The Atrazine Catabolism GenesatzABCAre Widespread and Highly Conserved

Abstract

Pseudomonas strain ADP metabolizes the herbicide atrazine via three enzymatic steps, encoded by the genesatzABC, to yield cyanuric acid, a nitrogen source for many bacteria. Here, we show that five geographically distinct atrazine-degrading bacteria contain genes homologous toatzA, -B, and -C. The sequence identities of the atz genes from different atrazine-degrading bacteria were greater than 99% in all pairwise comparisons. This differs from bacterial genes involved in the catabolism of other chlorinated compounds, for which the average sequence identity in pairwise comparisons of the known members of a class ranged from 25 to 56%. Our results indicate that globally distributed atrazine-catabolic genes are highly conserved in diverse genera of bacteria.

Targeted metagenomics demonstrates the ecological role of IS1071in bacterial community adaptation to pesticide degradation

“…A more in-depth analysis of the predicted protein sequences was done by examining the presence of Hidden Markov Models (HMM) using hmmscan and protein similarities using BLASTp against the UnitProtKB/Swiss-Prot database and non-redundant protein database (Tables 2 and 3 and the Supplementary Annotation File). Proteins were recognized as such on 215, 50 and could be directly (with more than 99% aa identity) linked with known enzymes involved in pesticide degradation like HylA (contig 290 in BPS Kortrijk and contig 22 in L SM A) catalysing linuron hydrolysis (Bers et al, 2013a) and AtzA (contig 260 in BPS Kortrijk) catalysing atrazine chlorine hydrolysis (de Souza et al, 1998). Others showed moderate similarity to known pesticide biodegradation enzymes like TfdA/RdpA (contigs 132,205,265,298 and 302 in BPS Kortijk) and TfdB (contig 231 in BPS Kortrijk) involved in phenoxy herbicide biodegradation (Fukumori and Hausinger, 1993;Ledger et al, 2006;Müller et al, 2006).…”

Glutathione transferases in bacteria

“…For instance, in Pseudomonas ADP, atrazine is metabolized to cyanuric acid by three enzymatic steps. The first step is performed by atrazine chlorohydrolase followed by two dealkylations [104].…”

Isolation and characterisation of new Gram-negative and Gram-positive atrazine degrading bacteria from different French soils

“…For all pure strains, we attempted to amplify the genes atzA, atzB, atzC with primers described by de Souza et al [29]. From the gene sequence (accession number AF086815) described by Karns [32], we designed primers for the ampli¢cation of the trzD gene: the forward primer was trzD F1 (5P-CCTCGCGTTCAAGGTCTACT-3P), position 919^938 on the sequence, and the reverse primer was trzD R1 (5P-TCGAAGCGATAACTGCATTG-3P), position 1753^1772 on the sequence.…”

“…Among the 20 strains of C. heintzii, 16 mineralised 14 C ring labelled atrazine to carbon dioxide at 60^90% of the initially applied atrazine over an incubation period of 15 days. For all these 16 C. heintzii strains, the atzA, atzB and atzC genes were ampli¢ed using primers described by de Souza et al [29]. The expected 0.5-kb atzA or atzB PCR products and the expected 0.6-kb atzC PCR product were obtained.…”

“…The atrazine catabolic genes atzABC have been characterised from Pseudomonas sp. strain ADP [25^28]: the genes atzA, -B, -C which encode three hydrolases transforming atrazine into cyanuric acid are highly conserved [23,29] and are located on a large plasmid, pADP1 [30], which is self transmissible to Gram-negative bacteria and widespread. However, Topp et al [31] have isolated a Nocardioides sp.…”