|FISHMAN, MAXWELL - Cornell University|
Submitted to: International Conference on Pseudomonas syringae Pathovars
Publication Type: Abstract Only
Publication Acceptance Date: 4/27/2015
Publication Date: 5/20/2015
Citation: Fishman, M.R., D'Amico, K.M., Stodghill, P., Filiatrault, M.J. 2015. Characterizing the regulon of the two-component system, PSPTO_3380 and PSPTO_3381. International Conference on Pseudomonas syringae Pathovars. p. 99.
Technical Abstract: The two-component system, PSPTO_3380 (3380) and PSPTO_3381 (3381) in Pseudomonas syringae pv. tomato DC3000 (Pst) is involved in pathogenicity. We have reported that addition of a number of divalent cations to the medium induces expression of this two-component system. 3380/3381 regulates transcription of itself and of several genes including PSPTO_5255 (5255), which encodes for a carbonic anhydrase. To gain further insight into the role of this two-component system, we compared the region upstream of the open reading frame that encodes 3380/3381 to the orthologous regions in all sequenced Pseudomonads. Then we used the motif finder MEME to search for a binding motif for 3381. The putative binding motif generated consists of two direct repeats separated by six random base pairs. This is characteristic of OmpR-family response regulators, of which 3381 is a member. By generating a Hidden Markov model we were able to find 17 putative binding sites in the Pst genome. There are several 3381 binding sites within intergenic regions followed by a Rho-independent terminator, one of which is upstream of 5255. This suggests that 3381 regulates the transcription of small RNAs at these sites. Using quantitative reverse transcriptase PCR we verified transcriptional activity in a subset of these regions. When comparing RNA isolated from wild-type and delta3380 or delta3381 strains we saw differential gene expression for some of these areas, including the region upstream of 5255. The discovery of PSPTO_3380/3381 –regulated small RNAs adds complexity to the regulon of this two-component system and allows for the possibility of indirect regulation of a large number of genes. Further characterization of these small RNAs will help define the means by which 3380/3381 regulates virulence of Pst.