The outlier Pseudomonas aeruginosa strain ATCC 9027 harbors a defective LasR quorum-sensing transcriptional regulator. Issue 16 (21st July 2020)

• Record Type: Journal Article
• Authors: García-Reyes, Selene; Soto-Aceves, Martín P; Cocotl-Yañez, Miguel; González-Valdez, Abigail; Servín-González, Luis; Chávez, Gloria Soberón
• Is Part Of: FEMS microbiology letters. Volume 367:Issue 16(2020)
• Publication Date: 2020-07-21
• Subjects: PA7 clade -- LasR activity -- RhlR-expression -- quorum-sensing response; Microbiology -- Periodicals; 579
• DOI: 10.1093/femsle/fnaa122
• Languages: English
• ISSNs: 0378-1097

Abstract

ABSTRACT: Pseudomonas aeruginosa infections represent an important health problem that has been recognized by the World Health Organization as a research priority. A complex regulatory network called the quorum sensing (QS) regulates several P. aeruginosa virulence-related traits, including production of elastase, rhamnolipids and pyocyanin. The avirulent P. aeruginosa strain ATCC 9027 belongs to clade 3, which is the more distant phylogroup in relationship to the other four clades of this species. This strain does not produce QS-regulated virulence factors such as elastase and rhamnolipids when cultured in rich LB medium. We report here that ATCC 9027 harbors a defective LasR protein, presumably due to the presence of an aspartic acid in position 196 instead of a glutamic acid which is the amino acid present in this position in functional LasR proteins of the type strains PAO1 (clade 1) and PA7 (also belonging to clade 3), among others. In addition, we report that ATCC 9027 and PA7 strains present differences compared to the PAO1 strain in lasB which encodes elastase, and in the rhlR regulatory sequences that modify las- boxes, and that these mutations have a little effect in the expression of these genes by a functional LasR transcriptional regulator. Abstract : Pseudomonas aeruginosa ATCC 9027 is avirulent and its LasR transcriptional regulator is not functional, this explains why it does not synthesize virulence factors like elastase, rhamnolipids and pyocyanin.