Project description:Indole-3-acetic acid (IAA), knows as common plant hormone, is one of the most distributed indole derivatives in the environment. A novel strain, which was able to use IAA as sole source of carbon and nitrogen, was isolated from farm soil, identified and classified as Pseudomonas composti LY1 based on 16S rRNA sequence and genome analysis. The optimal growth conditions for LY1 with IAA are characterized. Proteome profile of strain LY1 to IAA and citrate were analyzed and compared using label free strategy with LC-MS/MS.
Project description:Purpose of study was to investigate whole genome expression changes of a strain with deletion of the two-component system TctD-TctE and determine genes dysregulate relative to the parental wildtype to gain insight into possible regulatory targets of TctD-TctE. TctD-TctE is a two-component system in Pseudomonas aeruginosa that responds to and regulates uptake of tricarboxylic acids such as citric acid. It accomplishes this through derepression of the porin encoding the gene opdH, thereby regulating influx of citrate metabolites from the surrounding environment. Deletion of the tctED operon (ΔtctED) resulted in a reduced growth phenotype when citric acid is present in media. In the ΔtctED strain the presence of citric acid was found to have an inhibitory effect on growth. When the alternative carbon source arginine was present, wildtype levels of growth could not be restored. Static cultures of ΔtctED had low cell density in the presence of citric acid but maintained the same levels of biofilm formation compared to conditions when no citric acid was present. This suggests a dysregulation of biofilm formation in the presence of citric acid. In the ΔtctED strain there was also greater accumulation of tobramycin within the biofilm compared to the PA14 wildtype strain. Additionally, analysis of whole-genome expression found that multiple metabolic genes were dysregulated in ΔtctED. Here it is concluded that TctD-TctE is involved in biofilm tolerance to tobramycin in the presence of citrate metabolites.
