Project description:The rhizosphere is a small region surrounding plant roots that is enriched in biochemicals from root exudates and populated with fungi, nematode, and bacteria. Interaction of rhizosphere organisms with plants is mainly promoted by exudates from the roots. Root exudates contain biochemicals that come from primary and secondary metabolisms of plants. These biochemicals attract microbes, which influence plant nutrition. The rhizosphere bacteria (microbiome) are vital to plant nutrient uptake and influence biotic and abiotic stress and pathogenesis. Pseudomonas is a genus of gammaproteobacteria known for its ubiquitous presence in natural habitats and its striking ecological, metabolic, and biochemical diversity. Within the genus, members of the Pseudomonas fluorescens group are common inhabitants of soil and plant surfaces, and certain strains function in the biological control of plant disease, protecting plants from infection by soilborne and aerial plant pathogens. The soil bacterium Pseudomonas protegens Pf-5 (also known as Pseudomonas fluorescens Pf-5) is a well-characterized biological strain, which is distinguished by its prolific production of the secondary metabolite, pyoverdine. Knowledge of the distribution of P. fluorescens secretory activity around plant roots is very important for understanding the interaction between P. fluorescens and plants and can be achieved by real time tracking of pyoverdine. To achieve the capability of real-time tracking in soil, we have used a structure-switching SELEX strategy to select high affinity ssDNA aptamers with specificity for pyoverdine over other siderophores. Two DNA aptamers were isolated, and their features compared. The aptamers were applied to a nanoporous aluminum oxide biosensor and demonstrated to successfully detect PYO-Pf5. This sensor provides a future opportunity to track the locations around plant roots of P. protegens and to monitor PYO-Pf5 production and movement through the soil.
Project description:Transcriptomic profiling of an rpoS mutant of Pseudomonas protegens Pf-5 in comparison to the wild-type Pf-5 strain grown on pea seed surfaces for 24h.
Project description:Transcriptomic profiling of a gacA mutant of Pseudomonas protegens Pf-5 in comparison to the wild-type Pf-5 strain grown on pea seed surfaces for 24h.
Project description:Transcriptomic profiling of an rpoS mutant of Pseudomonas protegens Pf-5 in comparison to the wild-type Pf-5 strain grown in nutrient broth supplemented with 1% glycerol to OD600=2.0-2.4 (early stationary phase).
Project description:KaiC is the central cog of the circadian clock in Cyanobacteria. Close homologs of this protein are widespread among bacteria not known to have a circadian physiology. The function, interaction network, and mechanism of action of these KaiC homologs are still largely unknown. Here, we focus on KaiC homologs found in environmental Pseudomonas species. We characterize experimentally the only KaiC homolog present in Pseudomonas putida KT2440 and Pseudomonas protegens CHA0. Through phenotypic assays and transcriptomics, we show that KaiC is involved in osmotic and oxidative stress resistance in P. putida and in biofilm production in both P. putida and P. protegens.
