|Kinscherf, Thomas - UNIVERSITY OF WISCONSIN|
|Knaack, William - UNIVERSITY OF WISCONSIN|
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: May 13, 1998
Publication Date: N/A
Technical Abstract: The rpoS gene encodes an alternate sigma factor that controls the expression of a number of secondary and stress induced metabolic pathways and is highly conserved among gram-negative bacteria. In many bacterial systems, mutations in the rpoS gene render the mutant bacteria sensitive to abiotic stress, such as exposure to hydrogen peroxide, and survival during the stationary phase of bacterial growth. In P. fluorescens, a rpoS mutation blocks the expression of several secreted molecules that are required for the biocontrol of disease. Hybridization experiments indicate that the rpoS gene is widely distributed within Pseudomonas. We have isolated the rpoS homolog from P. syringae pv. tomato strain DC3000 and we constructed site- specific mutations within the rpoS gene. A DC300 mutant containing a defect in rpoS was found to unaffected in its ability to form lesions or produce the chlorotic toxin coronatine on tomato plants. The DNA sequence of the P. syringae pv. tomato strain DC3000 rpoS gene has been determined and submitted to GenBank (accession number AF061853). This sequence reveals that the predicted P. syringae pv. tomato rpoS ORF is 93% identical in amino acid sequence to the P. fluorescens RpoS protein. This data reveals that the RpoS protein is indeed highly conserved within the genus Pseudomonas.