strong inhibition of fungal spore germination, with percentages ranging from 92 to 100%. Morphological effects as irregular membrane border, deformation, shrinkage, and collapsed conidia were observed on the conidia. Molecularly, the biosynthetic clusters of genes for the polyketide synthase (PKS) type I, PKS type II, and NRPS were detected in the genome of Streptomyces sp. CACIS-1.5CA. Conclusions This study presented a novel Streptomyces strain as a natural alternative to the use of synthetic fungicides or other commercial products having antagonistic microorganisms that were used in the postharvest control of phytopathogenic fungi affecting fruits.


Author(s):  
Mohammed M Matin ◽  
Mohammad Ibrahim ◽  
Md Shafiqur Rahman

A number of 2,3-di-O-acyl derivatives (6-11) of methyl 4-O-acetyl-a-Lrhamnopyranoside (5) obtained by using various acylating agents were screened for in vitro antifungal activity against four plant pathogenic fungi, viz., Alternaria alternata, Curvularia lunata. Fusarium equiseti and Macrophomina phaseolina. These compounds were also screened for in vitro antibacterial activity against ten human pathogenic bacteria, viz., Bacillus subtilis, Bacillus cereus, Bacillus megaterium, Staphylococcus aureus, Escherichia coli, INABA ET (Vibrio), Pseudomonas species, Salmonella paratyphi, Shigella dysenteriae and Salmonella typhi. The study reveal that these 4-O-acetyl-?-L-rhamnopyranoside derivatives are more prone towards antifungal activities than that of antibacterial activities. DOI: http://dx.doi.org/10.3329/cujbs.v3i1.13404 The Chittagong Univ. J. B. Sci.,Vol. 3(1&2):33-43, 2008


2016 ◽  
Vol 3 (2) ◽  
pp. 1-8 ◽  
Author(s):  
Milton Luiz da Paz Lima ◽  
Maria Cristina Araújo Vaz ◽  
Aline Suelen da Silva ◽  
Karoliny De Almeida Souza ◽  
Gabriel Isaias Lee Tuñon

The aim of this study was the confrontation of Trichoderma spp. with pathogenic and non-pathogenic fungi. The Trichoderma spp. and filamentous fungi (Fusarium solani, Alternaria sp., Colletotrichum gloeosporioides, and Aspergillus niger) were transferred to potato-dextrose-agar (PDA). The confrontation was performed using Petri dishes inoculated with mycelial disks in opposite position (9 mm) of Trichoderma spp. and filamentous fungi. After inoculation the plates remained under 25 ° C regime to 12 hours light for a period of seven days. After this period was evaluated qualitatively according to the scale of Bell et al. (1982), which consists of the suitability scores for the area percentage of the culture medium under expression of antagonism. The isolate of C. gloeosporioides (jatropha) was isolated which had statistically slightly inhibited growth by Trichoderma spp., Unlike the isolated Alternaria sp. (parsley) was isolated micelial fungi suffered the most antagonism. Statistically the Trichoderma isolate derived from pineapple promoted the highest antagonistic activity against isolates of pathogenic fungi tested, being a candidate for use in biocontrol.


2020 ◽  
Vol 98 (1) ◽  
pp. 34-39 ◽  
Author(s):  
Abbas Rahdar ◽  
Hamid Beyzaei ◽  
Mohsen Saadat ◽  
Xiao Yu ◽  
John F. Trant

Nanoparticles, 10–14 nm, consisting of either Fe3O4 or Co0.2Fe2.8O4 stabilized with oleic acid, were prepared using solution combustion. Their structural and magnetic properties were examined using X-ray diffractometry, scanning electron microscopy, vibrating sample magnetometry, and Fourier-transform infrared spectroscopy. The properties of both sets of materials are similar, except that the cobalt-doped particles are considerably less magnetic. The in vitro inhibitory activities of the nanoparticles were assessed against pathogenic bacteria Shigella dysenteriae, Klebsiella pneumoniae, Acinetobacter baumannii, Streptococcus pyogenes, and pathogenic fungi and molds Candida albicans, Fusarium oxysporum, and Aspergillus fumigatus. The magnetite nanoparticles were moderately effective against all tested pathogens, but the activity of the cobalt-doped nanoparticles was significantly lower, possibly due to an interruption of the Fenton reaction at the bacterial membrane. This work suggests that potentially doping magnetite with stronger metal oxidants may instead enhance their antimicrobial effects.


2021 ◽  
Vol 31 (1) ◽  
Author(s):  
The Anh Luu ◽  
Quyet Tien Phi ◽  
Thi Thu Hang Nguyen ◽  
Mai Van Dinh ◽  
Bich Ngoc Pham ◽  
...  

Abstract Background Fungal stem end rot disease of pitaya caused by Alternaria alternata is one of the most destructive diseases in Binh Thuan province, Vietnam. This study aimed to assess the antagonistic effects of some endophytic bacteria isolated from the weed plant (Echinochloa colonum) against A. alternata. Results A total of 19 endophytic bacteria were isolated and 5 of them presented in vitro antagonistic activity against A. alternata. Of five, strain EC80 significantly inhibited the pathogenic growth with a mean inhibition diameter of 11.88 ± 0.08 mm, while the other four (C79, EC83, EC90, and EC97) showed a weak inhibition. Interestingly, the combination of EC79 and EC80 reduced more biomass of pathogenic fungi than the single one did. EC79 showed positive results for amylase, indole acetic acid (IAA), and biofilm production, whereas EC80 presented positive capabilities for IAA and biofilm production and a negative one for amylase production. In addition, the combined filtrate of EC79 and EC80 presented non-antifungal activity on biocontrol tests in vitro, indicating that bacteria cells played a role in defending against the pathogen. Moreover, both isolates EC79 and EC80 significantly increased seedling biomass than the control. Conclusions The results suggest that those two strains in combination had the potential to be used as a biocontrol agent against A. alternata. More studies should be done in the future to evaluate their efficiency under the field conditions.


2021 ◽  
Vol 18 ◽  
Author(s):  
Jyoti Gaba ◽  
Sunita Sharma ◽  
Harleen Kaur ◽  
Pardeep Kaur

Background: Thymol is a bioactive compound having many pharmacological activities. Objective: The present study was carried out to evaluate the fungi toxic effects of thymol and derivatives against phytopathogenic fungi of maize. Method: Thymol was derivatized to get formylated thymol, Mannich bases, and imine derivatives. All the synthesized thymol derivatives were characterized by their physical and spectral properties. Synthesized thymol derivatives were screened for their in vitro antifungal effects using poisoned food technique against three maize pathogenic fungi namely Fusarium moniliforme, Rhizoctonia solani and Dreschlera maydis. Results: Thymol and formylated thymol showed promising results for control of D. maydis with ED50 values less than standard carbendazim and comparable to standard mancozeb. These two compounds were further evaluated for control of D. maydis causative maydis leaf blight disease on maize plants grown in the field during the Kharif season (June to October) 2018. Conclusion: Thymol exhibited significant control of maydis leaf blight disease of maize and emerged as a potential alternative to synthetic fungicides used in cereal crops.


2014 ◽  
Vol 40 (3) ◽  
pp. 212-220 ◽  
Author(s):  
Sinar David Granada García ◽  
Antoni Rueda Lorza ◽  
Carlos Alberto Peláez

Microorganisms for biological control are capable of producing active compounds that inhibit the development of phytopathogens, constituting a promising tool toob tain active principles that could replace synthetic pesticides. This study evaluatedtheability of severalpotentialbiocontrol microorganismsto produce active extracellular metabolites. In vitro antagonistic capability of 50 bacterial isolates from rhizospheric soils of "criolla" potato (Solanum phureja) was tested through dual culture in this plant with different plant pathogenic fungi and bacteria. Isolates that showed significantly higher antagonistic activity were fermented in liquid media and crude extracts from the supernatants had their biological activities assessed by optical density techniques. Inhibitory effecton tested pathogens was observed for concentrations between 0.5% and 1% of crude extracts. There was a correlation between the antimicrobial activity of extracts and the use of nutrient-rich media in bacteria fermentation. Using a bioguided method, a peptidic compound, active against Fusarium oxysporum, was obtained from the 7ANT04 strain (Pyrobaculum sp.). Analysis by nuclear magnetic resonance and liquid chromatography coupled to mass detector evidenced an 11-amino acid compound. Bioinformatic software using raw mass data confirmed the presence of a cyclic peptide conformed by 11 mostly non-standard amino acids.


2021 ◽  
Author(s):  
Pedro W Crous ◽  
Amy Y Rossman ◽  
Catherine Aime ◽  
Cavan Allen ◽  
Treena Burgess ◽  
...  

Names of phytopathogenic fungi and oomycetes are essential to communicate knowledge about species and their biology, control, and quarantine as well as for trade and research purposes. Many plant pathogenic fungi are pleomorphic, meaning that they produce different asexual (anamorph) and sexual (teleomorph) morphs in their lifecycles. Because of this, more than one name has been applied to different morphs of the same species, which has confused users of names. The onset of DNA technologies makes it possible to connect different morphs of the same species, resulting in a move to a more natural classification system for fungi, in which a single name for a genus as well as species can now be used. The move to a single nomenclature, as well as the advent of molecular phylogeny and the introduction of polythetic taxonomic approaches has been the main driving force for the re-classification of fungi, including pathogens. Nonetheless, finding the correct name for species remains challenging, but there is a series of steps or considerations that could greatly simplify this process, as outlined here. In addition to various online databases and resources, a list of accurate names is herewith provided of the accepted names of the most common genera and species of phytopathogenic fungi.


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