Dynamic response of P. putida S12 and S12M-NM-^TtrgI to sudden addition of toluene

ABSTRACT: Pseudomonas putida S12 is exceptionally tolerant to various organic solvents. To obtain further insight in this bacteriumM-bM-^@M-^Ys primary defence mechanisms towards these potentially harmful substances, we studied its genome wide transcriptional response to sudden addition of toluene. Global gene expression profiles were monitored for 30 minutes after toluene addition. During toluene exposure, high oxygen-affinity cytochrome c oxidase is specifically expressed to provide for an adequate proton gradient supporting solvent efflux mechanisms. Concomitantly, the glyoxylate bypass route was up-regulated, to repair an apparent toluene stress-induced redox imbalance. A knock-out mutant of trgI, a recently identified toluene-repressed gene, was investigated in order to identify TrgI function. Remarkably, upon addition of toluene the number of differentially expressed genes initially was much lower in the trgI-mutant than in the wild-type strain. This suggested that after deletion of trgI cells were better prepared for sudden organic solvent stress. Before, as well as after, addition of toluene many genes of highly diverse functions were differentially expressed in trgI-mutant cells as compared to wild-type cells. This led to the hypothesis that TrgI may not only be involved in the modulation of solvent-elicited responses but in addition may affect basal expression levels of large groups of genes. Differential gene expression after a sudden addition of 5 mM toluene was analysed in early exponential phase cultures (optical density at 600 nm of 0.5-0.6) of P. putida strains S12 (wild-type) and S12M-NM-^TtrgI. Samples were drawn immediately before (t=0) and at set intervals (1, 2, 5, 10 and 30 minutes) after toluene exposure. Duplicat samples were drawn. This resulted in 12 samples per strain, 24 in total.

ORGANISM(S): Pseudomonas putida S12

SUBMITTER: Johannes de Winde 

PROVIDER: E-GEOD-64791 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress