Submitted to: Phytopathology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/1/1998
Publication Date: N/A
Citation: Interpretive Summary:
Technical Abstract: Pseudomonas fluorescens strain Pf-5 is a biological control agent for fungal damping-off diseases. P. fluorescens strain A506 is a commercial biocontrol bacterium for fire blight. In E. coli, rpoS encodes for a protein (RpoS) that mediates coordinated expression of phenotypes associated with stationary phase cells (i.e. production of secondary metabolites and tolerance to environmental stresses). An RpoS- mutant of Pf-5 established lower populations than Pf-5 in the rhizosphere of bean planted in dry soils. Stock cultures of A506 had a frame-shift mutation in rpoS that resulted in the production of a truncated RpoS. A506 established similar population sizes on pear blossoms as a derivative with an npt1-insertion in rpoS, and an isolate with a repaired rpoS, which produced a full-length transcript of RpoS. The importance of rpoS in expression of attributes associated with stationary phases cells and its influence on fitness of bacteria on plant tissues may be strain dependent.