Effects of the Fnr homologue AadR on global gene expression

In order to define the AadR regulon we did transcriptome analysis of an aadR in frame-deletion mutant and compared to that of wild type. We found that AadR positively modulated expression of 43 genes, most of which are involved in degradation of aromatic acids under anaerobic conditions. It also activated expression of four genes encoding for unknown proteins and a possible DNA-binding stress protein. Furthermore, AadR repressed the expression of 100 genes, including fixK and many genes controlled by FixK, mainly those involved in a microaerobic lifestyle R. palustris strains were grown in defined medium anaerobically in light (photosynthetically) in sealed tubes with nitrogen gas in the headspace. Succinate and p-coumarate were provided as carbon sources.