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Burkholderia contaminans isolated from root of blueberry shrub produces occidiofungins and pyrrolnitrin useful to prevent postharvest decays of blueberry fruits caused by Botrytis cinerea
No full textBACKGROUND: Botrytis cinerea is a relevant fungal pathogen in the production of blueberries, which is managed mainly with fungicides. However, the intensive usage has led to the emergence of resistant strains. The use of microbial biocontrol agents is a sustainable strategy to overcome limitations associated with fungicides. The objectives of this work were to know the capability of the endophytic bacterium Burkholderia contaminans 128 to inhibit different phytopathogens in vitro and to prevent B. cinerea rot in blueberry fruits.
RESULTS: Burkholderia contaminans 128 able to grow on filaments of Trichoderma citrinoviride was isolated from roots of blueberry shrub. The bacterial cell-free supernatant (Bc128 CFS) inhibited efficiently the mycelia growth and conidia germination of B. cinerea and other important pathogens affecting blueberry such as Alternaria sp., Colletotrichum gloeosporioides and Fusarium graminearum. HPLC–MS/MS analyses of Bc128 CFS confirmed production of occidiofungins and pyrrolnitrin, compounds with fungicide activity but different inhibition mechanisms. Qualitative and quantitative HPLC-MS/MS analyses determined the presence of indole-3-acetic acid in Bc128 CFS, a phytohormone involved in plant-growth promotion. Bc128 CFS inhibited completely the natural occurrence of conidia of Alternaria sp., Colletotrichum sp. and Pestalotiopsis sp. and reduced significantly the incidence of B. cinerea conidia in blueberry flowers. Bc128 CFS decreased the virulence of B. cinerea in blueberries approximately 90%. Bc128 CFS was more efficient to control B. cinerea in preventive than curative treatments and did not affect fruit quality.
CONCLUSION: B. contaminans 128 provides direct and indirect antibiosis mechanisms useful to prevent rots in blueberries caused by B. cinerea.EEA ConcordiaFil: Ferreira, Flavia Vanina. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Ciencia y Tecnología de los Alimentos de Entre Ríos; ArgentinaFil: Rivadeneira, Maria Fernanda. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Concordia; ArgentinaFil: Bello, Fernando. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Concordia; ArgentinaFil: Giudici, Vanesa. Universidad Nacional de Entre Ríos. Facultad de Ciencias de la Alimentación; ArgentinaFil: Musumeci, Matías Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Ciencia y Tecnología de los Alimentos de Entre Ríos; ArgentinaFil: Musumeci, Matías Alejandro. Universidad Nacional de Entre Ríos. Facultad de Ciencias de la Alimentación; Argentin
Mycofumigation of postharvest blueberries with volatile compounds from Trichoderma atroviride IC-11 is a promising tool to control rots caused by Botrytis cinerea
Get PDFBotrytis cinerea, the causal agent of the gray mold, is a filamentous fungus that infects blueberries and can cause important production losses in postharvest storage. Considering that the use of synthetic fungicides is not allowed on blueberries in postharvest conditions, alternative and natural strategies are needed to control gray mold. The objective of this work was to evaluate the capability of volatile organic compounds (VOCs) produced by Trichoderma atroviride IC-11 to control B. cinerea growth in blueberries after harvest.These VOCs inhibited almost completely B. cinerea growth in vitro. The most abundant volatile compound was 6-pentyl-α-pyrone (6PP). In vitro assays with pure 6PP confirmed its antifungal activity. The incidence of gray mold was evaluated in blueberries inoculated with B. cinerea and exposed to volatiles of T. atroviride IC-11. Gray mold incidence among those stored in air at 20 °C for 14 days was 100%, while the incidence among the volatile-treated fruit was 17%. Gray mold incidence among those stored in air at 4 °C for 31 days was 82%, while the incidence among the volatile-treated fruit was 11%. T. atroviride IC-11 VOCs inhibited mycelial growth and conidia germination of B. cinerea. The binding of VOCs to the surface of hyphae caused their vacuolation and deterioration. Selective cytotoxicity of 6PP on B. cinerea was observed but not on human intestinal cells at specific concentrations that controlled gray mold.
The postharvest mycofumigation of blueberries with T. atroviride IC-11 VOCs is a promising approach to protect these fruits from gray mold.EEA ConcordiaFil: Bello, Fernando. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Concordia; ArgentinaFil: Montironi, Ivana Dalila. Universidad Nacional de Río Cuarto. Facultad de Agronomía y Veterinaria. Cátedra de Farmacología; ArgentinaFil: Medina, María Belén. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Ciencia y Tecnología de los Alimentos de Entre Ríos; ArgentinaFil: Medina, María Belén. Universidad Nacional de Entre Ríos. Facultad de Ciencias de la Alimentación; ArgentinaFil: Munitz, Martín Sebastián. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Ciencia y Tecnología de los Alimentos de Entre Ríos; ArgentinaFil: Munitz, Martín Sebastián. Universidad Nacional de Entre Ríos. Facultad de Ciencias de la Alimentación; ArgentinaFil: Ferreira, Flavia Vanina. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Ciencia y Tecnología de los Alimentos de Entre Ríos; ArgentinaFil: Williman, Celia. Universidad Nacional de Entre Ríos. Facultad de Ciencias de la Alimentación; ArgentinaFil: Vazquez, Daniel Eduardo. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Concordia; ArgentinaFil: Cariddi, Noelia. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas, Físico-Químicas y Naturales. Departamento de Microbiología e Inmunología. Laboratorio de Inmunología; Argentina.Fil: Cariddi, Noelia. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biotecnología Ambiental y Salud; ArgentinaFil: Cariddi, Noelia. Universidad Nacional de Río Cuarto. Instituto de Biotecnología Ambiental y Salud; ArgentinaFil: Musumeci, Matías Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Ciencia y Tecnología de los Alimentos de Entre Ríos; ArgentinaFil: Musumeci, Matías Alejandro. Universidad Nacional de Entre Ríos. Facultad de Ciencias de la Alimentación; Argentin
Biocontrol of Penicillium digitatum by native Bacillus and Pseudomonas strains isolated from orange peel
No full textPenicillium digitatum is a filamentous fungus that infects citrus fruits, causing decays that result in significant production losses. The application of synthetic fungicides is the main approach to control P. digitatum. However, intensive usage of fungicides has led to the proliferation of resistant P. digitatum strains. Besides, this practice poses a risk for the human and environmental health and is incompatible with organic markets. Alternative approaches that may overcome these limitations are valuable innovations for citrus production. The objective of this work was to evaluate the potential of bacterial strains inhabiting naturally in oranges to control the growth of sensitive and resistant to pyrimethanil P. digitatum strains. Around 50 bacteria were isolated from oranges peel but only three showed optimal antagonistic activity against sensitive P. digitatum after qualitative screening assays. These bacteria were identified by molecular and biochemical analyses and corresponded to Bacillus mojavensis SC-45, Bacillus velezensis SC-31 and Pseudomonas psychrotolerans SC-29. The antifungal activity of bacterial extracellular cultures against P. digitatum strains was quantified in vitro by the poison agar method and by measuring the mycelial growth at 600 nm in a microplate assay. B. velezensis SC-31 showed the highest growth inhibition of both P. digitatum strains. Lipopeptides with antifungal activity were identified by HPLC-ESI-MS in bacterial extracellular cultures. Surfactin and iturin were the most abundant lipopeptides produced by Bacillus spp., but higher yields were observed in B. velezensis SC-31 supernatant; whereas viscosin was mainly produced by P. psychrotolerans SC-29. B. velezensis SC-31 also showed the highest proteolytic activity and the highest capability to form biofilms. B. velezensis SC-31 and B. mojavensis SC-45 produced the lowest incidence and severity of disease in vivo after infection with both P. digitatum strains in preventive treatments. Besides, bacteria were compatible with concentrations of fungicides corresponding to maximum residue levels (MRL) on citrus fruits and higher concentrations used in drenches. B. velezensis SC-31 and B. mojavensis SC-45 are proficient antagonists to control green mould in oranges, which can be used together with fungicides to improve the inhibition of P. digitatum and avoid the emergence of resistant strains.EEA ConcordiaFil: Ferreira, Flavia Vanina. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Ciencia y Tecnología de los Alimentos de Entre Ríos; ArgentinaFil: Bello, Fernando. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Concordia; ArgentinaFil: Rivadeneira, Maria Fernanda. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Concordia; ArgentinaFil: Vazquez, Daniel Eduardo. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Concordia; ArgentinaFil: Musumeci, Matías Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Ciencia y Tecnología de los Alimentos de Entre Ríos; ArgentinaFil: Musumeci, Matías Alejandro. Universidad Nacional de Entre Ríos. Facultad de Ciencias de la Alimentación; Argentin
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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