Distribution of quorum-sensing genes in the Burkholderia cepacia complex

Abstract

The distribution of quorum-sensing genes among strains from seven genomovars of the Burkholderia cepacia complex was examined by PCR. cepR and cepI were amplified from B. cepacia genomovars I and III, B. stabilis, and B. vietnamiensis. cepR was also amplified from B. multivorans and B. cepacia genomovar VI. bviIR were amplified from B. vietnamiensis. All genomovars produced N-octanoyl-L-homoserine lactone and N-hexanoyl-L-homoserine lactone. B. vietnamiensis and B. cepacia genomovar VII produced additional N-acyl-L-homoserine lactones.

FIG. 1

Detection of cepIR and bviIR genes in strains of the B. cepacia complex by PCR. (A) cepR; (B) cepI; (C) bviI; (D) bviR. Lanes 1, ATCC 25416; lanes 2, ATCC 17759; lanes 3, CEP 509; lanes 4, C5393; lanes 5, 249-2; lanes 6, LMG13010; lanes 7, K56-2; lanes 8, J2315; lanes 9, C5424; lanes 10, LMG14294; lanes 11, LMG07000; lanes 12, LMG14291; lanes 13, PC259; lanes 14, LMG16232; lanes 15, LMG10929; lanes 17, pUCP28T; lanes 18, H₂O control; lanes 19, LMG18943; lanes 20, L06; lanes 21, ATCC 53266; lanes 22, AMMD; lanes 23, CEP996; lanes 25, pUCP28T; lanes 26, H₂O control. Lanes 16 and 24 contain the positive controls pSLA3.2 (A and B) p824E-9 (C), and p824E-3 (D). Abbreviations: Gmv, genomovar; B. mult., B. multivorans; B. stab., B. stabilis; B. viet., B. vietnamiensis.

FIG. 2

Computer-generated alignment of the deduced amino acid sequence of CepI from B. cepacia K56-2 (accession no. AF019654) (16) with B. vietnamiensis BviI (accession no. AF296284) (A) and CepR from B. cepacia K56-2 (accession no. AF019654) (16) with B. vietnamiensis BviR (accession no. AF296284) (B). Sequence alignments were performed using DNAMAN Sequence Analysis Software (Lynnon Biosoft). Shaded areas indicate identical amino acids.

FIG. 3

TLC of acyl-HSLs. Ethyl acetate extracts were chromatographed on C₁₈ reversed-phase thin-layer plates developed with methanol-water (60:40, vol/vol). The spots were visualized using the A. tumefaciens reporter strain. Samples from each genomovar were chromatographed as follows: lane 1, B. cepacia genomovar I (strain CEP509); lane 2, B. multivorans (strain C5393); lane 3, B. cepacia genomovar III (strain K56-2); lane 4, B. stabilis (strain LMG14294); lane 5, B. vietnamiensis (strain G4); lane 6, genomovar VI (strain LMG18943); lane 7, genomovar VII (strain CEP996); lane 8, synthetic N-hexanoyl-HSL; lane 9, synthetic N-octanoyl-HSL.