Submitted to: Applied and Environmental Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/31/2012
Publication Date: 1/1/2013
Citation: Swingle, B.M., Markel, E.J., Butcher, B.G., Myers, C.R., Stodghill, P., Cartinhour, S.W. 2013. Regulons of the Pseudomonas syringae pv. tomato DC3000 iron starvation sigma factors PSPTO_0444, PSPTO_1209 and PSPTO_1286. Applied and Environmental Microbiology. 79(2):725-727. Interpretive Summary: There are important differences between bacteria that cause diseases in plants and those that cause disease in animals. One difference is that plant pathogenic bacteria are able to survive in diverse conditions found in the terrestrial and aquatic environments, in contrast animal pathogens tend to be specialized for growth in a specific host or organ. The ability for plant pathogenic bacteria to grow freely in the environment is likely due to an ability to change and adapt to different conditions. In this paper we present the results of a study of three proteins that may be used to help Pseudomonas syringae adapt to low iron environments. We found that these proteins are very specialized and control the organism in very specific ways.
Technical Abstract: Pseudomonas syringae is a globally dispersed environmental bacteria that is well known for its ability to cause destructive plant diseases in agricultural and horticultural settings. The ability of bacteria to survive in diverse environments is correlated with a large number of transcription regulators. Bacteria presumably use these regulators to control transcription of genes needed for survival as conditions change. Consistent with this hypothesis P. syringae pv. tomato DC3000 encodes five putative cell surface signaling systems. These are multi protein systems that respond to specific extracellular stimuli and transduce a signal into the cytoplasm to activate a specific sigma factor, which is responsible for controlling expression of a discrete set of genes. Sigma factors are an exchangeable subunit of RNA polymerase that function in promoter recognition and transcription initiation. The sigma factors associated with these cell surface signaling systems typically regulate genes that are involved with iron uptake and are therefore known as iron starvation sigma factors. In this study, we identified the genes regulated by three of these iron starvation sigma factors.