Submitted to: American Society for Microbiology
Publication Type: Abstract Only
Publication Acceptance Date: 2/20/2009
Publication Date: 6/17/2009
Citation: Bronstein, P., Filiatrault, M.J., Stodghill, P., Schneider, D.J., Cartinhour, S.W. 2009. Investigating the role of two iron-regulated small RNAs of Pseudomonas syringae. American Society for Microbiology. p. 20.
Technical Abstract: Small RNAs (sRNAs) have emerged as important components of many regulatory pathways and have been shown to have key roles in the regulation of iron homeostasis in a number of bacteria. To date, only a few sRNAs have been described for the bacterial plant pathogen Pseudomonas syringae pathovar tomato DC3000 (DC3000). It has been predicted that the P. syringae genome contains sequences for two iron-regulated sRNAs, which are homologues of the Pseudomonas aeruginosa prrFs. In this study, we applied a ferric uptake regulator protein (FUR) binding motif to the genome of P. syringae in combination with terminator predictions and identified the genomic locations that encode for the sRNAs prrF1 and prrF2. The expression and size of these sRNAs under iron-limited conditions was validated using Northern blots. We then used several bioinformatics approaches to identify putative regulatory targets of these small RNAs. By identifying genes whose expression patterns co-clustered with prrF2 in microarray experiments, we were able to identify several genes this sRNA regulates. The negative regulation of several genes was tested and verified by comparing strains that over-express prrF1 or prrF2 to the wild-type strain. We also identified other putative novel targets using the web-based program TargetRNA. We demonstrated that these sRNAs affected several facets of DC3000 physiology. Interestingly, we also found that the expression of genes involved in Type III secretion is influenced by prrF2. These results provide initial insights into the complex regulatory systems that regulate gene expression in this pathogen.