Comparative analysis of the response to iron-limitation in the presence or absence of oxygen in R. sphaeroides and role of the OxyR protein [RNA-Seq]
High intracellular levels of unbound iron can contribute to the production of reactive oxygen species (ROS) in the Fenton reaction, while depletion of iron limits the availability of iron containing proteins, some of which have important functions in the oxidative stress defense. Vice versa increased ROS levels lead to damage of proteins with iron sulfur centers. Thus organisms have to coordinate and balance their responses to oxidative stress and iron availability. Our knowledge on the molecular mechanisms underlying the coregulation of these responses is still limited. To discriminate between a direct cellular response to iron limitation and indirect responses, which are the consequence of increased levels of ROS, we compared the response of the alpha proteobacterium Rhodobacter sphaeroides to iron limitation in presence or absence of oxygen. While some genes respond to iron limitation exclusively or much stronger in presence of oxygen, other genes show much stronger response in anaerobic conditions. Remarkably few genes show even opposite response to iron depletion in presence or absence of iron. Overall design: RNA samples collected from anaerobically or microaerobically grown cultures in presence or absence of iron were analyzed by RNA_sequencing