The basidiomycete fungus Crinipellis perniciosa (Stahel) Singer is the causal agent of Witches' Broom Disease of Cacao (Theobroma cacao L.) which is the main factor limiting cacao production in the Americas. Pod losses of up to 90% are experienced in affected areas as evidenced by the 50% drop in production in Bahia province, Brazil following the arrival of the C. perniciosa in the area in 1989. The disease has proven particularly difficult to control and many farmers in affected areas have given up cacao cultivation. In order to evaluate the potential of endophytes as a biological control agent of this phytopathogen, the endophytic fungal community of resistant and susceptible cacao plants as well as affected branches was studied between 2001 and 2002. The fungal community was identified by morphological traits and rDNA sequencing as belonging to the genera Acremonium, Blastomyces, Botryosphaeria, Cladosporium, Colletotrichum, Cordyceps, Diaporthe, Fusarium, Geotrichum, Gibberella, Gliocladium, Lasiodiplodia, Monilochoetes, Nectria, Pestalotiopsis, Phomopsis, Pleurotus, Pseudofusarium, Rhizopycnis, Syncephalastrum, Trichoderma, Verticillium and Xylaria. These fungi were evaluated both in vitro and in vivo by their ability to inhibit C. perniciosa. Among these, some were identified as potential antagonists, but only one fungus (Gliocladium catenulatum) reduced the incidence of Witches' Broom Disease in cacao seedlings to 70%.
ABSTRACT. We investigated the diversity of endophytic fungi found on grape (Vitis labrusca cv. Niagara Rosada) leaves collected from Salesópolis, SP, Brazil. The fungi were isolated and characterized by amplified ribosomal DNA restriction analysis, followed by sequencing of the ITS1-5.8S-ITS2 rDNA. In addition, the ability of these endophytic fungi to inhibit the grapevine pathogen Fusarium oxysporum f. sp herbemontis was determined in vitro. We also observed that the climatic factors, such as temperature and rainfall, have no effect on the frequency of infection by endophytic fungi. The endophytic fungal community that was identified included Aporospora terricola, Aureobasidium pullulans, Bjerkandera adusta, Colletotrichum boninense, C. gloeosporioides, Diaporthe helianthi,
The growth of thirty-four Lentinula edodes strains submitted to different mycelial cultivation conditions (pH and temperature) was evaluated and strain variability was assessed by RAPD molecular markers. The growth at three pH values (5, 6 and 7) and four different temperatures (16, 25, 28 and 37ºC) was measured using the in vitro mycelial development rate and water retention as parameters. Mycelial cultivation was successful at all pH tested, while the ideal temperature for mycelial cultivation ranged between 25 and 28ºC. The water content was lower in strains grown at 37ºC. Among 20 OPA primers (Operon Technologies, Inc.) used for the RAPD analyses, seventeen presented good polymorphism (OPA01 to OPA05, OPA07 to OPA14, OPA17 to OPA20). The clustering based on similarity coefficients allowed the separation of strain in two groups with different geographic origins.
Endophytes are all microorganisms, culturable or not, that inhabit the interior of plant tissues, causing no harm to the host, and that do not develop external structures, excluding in this way, nodulating bacteria and mycorrhizal fungi. Theobroma cacao L. is important to food and cosmetic industry due the fact that it is used for production of cacao butter. Considering the importance of cacao and associated endophytic fungal community studies, the objectives of this work were to: i) study the diversity on endophytic community of cacao; ii) evaluate the potential of this community to biological control of Crinipellis perniciosa, causal agent of witches' broom disease and other phytopathogens and iii) study the interaction endophyte-pathogen and endophyte-host. The work began with isolation of the cacao endophytic fungi that was characterizated based on morphological and molecelar characters. The diversity was evaluated by rDNA (ITS1, ITS2 e 5.8 subunit regions) analyses (ARDRA and sequencing). The ARDRA analysis generated 64 haplotypes, which included at least 16 species. Following, antagonistic endophytic fungi from cacao were selected in vitro against C. perniciosa. It was observed that in 145 evaluated isolates, 38.6% was classified as antagonic, while 13.1% were classified as parasitic. After the selection, isolates were used for secondary metabolites extraction and further characterization. Also, detection of δ-(L-α-aminoadipil)-L-cisteinil-D-valin (ACV) gene, which is the precursor of β-lactans, antibiotics like penicilins and cephalosporins, was carried out. The amplification of this gene generated a fragment of 600pb in 9.1% of the isolates evaluated. Some isolates were further evaluated against phytophathogenic fungi (Colletotrichum falcatum, C. sublineorum, Erythricium salmonicolor, Rhizoctonia solani, Ceratocystis paradoxa, Phytophthora sp., P. parasitica, P. palmivora and Fusarium moniliforme). Only C. sublineorum of sorghum and Ceratocystis paradoxa of sugarcane were in vitro inhibited by the endophytes 42.3 and 2, respectively. The investigation of the penetration and colonization ability of endophytic fungus 42.3 on susceptible cacao comum was carried out, using RAPD and SEM techniques. The penetration of the fungus was initiated between 3 and 6 hours after inoculation. The interaction between cacao endophyte 42.3 with C. perniciosa 281 (pathogenic), was evaluated by SDS-PAGE, aiming the detection of expressed proteins by pathogen and endophyte. The SDS-PAGE allowed the visualization of bands expressed in the interaction, when the microorganisms were grown together. In the presence of the endophyte growth substrate, C. perniciosa do not express visible proteins or, at least, distinguishable in SDS-PAGE, but the co-cultive of these fungi generated non observed bands in previously analysis.
The Amazon has a high diversity of fungi, including species of the genus Daldinia (Ascomycota, Xylariaceae), which produce secondary metabolites with recognized nematicidal and antimicrobial activity. The ecological role of Daldinia is important, as stromata serve as refuges to many insects and arthropodes, and the fungi contribute to the degradation of vegetable organic matter. The aim of this study was to analyze the taxonomic features and mycelial growth conditions in vitro of a Daldinia specimen collected in the Brazilian Amazon. Morphological and molecular studies of the fungus identified it as D. eschscholtzii. To evaluate mycelial growth, we cultivated the fungus at 20, 25, 30, 35, and 40 ºC in malt extract-peptone agar (MEPA), malt extract-peptone (MEP), potato dextrose (PD), and minimum medium (MM). The best mycelial growth occurred at 35 ºC, although the greatest amount of biomass was obtained at 25 ºC and 30 ºC. PD proved to be the best medium for biomass production. KEYWORDS: Daldinia eschscholzii, fungal diversity, macrofungus, occurrence. Daldinia eschscholzii (Ascomycota, Xylariaceae) isolado na Amazônia brasileira: características taxonômicas e condições de crescimento micelial RESUMOA Amazônia apresenta alta diversidade de fungos, incluindo Daldinia (Ascomycota, Xylariaceae), cujas espécies produzem metabólitos secundários com reconhecida atividade antimicrobiana e nematicida. O papel ecológico é importante, visto que estromas servem de abrigo para muitos insetos e artrópodes, além de contribuir na degradação da matéria orgânica vegetal. O objetivo desse estudo foi analizar as características taxonômicas e as condições do crescimento micelial in vitro de um espécime de Daldinia coletado na Amazônia brasileira. Estudos morfológicos e moleculares do fungo o indetificaram como D. eschscholtzii. Para avaliação do crescimento micelial o fungo foi cultivado nas temperaturas de 20, 25, 30, 35 e 40 ºC e nos meios de cultura extrato de malte-peptona ágar (EMPA), extrato de malte-peptona (EMP), batata dextrose (BD) e meio mínimo (MM). O melhor crescimento micelial ocorreu a 35 ºC, entretanto, a maior quantidade de biomassa foi obtida a 25 e 30 ºC. O meio BD provou ser o melhor meio para produção de biomassa.
The Pink Disease is caused by Erythricium salmonicolor, which attacks broad hosts, such as citrus, coffee, rubber, Eucalyptus spp. and Acacia spp., infecting mainly branches. This disease became a serious problem in Brazil, reducing the citrus production up to 10%. However the genetic diversity and compatibility of the fungus E. salmonicolor from Brazilian citrus plants is not yet evaluated. Therefore, the aims of this study were to evaluate: i) the genetic variability of E. salmonicolor in the São Paulo and Minas Gerais States by the RAPD technique, and ii) the vegetative compatibility between these isolates. After RAPD analysis, six distinct groups were observed without correlation between the isolation site or host species. In the vegetative compatibility test, the contact of fungal hyphae between all evaluated crosses was observed, of which 84% presented hyphal fusion. Although the compatibility between strains was observed, no correlation between RAPD haplotypes and hyphal anastomosis was verified. These results show the importance of future studies on the sexual cycle of E. salmonicolor, since hyphal fusion, which precedes the formation of heterokaryons (sexual and parasexual reproduction) that could be responsible for the genetic variability in this species.
Five species of edible mushrooms, Lentinula edodes, Pleurotus ostreatus, Pholiota nameko, Macrolepiota bonaerensis and Agaricus blazei, were tested for their potential to inhibit the in vitro growth of the pathogenic yeast Candida albicans. Only L. edodes had a fungistatic effect on this human pathogen. The inhibitory compound was produced intra and extracellularly in submersed L. edodes culture, and was also present in fresh and dehydrated mushroom basidiocarps. The fungistatic compound was heat sensitive and lost activity after 72 hours.
Tuberculosis (TB) remains one of the most deadly communicable infectious diseases, causing 1.4 million deaths in 2015 worldwide due to many conditions, including the inadequate treatment and the emergence of multidrug-resistant strains of the causal agent, Mycobacterium tuberculosis. Therefore, drugs developed from natural sources, as microorganisms and plant extracts, are a frequent target for the research and discovery of antimicrobial compounds. The current study started the characterization of compounds produced by an Aspergillus fumigatus isolated from copaíba (Copaifera multijuga) that efficiently inhibits M. tuberculosis by releasing the compounds into the fermentation broth under specific culture conditions. A preliminary assay was carried out with a correlate species, M. smegmatis, aiming to detect an antimicrobial effect related to A. fumigatus fermentation broth. The direct use of this substrate in antibiosis assays againstM. tuberculosis H 37 Rv strain (ATCC 27294) allowed the detection of antimicrobial activity with a minimal inhibitory concentration of 256 μg mL -1 , demonstrating that purification processes developed by the Biotage Flash Chromatography System are robust and reliable techniques for purification of compounds from natural sources. Also, this chromatographic system can be used in combination with specific biochemical tests, improving the search for reliable results. We conclude that this fraction can express a broad action range, inhibiting both Mycobacterium species used as target organisms.KEYWORDS: Mycobacterium spp., antimicrobial activity, copaíba, chromatography Metabolitos de Aspergillus fumigatus endofítico e seu efeito in vitro contra o agente causal da tuberculose RESUMO A tuberculose continua a ser uma das doenças infecciosas transmissíveis mais mortais, causando 1,4 milhão de mortes em 2015 em todo o mundo devido a vários fatores, incluindo o tratamento inadequado e o surgimento de cepas multirresistentes do agente causal, Mycobacterium tuberculosis. Portanto, as drogas desenvolvidas a partir de fontes naturais, como micro-organismos e extratos de plantas, são um alvo freqüente para a pesquisa e descoberta de compostos antimicrobianos. O presente estudo foi um ponto de partida para caracterizar compostos produzidos por um Aspergillus fumigatus isolado de copaíba (Copaifera multijuga) que inibe eficientemente M. tuberculosis, liberando os compostos no caldo de fermentação em condições de cultura específicas. Realizou-se um ensaio preliminar com uma espécie correlata, M. smegmatis, com o objetivo de detectar um efeito antimicrobiano relacionado ao caldo de fermentação de A. fumigatus. O uso direto deste substrato em ensaios de antibiose contra a estirpe H37Rv de M. tuberculosis (ATCC 27294) permitiu a detecção de atividade antimicrobiana com uma concentração inibitória mínima de 256 μg mL -1 , demonstrando que os processos de purificação desenvolvidos pelo Biotage Flash Chromatography System são técnicas robustas e confiáveis para purificar compostos de fontes nat...
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