Rhodobacter sphaeroides 2.4.1 pRKSorX144 versus pRK415 under singlet oxygen stress.

To learn more about the function of SorX, we constructed an over-expression strain. For this purpose, the sorX gene together with its 28-bp upstream region was cloned into the over-expression vector pRK4352 and expressed in the R. sphaeroides wild-type 2.4.1 background. The corresponding strain consequently exhibits a SorX over-expression that is driven by the constitutive 16S rRNA (RSP_4352) promoter. The over-expression strain was compared to an empty vector control (pRK415). Total RNA from the over-expression (pRKSorX144) and from the empty vector control (pRK415) strain was extracted after 7 min of singlet oxygen stress and used for microarray analysis to investigate SorX-induced changes on transcriptome level. RNA samples collected after 7 min of singlet oxygen stress were analyzed by two-color microarrays. Each microarray contains a pool of three independent biological replicates for each sample.