title: Comparison of 16S rRNA gene phylogeny and functional tfdA gene distribution in thirty-one different 2,4-dichlorophenoxyacetic acid and 4-chloro-2-methylphenoxyacetic acid degraders.
abstract: 31 different bacterial strains isolated using the herbicide 2,4-dichlorophenoxyacetic acid (2,4-D) as the sole source of carbon, were investigated for their ability to mineralize 2,4-D and the related herbicide 4-chloro-2-methylphenoxyacetic acid (MCPA). Most of the strains mineralize 2,4-D considerably faster than MCPA. Three novel primer sets were developed enabling amplification of full-length coding sequences (CDS) of the three known tfdA gene classes known to be involved in phenoxy acid degradation. 16S rRNA genes were also sequenced; and in order to investigate possible linkage between tfdA gene classes and bacterial species, tfdA and 16S rRNA gene phylogeny was compared. Three distinctly different classes of tfdA genes were observed, with class I tfdA sequences further partitioned into the two sub-classes I-a and I-b based on more subtle differences. Comparison of phylogenies derived from 16S rRNA gene sequences and tfdA gene sequences revealed that most class II tfdA genes were encoded by Burkholderia sp., while class I-a, I-b and III genes were found in a more diverse array of bacteria.
authors.affiliation: Geological Survey of Denmark and Greenland (GEUS), Department of Geochemistry, Copenhagen K, Denmark.
authors.forename: Jacob
authors.initials: J
authors.lastname: Baelum
authors.forename: Carsten S
authors.initials: CS
authors.lastname: Jacobsen
authors.forename: William E
authors.initials: WE
authors.lastname: Holben
mesh_terms: D015084:2,4-Dichlorophenoxyacetic Acid / Q000378:metabolism*; D008456:2-Methyl-4-chlorophenoxyacetic Acid / Q000378:metabolism*; D001419:Bacteria / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D001426:Bacterial Proteins / Q000235:genetics*; D016000:Cluster Analysis; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D004275:DNA, Ribosomal / Q000737:chemistry / Q000235:genetics; D006540:Herbicides / Q000378:metabolism*; D008969:Molecular Sequence Data; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D017422:Sequence Analysis, DNA
chemical_list: D001426:Bacterial Proteins; D004269:DNA, Bacterial; D004275:DNA, Ribosomal; D006540:Herbicides; D012336:RNA, Ribosomal, 16S; D015084:2,4-Dichlorophenoxyacetic Acid; D008456:2-Methyl-4-chlorophenoxyacetic Acid