Molecular genetic analysis of the response of three soil microbial communities to the application of 2,4-D.
The responses of three different soil microbial communities to the experimental application of 2,4-dichlorophenoxyacetic acid (2,4-D) were evaluated with a variety of molecular genetic techniques. Two of the three soil communities had histories of prior direct exposure to 2,4-D, and one had no prior direct application of any herbicide. Dominant 2,4-D degrading strains isolated from these soils the previous year were screened for hybridization with three catabolic genes (tfdA, tfdAII, and tfdB) cloned from the well-studied 2,4-D degradative plasmid, pJP4, revealing varying degrees of similarity with the three genes. Hybridization of total community DNA from the three soils with the tfd gene probes also indicated that pJP4-like tfd genes were not harboured by a significant percentage of the community. Community level response was evaluated by the comparison of different treatments by Random Amplified Polymorphic DNA (RAPD) fingerprints and by community DNA cross-hybridization. No differences between treatments within the same soil were detected in any of the RAPD fingerprints generated with 17 primers. Community DNA cross-hybridization also indicated that the application of 2,4-D at the applied rates did not quantitatively affect the structure of the soil microbial communities present in the three soils during the time-frame studied.
Xia
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Department of Crop and Soil Sciences, Washington State University, Pullman 99164-6420.
Bollinger
J
J
Ogram
A
A
D015084:2,4-Dichlorophenoxyacetic Acid / Q000378:metabolism / Q000494:pharmacology*; D001419:Bacteria / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism; D001483:Base Sequence; D001673:Biodegradation, Environmental; D016172:DNA Fingerprinting; D017931:DNA Primers / Q000235:genetics; D004269:DNA, Bacterial / Q000235:genetics; D017753:Ecosystem; D005798:Genes, Bacterial; D008967:Molecular Biology; D008969:Molecular Sequence Data; D009693:Nucleic Acid Hybridization; D010957:Plasmids / Q000235:genetics; D012689:Sequence Homology, Nucleic Acid; D012988:Soil Microbiology
D017931:DNA Primers; D004269:DNA, Bacterial; D015084:2,4-Dichlorophenoxyacetic Acid