scholarly journals Potential of Trichosporon asahii against Alternaria sp. and mechanisms of actions

2020 ◽  
Vol 46 (1) ◽  
pp. 20-25
Author(s):  
Ariane Silva Bosqueiro ◽  
Rodolfo Bizarria Júnior ◽  
Márcia Maria Rosa-Magri

ABSTRACT Alternaria sp. is a fungus that causes rot in several crops, causing damage to the agricultural production chain. Biological control agents constitute an alternative to reduce the use of pesticides in the crops, a social demand for modern agriculture. The aim of the present study is to demonstrate the antagonistic effect of the yeast Trichosporon asahii (3S44) on the mycelial development of Alternaria sp. and some in vitro mechanisms of action. Trichosporon asahii showed antagonistic activity towards Alternaria sp., presenting mycelial inhibition (57.47%). The assays indicated production of volatile organic compounds (VOCs), competition for nutrients, biofilm formation, production of killer toxins and β-1,3-glucanase as mechanisms of action of T. asahii. Collectively, our results showed the potential of T. asahii to control the mycelial development of Alternaria sp. and some mechanisms of action of this yeast for future biotechnological studies.

2012 ◽  
Vol 2012 ◽  
pp. 1-6 ◽  
Author(s):  
M. M. Rahman ◽  
M. E. Ali ◽  
A. A. Khan ◽  
A. M. Akanda ◽  
Md. Kamal Uddin ◽  
...  

A total of 91 isolates of probable antagonistic bacteria of potato soft rot bacteriumErwinia carotovorasubsp.carotovora(Ecc) were extracted from rhizospheres and endophytes of various crop plants, different soil varieties, and atmospheres in the potato farming areas of Bangladesh. Antibacterial activity of the isolated probable antagonistic bacteria was testedin vitroagainst the previously identified most common and most virulent soft rot causing bacterial strain Ecc P-138. Only two isolates E-45 and E-65 significantly inhibited thein vitrogrowth of Ecc P-138. Physiological, biochemical, and carbon source utilization tests identified isolate E-65 as a member of the genusBacillusand the isolate E-45 asLactobacillussp. The stronger antagonistic activity against Ecc P-138 was found in E-65in vitroscreening and storage potatoes. E-65 reduced the soft rot infection to 22-week storage potatoes of different varieties by 32.5–62.5% in model experiment, demonstrating its strong potential to be used as an effective biological control agent for the major pectolytic bacteria Ecc. The highest (62.5%) antagonistic effect of E-65 was observed in the Granola and the lowest (32.7%) of that was found in the Cardinal varieties of the Bangladeshi potatoes. The findings suggest that isolate E-65 could be exploited as a biocontrol agent for potato tubers.


2018 ◽  
Vol 8 (1) ◽  
pp. 88-91 ◽  
Author(s):  
M. Skaptsov ◽  
S. Smirnov ◽  
M. Kutsev ◽  
O. Uvarova ◽  
T. Sinitsyna ◽  
...  

<p><em>Trichoderma</em> isolates (SSBGT07, SSBGT08, SSBGT09, SSBGT10) were isolated from the soil samples of the South-Siberian Botanical Garden and identified using morphological observation and ITS region analysis as <em>Trichoderma harzianum</em>, <em>T. asperellum, T. ghanense</em>, and <em>T. longibranchiatum</em>. Antagonistic activity against <em>Cladosporium </em>sp. and<em> Botrytis </em>sp. was evaluated <em>in vitro</em>. All isolates showed antagonistic effect by competition against <em>Cladosporium </em>sp. <em>T. asperellum </em>and <em>T. longibranchiatum</em> showed antagonism against <em>Botrytis </em>sp. All isolates showed hyper sporulation on the sclerotia of <em>Botrytis</em> sp. (except the <em>T. ghanense</em>) and colonies of the <em>Cladosporium</em> sp. Our study provides new isolates that affect the <em>Cladosporium </em>sp. and<em> Botrytis </em>sp.</p>


Author(s):  
Eva Wambacq ◽  
Kris Audenaert ◽  
Monica Höfte ◽  
Sarah De Saeger ◽  
Geert Haesaert

In Belgium, silages are often infected by Penicillium roqueforti sensu lato (s.l.). These toxigenic fungi are well adapted to silage conditions, and their prevention during feed-out is difficult. Bacillus velezensis strain NRRL B-23189 has been reported to inhibit P.&nbsp;roqueforti&nbsp;s.s. conidiospore germination in vitro by the production of lipopeptides. In the present study, the antagonistic effect of this B. velezensis strain towards P.&nbsp;roqueforti&nbsp;s.l. was evaluated in vitro and in vivo. In vitro, corn silage conditions were simulated, and the impact of B.&nbsp;velezensis culture supernatant or cell suspension on P.&nbsp;roqueforti&nbsp;s.l. growth, conidiospore germination and survival and roquefortine C production was evaluated. The antagonism was promising, but growth of B.&nbsp;velezensis in corn silage infusion was poor. An in vivo experiment with microsilos containing a mixture of perennial ryegrass and white clover artificially contaminated with P.&nbsp;roqueforti&nbsp;s.l. was carried out to determine if B.&nbsp;velezensis cell suspension could be used as an antagonistic silage inoculant. The B.&nbsp;velezensis cell suspension applied was unsuccessful in reducing P.&nbsp;roqueforti&nbsp;s.l. numbers at desiling after 56 days compared to no additive application. However, feed-out of the silage was not simulated, so it remains elusive whether or not B.&nbsp;velezensis exerts antagonistic activity during this phase.&nbsp;


2019 ◽  
Vol 57 (2) ◽  
pp. 222-229
Author(s):  
Alexandra González-Esparza ◽  
Kong S. Ah-Hen ◽  
Osvaldo Montenegro ◽  
Erika Briceño ◽  
Joaquín Stevenson ◽  
...  

The aim of this study is to evaluate the survival rate and effective antagonistic activity against Botrytis cinerea, responsible for grey mould on harvested fruits and vegetables, of yeast Rhodotorula mucilaginosa, isolated and identified from the natural microbiota of murta (Chilean guava) berries, after spray drying at different inlet air temperatures, mass per volume ratio of encapsulating agent (maltodextrin) and feed flow rates. The 100 % survival of the yeast was obtained after spray drying with 18 % maltodextrin at 130 °C inlet temperature and a feed flow rate of 9.25 mL/min. The dried yeast obtained under such conditions had the highest antagonistic activity in vitro and in vivo on apples, which showed that spray drying is a valid method to produce active dried cells of R. mucilaginosa that can be used for biocontrol of grey mould spoilage. It was also found that the encapsulating agent maltodextrin improved the in vitro antagonistic activity of R. mucilaginosa.


2020 ◽  
Vol 55 (1) ◽  
pp. 35-42
Author(s):  
M. Harba ◽  
M. Jawhar ◽  
M. I. E. Arabi

Antagonistic microorganisms have been used as biological control agents to reduce the use of chemical fungicides in the control of crop diseases. The present work was conducted to determine the antagonistic potential of Bacillus sp. isolates against the soil-borne fungus Cochliobolus sativus, the causal agent of barley common root (CRR) disease. Out of 525 isolates, 40 were showed in vitro antagonistic activity against the virulent C. sativus isolate CRR16. On the basis of 16S rRNA gene sequencing Bacillus sp. isolates are identified as B. atrophaeus, B. subtilis, Paenibacillus polymyxa, B. amyloliquefaciens, B. simplex and B. tequilensis. Results showed that Bacillus sp. had significant (P<0.05) antagonistic activities against the C. sativus where the percentage of radial growth inhibition of the fungi colonies ranged from 59 to 92%, compared to the untreated control. The B. subtilis isolate SY41B had the highest inhibition effect on the vegetative growth zones as compared with the other species isolates. In view of these, our results indicate that the antagonistic effect of the Bacillus sp. isolates may be important contributors as a biocontrol approach that could be employed as a part of integrated CRR management system.


2021 ◽  
Vol 2(26) ◽  
pp. 191-199
Author(s):  
T.M. Sidorova ◽  
◽  
A.M. Asaturova ◽  
V.V. Allakhverdyan ◽  
◽  
...  

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.


Author(s):  
Daniel Alonso Pérez Corral ◽  
José de Jesús Ornelas Paz ◽  
Guadalupe Isela Olivas Orozco ◽  
Carlos Horacio Acosta Muñiz ◽  
Miguel Ángel Salas Marina ◽  
...  

Fungi and oomycetes are important plant pathogens that constantly attacked plants, thus compromising the production of foods worldwide. Streptomyces strains might be useful to control fungal pathogens by different mechanism. The in vitro antagonistic activity of non-volatile and volatile metabolites from four Streptomyces strains was evaluated over cultures of phytopathogenic fungi and oomycetes. The non-volatile compounds from Streptomyces strains significantly reduced (44.2 to 92.1%) the growth of aerial mycelium of pathogens. The volatile compounds (VOCs) from Streptomyces strains reduced both aerial mycelium (22.5 to 96.7%) and mycelium growing inside of culture medium (0.0 - 9.4%). The pathogens maintained their capacity to grow normally in fresh culture medium without antagonists after confrontations with antagonist VOCs. The analysis of VOCs by gas chromatography coupled to mass spectrometry revealed different kinds of VOCs included alcohols, aldehydes, ketones, esters, terpenes, terpenoids, thioethers, among others. The most abundant VOCs were trans-1,10-dimethyl-trans-9-decalol (geosmin), 2-methylisoborneol, 2-methyl-2-bornene, 1,4-dimethyladamantane, and 4-penten-1-ol, trifluoroacetate. The antipathogenic activity of nine pure VOCs that had been identified in cultures of the Streptomyces strains alone was evaluated in vitro against phytopathogenic fungi and oomycetes. Trans-2-hexenal was the most effective of these VOCs, inhibiting completely the growth of tested phytopathogens. The volatile and non-volatile compounds from Streptomyces strains effectively reduced the in vitro growth of phytopathogens and they might be used as biological control. Further studies are required to demonstrate this activity on open field conditions.


PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e12437
Author(s):  
Jannette Wen Fang Wu Wu ◽  
Mauricio Redondo-Solano ◽  
Lidieth Uribe ◽  
Rodolfo WingChing-Jones ◽  
Jessie Usaga ◽  
...  

Background Agro-industrial waste from tropical environments could be an important source of lactic acid bacteria (LAB) with probiotic potential. Methods Twelve LAB isolates were isolated from pineapple silages. The species identification was carried out considering 16S rRNA and pheS genes. Experiments to evaluate the probiotic potential of the isolates included survival under simulated gastrointestinal environment, in vitro antagonistic activity (against Salmonella spp. and Listeria monocytogenes), auto-aggregation assays, antibiotic susceptibility, presence of plasmids, adhesiveness to epithelial cells, and antagonistic activity against Salmonella in HeLa cells. Results Lacticaseibacillus paracasei, Lentilactobacillus parafarraginis, Limosilactobacillus fermentum, and Weissella ghanensis were identified. Survival of one of the isolates was 90% or higher after exposure to acidic conditions (pH: 2), six isolates showed at least 61% survival after exposure to bile salts. The three most promising isolates, based on survivability tests, showed a strong antagonistic effect against Salmonella. However, only L. paracasei_6714 showed a strong Listeria inhibition pattern; this isolate showed a good auto-aggregation ability, was resistant to some of the tested antibiotics but was not found to harbor plasmids; it also showed a high capacity for adhesion to epithelial cells and prevented the invasion of Salmonella in HeLa cells. After further in vivo evaluations, L. paracasei_6714 may be considered a probiotic candidate for food industry applications and may have promising performance in acidic products due to its origin.


2018 ◽  
Vol 16 (1) ◽  
pp. e1002 ◽  
Author(s):  
Kazem Kasfi ◽  
Parissa Taheri ◽  
Behrooz Jafarpour ◽  
Saeed Tarighi

The objective of this study was to identify grapevine epiphytic yeasts and bacteria for biocontrol of Botrytis cinerea on grapes. Antagonistic yeasts and bacteria were isolated from the epiphytic flora associated with grape berries and leaves cv. ‘Thompson seedless’ from vineyards in Iran and identified by sequencing the conserved genomic regions. A total of 130 yeast and bacterial isolates from the surface of grapevine were screened in vitro for determining their antagonistic effect against B. cinerea and used to control postharvest gray mold. Among the 130 isolates, five yeasts and four bacterial isolates showed the greatest antagonistic activity in vitro against B. cinerea. Two yeasts species including Meyerozyma guilliermondii and Candida membranifaciens had high antagonistic capability against the pathogen. Also, 4 bacterial isolates belonging to Bacillus sp. and Ralstonia sp. showed significant biocontrol effect against B. cinerea. The isolates were capable of producing volatile and non-volatile substances, which suppressed the pathogen growth. The antagonistic activity of selected yeasts and bacteria against the pathogen was investigated on wounded berries of ‘Thompson seedless’. On small clusters with intact berries, all of the antagonistic isolates considerably reduced the decay on grape berries and inhibition of gray mold incidence on fruits treated by these isolates was less than 50%, except for the isolate N1, which had higher capability in inhibiting the disease incidence. These results suggest that antagonist yeasts and bacteria with potential to control B. cinerea on grape can be found in the microflora of grape berries and leaves.


2016 ◽  
Vol 5 (3) ◽  
pp. 799-803
Author(s):  
Sergiu Fendrihan ◽  
Sorina Dinu ◽  
Oana Alina Sicuia ◽  
Florica Constantinescu

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).


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