A putative type III secretion gene cluster is widely distributed in the Burkholderia cepacia complex but absent from genomovar I

Using probes constructed from Ralstonia solanacearum and Burkholderia pseud omallei, putative type III secretion (TTS) genes were identified in Burkhol deria cepacia J2315 (genomovar III). A cosmid clone containing DNA with hom ology to five TTS genes was sub-cloned and regions were sequenced in order to design oligonucleotides for polymerase chain reaction assays. These indi cated that two putative TTS genes (bcscQ and bcscV) were present in all mem bers of the B. cepacia complex with the exception of strains from genomovar I. Southern blot assays confirmed this observation, suggesting that the la ck of a TTS gene cluster may define a major difference between B. cepacia g enomovar I and other members of the B. cepacia complex, including genomovar III. In contrast to TTS gene clusters in other bacteria, a Putative gene h omologous to the virB1 gene of Brucella sids was located directly downstrea m of bcscQR. (C) 2001 Federation of European Microbiological Societies. Pub lished by Elsevier Science B.V. All rights reserved.