Examinando por Autor "Posada, L.F."

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    Bacillus subtilis EA-CB0575 genome reveals clues for plant growth promotion and potential for sustainable agriculture
    (Springer, 2020-01-01) Franco-Sierra, N.D.; Posada, L.F.; Santa-María, G.; Romero-Tabarez, M.; Villegas-Escobar, V.; Álvarez, J.C.; Universidad EAFIT. Departamento de Ciencias; Biodiversidad, Evolución y Conservación
    Bacillus subtilis is a remarkably diverse bacterial species that displays many ecological functions. Given its genomic diversity, the strain Bacillus subtilis EA-CB0575, isolated from the rhizosphere of a banana plant, was sequenced and assembled to determine the genomic potential associated with its plant growth promotion potential. The genome was sequenced by Illumina technology and assembled using Velvet 1.2.10, resulting in a whole genome of 4.09 Mb with 4332 genes. Genes involved in the production of indoles, siderophores, lipopeptides, volatile compounds, phytase, bacilibactin, and nitrogenase were predicted by gene annotation or by metabolic pathway prediction by RAST. These potential traits were determined using in vitro biochemical tests, finding that B. subtilis EA-CB0575 produces two families of lipopeptides (surfactin and fengycin), solubilizes phosphate, fixes nitrogen, and produces indole and siderophores compounds. Finally, strain EA-CB0575 increased 34.60% the total dry weight (TDW) of tomato plants with respect to non-inoculated plants at greenhouse level. These results suggest that the identification of strain-specific genes and predicted metabolic pathways might explain the strain potential to promote plant growth by several mechanisms of action, accelerating the development of plant biostimulants for sustainable agricultural. © 2020, Springer-Verlag GmbH Germany, part of Springer Nature.
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    Bacillus subtilis EA-CB0575 genome reveals clues for plant growth promotion and potential for sustainable agriculture
    (Springer, 2020-01-01) Franco-Sierra, N.D.; Posada, L.F.; Santa-María, G.; Romero-Tabarez, M.; Villegas-Escobar, V.; Álvarez, J.C.; Universidad EAFIT. Departamento de Ciencias; Ciencias Biológicas y Bioprocesos (CIBIOP)
    Bacillus subtilis is a remarkably diverse bacterial species that displays many ecological functions. Given its genomic diversity, the strain Bacillus subtilis EA-CB0575, isolated from the rhizosphere of a banana plant, was sequenced and assembled to determine the genomic potential associated with its plant growth promotion potential. The genome was sequenced by Illumina technology and assembled using Velvet 1.2.10, resulting in a whole genome of 4.09 Mb with 4332 genes. Genes involved in the production of indoles, siderophores, lipopeptides, volatile compounds, phytase, bacilibactin, and nitrogenase were predicted by gene annotation or by metabolic pathway prediction by RAST. These potential traits were determined using in vitro biochemical tests, finding that B. subtilis EA-CB0575 produces two families of lipopeptides (surfactin and fengycin), solubilizes phosphate, fixes nitrogen, and produces indole and siderophores compounds. Finally, strain EA-CB0575 increased 34.60% the total dry weight (TDW) of tomato plants with respect to non-inoculated plants at greenhouse level. These results suggest that the identification of strain-specific genes and predicted metabolic pathways might explain the strain potential to promote plant growth by several mechanisms of action, accelerating the development of plant biostimulants for sustainable agricultural. © 2020, Springer-Verlag GmbH Germany, part of Springer Nature.
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    Bioprospecting of aerobic endospore-forming bacteria with biotechnological potential for growth promotion of banana plants
    (Elsevier, 2016-11-22) Posada, L.F.; Ramírez, M.; Ochoa-Gómez, N.; Cuellar-Gaviria, T.Z.; Argel-Roldan, L.E.; Ramírez, C.A.; Villegas-Escobar, V.; Universidad EAFIT. Departamento de Ciencias; Ciencias Biológicas y Bioprocesos (CIBIOP)
    High amounts of agrochemicals are regularly used for increasing yields in cultivation of banana. The use of plant growth-promoting rhizobacteria (PGPR) could represent an environmentally friendly alternative that can improve productivity. In this study, we tested a funnel-like strategy to bioprospect aerobic endospore-forming bacteria (AEFB) that could be useful to develop a biotechnological product to promote the growth of banana plants. First, 837 aerobic endospore-forming bacteria were obtained from the rhizosphere of banana and plantain. Then, the isolates were assessed for both: their capacity to promote growth of maize seedlings (used as a model plant) and to display specific biochemical PGPR-associated traits. Twenty-two of these strains significantly increased the dry weight of maize seedlings, some of them showing in vitro PGPR traits. Based on this screening, four isolates were selected to conduct evaluations on banana plants, from which, the bacterial strain Bacillus subtilis EA-CB0575 was chosen as a promising plant growth -promoting isolate. Further studies with this strain showed that the application of either spores, vegetative cells (both at concentrations 1 x 10(7) and 1 x 10(8) CFU/mL), or the cell-free supernatant (CFS) of its fermentation significantly increased the dry weight of banana plants, compared with the non-treated control. Our results suggest that both cellular structures of B. subtilis EA-CB0575 and the metabolites and/or elements contained in its CFS enhance the growth and development of banana plants. (C) 2016 Elsevier B.V. All rights reserved.
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    Construction of probe of the plant growth-promoting bacteria Bacillus subtilis useful for fluorescence in situ hybridization
    (Elsevier, 2016-09-01) Posada, L.F.; Alvarez, J.C.; Hu, C.-H.; de-Bashan, L.E.; Bashan, Y.; Universidad EAFIT. Departamento de Ciencias; Biodiversidad, Evolución y Conservación
    Strains of Bacillus subtilis are plant growth-promoting bacteria (PGPB) of many crops and are used as inoculants. PGPB colonization is an important trait for success of a PGPB on plants. A specific probe, based on the 16 s rRNA of Bacillus subtilis, was designed and evaluated to distinguishing, by fluorescence in situ hybridization (FISH), between this species and the closely related Bacillus amyloliquefaciens. The selected target for the probe was between nucleotides 465 and 483 of the gene, where three different nucleotides can be identified. The designed probe successfully hybridized with several strains of Bacillus subtilis, but failed to hybridize not only with B. amyloliquefaciens, but also with other strains such as Bacillus altitudinis, Bacillus cereus, Bacillus gibsonii, Bacillus megaterium, Bacillus pumilus; and with the external phylogenetic strains Azospirillum brasilense Cd, Micrococcus sp. and Paenibacillus sp. The results showed the specificity of this molecular probe for B. subtilis. (C) 2016 Elsevier B.V. All rights reserved.
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    Construction of probe of the plant growth-promoting bacteria Bacillus subtilis useful for fluorescence in situ hybridization
    (Elsevier, 2016-09-01) Posada, L.F.; Alvarez, J.C.; Hu, C.-H.; de-Bashan, L.E.; Bashan, Y.; Universidad EAFIT. Departamento de Ciencias; Ciencias Biológicas y Bioprocesos (CIBIOP)
    Strains of Bacillus subtilis are plant growth-promoting bacteria (PGPB) of many crops and are used as inoculants. PGPB colonization is an important trait for success of a PGPB on plants. A specific probe, based on the 16 s rRNA of Bacillus subtilis, was designed and evaluated to distinguishing, by fluorescence in situ hybridization (FISH), between this species and the closely related Bacillus amyloliquefaciens. The selected target for the probe was between nucleotides 465 and 483 of the gene, where three different nucleotides can be identified. The designed probe successfully hybridized with several strains of Bacillus subtilis, but failed to hybridize not only with B. amyloliquefaciens, but also with other strains such as Bacillus altitudinis, Bacillus cereus, Bacillus gibsonii, Bacillus megaterium, Bacillus pumilus; and with the external phylogenetic strains Azospirillum brasilense Cd, Micrococcus sp. and Paenibacillus sp. The results showed the specificity of this molecular probe for B. subtilis. (C) 2016 Elsevier B.V. All rights reserved.
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    Enhanced molecular visualization of root colonization and growth promotion by Bacillus subtilis EA-CB0575 in different growth systems
    (Elsevier GmbH, 2018-01-01) Posada, L.F.; Álvarez, J.C.; Romero-Tabarez, M.; de-Bashan, L.; Villegas-Escobar, V.; Universidad EAFIT. Departamento de Ciencias; Biodiversidad, Evolución y Conservación
    Bacillus subtilis EA-CB0575 is a plant growth-promoting bacterium (PGPB) associated with banana and tomato crops. Root colonization is an important trait for PGPB microorganisms and potentiates the bacterial effect related to the mechanisms of plant growth promotion. Therefore, detection of bacterial colonization of roots in different culture systems is important in the study of plant–microorganism interactions. In this study, fluorescent in situ hybridization (FISH) and catalyzed reporter deposition–FISH (CARD–FISH) were evaluated to determine the colonization ability of B. subtilis EA-CB0575 on banana and tomato roots planted on solid and liquid Murashige and Skoog medium (MS(S) and MS(L), respectively) and in soil for tomato plants. Results showed B. subtilis colonization 0–30 days post inoculation for banana and tomato plants in different culture systems with differential distribution of bacterial cells along tomato and banana roots. FISH and CARD–FISH methodologies were both successful in detecting B. subtilis colonies, but CARD–FISH proved to be superior due to its enhanced fluorescence signal. The presence of bacteria correlated with the promotion of plant growth in both plant species, providing clues to relate rhizospheric colonization with improvement in plant growth. FISH and CARD–FISH analysis results suggested the presence of native microbiota on the roots of in vitro banana plants, but not on those of tomato plants. © 2018 Elsevier GmbH
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    Enhanced molecular visualization of root colonization and growth promotion by Bacillus subtilis EA-CB0575 in different growth systems
    (Elsevier GmbH, 2018-01-01) Posada, L.F.; Álvarez, J.C.; Romero-Tabarez, M.; de-Bashan, L.; Villegas-Escobar, V.; Universidad EAFIT. Departamento de Ciencias; Ciencias Biológicas y Bioprocesos (CIBIOP)
    Bacillus subtilis EA-CB0575 is a plant growth-promoting bacterium (PGPB) associated with banana and tomato crops. Root colonization is an important trait for PGPB microorganisms and potentiates the bacterial effect related to the mechanisms of plant growth promotion. Therefore, detection of bacterial colonization of roots in different culture systems is important in the study of plant–microorganism interactions. In this study, fluorescent in situ hybridization (FISH) and catalyzed reporter deposition–FISH (CARD–FISH) were evaluated to determine the colonization ability of B. subtilis EA-CB0575 on banana and tomato roots planted on solid and liquid Murashige and Skoog medium (MS(S) and MS(L), respectively) and in soil for tomato plants. Results showed B. subtilis colonization 0–30 days post inoculation for banana and tomato plants in different culture systems with differential distribution of bacterial cells along tomato and banana roots. FISH and CARD–FISH methodologies were both successful in detecting B. subtilis colonies, but CARD–FISH proved to be superior due to its enhanced fluorescence signal. The presence of bacteria correlated with the promotion of plant growth in both plant species, providing clues to relate rhizospheric colonization with improvement in plant growth. FISH and CARD–FISH analysis results suggested the presence of native microbiota on the roots of in vitro banana plants, but not on those of tomato plants. © 2018 Elsevier GmbH
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    Spatial layout and surface reconstruction from omnidirectional images
    (Institute of Electrical and Electronics Engineers Inc., 2016-01-01) Posada, L.F.; Velasquez-Lopez, A.
    This paper presents a spatial layout recovery approach from single omnidirectional images. Vertical structures in the scene are extracted via classification from heterogeneous features computed at the superpixel level. Vertical surfaces are further classified according to their main orientation by fusing oriented line features, floor-wall boundary features and histogram of oriented gradients (HOG) with a Random Forest classifier. Oriented line features are used to build an orientation map that considers the main vanishing points. The floor-wall boundary feature attempts to reconstruct the scene shape as if it were observed from a bird's-eye view. Finally, the HOG descriptors are aggregated per superpixel and summarize the gradient distribution at homogeneous appearance regions. Compared to existing methods in the literature which rely only on corners or lines, our method gains statistical support from multiple cues aggregated per superpixel which provide more robustness against noise, occlusion, and clutter. © 2016 IEEE.
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    Spatial layout and surface reconstruction from omnidirectional images
    (Institute of Electrical and Electronics Engineers Inc., 2016-01-01) Posada, L.F.; Velasquez-Lopez, A.; Posada, L.F.; Velasquez-Lopez, A.; Universidad EAFIT. Departamento de Ciencias; Ciencias Biológicas y Bioprocesos (CIBIOP)
    This paper presents a spatial layout recovery approach from single omnidirectional images. Vertical structures in the scene are extracted via classification from heterogeneous features computed at the superpixel level. Vertical surfaces are further classified according to their main orientation by fusing oriented line features, floor-wall boundary features and histogram of oriented gradients (HOG) with a Random Forest classifier. Oriented line features are used to build an orientation map that considers the main vanishing points. The floor-wall boundary feature attempts to reconstruct the scene shape as if it were observed from a bird's-eye view. Finally, the HOG descriptors are aggregated per superpixel and summarize the gradient distribution at homogeneous appearance regions. Compared to existing methods in the literature which rely only on corners or lines, our method gains statistical support from multiple cues aggregated per superpixel which provide more robustness against noise, occlusion, and clutter. © 2016 IEEE.