Search results for "pseudomonas fluorescens"
showing 10 items of 56 documents
Costs-benfits trade-off in the intercation between Medicago truncatula and Pseudomonas fluorescens C7R12 across atmospheric carbon dioxide modulation
2011
The interactions between plants and soil microorganisms are mainly based on trophic relationships. The compounds exchanged represent cost for the organism produces them but a benefit for the one who receive those compounds. A mutualistic relation leads to stability in the cost-benefit balance resulting from a co-evolution between the two organisms. The cost corresponding for the release of carbon compounds by the plant would be offset by benefits in return corresponding for the activities of microorganisms that use them. We tested by an experimental way the effect of CO2 concentration on the interaction between M. truncatula and the bacterium P. fluorescens C7R12. The results allowed a best…
Establishment of tools for investigating pyoverdine impact on iron homeostasis and plant defense responses
2013
Iron, the fourth major element in the Earth crust, is essential for growth and development of living organisms. However, due to its low solubility in the soil, it is weakly available for plants and micro-organisms. To efficiently assimilate iron, living organisms have evolved specific strategies. In plants such as Arabidopsis thaliana three trans-membrane proteins are involved in iron assimilation while in bacteria such as Pseudomonas fluorescens iron is taken up from the soil thanks to molecules displaying high affinity for iron called siderophores. It has been recently shown that pyoverdine, the major siderophore of the beneficial bacterium Pseudomonas fluorescens, is assimilated by A. th…
Analysis of the cross‐regulation between immunity, growth and iron homeostasis in plants
2019
The existence of a tightly regulated balance between growth and immunity in plants has recently emerged. In this study, we challenged this concept thanks to the biological model pyoverdine-Arabidopsis thaliana. Pyoverdine is a siderophore produced by the plant growth promoting rhizobacteria Pseudomonas fluorescens C7R12. Under iron deficiency, P. fluorescens excretes the iron free form of pyoverdine (apo‐pyo) in the soil. Once chelated with iron (ferri‐pyo), the complex is internalized by the bacteria. We demonstrated that Arabidopsis thaliana plants treated by apo‐pyo in a medium containing or not iron internalize pyoverdine. Interestingly, apo‐pyo-treated plants did not show a typical gro…
Analysis of the role of nitric oxide (NO) in the cross‐regulation between immunity, growth and iron homeostasis in plants
2019
Studies performed in our Agroecology Department show that the immune response of plants is linked to their iron nutrition and is modulated by pyoverdine, a siderophore produced by the plant beneficial rhizobacteria Pseudomonas fluorescens C7R12. Accordingly, Arabidopsis thaliana plantlets exposed to iron deficiency and treated with pyoverdine in its iron non‐chelated structure (apo‐pyo) show an enhanced growth but a decreased immune response capacity. We hypothesize that nitric oxide (NO), a universal signaling molecule, is a key component of the regulation of the immune response in plants exposed to apo‐pyo and to the C7R12 strain. We checked by fluorescence microscopy that NO is actually …
The role of Pseudomonas fluorescens in the process of Rhizoctonia solani growth inhibition
2014
The aim of conducted research was to determine influence of metabolites produced by Pseudomonas fluorescens on the growth of 4 phytopathogenic strains of Rhizoctonia solani marked R1, R2, R3 and R4 which infect sugar beetroot. The antagonistic properties were assessed with the culture-plate method on PDA medium for P. fluorescens cultured for 4, 6 8, 10 and 24 hours at 25 o C for 5 days. The fungistatic activity of P. fluorescens was determined against the growth rate index and the rate of mycelial growth inhibition. Obtained results prove, that Rhizoctonia spp. strains were both sensitive and resistant to metabolites produced by P. fluorescens. The highest inhibition of the linear growth o…
Biological control of Fusarium culmorum isolated from the cultivation of white asparagus by Pseudomonas fluorescens
2017
Celem badań była ocena wpływu Pseudomonas fluorescens I-4 (Ps I-4) na Fusarium culmorum wyizolowanego z uprawy białego szparaga. Fusarium culmorum i pozostałe grzyby izolowano na podłożach PDA i szparagowym. Wśród izolatów uzyskanych z gleby najbardziej dominującymi patogenami były F. oxysporum i F. culmorum. Właściwości biologiczne nielotnych i lotnych związków Ps I-4 oceniano metodą hodowlano-płytkową na podłożach PDA i Czapka. Aktywność przeciwgrzybową określano na podstawie indeksu tempa wzrostu, zdolności kiełkowania zarodników, stopnia zahamowania wzrostu grzybni i zarodników. Wyniki wykazały różnice w aktywności przeciwgrzybowej P. fluorescens, w zależności od wieku i gęstości hodowl…
Biocontrol activities of Pseudomonas fluorescens against asparagus pathogen
2016
Pseudomonas spp. and their metabolites present environmentally friendly alternative to chemical products to improve plant growth in many different applications. Extensive studies have shown that these microorganisms and their metabolites could have an important role in agriculture and horticulture in improving crop productivity. The aim of the research was to assess a potential biological activity of Pseudomonas fluorescens against Fusarium oxysporum isolated from the spears of asparagus. The antagonistic properties of metabolites were assayed with a dual culture plate method on PDA and Czapek media for supernatants obtained from 6, 12, 24 and 48-hour culture of P. fluorescens. The culturin…
Identification of phytopathogenic bacteria in maize seeds in Ukraine
2018
The main bacterial diseases of maize: bacterial wilt of maize (Pantoea stewartii subsp. stewartii), goss’s bacterial wilt (Clavibacter michiganensis subsp. nebraskensis), seed rot-seedling blight of maize (Bacillus subtilis), bacterial spot of maize (Pseudomonas syringae pv. syringae), bacterial leaf spot of maize (Pantoea agglomerans) and bacterial stalk rot of maize caused by several causative agents, were described. The causative agents of these diseases are often stored and transmitted with seeds, so seed analysis for the presence of phytopathogenic bacteria is an important step in the pathogen control system. For analysis, the corn seeds that were grown in the Poltava and Kiev regions …
Survival in the soil of the ectomycorrhizal fungus Laccaria bicolor and the effects of a mycorrhiza helper Pseudomonas fluorescens
2001
In disinfected forest nursery soils, inoculating Douglas fir (Pseudotsuga menziesii) seedlings with the ectomycorrhizal fungal strain Laccaria bicolor S238N significantly increases tree growth after outplantating. However, the success of the inoculation depends on survival of the fungal inoculum in the soil during the pre-symbiotic life of the fungus. We followed the survival of L. bicolor S238N in autoclaved nursery soil in the glasshouse, and under gnotobiotic conditions in autoclaved or γ-irradiated nursery soil. We also studied the effect of the mycorrhiza helper bacterium Pseudomonas fluorescens BBc6R8, which promotes the Douglas fir-L. bicolor S238N symbiosis, on fungal viability. In …
Influence of Bacteria <i>Pseudomonas fluorescens</i> on the Properties of Latvian Clay
2014
Wide varieties of bacteria are able to produce extracellular polymeric substances (EPS) which are mostly composed of polysaccharides. It is suggested that EPS substances can alter certain clay soil properties due to their ability to adhere to the surface of mineral particles. Most common used microorganisms by the researchers for this purpose are of either genus Bacillus or genus Pseudomonas. In this study growth of bacteria P. fluorescens AM PS11 culture in locally obtained clay is studied for the purpose of establishing their influence on rheological properties of clay. An attempt to evaluate it has been made using FT-IR and XRD. Change in plasticity of clay using Atterberg limits method …