Structural and Functional Characterization of Diffusible Signal Factor Family Quorum-Sensing Signals Produced by Members of the Burkholderia cepacia Complex

ABSTRACT Previous work has shown that Burkholderia cenocepacia produces the diffusible signal factor (DSF) family signal cis -2-dodecenoic acid (C 12 :Δ 2 , also known as BDSF), which is involved in the regulation of virulence. In this study, we determined whether C 12 :Δ 2 production is conserved in other members of the Burkholderia cepacia complex (Bcc) by using a combination of high-performance liquid chromatography, mass spectrometry, and bioassays. Our results show that five Bcc species are capable of producing C 12 :Δ 2 as a sole DSF family signal, while four species produce not only C 12 :Δ 2 but also a new DSF family signal, which was identified as cis , cis -11-methyldodeca-2,5-dienoic acid (11-Me-C 12 :Δ 2,5 ). In addition, we demonstrate that the quorum-sensing signal cis -11-methyl-2-dodecenoic acid (11-Me-C 12 :Δ 2 ), which was originally identified in Xanthomonas campestris supernatants, is produced by Burkholderia multivorans . It is shown that, similar to 11-Me-C 12 :Δ 2 and C 12 :Δ 2 , the newly identified molecule 11-Me-C 12 :Δ 2,5 is a potent signal in the regulation of biofilm formation, the production of virulence factors, and the morphological transition of Candida albicans . These data provide evidence that DSF family molecules are highly conserved bacterial cell-cell communication signals that play key roles in the ecology of the organisms that produce them.