Examinando por Autor "Villegas-Escobar, V."
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Ítem 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 ConservaciónBacillus 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.Ítem 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.Ítem 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.Ítem Effective control of black Sigatoka disease using a microbial fungicide based on Bacillus subtilis EA-CB0015 culture(Academic Press Inc., 2015-08-01) Gutierrez-Monsalve, J.A.; Mosquera, S.; González-Jaramillo, L.M.; Mira, J.J.; Villegas-Escobar, V.; Universidad EAFIT. Departamento de Ciencias; Ciencias Biológicas y Bioprocesos (CIBIOP)Black Sigatoka disease caused by the fungus Mycosphaerella fijiensis Morelet is the most devastating disease of bananas worldwide. Its management is reliant on protectant and systemic fungicides despite their environmental concerns. This study evaluated the effect of a microbial fungicide (MF) based on Bacillus subtilis EA-CB0015 and its metabolites for the control of black Sigatoka disease on banana plants in greenhouse and field conditions. The MF applied at 1.5. L/ha and 3.0. L/ha provided control of the disease comparable to the protectant fungicide chlorothalonil in greenhouse. In the field, the MF applied in solution with water at 0.15. L/ha and 1.5. L/ha every 11. days during 10. weeks reduced black Sigatoka disease severity in 20.2% and 28.1% respectively; reductions comparable to those obtained with the protectant fungicides chlorothalonil (1.5. L/ha) and mancozeb (3.8. L/ha). The MF incorporated into different programs with systemic fungicides reduced disease level up to 42.9% with no significant differences with the conventional program. To determine which component of the MF is responsible for the activity against M. fijiensis, greenhouse and in vitro tests were set up to evaluate individually the spores, vegetative cells and secondary metabolites of B. subtilis EA-CB0015. All components reduced the severity of the disease and the germination of ascospores. For both trials the activity of the metabolites was higher and comparable to the activity obtained with the MF, indicating that the efficacy of the MF depends mainly on the metabolites and in lesser extent to B. subtilis EA-CB0015 cells. © 2015 Elsevier Inc.Ítem 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 ConservaciónBacillus 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 GmbHÍtem 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 GmbHÍtem Multiple response optimization of Bacillus subtilis EA-CB0015 culture and identification of antifungal metabolites(Elsevier Ltd, 2014-01-01) Mosquera, S.; González-Jaramillo, L.M.; Orduz, S.; Villegas-Escobar, V.; Universidad EAFIT. Departamento de Ciencias; Ciencias Biológicas y Bioprocesos (CIBIOP)The low yields of biomass and antimicrobial metabolites obtained in fermentation processes are limiting factors for implementing biological control agents in the field. In this context, optimization of the culture medium for the biological control agent Bacillus subtilis EA-CB0015 was conducted in submerged culture to maximize the biomass production and antifungal activity. Additionally, the active metabolites against the phytopathogen Mycosphaerella fijiensis produced under optimized conditions were identified. Carbon and nitrogen constituents of the culture medium were optimized using a 22 factorial design with central point followed by a multiple response optimization coupled to the desirability function approach. The optimized medium (33.4g/L of glucose and 32.5g/L of yeast extract), showed significant increases in both, cell density by 3.6 folds (13.2±1.0g/L) and antifungal activity by 1.2 folds (77.7±0.3% inhibition). To gain insight into the type of active compounds, they were purified and identified by mass spectrometry (MS). The MS analysis revealed the presence of three families of lipopeptides: surfactin, fengycin and iturin. The high antifungal activity was associated with the novel fengycin C and with iturin A which were partially growth-associated with a maximum concentration of 781.4 and 355.4mg/L at 36h of growth, respectively. These results indicate the potential of B. subtilis EA-CB0015 to produce high concentrations of biomass and lipopeptides that can be exploited for biotechnological application. © 2014 Elsevier Ltd.Ítem Phylogenetic and pathogenic variability of strains of Ralstonia solanacearum causing moko disease in Colombia(Blackwell Publishing Inc., 2020-02-01) Ramirez, M.; Moncada, R. N.; Villegas-Escobar, V.; Jackson, R. W.; Ramirez, C. A.; Universidad EAFIT. Departamento de Ciencias; Ciencias Biológicas y Bioprocesos (CIBIOP)Moko disease, caused by the bacterium Ralstonia solanacearum, is one of the most devastating diseases of Musa spp. in Colombia, where banana and plantain are major crops. The disease epidemiology is poorly understood and little is known about the diversity of the bacterial populations associated with this disease. This study assessed the diversity, phylogenetic relationship and pathogenicity of R. solanacearum strains associated with moko disease in Colombia. For this, the genetic diversity of 65 isolates obtained from four banana/plantain-growing regions was evaluated by using multiplex PCR and analysing the partial sequences of the mutS, rplB and egl genes. These analyses revealed that all the strains belonged to the R. solanacearum phylotype II, sequevars 4 and 6. In addition, the phylogenetic analysis assorted the strains into three subgroups, which matched the region of isolation: (i) central region (i.e. Eastern plains and Andes, IIB/4); (ii) northwest (i.e. Uraba and a few strains from Magdalena, IIB/4); and (iii) north coast (Magdalena and a few strains from Uraba, IIA/6). In addition, this evolutionary pattern was associated with pathogenicity, as 63 of the 65 isolates caused wilting of banana and plantain plants under greenhouse conditions, whilst only 32, those isolated from the central region, caused such symptoms in tomato plants. In conclusion, this study shows that banana and plantain crops in Colombia foster genetically diverse strains of R. solanacearum that belong to at least three different genetic groups, which show biogeographic and host range association.