Estimation of atrazine-degrading genetic potential and activity in three French agricultural soils

Abstract

The impact of organic amendment (sewage sludge or waste water) used to fertilize agricultural soils was estimated on the atrazine-degrading activity, the atrazine-degrading genetic potential and the bacterial community structure of soils continuously cropped with corn. Long-term application of organic amendment did not modify atrazine-mineralizing activity, which was found to essentially depend on the soil type. It also did not modify atrazine-degrading genetic potential estimated by quantitative PCR targeting atzA, B and C genes, which was shown to depend on soil type. The structure of soil bacterial community determined by RISA fingerprinting was significantly affected by organic amendment. These results showed that modification of the structure of soil bacterial community in response to organic amendment is not necessarily accompanied by a modification of atrazine-degrading genetic potential or activity. In addition, these results revealed that different soils showing similar atrazine-degrading genetic potentials may exhibit different atrazine-degrading activities.

Dynamics of the Linuron HydrolaselibAGene Pool Size in Response to Linuron Application and Environmental Perturbations in Agricultural Soil and On-Farm Biopurification Systems

“…Indeed, omitting the data from the first 5 days of incubation in the correlation analysis showed an improved negative correlation between lag time and log libA numbers [y ϭ Ϫ3.77 log(x) ϩ 25.90; R 2 ϭ 0.68]. Previously, Tuomi et al (27) also reported a correlation (R 2 ϭ 0.459) between nahAc gene abundance and aerobic [ 14 C]naphthalene mineralization potential, while Martin-Laurent et al (14) found discrepancies between the number of atz genes and the atrazinemineralization lag times.…”

“…These detection limits are superior or comparable to those of other SYBR green-based qPCRs targeting organic pollutant catabolic genes. Martin-Laurent et al (14) reported detection limits of 10 copies l of reaction volume Ϫ1 or 4.0 ϫ 10 3 copies g of soil Ϫ1 for the detection of atzA, atzB, and atzC. Other reported detection limits range from 80 copies g of soil Ϫ1 (1) to 2.0 ϫ 10 2 copies l of reaction mixture Ϫ1 (2).…”

“…The target genes are often involved in the degradation of aromatic hydrocarbons. Assessment of the genes involved in pesticide degradation is limited to triazine and phenoxyacetic acid pesticides (14,15). The present study shows for the first time a qPCR methodology which targets a gene involved in phenylurea pesticide degradation.…”

“…Monitoring genes associated with the catabolism of pollutants has been proposed as a better molecular approach to assess pollutant degradation potential (11). Previously, tfdA and tfdB, involved in 2,4-dichlorophenoxyacetic acid (2,4-D) degradation, and atzA, atzB, and atzC, involved in atrazine catabolism, have been reported as molecular markers to assess, respectively, the 2,4-D (9) and atrazine (14) degradation potential in natural communities. Recently, it has been shown that linuron mineralization in the linuron-mineralizing Variovorax sp.…”

Determination of Denitrification Genes Abundance in Environmental Samples

“…Based on these data, a method was developed and published that has been shown to provide good quantity and quality DNA [65]. In addition to good reproducibility, the method provided results for DNA extraction from diverse environmental samples, including soils from a range of origins and different physical and chemical characteristics [17,59,64,79,85]. Accordingly, this method was proposed in 2006 by the Agence Française pour la Normalisation (AFNOR) to the International Organization for Standardization (ISO).…”