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: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:Pseudomonas putida KT2440 is a metabolically versatile soil bacterium useful both as a model biodegradative organism and as a host of catalytic activities of biotechnological interest. In this report, we present the high-resolution transcriptome of P. putida grown in different carbon sources as revealed by deep sequencing of the corresponding RNA pools. Examination of the data from growth on glycolytic (glucose, fructose) and gluconeogenic (succinate or glycerol) substrates revealed that > 20% of the P. putida genome is differentially expressed depending on the ensuing metabolic regime. Changes affected not only metabolic genes but also a suite of global regulators, e.g. the rpoS sigma subunit of RNAP, various cold-shock proteins and the three HU histone-like proteins. Specifically, the genes encoding HU subunit variants hupA, hupB and hupN drastically altered their expression levels (and thus their ability to form heterodimeric combinations) under the different growth conditions. Furthermore, we found that the two small RNAs crcZ and crcY, known to inhibit the Crc protein that mediates catabolite repression in P. putida, were both down-regulated by glucose.
Project description:Pseudomonas putida KT2440 is a metabolically versatile soil bacterium useful both as a model biodegradative organism and as a host of catalytic activities of biotechnological interest. In this report, we present the high-resolution transcriptome of P. putida grown in different carbon sources as revealed by deep sequencing of the corresponding RNA pools. Examination of the data from growth on glycolytic (glucose, fructose) and gluconeogenic (succinate or glycerol) substrates revealed that > 20% of the P. putida genome is differentially expressed depending on the ensuing metabolic regime. Changes affected not only metabolic genes but also a suite of global regulators, e.g. the rpoS sigma subunit of RNAP, various cold-shock proteins and the three HU histone-like proteins. Specifically, the genes encoding HU subunit variants hupA, hupB and hupN drastically altered their expression levels (and thus their ability to form heterodimeric combinations) under the different growth conditions. Furthermore, we found that the two small RNAs crcZ and crcY, known to inhibit the Crc protein that mediates catabolite repression in P. putida, were both down-regulated by glucose. cDNA libraries from Pseudomonas supplemented with different carbon sources (glucose, glycerol, fructose, succinate) were sequenced using HiSeq 2000 to yield 91 paired-end reads. Gene expression values were compared.
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:The metabolically versatile Pseudomonas putida strain KT2440 is the first Gram-negative soil bacterium certified as a biosafety strain and is being used for applications in agriculture, biotechnology and bioremediation. P. putida has to cope in its niche with numerous abiotic stresses. The stress response to 4°C, pH 4.5, 0.8 M urea or 45 mM sodium benzoate, respectively, was analyzed by the global mRNA expression profile and screening for stress-intolerant Tn5 transposon mutants. In total we identified 49 gene regions to be differentially expressed and 32 genes in 22 operons to be indispensable for growth during exposure to one or the other abiotic stresses. We propose that stress is sensed by the outer membrane proteins OmlA and FepA and the inner membrane constituents PtsP, PhoPQ and CbrAB. The metabolic response is regulated by the cyo operon, the RelA/SpoT modulon, PcnB and VacB that control mRNA stability and BipA that exerts transcript-specific translational control. The adaptation of the membrane barrier, the uptake of phosphate, the maintenance of intracellular pH and redox status and the translational control of metabolism are the indispensable key mechanisms of the P. putida stress response. Keywords: functional genomics
Project description:Transcriptome profiling of Pseudomonas putida KT2440 comparing cells exposed for 1 hour to DIMBOA from maize (Zea mays) to unexposed cells