title: Hierarchical management of carbon sources is regulated similarly by the CbrA/B systems in Pseudomonas aeruginosa and Pseudomonas putida.
abstract: The CbrA/B system in pseudomonads is involved in the utilization of carbon sources and carbon catabolite repression (CCR) through the activation of the small RNAs crcZ in Pseudomonas aeruginosa, and crcZ and crcY in Pseudomonas putida. Interestingly, previous works reported that the CbrA/B system activity in P. aeruginosa PAO1 and P. putida KT2442 responded differently to the presence of different carbon sources, thus raising the question of the exact nature of the signal(s) detected by CbrA. Here, we demonstrated that the CbrA/B/CrcZ(Y) signal transduction pathway is similarly activated in the two Pseudomonas species. We show that the CbrA sensor kinase is fully interchangeable between the two species and, moreover, responds similarly to the presence of different carbon sources. In addition, a metabolomics analysis supported the hypothesis that CCR responds to the internal energy status of the cell, as the internal carbon/nitrogen ratio seems to determine CCR and non-CCR conditions. The strong difference found in the 2-oxoglutarate/glutamine ratio between CCR and non-CCR conditions points to the close relationship between carbon and nitrogen availability, or the relationship between the CbrA/B and NtrB/C systems, suggesting that both regulatory systems sense the same sort or interrelated signal.
authors.affiliation: Department of Fundamental Microbiology, University of Lausanne, 1015 Lausanne, Switzerland.
authors.forename: Martina
authors.initials: M
authors.lastname: Valentini
authors.affiliation: Centro Andaluz de Biología del Desarollo/CSIC/Universidad Pablo de Olavide, 41013 Seville, Spain.
authors.forename: Sofía M
authors.initials: SM
authors.lastname: García-Mauriño
authors.affiliation: Centro Andaluz de Biología del Desarollo/CSIC/Universidad Pablo de Olavide, 41013 Seville, Spain.
authors.forename: Isabel
authors.initials: I
authors.lastname: Pérez-Martínez
authors.affiliation: Centro Andaluz de Biología del Desarollo/CSIC/Universidad Pablo de Olavide, 41013 Seville, Spain.
authors.forename: Eduardo
authors.initials: E
authors.lastname: Santero
authors.affiliation: Centro Andaluz de Biología del Desarollo/CSIC/Universidad Pablo de Olavide, 41013 Seville, Spain.
authors.forename: Inés
authors.initials: I
authors.lastname: Canosa
authors.affiliation: Department of Fundamental Microbiology, University of Lausanne, 1015 Lausanne, Switzerland.
authors.forename: Karine
authors.initials: K
authors.lastname: Lapouge
mesh_terms: D002244:Carbon / Q000378:metabolism*; D015964:Gene Expression Regulation, Bacterial; D000071677:Histidine Kinase; D011494:Protein Kinases / Q000378:metabolism; D011550:Pseudomonas aeruginosa / Q000235:genetics* / Q000378:metabolism*; D016958:Pseudomonas putida / Q000235:genetics* / Q000378:metabolism*; D014157:Transcription Factors / Q000378:metabolism*
chemical_list: D014157:Transcription Factors; D002244:Carbon; D011494:Protein Kinases; D000071677:Histidine Kinase