Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 1.265
Filtrar
Mais filtros










Intervalo de ano de publicação
1.
Food Microbiol ; 87: 103395, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-31948636

RESUMO

Volatile compounds produced by L1 and L8 strains were assayed against mycelia and conidia growth of Monilinia laxa, M. fructicola, M. polystroma, and M. fructigena of stone fruits. Results showed that volatile metabolites inhibited significantly pathogens growth, in particular M. fructigena mycelium growth (70% by L1 and 50% by L8) and M. fructicola conidia germination (85% by L1 and 70% by L8) compared to the control. Moreover, the antagonistic activity was enhanced by the addition of asparagine (120 mg L-1) in the culture media composition. Synthetic pure compounds were tested in vitro on pathogens mycelial and conidia growth and their EC50 values were estimated, confirming 2-phenethyl as the most active compound. For this reason 2-phenethyl and VOCs of both yeast strains were assayed in vivo on cherry, peach, and apricot fruits. Regarding peach fruit, both treatments, yeasts and pure compounds, displayed the best inhibiting action against all the pathogens especially against M. laxa (100% by L1, 84% by L8 and 2-phenethyl). ATR/IR spectroscopy analysis showed how VOCs produced by both strains increase the fruit waxes complexity reducing the pathogens attack so playing an essential role in the antagonistic activity of both yeast strains and on fruit structural composition.


Assuntos
Ascomicetos/química , Fungicidas Industriais/farmacologia , Doenças das Plantas/microbiologia , Compostos Orgânicos Voláteis/farmacologia , Ascomicetos/crescimento & desenvolvimento , Ascomicetos/metabolismo , Frutas/microbiologia , Fungicidas Industriais/química , Fungicidas Industriais/metabolismo , Micélio/efeitos dos fármacos , Micélio/crescimento & desenvolvimento , Prunus persica/microbiologia , Esporos Fúngicos/efeitos dos fármacos , Esporos Fúngicos/crescimento & desenvolvimento , Compostos Orgânicos Voláteis/química , Compostos Orgânicos Voláteis/metabolismo
2.
J Sci Food Agric ; 100(1): 441-446, 2020 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-31512241

RESUMO

BACKGROUND: The production of mycelium from endophytic fungi is of interest for applications ranging from inoculants and biofertilizers for crop production to fermentations for enzyme and metabolite production. The purpose of this study was to test the capacity of a solid growth medium based on beet pulp for growing different strains of endophytes. RESULTS: The ergosterol content of inoculated medium was measured to estimate fungal growth. Several parameters related to the preparation of the growth medium, such as water content, calcium salts and incubation time, were evaluated. The greatest fungal biomass production was observed in a medium prepared with a 1:2 (beet pulp:water) ratio, containing calcium sulfate and carbonate. Strains belonging to different fungal species grew well in the growth medium finally selected, producing yields ranging from 50 to 500 g mycelium per kilogram of dry culture, after 22-27 days. Cultures containing up to 400 g beet pulp grew successfully, and could be scaled up. CONCLUSION: A solid culture medium based on beet pulp supported the growth of diverse taxa of fungal endophytes. Both the water and calcium salt content of the growth medium affected the efficiency of mycelium production. Considering these factors, beet pulp medium was an excellent endophyte cultivation medium because of the high yield of fungal biomass observed, together with its ease of handling and scaling-up production. © 2019 Society of Chemical Industry.


Assuntos
Beta vulgaris/microbiologia , Meios de Cultura/metabolismo , Endófitos/crescimento & desenvolvimento , Fungos/crescimento & desenvolvimento , Beta vulgaris/química , Biomassa , Meios de Cultura/química , Endófitos/metabolismo , Fermentação , Fungos/metabolismo , Micélio/crescimento & desenvolvimento , Micélio/metabolismo
3.
J Sci Food Agric ; 100(2): 803-810, 2020 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-31612503

RESUMO

BACKGROUND: New evidence has shown that arbuscular mycorrhizal (AM) fungi can contribute to the aluminum (Al3+ ) tolerance of host plants growing in acidic soils with phytotoxic levels of Al3+ . The aim of this study was to investigate the role of AM fungi isolated from naturally occurring Al3+ acidic soils in conferring host tolerance to Al3+ toxicity in three wheat cultivars differing in Al3+ sensitivity. The experiment was conducted in a soilless substrate (vermiculite/perlite, 2:1 v/v) using two Al3+ -tolerant wheat genotypes and one Al3+ -sensitive wheat genotype. The wheat was colonized with a consortium of AM fungi isolated from an Andisol, with or without Al3+ at a concentration of 200 µmol L-1 . RESULTS: The response of wheat to Al3+ in the medium was dependent on both the plant genotype and AM colonization. The benefits of the AM fungi to the wheat cultivars included an increased P concentration and relatively low Al3+ accumulation in the plants. This was achieved through two mechanisms. First, the metal-chelating capacity of the AM fungi was clear in two of the cultivars ('Tukan' and 'Porfiado'), in which the enhanced extraradical mycelium development was able to retain Al3+ in the glomalin and hyphae. Second, the increased AM-induced acid phosphatase activity in the rhizosphere of the other cultivar ('Atlas 66') increased host nutrition possibly by hyphae-mediated nutrient uptake and glomalin-related soil protein. CONCLUSION: The results suggest that the role of AM fungi in cultivar-specific Al3+ detoxification can be achieved by increased extraradical mycelial filters and enhanced bioavailability of P in the host rhizosphere. © 2019 Society of Chemical Industry.


Assuntos
Alumínio/metabolismo , Micorrizas/metabolismo , Fósforo/metabolismo , Poluentes do Solo/metabolismo , Triticum/microbiologia , Alumínio/análise , Alumínio/toxicidade , Hifas/crescimento & desenvolvimento , Hifas/metabolismo , Micélio/crescimento & desenvolvimento , Micélio/metabolismo , Micorrizas/crescimento & desenvolvimento , Fósforo/análise , Poluentes do Solo/análise , Poluentes do Solo/toxicidade , Triticum/crescimento & desenvolvimento , Triticum/metabolismo
4.
J Sci Food Agric ; 100(2): 744-754, 2020 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-31637724

RESUMO

BACKGROUND: The application of chemical fungicides is currently the main method for the control of postharvest decay of fruits and vegetables. However, public concern has been growing towards the effect of fungicides on food safety, human health and environmental pollution. Thus, interest in microbial biocontrol agent development has grown, such agents being considered both safe and environmentally friendly. Pseudomonas fluorescens is widely distributed in nature, and one of the most valuable biocontrol and plant growth-promoting rhizobacteria. In this study, the efficacy and the potential associated modes of action of P. fluorescens ZX against Penicillium italicum on oranges (Citrus sinensis Osbeck) were investigated. RESULTS: The application of P. fluorescens ZX significantly reduced blue mold lesion size and incidence in comparison to the control, where P. fluorescens ZX was effective when applied preventatively but not curatively. In dual cultures, treatment with cell-free autoclaved cultures or culture filtrate had a limited capacity to suppress P. italicum, while P. italicum was inhibited by bacterial fluid and bacterial suspension with living cells in vitro. The P. fluorescens ZX isolate displayed protease, but not chitinase, glucanase or cellulose, activity, and produced siderophores and volatile organic compounds with antifungal abilities. Competition tests showed P. fluorescens ZX could use fructose, sucrose, aspartic acid, threonine, serine, glycine, valine, lysine and proline better than P. italicum. Furthermore, an effective biofilm that peaked after a 24-hour incubation at 30 °C was formed by the P. fluorescens ZX isolate. Light microscopy and scanning electron microscopy observations indicate the P. fluorescens ZX isolate could not undergo direct parasitism or hyperparasitism. CONCLUSIONS: Competition for nutrients and niches, biofilm formation, inhibition of spore germination and mycelial growth, and production of inhibitory metabolites may play important roles in P. fluorescens ZX antagonism of P. italicum. © 2019 Society of Chemical Industry.


Assuntos
Antibiose , Citrus/microbiologia , Pseudomonas fluorescens/fisiologia , Biofilmes , Frutas/microbiologia , Micélio/crescimento & desenvolvimento , Micélio/metabolismo , Penicillium/crescimento & desenvolvimento , Penicillium/metabolismo , Doenças das Plantas/microbiologia , Doenças das Plantas/prevenção & controle
5.
PLoS Comput Biol ; 15(10): e1007428, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31671091

RESUMO

Filamentous fungi are ubiquitous in nature and serve as important biological models in various scientific fields including genetics, cell biology, ecology, evolution, and chemistry. A significant obstacle in studying filamentous fungi is the lack of tools for characterizing their growth and morphology in an efficient and quantitative manner. Consequently, assessments of the growth of filamentous fungi are often subjective and imprecise. In order to remedy this problem, we developed Fungal Feature Tracker (FFT), a user-friendly software comprised of different image analysis tools to automatically quantify different fungal characteristics, such as spore number, spore morphology, and measurements of total length, number of hyphal tips and the area covered by the mycelium. In addition, FFT can recognize and quantify specialized structures such as the traps generated by nematode-trapping fungi, which could be tuned to quantify other distinctive fungal structures in different fungi. We present a detailed characterization and comparison of a few fungal species as a case study to demonstrate the capabilities and potential of our software. Using FFT, we were able to quantify various features at strain and species level, such as mycelial growth over time and the length and width of spores, which would be difficult to track using classical approaches. In summary, FFT is a powerful tool that enables quantitative measurements of fungal features and growth, allowing objective and precise characterization of fungal phenotypes.


Assuntos
Fungos/crescimento & desenvolvimento , Processamento de Imagem Assistida por Computador/métodos , Fenômenos Biológicos , Modelos Biológicos , Micélio/crescimento & desenvolvimento , Software
6.
World J Microbiol Biotechnol ; 35(11): 163, 2019 Oct 21.
Artigo em Inglês | MEDLINE | ID: mdl-31637600

RESUMO

To simplify industrial mushroom cultivation, we introduced a bacterial Pseudomonas sp. UW4 acdS gene, encoding 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase (AcdS), into fungus Agaricus bisporus. Transformant A. bisporus-acdS14 cased with sterilized-vermiculite generated primordia 5 days sooner than wild-type strain, confirming the specific role of the AcdS enzyme. Being consistent with the AcdS enzyme activity increased by 84%, the mycelium growth rate was increased by 25%; but, the ACC and ethylene concentrations were reduced by 71% and 36%, respectively, in the A. bisporus-acdS14 transformant. And the bacterium P. sp. UW4 attachment on the mycelium of the A. bisporus-acdS14 transformant was drastically reduced. We conclude that the heterogeneously expressed bacterial acdS gene degrades ACC and reduces ethylene-synthesis, eliminating ethylene inhibition on the mycelium growth and primordium formation in A. bisporus. Our results provide new insights into the mechanism underlying casing soil bacterium, and help formulate a casing-less cultivation for the next-generation mushroom industry.


Assuntos
Agaricus/crescimento & desenvolvimento , Agaricus/genética , Carpóforos/crescimento & desenvolvimento , Pseudomonas/enzimologia , Pseudomonas/genética , Aminoácidos Cíclicos/metabolismo , Carbono-Carbono Liases/genética , Carbono-Carbono Liases/metabolismo , Clonagem Molecular , Etilenos/metabolismo , Regulação Fúngica da Expressão Gênica , Micélio/crescimento & desenvolvimento , Solo , Transformação Genética
7.
Pestic Biochem Physiol ; 160: 70-78, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31519259

RESUMO

Sclerotinia sclerotiorum, which can cause Sclerotinia stem rot, is a devastating plant pathogen. This study aimed to assess the potential of pydiflumetofen, a new-generation succinate dehydrogenase inhibitor (SDHI) fungicide, to control Sclerotinia stem rot. Pydiflumetofen exhibited favorable bioactivity in suppressing mycelial growth, sclerotial production and morphological changes, and the myceliogenic and carpogenic germination of sclerotia. Treatment with pydiflumetofen increased the cell membrane permeability of S. sclerotiorum and decreased oxalic acid production. In addition, inoculation tests demonstrated that the protective activity of 40 µg/mL pydiflumetofen against the fungus was better than its curative activity. Under natural infection conditions, the spraying of pydiflumetofen at 200 g a.i. ha-1 significantly reduced the incidence and severity of Sclerotinia stem rot. In addition, the sensitivity baseline to pydiflumetofen was established using 171 isolates collected from various crops in China. The results showed that the frequency distribution of the EC50 values of pydiflumetofen was a unimodal curve with a mean EC50 value of 0.0095 ±â€¯0.0005 µg/mL. This study confirmed the favorable bioactivity of pydiflumetofen against S. sclerotiorum at various developmental stages and its high effectiveness under natural infection conditions, which indicates that pydiflumetofen is a promising tool for the management of Sclerotinia stem rot.


Assuntos
Ascomicetos/efeitos dos fármacos , Fungicidas Industriais/farmacologia , Pirazóis/farmacologia , Succinato Desidrogenase/antagonistas & inibidores , Ascomicetos/crescimento & desenvolvimento , Ascomicetos/metabolismo , Permeabilidade da Membrana Celular/efeitos dos fármacos , Inibidores Enzimáticos/farmacologia , Micélio/efeitos dos fármacos , Micélio/crescimento & desenvolvimento , Ácido Oxálico/metabolismo
8.
Genes (Basel) ; 10(9)2019 09 11.
Artigo em Inglês | MEDLINE | ID: mdl-31514481

RESUMO

Pleurotus tuoliensis is a precious edible fungus with extremely high nutritive and medicinal value. The cultivation period of P. tuoliensis is longer than those of other Pleurotus species, which is mainly due to a longer mycelium physiological maturation period (30-60 days). Currently, the molecular processes underlying physiological maturation of the mycelium remain unclear. We performed a comparative transcriptomic analysis of immature and mature mycelia using RNA-seq. De novo transcriptome assembly resulted in identification of 17,030 unigenes. 451 differentially expressed genes-including those encoding nucleoside diphosphate kinase (NDPK), glycoside hydrolase family proteins, exopolygalacturonase, and versatile peroxidases-were identified. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses revealed that nucleotide synthesis and energy metabolism are highly active during the physiological maturation of mycelia, and genes related to these pathways were significantly upregulated in mature mycelia. NDPK is predicted to be essential for mycelia maturation. Our findings contribute to a comprehensive understanding of mycelia maturation in a commercially important fungal species. Future efforts will focus on the function of NDPK and the mechanism by which it regulates mycelia maturation.


Assuntos
Micélio/genética , Pleurotus/genética , Transcriptoma , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Glicosídeo Hidrolases/genética , Glicosídeo Hidrolases/metabolismo , Micélio/crescimento & desenvolvimento , Núcleosídeo-Difosfato Quinase/genética , Núcleosídeo-Difosfato Quinase/metabolismo , Peroxidases/genética , Peroxidases/metabolismo , Pleurotus/crescimento & desenvolvimento
9.
Ecotoxicol Environ Saf ; 183: 109503, 2019 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-31394376

RESUMO

Sclerotinia sclerotiorum (S. sclerotiorum) is a devastating fungal pathogen with worldwide distribution, and threatened the agro-ecological safety in the long term. To control the damage caused by Sclerotinia diseases, as well as consider the fungicide resistance and chemical residues, strategy of which plant nutritional regulation, as an eco-friendly approach, is gaining much significance. Selenium (Se), as a beneficial microelement for plant, has been manifested to be effective in inhibiting the mycelial growth of S.sclerotiorum in our previous study. In the present study, we observed that Se (both selenate and selenite) inhibited the formation of sclerotia, which is an important life form in the disease cycle of S. sclerotiorum. And the inhibition ratios of number of sclerotia in treatments of Se(VI)5.0 and Se(IV)5.0 were 54.55% and 43.84%, respectively; the inhibition ratios of weight of sclerotia in treatments of Se(VI)5.0 and Se(IV)5.0 were 42.29% and 25.67%, respectively. Results suggested that Se inhibited mycelial growth, severely damaged sclerotial ultrastructure, reduced the capacity of acid production, decreased superoxide dismutase (SOD) and catalase (CAT) activities, increased the content of hydrogen peroxide (H2O2) and superoxide anion (O2-) in mycelium, and all of these resulted in the reduction in sclerotial formation. Further studies revealed that Se application in medium increased Se concentration in sclerotia and thus inhibited sclerotial germination. Moreover, the pathogenicity of mycelia germinating from sclerotia that pretreated with Se, decreased significantly to rape leaves. These findings broadened our understanding of Se application in plant protection, as well as provided evidences for developing environment-friendly fungicide for S. sclerotiorum control.


Assuntos
Ascomicetos/efeitos dos fármacos , Ascomicetos/patogenicidade , Fungicidas Industriais/farmacologia , Selênio/farmacologia , Antioxidantes/metabolismo , Ascomicetos/crescimento & desenvolvimento , Ascomicetos/metabolismo , Peróxido de Hidrogênio/metabolismo , Micélio/efeitos dos fármacos , Micélio/crescimento & desenvolvimento , Micélio/metabolismo , Micélio/patogenicidade , Selênio/metabolismo , Virulência
10.
J Agric Food Chem ; 67(31): 8476-8484, 2019 Aug 07.
Artigo em Inglês | MEDLINE | ID: mdl-31298527

RESUMO

Cicada flowers, which are edible and medicinal mushrooms, are the fruiting bodies of Isaria cicadae, a fungus that is parasitic on the larvae of cicada pupae. We hypothesize that host factors might possess stimulatory activity on metabolite synthesis in Isaria cicadae. Here, we first compared the microbial community structures of different wild cicada flowers across geographical regions, compartments, and growth stages via high-throughput sequencing. Isaria cicadae TZC-3, an isolate of the most abundant operational taxonomic unit (OTU6782) in all the fungal communities, was isolated from wild cicada flowers. Furthermore, the effects of cicada pupae on metabolite synthesis in Isaria cicadae TZC-3 were studied in submerged culture. The contents of intercellular polysaccharides, adenosine, N6-(2-hydroxyethyl)-adenosine, free amino acids, and hydrolyzed monosaccharides in the mycelia cultured with cicada pupa powder (4%) were significantly increased as compared with the contents in the control group. This indicates that a cicada pupa can act as an elicitor for metabolite synthesis in Isaria cicadae.


Assuntos
Cordyceps/metabolismo , Carpóforos/química , Hemípteros/microbiologia , Pupa/microbiologia , Adenosina/análise , Adenosina/metabolismo , Aminoácidos/análise , Aminoácidos/metabolismo , Animais , Cordyceps/química , Cordyceps/crescimento & desenvolvimento , Carpóforos/crescimento & desenvolvimento , Carpóforos/metabolismo , Hemípteros/química , Hemípteros/metabolismo , Interações Hospedeiro-Patógeno , Microbiota , Micélio/química , Micélio/crescimento & desenvolvimento , Micélio/metabolismo , Pupa/química , Pupa/metabolismo
11.
Artigo em Inglês | MEDLINE | ID: mdl-31294650

RESUMO

The present study examines the influence of the natural preservatives carvacrol, eugenol, trans-cinnamaldehyde and the essential oil (EO) Origanum vulgare on ochratoxin A (OTA) production and the mycelial growth of two food-related moulds, Penicillium verrucosum and Aspergillus westerdijkiae, by broth macro-dilution assay for 21 days. With the addition of ½ minimum inhibitory concentration (MIC) carvacrol, eugenol and O. vulgare EO, the mycelial dry weight of both moulds decreased significantly over the whole incubation period of 7, 14 and 21 days. Trans-cinnamaldehyde slightly stimulated the growth of A. westerdijkiae and P. verrucosum at 14 and 21 days of incubation. Growth inhibition did not accompany inhibition of OTA production. Although the growth of both moulds was inhibited after the addition of ½ MIC carvacrol, eugenol and O. vulgare EO, the OTA production of the strong mycotoxin producer A. westerdijkiae was stimulated. Only trans-cinnamaldehyde inhibited the production of OTA with the addition of ½ MIC. P. verrucosum produced significantly less OTA than A. westerdijkiae, and its mycotoxin production was almost completely inhibited by the addition of ½ MIC of the natural preservatives.


Assuntos
Aspergillus/efeitos dos fármacos , Microbiologia de Alimentos , Conservantes de Alimentos/farmacologia , Micélio/efeitos dos fármacos , Ocratoxinas/biossíntese , Penicillium/efeitos dos fármacos , Acroleína/análogos & derivados , Acroleína/química , Acroleína/farmacologia , Aspergillus/química , Eugenol/química , Eugenol/farmacologia , Conservantes de Alimentos/química , Monoterpenos/química , Monoterpenos/farmacologia , Micélio/crescimento & desenvolvimento , Ocratoxinas/química , Óleos Voláteis/química , Óleos Voláteis/farmacologia , Penicillium/química
12.
Chemosphere ; 235: 538-542, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31276867

RESUMO

Lentinus crinitus is an important basidiomycete consumed by ethnic groups from the Amazon, commonly found in decomposing trees with high lignolytic and antioxidant activities. Lithium is a mood stabilizer, antiepileptic, antipsychotic, and antidepressant used in clinical practice. This study aimed to evaluate L. crinitus mycelial biomass bioaccumulated with lithium in liquid cultivation medium. The malt extract medium was added from zero to 100 mg L-1 lithium from two lithium sources (Li2CO3 and LiCl). The maximum mycelial biomass production was 7218.89 mg L-1 in the culture medium added with 5 mg L-1 lithium from LiCl. The highest lithium concentration in the mycelial biomass was of 574.72 µg g-1 produced in the culture medium with 25 mg L-1 lithium from Li2CO3. Pearson's correlation showed that Li2CO3 reduces the mycelial biomass and increases lithium bioaccumulation. The maximum translocated lithium from cultivation medium to mycelial biomass was up to 19 or 28% with LiCl or Li2CO3, respectively. Therefore, although Li2CO3 presents greater inhibition on the mycelial biomass production, it promoted greater lithium bioaccumulation in L. crinitus mycelial biomass and resulted in greater yield of lithium translocation. The equivalent daily dose of lithium for psychiatric treatment, without bioavailability studies, could be reached with 97.4 g lithium-enriched mycelial biomass and, based in the literature, for reduction of violence and criminality rates the amount could be reached with 0.24-0.58 mg. Thus, the development of lithium-enriched mycelial biomass could be an alternative functional food.


Assuntos
Alimento Funcional , Lentinula/metabolismo , Lítio/metabolismo , Basidiomycota , Biomassa , Meios de Cultura , Micélio/crescimento & desenvolvimento , Radioisótopos
13.
J Sci Food Agric ; 99(14): 6552-6561, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31321781

RESUMO

BACKGROUND: Essential oils (EOs) are volatile natural compounds produced by plant secondary metabolism, and some of them exhibit antimicrobial activity. The objective of the present study was to determine the chemical composition the EOs of Eucalyptus staigeriana and Eucalyptus globulus, and their effect in vitro and in vivo against Botrytis cinerea and Colletotrichum acutatum, the most important fungal rot diseases of grapes. Moreover, grapes collected from field experiments were used to evaluate the impact of the alternative control on the alcoholic fermentation and wine composition. RESULTS: The major compound of E. staigeriana EO were citral 30.91% (19.74% geranial, 11.17% neral), 1.8-cineole (24.59%) and limonene (19.47%), while 1.8-cineole represented 68.26% of E. globulus EO. The two EOs showed in vitro antifungal activity against both pathogens. Eucalyptus staigeriana EO exhibited the highest activity inhibiting mycelial growth (MG) and conidial germination at 0.5 µL mL-1 . Moreover, this EO was able to reduce the incidence and severity of grey rot caused by B. cinerea and the severity of ripe rot caused by C. acutatum The alternative control did not significantly influence alcoholic fermentation, the physicochemical characteristics, and the volatile composition of wines. CONCLUSION: These results are promising and indicate that E. staigeriana EO might be further investigated as a natural alternative for the control of fungal rots on wine grapes. © 2019 Society of Chemical Industry.


Assuntos
Antifúngicos/farmacologia , Eucalyptus/química , Óleos Voláteis/farmacologia , Doenças das Plantas/prevenção & controle , Extratos Vegetais/farmacologia , Vitis/microbiologia , Antifúngicos/química , Botrytis/efeitos dos fármacos , Botrytis/crescimento & desenvolvimento , Colletotrichum/efeitos dos fármacos , Colletotrichum/crescimento & desenvolvimento , Testes de Sensibilidade Microbiana , Micélio/efeitos dos fármacos , Micélio/crescimento & desenvolvimento , Óleos Voláteis/química , Doenças das Plantas/microbiologia , Extratos Vegetais/química
14.
Elife ; 82019 07 16.
Artigo em Inglês | MEDLINE | ID: mdl-31307571

RESUMO

Mutualistic interactions between free-living algae and fungi are widespread in nature and are hypothesized to have facilitated the evolution of land plants and lichens. In all known algal-fungal mutualisms, including lichens, algal cells remain external to fungal cells. Here, we report on an algal-fungal interaction in which Nannochloropsis oceanica algal cells become internalized within the hyphae of the fungus Mortierella elongata. This apparent symbiosis begins with close physical contact and nutrient exchange, including carbon and nitrogen transfer between fungal and algal cells as demonstrated by isotope tracer experiments. This mutualism appears to be stable, as both partners remain physiologically active over months of co-cultivation, leading to the eventual internalization of photosynthetic algal cells, which persist to function, grow and divide within fungal hyphae. Nannochloropsis and Mortierella are biotechnologically important species for lipids and biofuel production, with available genomes and molecular tool kits. Based on the current observations, they provide unique opportunities for studying fungal-algal mutualisms including mechanisms leading to endosymbiosis.


Assuntos
Endocitose , Mortierella/metabolismo , Micélio/metabolismo , Fotossíntese , Estramenópilas/metabolismo , Simbiose , Biocombustíveis , Metabolismo dos Lipídeos , Mortierella/crescimento & desenvolvimento , Micélio/crescimento & desenvolvimento , Estramenópilas/crescimento & desenvolvimento
15.
Sci Total Environ ; 692: 267-280, 2019 Nov 20.
Artigo em Inglês | MEDLINE | ID: mdl-31349168

RESUMO

Biotic interactions through diffusible and volatile organic compounds (VOCs) are frequent in nature. Soil bacteria are well-known producers of a wide range of volatile compounds (both organic and inorganic) with various biologically relevant activities. Since the last decade, they have been identified as natural biocontrol agents. Volatiles are airborne chemicals, which when released by bacteria, can trigger plant responses such as defence and growth promotion. In this study, we tested whether diffusible and volatile organic compounds (VOCs) produced by soil bacterial isolates exert anti-oomycete and plant growth-promoting effects. We also investigated the effects of inoculation with VOC-producing bacteria on the growth and development of Capsicum annuum and Arabidopsis thaliana seedlings. Our results demonstrate that organic VOCs emitted by bacterial antagonists negatively influence mycelial growth of the soil-borne phytopathogenic oomycete Phytophthora capsici by 35% in vitro. The bacteria showed plant growth promoting effects by stimulating biomass production, primary root growth and root hair development. Additionally, we provide evidence to suggest that these activities were deployed by the emission of either diffusible organic compounds or VOCs. Bacterial VOC profiles were obtained through solid phase microextraction (SPME) and analysis by gas chromatography coupled with mass spectrometry (GC-MS). This elucidated the main volatiles emitted by the isolates, which covered a wide range of aldehydes, alcohols, esters, carboxylic acids, and ketones. Collectively, twenty-five VOCs were identified to be produced by three bacteria; some being species-specific. Our data show that bacterial volatiles inhibits P. capsici in vitro and modulate both plant growth promotion and root system development. These results confirm the significance of soil bacteria and highlights that ways of harnessing them to improve plant growth, and as a biocontrol agent for soil-borne oomycetes through their volatile emissions deserve further investigation.


Assuntos
Arabidopsis/efeitos dos fármacos , Bactérias/química , Capsicum/efeitos dos fármacos , Phytophthora/efeitos dos fármacos , Microbiologia do Solo , Compostos Orgânicos Voláteis/metabolismo , Arabidopsis/crescimento & desenvolvimento , Capsicum/crescimento & desenvolvimento , Micélio/efeitos dos fármacos , Micélio/crescimento & desenvolvimento , Phytophthora/crescimento & desenvolvimento , Plântula/efeitos dos fármacos , Plântula/crescimento & desenvolvimento
16.
J Agric Food Chem ; 67(32): 8875-8883, 2019 Aug 14.
Artigo em Inglês | MEDLINE | ID: mdl-31347830

RESUMO

Glucan synthase (GLS) gene is known to be involved in the fungal biosynthesis of cell wall, differentiation, and growth. In the present study, a glucan synthase gene (GFGLS) in the edible mushroom Grifola frondosa with a full sequence of 5927 bp encoding a total of 1781 amino acids was cloned and characterized for the first time. GFGLSp is a membrane protein containing two large transmembrane domains connected with a hydrophilic cytoplasmic domain. With a constructed dual promoter RNA silencing vector pAN7-gfgls-dual, a GFGLS-silencing transformant iGFGLS-3 had the lowest GFGLS transcriptional expression level (26.1%) with a shorter length and thinner appearance of the mycelia, as well as decreased mycelial biomass and exo-polysaccharide production of 5.02 and 0.38 g/L, respectively. Further analysis indicated that GFGLS silence influenced slightly the monosaccharide compositions and ratios of mycelial and exo-polysaccharide. These findings suggest that GFGLS could affect mycelial growth and polysaccharide production by downregulating the glucan synthesis.


Assuntos
Polissacarídeos Fúngicos/biossíntese , Proteínas Fúngicas/metabolismo , Glucosiltransferases/metabolismo , Grifola/enzimologia , Micélio/crescimento & desenvolvimento , Proteínas Fúngicas/genética , Glucosiltransferases/genética , Grifola/genética , Grifola/crescimento & desenvolvimento , Grifola/metabolismo , Micélio/enzimologia , Micélio/genética , Micélio/metabolismo , Interferência de RNA , RNA Interferente Pequeno/genética , RNA Interferente Pequeno/metabolismo
17.
Biocontrol Sci ; 24(2): 123-127, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31204357

RESUMO

Fumigation has been the most convenient method in the field of pest control in museums. In this study, as fumigants, ethanol 70%, deltamethrin (commercial pesticide (CP) ) , essential oil (EO) from Pinus regida, and low oxygen microenvironment (0.1%, (LOM) ) were tested individually and jointly against museum fungal strain Alternaria alternata. Three concentrations of each CP and EO were chosen for evaluating the individual effect. In the joint action fumigation process, three lower concentrations of CP and EO were tested in LOM. The rate of mycelial growth inhibition at each fumigation process was determined by two steps: 1) directly after the fumigation process and 2) after 7 d of the inoculation of the fumigated spores in new medium and incubating it in normal condition. The results demonstrated that applying of each chemical (CP or EO) in LOM enhanced its fungicidal activity and that effect of EO improved from fungistatic to fungicidal by jointing with LOM.


Assuntos
Alternaria/efeitos dos fármacos , Fumigação/métodos , Fungicidas Industriais/farmacologia , Viabilidade Microbiana/efeitos dos fármacos , Óleos Voláteis/farmacologia , Oxigênio/farmacologia , Alternaria/crescimento & desenvolvimento , Sinergismo Farmacológico , Micélio/efeitos dos fármacos , Micélio/crescimento & desenvolvimento
18.
Mycorrhiza ; 29(4): 341-349, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31190279

RESUMO

The extraradical mycelium (ERM) produced by arbuscular mycorrhizal fungi is fundamental for the maintenance of biological fertility in agricultural soils, representing an important inoculum source, together with spores and mycorrhizal root fragments. Its viability and structural traits, such as density, extent and interconnectedness, which are positively correlated with the growth and nutrition of host plants, may be affected by different agronomic practices, including the use of pesticides and by different mycorrhizospheric communities. This work, carried out using a whole-plant experimental model system, showed that structural traits of ERM, such as length and density, were strongly decreased by the herbicides dicamba and glufosinolate and the fungicides benomyl and fenhexamid, while anastomosis frequency and hyphal branching were differentially modulated by singly inoculated mycorrhizospheric bacteria, depending on their identity.


Assuntos
Fenômenos Fisiológicos Bacterianos , Chicória/microbiologia , Fungicidas Industriais/farmacologia , Glomeromycota/efeitos dos fármacos , Glomeromycota/crescimento & desenvolvimento , Herbicidas/farmacologia , Micélio/crescimento & desenvolvimento , Micorrizas/efeitos dos fármacos , Bactérias/genética , Bactérias/isolamento & purificação , Benomilo/farmacologia , Chicória/crescimento & desenvolvimento , Dicamba/farmacologia , Hifas/efeitos dos fármacos , Hifas/crescimento & desenvolvimento , Micélio/efeitos dos fármacos , Micorrizas/crescimento & desenvolvimento , Raízes de Plantas/crescimento & desenvolvimento , Raízes de Plantas/microbiologia , Esporos Bacterianos/genética , Esporos Bacterianos/isolamento & purificação , Esporos Bacterianos/fisiologia
19.
Microbes Environ ; 34(2): 191-198, 2019 Jun 27.
Artigo em Inglês | MEDLINE | ID: mdl-31080215

RESUMO

We investigated whether ectomycorrhizal (ECM) fungal species exhibit antibacterial activity towards culturable bacterial communities in mycorrhizospheres. Four hundred and thirty bacterial strains were isolated from the ECM root tips of Pinus densiflora and bulk soil, and 21 were co-cultured with six ECM fungal species. Three hundred and twenty-nine bacterial 16S rDNA sequences were identified in ECM roots (n=185) and bulk soil (n=144). Mycorrhizosphere isolates were dominated by Gram-negative Proteobacteria from 16 genera, including Burkholderia, Collimonas, Paraburkholderia, and Rhizobium. Paraburkholderia accounted for approximately 60%. In contrast, bulk soil isolates contained a high number of Gram-positive Firmicutes, particularly from Bacillus. Paraburkholderia accounted for ≤20% of the bacterial isolates from bulk soil, which was significantly lower than its percentage in ECM root tips. Co-cultures of six ECM fungal species with the 21 bacterial strains revealed that eight strains of three Gram-positive genera-Arthrobacter, Bacillus, and Lysinibacillus-were sensitive to the antibacterial activity of the fungi. In contrast, the Gram-negative strains, including five Paraburkholderia strains, two Burkholderia strains, and a Rhizobium sp., were not sensitive. The strength of fungal antibacterial activity varied in a species-dependent manner, but consistently affected Gram-positive bacteria. These results suggest that Gram-positive bacteria are excluded from the mycorrhizosphere by the antibacterial activity of ECM fungi, which develops specific soil bacterial communities in the mycorrhizosphere.


Assuntos
Antibacterianos/farmacologia , Bactérias/efeitos dos fármacos , Microbiota , Micorrizas/metabolismo , Rizosfera , Antibacterianos/metabolismo , Bactérias/classificação , Bactérias/crescimento & desenvolvimento , Bactérias/isolamento & purificação , Técnicas de Cocultura , Fungos/classificação , Fungos/crescimento & desenvolvimento , Fungos/metabolismo , Microbiota/efeitos dos fármacos , Microbiota/genética , Micélio/crescimento & desenvolvimento , Micorrizas/classificação , Micorrizas/crescimento & desenvolvimento , Pinus/microbiologia , Raízes de Plantas/microbiologia , Microbiologia do Solo
20.
Appl Microbiol Biotechnol ; 103(14): 5831-5841, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31115628

RESUMO

In coffee-producing countries, waste products from coffee production are useful substrates for cultivation of Pleurotus ostreatus. This species is relatively easy to grow, coffee waste substrates are readily available and the mushroom fruiting bodies are a valuable source of nutrition and income. In developed countries, cultivation of P. ostreatus on spent coffee grounds (SCG) from coffee consumption is a novel way to recycle this urban waste product. Here, we studied the effect of SCG and caffeine on growth of a commercial strain of P. ostreatus in liquid and solid cultures, and on a commercial scale. The presence of caffeine inhibited mycelial growth on agar and in liquid culture in the laboratory. Increased levels of SCG in an SCG/sawdust substrate also delayed mycelial growth and delayed or prevented fruiting during commercial cultivation. Despite growth inhibition, partial degradation of caffeine to xanthine by P. ostreatus mycelium was observed in all SCG-containing substrate mixtures. Degradation of caffeine proceeded mainly via sequential N-demethylation to theophylline (1,3-dimethylxanthine) and 3-methylxanthine, although both paraxanthine and theobromine also accumulated in the substrate. Caffeine and its demethylated metabolites were also detected in fruiting bodies, but it was not clear whether caffeine metabolism occurred in the fruiting bodies themselves or whether caffeine metabolites were translocated there from the mycelium. Based on the caffeine concentrations measured in fruiting bodies after growth with SCG, it would be necessary to consume ~ 250 kg of fresh oyster mushrooms to obtain the amount of caffeine equivalent to one cup of espresso coffee, suggesting that the health impact of caffeine in these mushrooms is low. However, the ability of P. ostreatus to degrade caffeine indicates that this and other species in this genus may have potential applications in detoxification of coffee production wastes.


Assuntos
Cafeína/metabolismo , Pleurotus/crescimento & desenvolvimento , Pleurotus/metabolismo , Resíduos/análise , Café/química , Meios de Cultura/química , Carpóforos/crescimento & desenvolvimento , Carpóforos/metabolismo , Microbiologia Industrial , Resíduos Industriais/análise , Micélio/crescimento & desenvolvimento , Micélio/metabolismo , Xantina/metabolismo
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA