Multiple quorum-sensing systems in phenazine-producing Pseudomonas chlororaphis subsp. aurantiaca StFRB508
T. MOROHOSHI (1), T. Yamaguchi (1), N. Someya (2), T. Ikeda (1) (1) Utsunomiya University, Japan; (2) National Agriculture and Food Research Organization (NARO), Japan

Many gram-negative bacteria have a quorum-sensing system and produce N-acylhomoserine lactone (AHL) as a quorum-sensing signal molecule. Phenazine antibiotics are synthesized by a number of bacteria and known for their antimicrobial and antifungal activities. It has been reported that quorum-sensing system regulates phenazine antibiotic production in Pseudomonas chlororaphis subsp. aureofaciens 30-84. P. chlororaphis subsp. aurantiaca StFRB508 has been isolated from the root of potato and has an ability to produce phenazine-1-carboxylic acid (PCA). In previous study, we have found two AHL synthase genes (phzI and aurI) in the draft genome of StFRB508. However, phzI and aurI double mutant of StFRB508 produced a small amount of AHL and PCA. To identify the additional AHL synthase gene, we determined the complete genome sequence of StFRB508. As the results, one predicted ORF, designed csaI, showed high similarity to csaI from P. chlororaphis subsp. aureofaciens 30-84. To investigate the relationship between three AHL synthase genes and PCA production, phzI, aurI, and csaI triple mutant of StFRB508 was constructed. As the results, the triple mutant did not show any AHL and PCA production. These results demonstrated that PCA production in StFRB508 was regulated by AHLs produced by PhzI, AurI, and CsaI.

Abstract Number: P7-194
Session Type: Poster