The hfq gene is required for stress resistance and full virulence of Burkholderia cepacia to the nematode Caenorhabditis elegans.
The Burkholderia cepacia complex (Bcc) emerged as problematic opportunistic pathogens to cystic fibrosis (CF) patients. Although several virulence factors have been identified in Bcc, the knowledge of their relative contribution to Bcc pathogenicity remains scarce. In this work, we describe the identification and characterization of a B. cepacia IST408 mutant containing a disruption in the hfq gene. In other bacteria, Hfq is a global regulator of metabolism, acting as an RNA chaperone involved in the riboregulation of target mRNAs by small regulatory non-coding RNAs (sRNAs). The B. cepacia Hfq protein was overproduced as a histidine-tagged derivative, and we show evidence that the protein forms hexamers and binds sRNAs. When provided in trans, the B. cepacia IST408 hfq gene complemented the Escherichia coli hfq mutant strain GS081. Our results also show that the B. cepacia hfq mutant is more susceptible to stress conditions mimicking those faced by Bcc bacteria when infecting the CF host. In addition, the B. cepacia hfq mutant and two hfq mutants derived from B. dolosa and B. ambifaria clinical isolates also exhibited a reduced ability to colonize and kill the nematode Caenorhabditis elegans, used as an infection model. These data, together with the conservation of Hfq orthologues among Bcc, strongly suggest that Hfq plays a major role in the survival of Bcc under stress conditions, contributing to the success of Bcc as CF pathogens.
Sousa
Silvia A
SA
IBB - Institute for Biotechnology and Bioengineering, Centre for Biological and Chemical Engineering, Instituto Superior Técnico, Av. Rovisco Pais, 1049-001 Lisboa, Portugal.
Ramos
Christian G
CG
IBB - Institute for Biotechnology and Bioengineering, Centre for Biological and Chemical Engineering, Instituto Superior Técnico, Av. Rovisco Pais, 1049-001 Lisboa, Portugal.
Moreira
Leonilde M
LM
IBB - Institute for Biotechnology and Bioengineering, Centre for Biological and Chemical Engineering, Instituto Superior Técnico, Av. Rovisco Pais, 1049-001 Lisboa, Portugal.
Leitão
Jorge H
JH
IBB - Institute for Biotechnology and Bioengineering, Centre for Biological and Chemical Engineering, Instituto Superior Técnico, Av. Rovisco Pais, 1049-001 Lisboa, Portugal.
D000595:Amino Acid Sequence; D000818:Animals; D019121:Burkholderia Infections / Q000382:microbiology*; D042602:Burkholderia cepacia complex / Q000235:genetics* / Q000254:growth & development / Q000472:pathogenicity; D017173:Caenorhabditis elegans / Q000382:microbiology*; D003001:Cloning, Molecular; D024202:Electrophoretic Mobility Shift Assay; D005816:Genetic Complementation Test; D035001:Host Factor 1 Protein / Q000235:genetics*; D008969:Molecular Sequence Data; D016254:Mutagenesis, Insertional; D012329:RNA, Bacterial / Q000235:genetics; D016415:Sequence Alignment; D014774:Virulence
D035001:Host Factor 1 Protein; D012329:RNA, Bacterial