Title | Modeling of phenoxy acid herbicide mineralization and growth of microbial degraders in 15 soils monitored by quantitative real-time PCR of the functional tfdA gene. |
Publication Type | Journal Article |
Year of Publication | 2012 |
Authors | Bælum J, Prestat E, David MM, Strobel BW, Jacobsen CS |
Journal | Appl Environ Microbiol |
Volume | 78 |
Issue | 15 |
Pagination | 5305-12 |
Date Published | 2012 Aug |
ISSN | 1098-5336 |
Keywords | 2,4-Dichlorophenoxyacetic Acid, 2-Methyl-4-chlorophenoxyacetic Acid, Dioxygenases, DNA Primers, Genes, Bacterial, Herbicides, Kinetics, Minerals, Models, Biological, Real-Time Polymerase Chain Reaction, Soil Microbiology |
Abstract | Mineralization potentials, rates, and kinetics of the three phenoxy acid (PA) herbicides, 2,4-dichlorophenoxyacetic acid (2,4-D), 4-chloro-2-methylphenoxyacetic acid (MCPA), and 2-(4-chloro-2-methylphenoxy)propanoic acid (MCPP), were investigated and compared in 15 soils collected from five continents. The mineralization patterns were fitted by zero/linear or exponential growth forms of the three-half-order models and by logarithmic (log), first-order, or zero-order kinetic models. Prior and subsequent to the mineralization event, tfdA genes were quantified using real-time PCR to estimate the genetic potential for degrading PA in the soils. In 25 of the 45 mineralization scenarios, ∼60% mineralization was observed within 118 days. Elevated concentrations of tfdA in the range 1 × 10(5) to 5 × 10(7) gene copies g(-1) of soil were observed in soils where mineralization could be described by using growth-linked kinetic models. A clear trend was observed that the mineralization rates of the three PAs occurred in the order 2,4-D > MCPA > MCPP, and a correlation was observed between rapid mineralization and soils exposed to PA previously. Finally, for 2,4-D mineralization, all seven mineralization patterns which were best fitted by the exponential model yielded a higher tfdA gene potential after mineralization had occurred than the three mineralization patterns best fitted by the Lin model. |
DOI | 10.1128/AEM.00990-12 |
Alternate Journal | Appl. Environ. Microbiol. |
PubMed ID | 22635998 |
PubMed Central ID | PMC3416398 |