scholarly journals Identification of Traits Implicated in the Rhizosphere Competence of Fluorescent Pseudomonads: Description of a Strategy Based on Population and Model Strain Studies

2009 ◽  
pp. 285-296 ◽  
Author(s):  
Xavier Latour ◽  
Sandrine Delorme ◽  
Pascal Mirleau ◽  
Philippe Lemanceau
Keyword(s):  
Fluorescent Pseudomonads ◽  
Rhizosphere Competence ◽  
Model Strain

scholarly journals Strain- and Substrate-Dependent Redox Mediator and Electricity Production by Pseudomonas aeruginosa

2016 ◽  
Vol 82 (16) ◽  
pp. 5026-5038 ◽  
Author(s):  
Erick M. Bosire ◽  
Lars M. Blank ◽  
Miriam A. Rosenbaum
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Electron Transfer ◽  
Fuel Cells ◽  
Microbial Fuel Cells ◽  
Pure Culture ◽  
Bioelectrochemical Systems ◽  
Content Type ◽  
Mediated Electron Transfer ◽  
Phenazine Production ◽  
Model Strain

ABSTRACTPseudomonas aeruginosais an important, thriving member of microbial communities of microbial bioelectrochemical systems (BES) through the production of versatile phenazine redox mediators. Pure culture experiments with a model strain revealed synergistic interactions ofP. aeruginosawith fermenting microorganisms whereby the synergism was mediated through the shared fermentation product 2,3-butanediol. Our work here shows that the behavior and efficiency ofP. aeruginosain mediated current production is strongly dependent on the strain ofP. aeruginosa. We compared levels of phenazine production by the previously investigated model strainP. aeruginosaPA14, the alternative model strainP. aeruginosaPAO1, and the BES isolatePseudomonassp. strain KRP1 with glucose and the fermentation products 2,3-butanediol and ethanol as carbon substrates. We found significant differences in substrate-dependent phenazine production and resulting anodic current generation for the three strains, with the BES isolate KRP1 being overall the best current producer and showing the highest electrochemical activity with glucose as a substrate (19 μA cm−2with ∼150 μg ml−1phenazine carboxylic acid as a redox mediator). Surprisingly,P. aeruginosaPAO1 showed very low phenazine production and electrochemical activity under all tested conditions.IMPORTANCEMicrobial fuel cells and other microbial bioelectrochemical systems hold great promise for environmental technologies such as wastewater treatment and bioremediation. While there is much emphasis on the development of materials and devices to realize such systems, the investigation and a deeper understanding of the underlying microbiology and ecology are lagging behind. Physiological investigations focus on microorganisms exhibiting direct electron transfer in pure culture systems. Meanwhile, mediated electron transfer with natural redox compounds produced by, for example,Pseudomonas aeruginosamight enable an entire microbial community to access a solid electrode as an alternative electron acceptor. To better understand the ecological relationships between mediator producers and mediator utilizers, we here present a comparison of the phenazine-dependent electroactivities of threePseudomonasstrains. This work forms the foundation for more complex coculture investigations of mediated electron transfer in microbial fuel cells.

Development of mutants of Gliocladium virens tolerant to benomyl

1990 ◽  
Vol 36 (7) ◽  
pp. 484-489 ◽  
Author(s):  
G. C. Papavizas ◽  
D. P. Roberts ◽  
K. K. Kim
Keyword(s):  
Carbon Source ◽  
Type Strain ◽  
Wild Type Strain ◽  
Carbon Sources ◽  
Sclerotium Rolfsii ◽  
Wild Type ◽  
Gliocladium Virens ◽  
Rhizosphere Competence ◽  
Filter Paper Cellulase ◽  
Type Strains

Aqueous suspensions of conidia of Gliocladium virens strains Gl-3 and Gl-21 were exposed to both ultraviolet radiation and ethyl methanesulfonate. Two mutants of Gl-3 and three of Gl-21 were selected for tolerance to benomyl at 10 μg∙mL−1, as indicated by growth and conidial germination on benomyl-amended potato dextrose agar. The mutants differed considerably from their respective wild-type strains in appearance, growth habit, sporulation, carbon-source utilization, and enzyme activity profiles. Of 10 carbon sources tested, cellobiose, xylose, and xylan were the best for growth, galactose and glucose were intermediate, and arabinose, ribose, and rhamnose were poor sources of carbon. The wild-type strains and the mutants did not utilize cellulose as the sole carbon source for growth. Two benomyl-tolerant mutants of Gl-3 produced less cellulase (β-1,4-glucosidase, carboxymethylcellulase, filter-paper cellulase) than Gl-3. In contrast, mutants of Gl-21 produced more cellulase than the wild-type strain. Only Gl-3 provided control of blight on snapbean caused by Sclerotium rolfsii. Wild-type strain Gl-21 and all mutants from both strains were ineffective biocontrol agents. Key words: Gliocladium, benomyl tolerance, Sclerotium, rhizosphere competence.

Phylogenetic analysis of alkaline proteinase producing fluorescent pseudomonads associated with green gram (Vigna radiata L.) rhizosphere

2012 ◽  
Vol 57 (2) ◽  
pp. 129-137 ◽  
Author(s):  
Rupak K. Sarma ◽  
Rajal Debnath ◽  
Ratul Saikia ◽  
Pratap J. Handique ◽  
Tarun C. Bora
Keyword(s):  
Phylogenetic Analysis ◽  
Vigna Radiata ◽  
Fluorescent Pseudomonads ◽  
Green Gram ◽  
Alkaline Proteinase

Utilization of heterologous siderophores and rhizosphere competence of fluorescent Pseudomonas spp.

1995 ◽  
Vol 41 (2) ◽  
pp. 126-135 ◽  
Author(s):  
Jos M. Raaijmakers ◽  
Lentse van der Sluis ◽  
Peter A. H. M. Bakker ◽  
Bob Schippers ◽  
Margot Koster ◽  
...  
Keyword(s):  
Wild Type Strain ◽  
Population Densities ◽  
Common Assumption ◽  
Fluorescent Pseudomonas ◽  
Siderophore Receptors ◽  
Rhizosphere Interactions ◽  
Rhizosphere Population ◽  
Rhizosphere Competence ◽  
The Common ◽  
Derivative Strain

In this study, the potential of different Pseudomonas strains to utilize heterologous siderophores was compared with their competitiveness in the rhizosphere of radish. This issue was investigated in interactions between Pseudomonas putida WCS358 and Pseudomonas fluoresceins WCS374 and in interactions between strain WCS358 and eight indigenous Pseudomonas strains capable of utilizing pseudobactin 358. During four successive plant growth cycles of radish, strain WCS358 significantly reduced rhizosphere population densities of the wild-type strain WCS374 by up to 30 times, whereas derivative strain WCS374(pMR), harboring the siderophore receptor PupA for ferric pseudobactin 358, maintained its population density. Studies involving interactions between strain WCS358 and eight different indigenous Pseudomonas strains demonstrated that despite the ability of these indigenous isolates to utilize pseudobactin 358, their rhizosphere population densities were significantly reduced by strain WCS358 by up to 20 times. Moreover, rhizosphere colonization by WCS358 was not affected by any of these indigenous strains, even though siderophore-mediated growth inhibition of WCS358 by a majority of these strains was demonstrated in a plate bioassay. In conclusion, it can be stated that siderophore-mediated competition for iron is a major determinant in interactions between WCS358 and WCS374 in the rhizosphere. Moreover, our findings support the common assumption that cloning of siderophore receptor genes from one Pseudomonas strain into another can confer a competitive advantage in interactions in the rhizosphere. Interactions between WCS358 and the selected indigenous rhizosphere isolates, however, indicate that other traits also contribute to the rhizosphere competence of fluorescent Pseudomonas spp.Key words: siderophore, siderophore receptors, root colonization, fluorescent Pseudomonas.

scholarly journals An Overview of Metabolic Activity, Beneficial and Pathogenic Aspects of Burkholderia Spp

Metabolites ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 321
Author(s):  
Hazem S. Elshafie ◽  
Ippolito Camele
Keyword(s):  
Secondary Metabolites ◽  
Plant Growth ◽  
Biochemical Characterization ◽  
Bacterial Species ◽  
Promoting Effect ◽  
Important Species ◽  
Beneficial Effects ◽  
Plant Growth Promoting ◽  
Rhizosphere Competence

Burkholderia is an important bacterial species which has different beneficial effects, such as promoting the plant growth, including rhizosphere competence for the secretion of allelochemicals, production of antibiotics, and siderophores. In addition, most of Burkholderia species have demonstrated promising biocontrol action against different phytopathogens for diverse crops. In particular, Burkholderia demonstrates significant biotechnological potential as a source of novel antibiotics and bioactive secondary metabolites. The current review is concerned with Burkholderia spp. covering the following aspects: discovering, classification, distribution, plant growth promoting effect, and antimicrobial activity of different species of Burkholderia, shedding light on the most important secondary metabolites, their pathogenic effects, and biochemical characterization of some important species of Burkholderia, such as B. cepacia, B. andropogonis, B. plantarii, B. rhizoxinica, B. glumae, B. caryophylli and B. gladioli.

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