13 research outputs found
Co-application of Difenoconazole with Thymol Results in Suppression of a Parastagonospora Nodorum Mutant Strain Resistant to this Triazole
Results of in vitro study of thymol, a natural chemosensitizer, as a potential agent for overcoming of difenoconazole resistance of Parastagonospora nodorum causing glume and leaf blotch of wheat are first reported. The level of difenoconazole resistance of a natural mutant PNm1 strain with low sensitivity to the Dividend fungicide (a.i. difenoconazole) was determined by the cultivation of this isolate on potato dextrose agar in the presence of the fungicide at sub-lethal and lethal (in relation to the initial fungicide-sensitive strain) concentrations. A principal possibility of the thymol use to overcome resistance of P. nodorum to DMI (demethylation inhibitors) fungicides is shown. Co-application of this compound with Dividend SC, 3 % resulted in a significant reduction of resistance of the mutant strain and enhancement of its sensitivity to difenoconazole up to the level corresponding to the initial non-resistant isolate
Co-application of Difenoconazole with Thymol Results in Suppression of A Parastagonospora Nodorum Mutant Strain Resistant to This Triazole
Results of in vitro study of thymol, a natural chemosensitizer, as a potential agent for overcoming of difenoconazole resistance of Parastagonospora nodorum causing glume and leaf blotch of wheat are first reported. The level of difenoconazole resistance of a natural mutant PNm1 strain with low sensitivity to the Dividend fungicide (a.i. difenoconazole) was determined by the cultivation of this isolate on potato dextrose agar in the presence of the fungicide at sub-lethal and lethal (in relation to the initial fungicide-sensitive strain) concentrations. A principal possibility of the thymol use to overcome resistance of P. nodorum to DMI (demethylation inhibitors) fungicides is shown. Co-application of this compound with Dividend SC, 3 % resulted in a significant reduction of resistance of the mutant strain and enhancement of its sensitivity to difenoconazole up to the level corresponding to the initial non-resistant isolate
Antifungal Activity of the Dry Biomass of Penicillium chrysogenum F-24-28 and Is Application in Combination with Azoxystrobin for Efficient Crop Protection
The developing resistance of plant pathogenic fungi to commercial fungicides has become a serious problem for efficient plant disease control. The use of antifungal preparations based on living microorganisms or their metabolites represents one of the possible environmentally friendly approaches. However, since a complete rejection of chemical fungicides is impossible, the combining of biopreparations and fungicides may be considered a promising biocontrol approach. Promising strains for the development of antifungal biopreparations include Penicillium fungi producing various biologically active compounds with antimicrobial and antiviral activities. A dry biomass of the P. chrysogenum F-24-28 strain (DMP) obtained from the P. chrysogenum VKPM F-1310 strain by induced mutagenesis possessed a high antifungal efficiency. According to in vitro experiments, supplementation of agarized medium with DMP (7.5–10 g/L) resulted in a significant growth inhibition in several plant pathogenic Fusarium fungi. The combination of DMP with a commercial azoxystrobin-based fungicide resulted in a prolonged growth inhibition in F. oxysporum, F. graminearum and F. culmorum even at fungicide concentrations significantly below the recommended level (0.5–2.5 mg/L or 2.5–12.5 g/ha vs. the recommended 100–275 g/ha). These results demonstrate a possibility to develop an efficient environmentally friendly biopreparation suitable to control crop diseases caused by a wide range of plant pathogens, and to prevent a possible selection and spreading of resistant pathogen strains
Biotransformation of Androstenedione by Filamentous Fungi Isolated from Cultural Heritage Sites in the State Tretyakov Gallery
The transformation of steroids by microorganisms is widely used in medical biotechnology. A huge group of filamentous fungi is one of the most promising taxa for screening new biocatalytic reactions in order to obtain pharmaceutically significant steroids. In this work, we screened 10 filamentous fungi-destructors of egg tempera for the ability to biotransform androst-4-en-3,17-dione (AD) during cultivation in a liquid nutrient medium or in a buffer solution. These taxonomically unrelated strains, belonging to the classes Eurotiomycetes, Dothideomycetes and Sordariomycetes, are dominant representatives of the microbiome from halls where works of tempera painting are stored in the State Tretyakov Gallery (STG, Moscow, Russia). Since the binder of tempera paints, egg yolk, contains about 2% cholesterol, these degrading fungi appear to be a promising group for screening for steroid converting activity. It turned out that all the studied fungi-destructors are able to transform AD. Some strains showed transformation efficiency close to the industrial strain Curvularia lunata RNCIM F-981. In total, 33 steroids formed during the transformation of AD were characterized, for 19 of them the structure was established by gas chromatography/mass spectrometry analysis. In this work, we have shown for the first time that fungi-destructors of tempera paintings can efficiently transform steroids
Effect of Various Compounds Blocking the Colony Pigmentation on the Aflatoxin B1 Production by Aspergillus flavus
Aflatoxins and melanins are the products of a polyketide biosynthesis. In this study, the search of potential inhibitors of the aflatoxin B1 (AFB1) biosynthesis was performed among compounds blocking the pigmentation in fungi. Four compounds—three natural (thymol, 3-hydroxybenzaldehyde, compactin) and one synthetic (fluconazole)—were examined for their ability to block the pigmentation and AFB1 production in Aspergillus flavus. All compounds inhibited the mycelium pigmentation of a fungus growing on solid medium. At the same time, thymol, fluconazole, and 3-hydroxybenzaldehyde stimulated AFB1 accumulation in culture broth of A. flavus under submerged fermentation, whereas the addition of 2.5 μg/mL of compactin resulted in a 50× reduction in AFB1 production. Moreover, compactin also suppressed the sporulation of A. flavus on solid medium. In vivo treatment of corn and wheat grain with compactin (50 μg/g of grain) reduced the level of AFB1 accumulation 14 and 15 times, respectively. Further prospects of the compactin study as potential AFB1 inhibitor are discussed
Evaluation of eliciting activity of peptidil prolyl cys/trans isomerase from <em>Pseudonomas fluorescens</em> encapsulated in sodium alginate regarding plant resistance to viral and fungal pahogens
Use of chemical pesticides poses a threat for environment and human health, so green technologies of crop protection are of high demand. Some microbial proteins able to activate plant defense mechanisms and prevent the development of resistance in plant pathogens, may be good alternative to chemicals, but practical use of such elicitors is limited due to need to protect them against adverse environment prior their delivery to target receptors of plant cells. In this study we examined a possibility to encapsulate heat resistant FKBP-type peptidyl prolyl cis-trans isomerase (PPIase) from Pseudomonas fluorescens, which possesses a significant eliciting activity in relation to a range of plant pathogens, in sodium alginate microparticles and evaluated the stability of resulted complex under long-term UV irradiation and in the presence of proteinase K, as well as its eliciting activity in three different “plant-pathogen” models comparing to that of free PPIase. The obtained PPIase-containing microparticles consisted of 70% of sodium alginate, 20% of bovine serum albumin, and 10% of PPIase. In contrast to free PPIase, which lost its eliciting properties after 8-h UV treatment, encapsulated PPIase kept its eliciting ability unchanged; after being exposed to proteinase K, its eliciting ability twice exceeded that of free PPIase. Using “tobacco-TMV”, “tobacco-Alternaria longipes”, and “wheat-Stagonospora nodorum” model systems, we showed that encapsulation process did not influence on the eliciting activity of PPIase. In the case of the “wheat-S. nodorum” model system, we also observed a significant eliciting activity of alginate-albumin complex and almost doubled activity of encapsulated PPIase as compared to the free PPIase. As far as we know, this is the first observation of a synergistic interaction between alginate and other compound possessing any bioactive properties. The results of the study show some prospects for a PPIase use in agriculture