|FISHMAN, MAXWELL - Cornell University|
|ZHANG, JOHNSON - Cornell University|
|BRONSTEIN, PHILIP - Food Safety Inspection Service (FSIS)|
Submitted to: American Phytopathology Society
Publication Type: Abstract Only
Publication Acceptance Date: 5/8/2015
Publication Date: 7/15/2015
Citation: Fishman, M.R., Zhang, J., Bronstein, P.A., Stodghill, P., Filiatrault, M.J. 2015. Identification of a previously uncharacterized global regulator in Pseudomonas syringae pv. tomato DC3000. American Phytopathology Society. 705-P.
Technical Abstract: Pseudomonas syringae pv. tomato DC3000 (Pst) is used as a model system to understand the dynamics behind molecular plant-microbe interactions. Identification of conserved genes necessary for survival of bacterial plant pathogens in the apoplast could lead to new management methods. We have identified a conserved two-component system (TCS) in Pst, PSPTO_3380 and PSPTO_3381 (3380/3381), that is involved in virulence. TCSs are signaling relays bacteria use to sense changes in their environment and adapt accordingly. To determine the environmental stimuli of 3380/3381, we designed a reporter gene construct and found that 3380/3381 is stimulated by Ca2+, Fe2+, Zn2+, and Cd2+. Ca2+ was also found to inhibit swarming motility and cause abnormal exopolysaccharide and calcium precipitation in delta 3380 and delta 3381 strains, but not wild-type Pst. Due to the phenotypic changes associated with Ca2+, we performed an RNA-seq experiment comparing WT Pst to delta 3380 and delta 3381 Pst grown in the presence of Ca2+. Analysis of the RNA-seq data showed differential expression of alginate and Psl biosynthesis genes, and genes related to motility, carbohydrate utilization, and lipopolysaccharide production. The small RNA rsmZ known to interact with GacS/A and regulate virulence also showed differential expression. This research shows that 3380/3381 is an important global regulator.