[Synthesis of N-acyl-homoserine lactones, phenazines, some enzymatic activities and antifungal activity of Pseudomonas chlororaphis 449 cells carrying an inactivated rpoS gene].

Inactivation of the rpoS gene encoding for sigma S subunit of RNA polymerase of the rhizospheric strain Pseudomonas chlororaphis 449 results in a sharp decrease (5-8 fold) of phenazine antibiotics synthesis, decline of acid and alkaline phosphatases (pH 2.5 and 8.8, respectively) activities and antagonistic activity of this strain against phytopathogenic fungus Rhizoctonia solani. A mutation in the rpoS gene causes a small decrease of lipase and proteolytic activities in supernatants of Pseudomonas chlororaphis 449 cultures, as well as does not substantially affect the synthesis of three types of N-acyl-homoserinelactones that are signal molecules of Quorum Sensing regulation, and the capacity of bacteria to motility on the surface of the medium (swarming).