A novel DSF-like signal from Burkholderia cenocepacia interferes with Candida albicans morphological transition.
In addition to producing lethal antibiotics, microorganisms may also use a new form of antagonistic mechanism in which signal molecules are exported to influence the gene expression and hence the ecological competence of their competitors. We report here the isolation and characterization of a novel signaling molecule, cis-2-dodecenoic acid (BDSF), from Burkholderia cenocepacia. BDSF is structurally similar to the diffusible signal factor (DSF) that is produced by the RpfF enzyme of Xanthomonas campestris. Deletion analysis demonstrated that Bcam0581, which encodes an RpfF homologue, was essential for BDSF production. The gene is highly conserved and widespread in the Burkholderia cepacia complex. Exogenous addition of BDSF restored the biofilm and extracellular polysaccharide production phenotypes of Xanthomonas campestris pv. campestris DSF-deficient mutants, highlighting its potential role in inter-species signaling. Further analyses showed that Candida albicans germ tube formation was strongly inhibited by either coculture with B. cenocepacia or by exogenous addition of physiological relevant levels of BDSF, whereas deletion of Bcam0581 abrogated the inhibitory ability of the bacterial pathogen. As B. cenocepacia and C. albicans are frequently encountered human pathogens, identification of the BDSF signal and its activity thus provides a new insight into the molecular grounds of their antagonistic interactions whose importance to microbial ecology and pathogenesis is now becoming evident.
Institute of Molecular and Cell Biology, Singapore.
Calvin
C
Boon
Yinyue
Y
Deng
Lian-Hui
LH
Wang
Yawen
Y
He
Jin-Ling
JL
Xu
Yang
Y
Fan
Shen Q
SQ
Pan
Lian-Hui
LH
Zhang
D000898:Antibiosis; D001426:Bacterial Proteins / Q000737:chemistry / Q000378:metabolism; D018441:Biofilms / Q000254:growth & development; D019121:Burkholderia Infections / Q000382:microbiology; D016956:Burkholderia cepacia / Q000201:enzymology / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D002176:Candida albicans / Q000166:cytology / Q000187:drug effects* / Q000254:growth & development; D004746:Enoyl-CoA Hydratase / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D005229:Fatty Acids, Monounsaturated / Q000737:chemistry / Q000378:metabolism* / Q000494:pharmacology; D015964:Gene Expression Regulation, Bacterial; D005816:Genetic Complementation Test; D050505:Mutant Proteins / Q000235:genetics; D016366:Open Reading Frames; D011135:Polysaccharides, Bacterial / Q000096:biosynthesis; D016415:Sequence Alignment; D017384:Sequence Deletion; D015398:Signal Transduction; D016959:Xanthomonas campestris / Q000737:chemistry / Q000235:genetics / Q000378:metabolism
C527562:2-dodecenoic acid; D001426:Bacterial Proteins; D005229:Fatty Acids, Monounsaturated; D050505:Mutant Proteins; D011135:Polysaccharides, Bacterial; D004746:Enoyl-CoA Hydratase