RESUMO
Endophytic bacteria serve key roles in the maintenance of plant health and growth. Few studies to date, however, have explored the antagonistic and plant growth-promoting (PGP) properties of Prunus cerasifera endophytes. To that end, we isolated endophytic bacteria from P. cerasifera tissue samples and used a dual culture plate assay to screen these microbes for antagonistic activity against Verticillium dahliae, Botryosphaeria dothidea, Fusarium oxysporum, F. graminearum, and F. moniliforme. Of the 36 strains of isolated bacteria, four (strains P1, P10, P16, and P20) exhibited antagonistic effects against all five model pathogens, and the P10 strain exhibited the strongest antagonistic to five pathogens. This P10 strain was then characterized in-depth via phenotypic assessments, physiological analyses, and 16s rDNA sequencing, revealing it to be a strain of Bacillus subtilis. Application of a P10 cell suspension (1×108 CFU/mL) significantly enhanced the seed germination and seedling growth of tomato in a greenhouse setting. This P10 strain further significantly suppressed tomato Verticillium wilt with much lower disease incidence and disease index scores being observed following P10 treatment relative to untreated plants in pot-based experiments. Tomato plants that had been treated with strain P10 also enhanced defense-related enzymes, peroxidase, superoxide dismutase, and catalase activity upon V. dahliae challenge relative to plants that had not been treated with this endophytic bacterium. The results revealed that the P10 bacterial strain has potential value as a biocontrol agent for use in the prevention of tomato Verticillium wilt.
As bactérias endofíticas desempenham papel fundamental na manutenção da saúde e do crescimento das plantas. Poucos estudos até o momento, no entanto, exploraram as propriedades antagônicas e promotoras de crescimento de plantas (PGP) de endófitos de Prunus cerasifera. Para esse fim, isolamos bactérias endofíticas de amostras de tecido de P. cerasifera e usamos um ensaio de placa de cultura dupla para rastrear esses micróbios quanto à atividade antagonista contra Verticillium dahliae, Botryosphaeria dothidea, Fusarium oxysporum, F. graminearum e F. moniliforme. Das 36 cepas de bactérias isoladas, quatro (cepas P1, P10, P16 e P20) exibiram efeitos antagônicos contra todos os cinco patógenos modelo, e a cepa P10 exibiu o antagonista mais forte para cinco patógenos. Essa cepa P10 foi então caracterizada em profundidade por meio de avaliações fenotípicas, análises fisiológicas e sequenciamento de rDNA 16s, revelando ser uma cepa de Bacillus subtilis. A aplicação de uma suspensão de células P10 (1 × 108 UFC / mL) aumentou significativamente a germinação das sementes e o crescimento das mudas de tomate em casa de vegetação. Essa cepa P10 suprimiu ainda mais a murcha de Verticillium do tomate com incidência de doença muito menor e pontuações de índice de doença sendo observadas após o tratamento com P10 em relação a plantas não tratadas em experimentos baseados em vasos. As plantas de tomate que foram tratadas com a cepa P10 também aumentaram as enzimas relacionadas à defesa, peroxidase, superóxido dismutase e atividade da catalase após o desafio de V. dahliae em relação às plantas que não foram tratadas com essa bactéria endofítica. Os resultados revelaram que a cepa bacteriana P10 tem valor potencial como agente de biocontrole para uso na prevenção da murcha de Verticillium em tomate.
Assuntos
Bacillus subtilis/fisiologia , Bacillus subtilis/genética , Endófitos/isolamento & purificação , Fusarium/patogenicidade , Prunus/microbiologia , Verticillium/patogenicidadeRESUMO
Endophytic bacteria serve key roles in the maintenance of plant health and growth. Few studies to date, however, have explored the antagonistic and plant growth-promoting (PGP) properties of Prunus cerasifera endophytes. To that end, we isolated endophytic bacteria from P. cerasifera tissue samples and used a dual culture plate assay to screen these microbes for antagonistic activity against Verticillium dahliae, Botryosphaeria dothidea, Fusarium oxysporum, F. graminearum, and F. moniliforme. Of the 36 strains of isolated bacteria, four (strains P1, P10, P16, and P20) exhibited antagonistic effects against all five model pathogens, and the P10 strain exhibited the strongest antagonistic to five pathogens. This P10 strain was then characterized in-depth via phenotypic assessments, physiological analyses, and 16s rDNA sequencing, revealing it to be a strain of Bacillus subtilis. Application of a P10 cell suspension (1×108 CFU/mL) significantly enhanced the seed germination and seedling growth of tomato in a greenhouse setting. This P10 strain further significantly suppressed tomato Verticillium wilt with much lower disease incidence and disease index scores being observed following P10 treatment relative to untreated plants in pot-based experiments. Tomato plants that had been treated with strain P10 also enhanced defense-related enzymes, peroxidase, superoxide dismutase, and catalase activity upon V. dahliae challenge relative to plants that had not been treated with this endophytic bacterium. The results revealed that the P10 bacterial strain has potential value as a biocontrol agent for use in the prevention of tomato Verticillium wilt.(AU)
As bactérias endofíticas desempenham papel fundamental na manutenção da saúde e do crescimento das plantas. Poucos estudos até o momento, no entanto, exploraram as propriedades antagônicas e promotoras de crescimento de plantas (PGP) de endófitos de Prunus cerasifera. Para esse fim, isolamos bactérias endofíticas de amostras de tecido de P. cerasifera e usamos um ensaio de placa de cultura dupla para rastrear esses micróbios quanto à atividade antagonista contra Verticillium dahliae, Botryosphaeria dothidea, Fusarium oxysporum, F. graminearum e F. moniliforme. Das 36 cepas de bactérias isoladas, quatro (cepas P1, P10, P16 e P20) exibiram efeitos antagônicos contra todos os cinco patógenos modelo, e a cepa P10 exibiu o antagonista mais forte para cinco patógenos. Essa cepa P10 foi então caracterizada em profundidade por meio de avaliações fenotípicas, análises fisiológicas e sequenciamento de rDNA 16s, revelando ser uma cepa de Bacillus subtilis. A aplicação de uma suspensão de células P10 (1 × 108 UFC / mL) aumentou significativamente a germinação das sementes e o crescimento das mudas de tomate em casa de vegetação. Essa cepa P10 suprimiu ainda mais a murcha de Verticillium do tomate com incidência de doença muito menor e pontuações de índice de doença sendo observadas após o tratamento com P10 em relação a plantas não tratadas em experimentos baseados em vasos. As plantas de tomate que foram tratadas com a cepa P10 também aumentaram as enzimas relacionadas à defesa, peroxidase, superóxido dismutase e atividade da catalase após o desafio de V. dahliae em relação às plantas que não foram tratadas com essa bactéria endofítica. Os resultados revelaram que a cepa bacteriana P10 tem valor potencial como agente de biocontrole para uso na prevenção da murcha de Verticillium em tomate.(AU)
Assuntos
Prunus/microbiologia , Bacillus subtilis/genética , Bacillus subtilis/fisiologia , Endófitos/isolamento & purificação , Verticillium/patogenicidade , Fusarium/patogenicidadeRESUMO
Brown rot (BR) caused by Monilinia spp., has been an economic problem for the stone fruit market due to dramatic losses, mainly during the postharvest period. There is much literature about basic aspects of Monilinia spp. infection, which indicates that environment significantly influences its occurrence in the orchard. However, progress is needed to sustainably limit this disease: the pathogen is able to develop resistance to pesticides, and most of BR resistance research programs in plant models perish. Solving this problem becomes important due to the need to decrease chemical treatments and reduce residues on fruit. Thus, research has recently increased, exploring a wide range of disease control strategies (e.g., genetic, chemical, physical). Summarizing this information is difficult, as studies evaluate different Monilinia and Prunus model species, with diverse strategies and protocols. Thus, the purpose of this review is to present the diversity and distribution of agents causing BR, focusing on the biochemical mechanisms of Monilinia spp. infection both of the fungi and of the fruit, and report on the resistance sources in Prunus germplasm. This review comprehensively compiles the information currently available to better understand mechanisms related to BR resistance.
Assuntos
Ascomicetos/fisiologia , Doenças das Plantas/microbiologia , Prunus/microbiologia , Ascomicetos/genética , Ascomicetos/isolamento & purificação , Frutas/microbiologia , Doenças das Plantas/prevenção & controleRESUMO
Introducción: la criptocococis es una micosis sistémica causada por C. neoformans y C. gattii, es frecuente y oportunista en inmunocomprometidos y patógeno primario en personas inmunocompetentes. C. neoformans tiene una distribución mundial y se ha aislado desde las excretas de palomas. C. gattii se considera restringida a regiones con clima tropical, subtropical, y templadas, se encuentra asociada frecuentemente a detritos de especies de Eucalyptus sp. La virulencia de estas levaduras le permite desarrollar patogénesis en mamíferos y supervivencia en el ambiente. Objetivo: Identificar y determinar la actividad de proteinasas y fosfolipasas, de C. neoformans y C. gattii aisladas desde las oquedades de árboles en lugares con alta afluencia de público. Materiales y Métodos: Se tomaron 200 muestras de hisopado desde distintas especies de árboles desde sectores de la región de OHiggins y el Maule. Se siembran en ASG, se aíslan y mantienen en ASD. Identificación con tinta china, Urea de Christensen, crecimiento a 37°C, asimilación y fermentación de azucares, y siembra en medio CGB. Se mide índice de actividad enzimática Prz de proteinasas y fofolipasas. Resultados y Conclusiones: Se obtuvieron 109 cepas de C. neoformans aisladas desde las oquedades de diferentes especies arbóreas y 3 cepas presuntivas de C. gattii desde Eucalyptus sp. y Prunus cerasifera artropurpurea. El 88,1 por ciento de las cepas C. neoformans y 100 por ciento de C. gattii, presentaron alta actividad proteolítica, El 49,5 por ciento de las cepas de C. neoformans y 33,3 por ciento de C. gattii mostraron alta actividad de fosfolipasas.
Introduction: criptocococis is a systemic mycosis caused by C. neoformans and C. gattii, frequent and opportunistic in immunocompromised and primary pathogen in immunocompetent persons. C. neoformans has a worldwide distribution and has been isolated from the excreta of pigeons. C. gattii is considered restricted to regions with tropical, subtropical, and temperate, is often associated with species of Eucalyptus sp. The virulence of these yeasts develop pathogenesis allows survival in mammals and the environment. Objective: To identify and determine the activity of proteinases and phospholipases of C. neoformans and C. gattii isolated from the hollows of trees in places with high turnout. Materials and Methods: 200 swab samples were taken from different species of trees from areas of the region of OHiggins and Maule. Planted in ASG, they are isolated and kept in ASD. Identification with ink, Urea Christensen, growth at 37 ° C, assimilation and fermentation of sugars, and planting medium CGB. Prz index proteinase enzyme activity is measured and phospholipases. Results and Conclusions: We manage to get 109 strains of C. neoformans isolated from the hollows of different tree species and 3 presumptive strains of C. gattii from Eucalyptus sp. and Prunus cerasifera artropurpurea. 88.1 percent of the strains C. neoformans and C. gattii 100 percent , they showed high proteolytic activity, 49.5 percent of the strains of C. neoformans and C. gattii 33.3 percent showed high activity phospholipases.
Assuntos
Humanos , Cryptococcus gattii/isolamento & purificação , Cryptococcus gattii/enzimologia , Cryptococcus gattii/patogenicidade , Cryptococcus neoformans/isolamento & purificação , Cryptococcus neoformans/enzimologia , Cryptococcus neoformans/patogenicidade , Peptídeo Hidrolases , Fosfolipases , Árvores/microbiologia , Chile , Criptococose/etiologia , Eucalyptus/microbiologia , Pneumopatias Fúngicas , Prunus/microbiologiaRESUMO
The aim of this study was to describe an outbreak of Shigella sonnei that occurred in the city of Lujan, Buenos Aires, Argentina, in July 2012. Five individuals were affected after eating a hand-made Viennese-style pastry at a family gathering. All of them presented with fever, joint pain, chills and non-bloody diarrhea containing mucus. Stool cultures were performed in all cases and the samples taken from the pastry ingredients were analyzed microbiologically. S.sonnei was isolated and identified in all the patients involved as well as in the almond cream filling. The isolates were analyzed for determining the antimicrobial susceptibility and genetic profiles by pulsed field gel electrophoresis (PFGE). The results showed the genetic relationship among the isolates, confirming that the cases occurred due to the patients' exposure to the same source of infection, i.e., the almond cream. Being the almond cream an industrially-manufactured ingredient, an initial contamination could have been unlikely; however contamination might have occurred as a result of manipulation in the bakery.
Assuntos
Surtos de Doenças , Disenteria Bacilar/epidemiologia , Fast Foods/microbiologia , Microbiologia de Alimentos , Doenças Transmitidas por Alimentos/epidemiologia , Shigella sonnei/isolamento & purificação , Idoso , Antibacterianos/farmacologia , Argentina/epidemiologia , Doces/microbiologia , DNA Bacteriano/genética , Disenteria Bacilar/microbiologia , Eletroforese em Gel de Campo Pulsado , Doenças Transmitidas por Alimentos/microbiologia , Genes Bacterianos , Humanos , Pessoa de Meia-Idade , Polimorfismo de Fragmento de Restrição , Prunus/microbiologia , Shigella sonnei/efeitos dos fármacos , Shigella sonnei/genética , Saúde da População UrbanaRESUMO
Salmonellosis outbreaks related to consumption of raw almonds have encouraged the scientific community to study the inactivation kinetics of pathogens in this dry commodity. However, the low moisture content of the product presents a challenge for thermal control, because the time required to achieve the desired thermal inactivation of microorganisms increases sharply with reduced moisture content and water activity. In this study, we explored and modeled the heat inactivation of Salmonella enterica serovar Enteritidis PT 30 in almond cultivar 'Nonpareil' kernel flour at four water activity (a(w)) values (0.601, 0.720, 0.888, and 0.946) using four temperatures for each a(w). The results showed that the inactivation was well fitted by both Weibull distribution (R(2) = 0.93 to 1.00) and first-order kinetics (R(2) = 0.82 to 0.96). At higher a(w) values, the rate of inactivation increased and less time was needed to achieve the required population reduction. These results suggest that, to avoid deterioration of product quality, shorter process times at lower temperatures may be used to achieve desired inactivation levels of Salmonella Enteritidis PT 30 by simply increasing the moisture content of almonds. These goals could be achieved with the use of existing procedures already practiced by the food industry, such as washing or prewetting scalding before heat inactivation.
Assuntos
Temperatura Alta , Prunus/microbiologia , Salmonella enteritidis/crescimento & desenvolvimento , Água/metabolismo , Tipagem de Bacteriófagos , Contagem de Colônia Microbiana , Qualidade de Produtos para o Consumidor , Surtos de Doenças , Contaminação de Alimentos/análise , Manipulação de Alimentos/métodos , Microbiologia de Alimentos , Inocuidade dos Alimentos , Humanos , Cinética , Modelos Biológicos , Fatores de Risco , Intoxicação Alimentar por Salmonella/epidemiologia , Intoxicação Alimentar por Salmonella/etiologia , Intoxicação Alimentar por Salmonella/prevenção & controle , Salmonella enteritidis/metabolismoRESUMO
The objective of this study was to evaluate the presence of fungi and mycotoxins (aflatoxins and cyclopiazonic acid) in Brazil nut samples collected in different states of the Brazilian Amazon region: Acre, Amazonas, Amapá, and Pará. A total of 200 husk samples and 200 almond samples were inoculated onto Aspergillus flavus-parasiticus agar for the detection of fungi. Mycotoxins were analyzed by high-performance liquid chromatography. The mycobiota comprised the following fungi, in decreasing order of frequency: almonds - Phialemonium spp. (54%), Penicillium spp. (16%), Fusarium spp. (13%), Phaeoacremonium spp. (11%), and Aspergillus spp. (4%), husks - Phialemonium spp. (62%), Phaeoacremonium spp. (11%), Penicillium spp. (10%), Fusarium spp. (9%), and Aspergillus spp. A polyphasic approach was used for identification of Aspergillus species. Aflatoxins were detected in 22 (11%) of the 200 almond samples, with 21 samples presenting aflatoxin B(1) levels above 8µg/kg, the limit established by the European Commission for Brazil nuts for further processing. Nineteen (9.5%) of the 200 husk samples contained aflatoxins, but at levels lower than those seen in almonds. Cyclopiazonic acid (CPA) was detected in 44 (22%) almond samples, with levels ranging from 98.65 to 161.2µg/kg. Aspergillus nomius and A. flavus were the most frequent Aspergillus species. The presence of fungi does not necessarily imply mycotoxin contamination, but almonds of the Brazil nut seem to be a good substrate for fungal growth.
Assuntos
Aflatoxinas/análise , Bertholletia/microbiologia , Micotoxinas/análise , Aspergillus , Aspergillus flavus , Brasil , Cromatografia Líquida de Alta Pressão , Microbiologia de Alimentos , Fungos , Fusarium/isolamento & purificação , Penicillium/isolamento & purificação , Prunus/microbiologiaRESUMO
Laboratory, greenhouse, and field experiments were performed with the objective of selecting efficient indigenous strains of entomopathogenic nematodes (EPNs) from Rio Grande do Sul (RS) state, Brazil, for controlling the South American fruit fly, Anastrepha fraterculus (Wied.). Laboratory experiments were conducted in 24 well-plates filled with sterile sand and one insect per well. In greenhouse experiments, plastic trays filled with soil collected from the field were used, while in field experiments, holes were made in soil under the edge of peach tree canopies. Among 19 EPN strains tested, Heterorhabditis bacteriophora Poinar RS88 and Steinernema riobrave Cabanillas, Poinar, & Raulston RS59 resulted in higher A. fraterculus larval (pre-pupal) and pupal mortality, with LD(90) of 1630, 457 and 2851, 423 infective juveniles (IJs)/cm(2), respectively. Greenhouse experiments showed no differences in pupal mortality at 250 and 500IJs/cm(2) of either nematode. In the field, H. bacteriophora RS88 and S. riobravae RS59 sprayed individually over natural and artificially infested fruit (250IJs/cm(2)) resulted in A. fraterculus larval mortality of 51.3%, 28.1% and 20%, 24.3%, respectively. There was no significant difference in A. fraterculus pupal mortality sprayed with an aqueous suspension of either nematode; however, when using infected insect cadavers, H. bacteriophora RS88 was more efficient than S. riobrave RS59. Our results showed that H. bacteriophora RS88 was more virulent to insect larvae, with an efficient host search inside the infested fruit and control of pupae in the soil after being applied by aqueous suspension or infected cadavers.
Assuntos
Interações Hospedeiro-Parasita/fisiologia , Nematoides/fisiologia , Controle Biológico de Vetores/métodos , Prunus/microbiologia , Tephritidae/parasitologia , Animais , BrasilRESUMO
Inoculation with Azospirillum brasilense Sp245 exerts beneficial effects on micropropagated plants of Prunus cerasifera L. clone Mr.S 2/5, as seen in the results of a comparative analysis of inoculated and non-inoculated explants, during both the rooting and acclimatation phases. The presence of Azospirillum brasilense Sp245 increased root system, root hair biomass production and apical activity. Although the presence of the bacteria had a positive effect on rooting, the addition of indolebutyric acid (IBA) to Murashige and Skoog (MS) medium was seen as indispensable in order to promote the rooting of explants. Aside from the promotion of plant growth, A. brasilense Sp245 protects plants against pathogen attacks, such as Rhizoctonia spp., with a plant survival rate of nearly 100% vs. 0% as seen in the negative control. The biocontrol effect of A. brasilense Sp245 on the fungal rhizospheric community has been confirmed by denaturing gradient gel electrophoresis (DGGE) profiles of the rhizospheric microbial community. This study indicates that A. brasilense Sp245 could be employed as a tool in plant biotechnology.
Assuntos
Azospirillum brasilense , Controle Biológico de Vetores/métodos , Prunus/crescimento & desenvolvimento , Prunus/microbiologia , Aclimatação/fisiologia , Antibiose/fisiologia , Azospirillum brasilense/fisiologia , Biomassa , Células Clonais , Genes Fúngicos , Incubadoras , Indóis/farmacologia , Doenças das Plantas/microbiologia , Doenças das Plantas/parasitologia , Raízes de Plantas/crescimento & desenvolvimento , Raízes de Plantas/microbiologia , Raízes de Plantas/parasitologia , Brotos de Planta/crescimento & desenvolvimento , Brotos de Planta/microbiologia , Brotos de Planta/parasitologia , Prunus/parasitologia , Rhizoctonia/citologia , Rhizoctonia/patogenicidadeRESUMO
There is little information about bacteriological quality of preroasted kernels available in the public domain. An investigation of the bacteriological quality of preroasted peanut, almond, cashew, hazelnut, and Brazil nut kernels received into three Australian nut-processing facilities was performed over a period of 3 years. A total of 836 samples were analyzed for aerobic plate count, and 921 samples for Salmonella and Escherichia coli. The 921 samples included 653 peanut, 100 cashew, 60 almond, 60 Brazil nut, and 48 hazelnut kernels. There was no E. coli detected in any sample. Salmonella subsp. II (Fremantle) was detected in one raw almond sample. The aerobic plate count percentages of positive samples with counts above the detection level of the plating method used (100 CFU/g) for peanuts, almonds, cashews, hazelnuts, and Brazil nuts were 84, 78, 74, 50, and 45%, respectively. Of the samples containing more than this detection limit, the means were 4.5, 4.4, 3.1, 2.5, and 3.8 log CFU/g respectively. Although roasted kernel quality was not within the scope of this survey, raw microbial bioload would be expected to reduce on roasting. The bacteriological quality of preroasted peanut, almond, cashew, hazelnut, and Brazil nut kernels received into nut-processing facilities in Australia does not appear to suggest a public health concern.