A NOVEL PLASMID PIJB1 POSSESSING A PUTATIVE 2,4-DICHLOROPHENOXYACETATE DEGRADATIVE TRANSPOSON TN5530 IN BURKHOLDERIA-CEPACIA STRAIN-2A

A 102-kb plasmid, pIJB1, was isolated from Burkholderia cepacia strain 2a, which is able to use 2,4-dichlorophenoxyacetate (2,4-D) as a sole carbon source, and a physical map of the plasmid has been established . It was observed that spontaneous loss of a 37-kb fragment of the pla smid after growth in nonselective medium occurred, generating a plasmi d of diminished size, pIJB2. The deletion event is concomitant with th e loss of the 2,4-D dissimilatory phenotype, indicating that at least some of the 2,4-D degradative genes are on the missing fragment. The m issing fragment is flanked by two identical 4.3-kb insertion sequences (IS) and shows a typical composite transposon structure of 41-kb in s ize, designated Tn5530. The mutant plasmid pIJB2 possesses a single co py of the IS element. (C) 1998 Academic Press.