title: The Burkholderia cenocepacia K56-2 pleiotropic regulator Pbr, is required for stress resistance and virulence.
abstract: Burkholderia cenocepacia is one of the most virulent species of the Burkholderia cepacia complex, a group of bacteria that emerged as important pathogens, especially to cystic fibrosis (CF) patients. In this study, we report the identification and characterization of a mutant strain derived form the CF isolate Burkholderia cenocepacia K56-2, carrying a plasposon insertion in a gene, located in a 3516 bp chromosomal region with an atypical G+C content, encoding a 80 amino acid putative regulatory protein named Pbr. Besides its inability to produce phenazines, the B. cenocepacia K56-2 pbr mutant exhibited a pleiotropic phenotype, including impaired survival to oxidative and osmotic stress, aromatic amino acid and prolonged nutrient starvation periods. In addition, the pbr mutant exhibited decreased virulence the nematode Caenorhabditis elegans. Altogether, our results demonstrate the involvement of Pbr on the regulation of phenazine biosynthesis, and an important role for this regulatory protein on several cellular processes related to stress resistance and virulence.
authors.affiliation: IBB - Institute for Biotechnology and Bioengineering, Centre for Biological and Chemical Engineering, Instituto Superior Técnico, Torre Sul, Piso 6. Av. Rovisco Pais, 1049-001 Lisboa, Portugal.
authors.forename: Christian G
authors.initials: CG
authors.lastname: Ramos
authors.forename: Silvia A
authors.initials: SA
authors.lastname: Sousa
authors.forename: André M
authors.initials: AM
authors.lastname: Grilo
authors.forename: Leo
authors.initials: L
authors.lastname: Eberl
authors.forename: Jorge H
authors.initials: JH
authors.lastname: Leitão
mesh_terms: D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D018441:Biofilms / Q000254:growth & development; D019121:Burkholderia Infections / Q000382:microbiology; D042602:Burkholderia cepacia complex / Q000235:genetics / Q000472:pathogenicity* / Q000502:physiology*; D017173:Caenorhabditis elegans / Q000382:microbiology; D003550:Cystic Fibrosis / Q000382:microbiology; D005798:Genes, Bacterial; D006801:Humans; D008969:Molecular Sequence Data; D016254:Mutagenesis, Insertional; D009994:Osmolar Concentration; D010619:Phenazines / Q000378:metabolism; D010957:Plasmids; D011401:Promoter Regions, Genetic; D013312:Stress, Physiological; D014158:Transcription, Genetic; D014774:Virulence / Q000235:genetics; D037521:Virulence Factors / Q000235:genetics / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; C551131:Pbr protein, Burkholderia cenocepacia; D010619:Phenazines; D037521:Virulence Factors