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.
Project description:The bacterium Pseudomonas putida KT2440 has the ability to reduce selenite forming nanoparticles of elemental selenium. This is the transcriptome of the organism when cultured in the presence of selenite.
Project description:Gene expression patterns of the plant colonizing bacterium,Pseudomonas putida KT2440 were evaluated as a function of growth in the Arabidopsis thaliana rhizosphere. Gene expression in rhizosphere grown P. putida cells was compared to gene expression in non-rhizosphere grown cells. Keywords: Gene expression
Project description:To gain an insight into molecular mechanisms underlying plant-microbe interactions gene expression changes in rice plants in response to a plant growth promoting rhizobacteria such as the Pseudomonas putida, root transcriptome analysis through microarray technology was performed from rice roots in response to P. putida RF3. Species of Pseudomonas are well known as biocontrol agents hence defense response and genes related to root exudation of phytochemicals were analysed in detail. For treatment of rice plants with P. putida, aseptically germinated rice seedlings from half strength MS medium were transferred to flasks containing Hoaglands’ nutrient solution, treated with P. putida and incubated for 48 hours in growth chamber in an orbital shaker. Gene expression changes in rice roots were then analyzed by microarray experiment. Untreated roots served as control. Data analysis revealed defense responsive genes to be upregulated with greater fold changes. In addition to defense response genes, few genes involved in secondary metabolism were also upregulated significantly. Validation of microarray data was performed using real time PCR for defense responsive genes (OsPBZ, OsPR101a, OsCHIA, etc). Detailed analysis of the differentially expressed genes reveal the role of P. putida RF3 in inducing systemic resistance in plants thereby immunizing the rice plants against future attacks by pests/pathogens. Our study enhances the current understanding on gene expression changes occurring during plant-microbe associations and thus demonstrates the potential of P. putida RF3 as a biocontrol agent.
Project description:Pseudomonas putida KT2440 encodes 3 homologs of the LitR/CarH family (designated PplR1–PplR3; Pseudomonas putida light-induced transcription; regulator), which is an adenosyl B12-dependent light-sensitive MerR family transcriptional regulator. Transcriptome and individual transcriptional analysis revealed the existence of a number of photo-inducible genes including pplR1, phrB (encoding DNA photolyase), cfaA (cyclopropane synthase), folE (GTP cyclohydrolase I), cryB (cryptochrome-like protein), and multiple hypothetical genes. Transcriptional analysis based on a β-galactosidase reporter assay with single-, double-, and triple-knockout mutants of pplR1–pplR3 showed that deletion of pplR1–pplR3 completely abolished the light-inducible transcription in P. putida, which indicates that the transcription of light-inducible genes is under the ternary regulation of PplR proteins. DNase I footprint assay showed that PplR1 protein specifically binds to the promoter regions of light-inducible genes, suggesting a consensus PplR1-binding site, 5’-T(G/A)TACAn12TGTA(C/T)A-3’, predicted upon nucleotide sequence alignment. The disruption of cobalamin biosynthesis cluster did not affect the light-inducible transcription; however, disruption of ppSB1-LOV and ppSB2-LOV, a blue light photoreceptor genes, which are adjacent to pplR3 and pplR2, respectively, led to the complete loss of light-inducible transcription. Overall, the results suggest that 3 PplR and 2 PpSB-LOV regulate light-induced gene transcription in response to illumination. The high conservation of the pplR/ppSB-LOV cognate pair in Pseudomonas spp. suggests that the response and adaptation to light is similarly regulated in the group of non-phototrophic bacteria.
Project description:Pseudomonas species have become promising cell factories for the production of natural products due to their inherent robustness. Here, we explored membrane adaptations of Pseudomonas putida KT2440, in particular outer membrane vesicle (OMV) formation in response to 1-octanol, PQS and prodigiosin, causing chemical membrane stress via RNA-seq of mRNA. Pseudomonas putida wild type KT2440 (Nelson et al. 2002) and the derived strains P. putida pig21 were cultivated in biological triplicates under continuous shaking (130 rpm) at 30 °C in 10 mL LB (lysogeny broth) medium (10 g L-1 tryptone, 5 g L-1 yeast extract, 10 g L-1 sodium chloride; Carl Roth®, Karlsruhe, Germany). Antibiotics were added to the culture medium when appropriate to the following final concentrations: 25 µg mL-1 kanamycin, 25 µg mL-1 irgasan, 25 µg mL-1 gentamicin, 50 µg mL-1 tetracycline. For chemical induction of OMV formation, P. putida KT2440 was exposed to 1 mM 1-octanol or 50 µM PQS (Pseudomonas quinolone signal) after reaching the logarithmic growth phase. For transcriptome analysis, cells were cultivated as described above, the cell pellet was harvested after 7 h, adjusted to an optical density (OD700 nm) of 1 and flash frozen . Total RNA was isolated from 3 biological replicates using Quick-RNA Miniprep Plus kit (Zymo Research). The samples were treated with DNase (Zymo Research) and RNA was again purified with an RNA Clean&Concentrator-5 kit (Zymo Research). Ribosomal rRNA was removed with a riboPOOL for bacteria (siTOOLs Biotech GmbH). The purity of RNA and removal of rRNA was then tested with an Agilent RNA Pico 6000 kit and an Agilent 2100 Bioanalyzer (Agilent Technologies). TruSeq Stranded mRNA Sample Preparation guide (Illumina) was then used to construct the cDNA library. The constructed cDNA library was then sequenced with Illumina NextSeq500 high output mode paired end using a read length of 75 bases.
Project description:Transcriptome profiling of Pseudomonas putida KT2440 comparing cells exposed for 1 hour to DIMBOA from maize (Zea mays) to unexposed cells