Development and application of PCR primers for the detection of the tfd genes in Delftia acidovorans P4a involved in the degradation of 2,4-D

Primers specific for the genes tfdD, tfdE and tfdF, derived from conserved aminoacid sequence motifs of the corresponding homologous enzymes, and prim ers specific for the genes tfdA and tfdB as well as tfdC taken from the lit erature were applied in PCR reactions using the genomic DNA of Delftia acid ovorans P4a as the template. PCR products were obtained with all primer pai rs that were similar in size to those found with the genomic DNA of strains harbouring plasmid pJP4 as the carrier of tfd genes. The nucleotide sequen ces and the corresponding amino acid sequences of the PCR products obtained with Strain P4a were compared with the sequence databases. According to BL AST analyses, the partial sequences of tfdA and tfdB exhibited a 94-99% deg ree of identity with the homologous sequences of the 2,4-D-degrading strain s Achromobacter xylosoxidans subsp. denitrificans EST4002 (pEST4011), Burkh olderia sp. RASC, Variovorax paradoxus TV1 (pTV1) and Burkholderia cepacia 2a (pIJB1), whereas the partial sequences of tho tfdC, tfdD, tfdE and tfdF genes revealed a 96-100% degree of identity with the homologous sequences o f the chlorobenzene-utilizing strains Ralstonia eutropha NH9 (pENH91), Pseu domonas chlororaphis RW71 and Pseudomonas sp. P51 (pP51).