Anastasia Dimopoulou - Academia.edu (original) (raw)
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Papers by Anastasia Dimopoulou
Bacillus amyloliquefaciens is considered the most successful biological control agent due to its ... more Bacillus amyloliquefaciens is considered the most successful biological control agent due to its ability to colonize the plant rhizosphere and phyllosphere where it outgrows plant pathogens by competition, antibiosis, and inducing plant defense. Its antimicrobial function is thought to depend on a diverse spectrum of secondary metabolites, including peptides, cyclic lipopeptides, and polyketides, which have been shown to target mostly fungal pathogens. In this study, we isolated and characterized the catecholate siderophore bacillibactin by B. amyloliquefaciens MBI600 under iron-limiting conditions and we further identified its potential antibiotic activity against plant pathogens. Our data show that bacillibactin production restrained in vitro and in planta growth of the nonsusceptible (to MBI600) pathogen Pseudomonas syringae pv. tomato. Notably, it was also related to increased antifungal activity of MBI600. In addition to bacillibactin biosynthesis, iron starvation led to upregu...
Biology
Bacterial biological control agents (BCAs) have been increasingly used against plant diseases. Th... more Bacterial biological control agents (BCAs) have been increasingly used against plant diseases. The traditional approach to manufacturing such commercial products was based on the selection of bacterial species able to produce secondary metabolites that inhibit mainly fungal growth in optimal media. Such species are required to be massively produced and sustain long-term self-storage. The endpoint of this pipeline is large-scale field tests in which BCAs are handled as any other pesticide. Despite recent knowledge of the importance of BCA-host-microbiome interactions to trigger plant defenses and allow colonization, holistic approaches to maximize their potential are still in their infancy. There is a gap in scientific knowledge between experiments in controlled conditions for optimal BCA and pathogen growth and the nutrient-limited field conditions in which they face niche microbiota competition. Moreover, BCAs are considered to be safe by competent authorities and the public, with ...
mSphere
Siderophores have mostly been studied concerning their contribution to the fitness and virulence ... more Siderophores have mostly been studied concerning their contribution to the fitness and virulence of bacterial pathogens. In the present work, we isolated and characterized for the first time the siderophore bacillibactin from a commercial bacterial biocontrol agent.
Pathogens
Copper nanoparticles (CuNPs) can offer an alternative to conventional copper bactericides and pos... more Copper nanoparticles (CuNPs) can offer an alternative to conventional copper bactericides and possibly slow down the development of bacterial resistance. This will consequently lower the accumulation rate of copper to soil and water and lower the environmental and health burden imposed by copper application. Physical and chemical methods have been reported to synthesize CuNPs but their use as bactericides in plants has been understudied. In this study, two different CuNPs products have been developed, CuNP1 and CuNP2 in two respective concentrations (1500 ppm or 300 ppm). Both products were characterized using Dynamic Light Scattering, Transmission Electron Microscopy, Attenuated Total Reflection measurements, X-ray Photoelectron Spectroscopy, X-ray Diffraction and Scattering, and Laser Doppler Electrophoresis. They were evaluated for their antibacterial efficacy in vitro against the gram-negative species Agrobacterium tumefaciens, Dickeya dadantii, Erwinia amylovora, Pectobacterium...
Scientific Reports
The success of Bacillus amyloliquefaciens as a biological control agent relies on its ability to ... more The success of Bacillus amyloliquefaciens as a biological control agent relies on its ability to outgrow plant pathogens. It is also thought to interact with its plant host by inducing systemic resistance. In this study, the ability of B. amyloliquefaciens MBI600 to elicit defense (or other) responses in tomato seedlings and plants was assessed upon the expression of marker genes and transcriptomic analysis. Spray application of Serifel, a commercial formulation of MBI600, induced responses in a dose-dependent manner. Low dosage primed plant defense by activation of SA-responsive genes. Suggested dosage induced defense by mediating synergistic cross-talk between JA/ET and SA-signaling. Saturation of tomato roots or leaves with MBI600 elicitors activated JA/ET signaling at the expense of SA-mediated responses. The complex signaling network that is implicated in MBI600-tomato seedling interactions was mapped. MBI600 and flg22 (a bacterial flagellin peptide) elicitors induced, in a sim...
Nanomaterials (Basel, Switzerland), Jan 10, 2017
Silver nanoparticles (AgNPs) have been demonstrated to restrain bacterial growth, while maintaini... more Silver nanoparticles (AgNPs) have been demonstrated to restrain bacterial growth, while maintaining minimal risk in development of bacterial resistance and human cell toxicity that conventional silver compounds exhibit. Several physical and chemical methods have been reported to synthesize AgNPs. However, these methods are expensive and involve heavy chemical reduction agents. An alternative approach to produce AgNPs in a cost-effective and environmentally friendly way employs a biological pathway using various plant extracts to reduce metal ions. The size control issue, and the stability of nanoparticles, remain some of the latest challenges in such methods. In this study, we used two different concentrations of fresh leaf extract of the plant Arbutus unedo (LEA) as a reducing and stabilizing agent to produce two size variations of AgNPs. UV-Vis spectroscopy, Dynamic Light Scattering, Transmission Electron Microscopy, and zeta potential were applied for the characterization of AgNP...
Plant Disease, 2016
Quinone outside inhibitors (QoI) are powerful fungicides, which have been reported, additionally ... more Quinone outside inhibitors (QoI) are powerful fungicides, which have been reported, additionally to their fungicide activity, to increase plant capacity to activate cellular defense responses and to promote plant growth. In this work, the effect of the QoI class fungicide pyraclostrobin was examined against Cucumber mosaic virus (CMV), Potato virus Y (PVY) and Pseudomonas syringae pv. tomato in tomato plants following artificial inoculation of the plants with the pathogens. Under controlled environmental conditions, pyraclostrobin delayed viral and bacterial disease development, even if P. syringae pv. tomato internal population levels were not affected significantly. In contrast, under field conditions in commercial greenhouses, a reduced CMV disease incidence throughout the tomato cultivation period was recorded. Gene expression analysis indicated an effect of pyraclostrobin application on tomato MAPKs transcript levels and a possible interference with plant stress responses.
PloS one, 2015
A multi-targeting protocol for the detection of three of the most important bacterial phytopathog... more A multi-targeting protocol for the detection of three of the most important bacterial phytopathogens, based on their scientific and economic importance, was developed using an acoustic biosensor (the Quartz Crystal Microbalance) for DNA detection. Acoustic detection was based on a novel approach where DNA amplicons were monitored and discriminated based on their length rather than mass. Experiments were performed during real time monitoring of analyte binding and in a direct manner, i.e. without the use of labels for enhancing signal transduction. The proposed protocol improves time processing by circumventing gel electrophoresis and can be incorporated as a routine detection method in a diagnostic lab or an automated lab-on-a-chip system for plant pathogen diagnostics.
Bacillus amyloliquefaciens is considered the most successful biological control agent due to its ... more Bacillus amyloliquefaciens is considered the most successful biological control agent due to its ability to colonize the plant rhizosphere and phyllosphere where it outgrows plant pathogens by competition, antibiosis, and inducing plant defense. Its antimicrobial function is thought to depend on a diverse spectrum of secondary metabolites, including peptides, cyclic lipopeptides, and polyketides, which have been shown to target mostly fungal pathogens. In this study, we isolated and characterized the catecholate siderophore bacillibactin by B. amyloliquefaciens MBI600 under iron-limiting conditions and we further identified its potential antibiotic activity against plant pathogens. Our data show that bacillibactin production restrained in vitro and in planta growth of the nonsusceptible (to MBI600) pathogen Pseudomonas syringae pv. tomato. Notably, it was also related to increased antifungal activity of MBI600. In addition to bacillibactin biosynthesis, iron starvation led to upregu...
Biology
Bacterial biological control agents (BCAs) have been increasingly used against plant diseases. Th... more Bacterial biological control agents (BCAs) have been increasingly used against plant diseases. The traditional approach to manufacturing such commercial products was based on the selection of bacterial species able to produce secondary metabolites that inhibit mainly fungal growth in optimal media. Such species are required to be massively produced and sustain long-term self-storage. The endpoint of this pipeline is large-scale field tests in which BCAs are handled as any other pesticide. Despite recent knowledge of the importance of BCA-host-microbiome interactions to trigger plant defenses and allow colonization, holistic approaches to maximize their potential are still in their infancy. There is a gap in scientific knowledge between experiments in controlled conditions for optimal BCA and pathogen growth and the nutrient-limited field conditions in which they face niche microbiota competition. Moreover, BCAs are considered to be safe by competent authorities and the public, with ...
mSphere
Siderophores have mostly been studied concerning their contribution to the fitness and virulence ... more Siderophores have mostly been studied concerning their contribution to the fitness and virulence of bacterial pathogens. In the present work, we isolated and characterized for the first time the siderophore bacillibactin from a commercial bacterial biocontrol agent.
Pathogens
Copper nanoparticles (CuNPs) can offer an alternative to conventional copper bactericides and pos... more Copper nanoparticles (CuNPs) can offer an alternative to conventional copper bactericides and possibly slow down the development of bacterial resistance. This will consequently lower the accumulation rate of copper to soil and water and lower the environmental and health burden imposed by copper application. Physical and chemical methods have been reported to synthesize CuNPs but their use as bactericides in plants has been understudied. In this study, two different CuNPs products have been developed, CuNP1 and CuNP2 in two respective concentrations (1500 ppm or 300 ppm). Both products were characterized using Dynamic Light Scattering, Transmission Electron Microscopy, Attenuated Total Reflection measurements, X-ray Photoelectron Spectroscopy, X-ray Diffraction and Scattering, and Laser Doppler Electrophoresis. They were evaluated for their antibacterial efficacy in vitro against the gram-negative species Agrobacterium tumefaciens, Dickeya dadantii, Erwinia amylovora, Pectobacterium...
Scientific Reports
The success of Bacillus amyloliquefaciens as a biological control agent relies on its ability to ... more The success of Bacillus amyloliquefaciens as a biological control agent relies on its ability to outgrow plant pathogens. It is also thought to interact with its plant host by inducing systemic resistance. In this study, the ability of B. amyloliquefaciens MBI600 to elicit defense (or other) responses in tomato seedlings and plants was assessed upon the expression of marker genes and transcriptomic analysis. Spray application of Serifel, a commercial formulation of MBI600, induced responses in a dose-dependent manner. Low dosage primed plant defense by activation of SA-responsive genes. Suggested dosage induced defense by mediating synergistic cross-talk between JA/ET and SA-signaling. Saturation of tomato roots or leaves with MBI600 elicitors activated JA/ET signaling at the expense of SA-mediated responses. The complex signaling network that is implicated in MBI600-tomato seedling interactions was mapped. MBI600 and flg22 (a bacterial flagellin peptide) elicitors induced, in a sim...
Nanomaterials (Basel, Switzerland), Jan 10, 2017
Silver nanoparticles (AgNPs) have been demonstrated to restrain bacterial growth, while maintaini... more Silver nanoparticles (AgNPs) have been demonstrated to restrain bacterial growth, while maintaining minimal risk in development of bacterial resistance and human cell toxicity that conventional silver compounds exhibit. Several physical and chemical methods have been reported to synthesize AgNPs. However, these methods are expensive and involve heavy chemical reduction agents. An alternative approach to produce AgNPs in a cost-effective and environmentally friendly way employs a biological pathway using various plant extracts to reduce metal ions. The size control issue, and the stability of nanoparticles, remain some of the latest challenges in such methods. In this study, we used two different concentrations of fresh leaf extract of the plant Arbutus unedo (LEA) as a reducing and stabilizing agent to produce two size variations of AgNPs. UV-Vis spectroscopy, Dynamic Light Scattering, Transmission Electron Microscopy, and zeta potential were applied for the characterization of AgNP...
Plant Disease, 2016
Quinone outside inhibitors (QoI) are powerful fungicides, which have been reported, additionally ... more Quinone outside inhibitors (QoI) are powerful fungicides, which have been reported, additionally to their fungicide activity, to increase plant capacity to activate cellular defense responses and to promote plant growth. In this work, the effect of the QoI class fungicide pyraclostrobin was examined against Cucumber mosaic virus (CMV), Potato virus Y (PVY) and Pseudomonas syringae pv. tomato in tomato plants following artificial inoculation of the plants with the pathogens. Under controlled environmental conditions, pyraclostrobin delayed viral and bacterial disease development, even if P. syringae pv. tomato internal population levels were not affected significantly. In contrast, under field conditions in commercial greenhouses, a reduced CMV disease incidence throughout the tomato cultivation period was recorded. Gene expression analysis indicated an effect of pyraclostrobin application on tomato MAPKs transcript levels and a possible interference with plant stress responses.
PloS one, 2015
A multi-targeting protocol for the detection of three of the most important bacterial phytopathog... more A multi-targeting protocol for the detection of three of the most important bacterial phytopathogens, based on their scientific and economic importance, was developed using an acoustic biosensor (the Quartz Crystal Microbalance) for DNA detection. Acoustic detection was based on a novel approach where DNA amplicons were monitored and discriminated based on their length rather than mass. Experiments were performed during real time monitoring of analyte binding and in a direct manner, i.e. without the use of labels for enhancing signal transduction. The proposed protocol improves time processing by circumventing gel electrophoresis and can be incorporated as a routine detection method in a diagnostic lab or an automated lab-on-a-chip system for plant pathogen diagnostics.