Atrazine biodegradation efficiency, metabolite detection, and trzD gene expression by enrichment bacterial cultures from agricultural soil

Abstract

Abstract:Atrazine is a selective herbicide used in agricultural fields to control the emergence of broadleaf and grassy weeds. The persistence of this herbicide is influenced by the metabolic action of habituated native microorganisms. This study provides information on the occurrence of atrazine mineralizing bacterial strains with faster metabolizing ability. The enrichment cultures were tested for the biodegradation of atrazine by high-performance liquid chromatography (HPLC) and mass spectrometry. Nine cultures JS01.Deg01 to JS09.Deg01 were identified as the degrader of atrazine in the enrichment culture. The three isolates JS04.Deg01, JS07.Deg01, and JS08.Deg01 were identified as efficient atrazine metabolizers. Isolates JS04.Deg01 and JS07.Deg01 produced hydroxyatrazine (HA) N-isopropylammelide and cyanuric acid by dealkylation reaction. The isolate JS08.Deg01 generated deethylatrazine (DEA), deisopropylatrazine (DIA), and cyanuric acid by N-dealkylation in the upper degradation pathway and later it incorporated cyanuric acid in their biomass by the lower degradation pathway. The optimum pH for degrading atrazine by JS08.Deg01 was 7.0 and 16S rDNA phylogenetic typing identified it as Enterobacter cloacae strain JS08.Deg01. The highest atrazine mineralization was observed in case of isolate JS08.Deg01, where an ample amount of trzD mRNA was quantified at 72 h of incubation with atrazine. Atrazine bioremediating isolate E. cloacae strain JS08.Deg01 could be the better environmental remediator of agricultural soils and the crop fields contaminated with atrazine could be the source of the efficient biodegrading microbial strains for the environmental cleanup process.

Atrazine nanoencapsulation improves pre‐emergence herbicidal activity against Bidens pilosa without enhancing long‐term residual effect on Glycine max

“…As expected, in the long‐term assay, an overall decrease in atrazine phytotoxicity occurred relative to the short‐term analysis. This result is consistent with the drastic reduction in atrazine levels in the soil over time in all treatments, which may have occurred due to herbicide degradation by microbial and physicochemical processes …”

“…This result is consistent with the drastic reduction in atrazine levels in the soil over time in all treatments, which may have occurred due to herbicide degradation by microbial and physicochemical processes. [46][47][48] Moreover, the comparison between cotyledonary and trifoliate leaves on the residual effects of all atrazine-containing formulations on macroscopic symptoms and physiological parameters indicated a gradual recovery of soybean plants from atrazine phytotoxicity. More importantly, we observed that tenfold-diluted nanoatrazine had a lower inhibitory effect on the photosystem II activity of trifoliate leaves and root dry matter accumulation than nano-and non-nanoatrazine at standard dosage, as well as it resulted in lower atrazine levels in the soil.…”

Ametryn removal by Metarhizium brunneum: Biodegradation pathway proposal and metabolic background revealed

“…Complete mineralization is the most favorable way of biodegradation; however, the vast majority of the xenobiotics biodegradation pathways (including triazines) end in the formation of by-products. Formation of ametryn metabolites during the experiments presented in this work is partially in agreement with the reactions of atrazine biodegradation, where the formation 2-hydroxyatrazine has been observed in many species (Atrazine Pathway Map, 2017; KEGG Atrazine degradation -Reference pathway, 2017; Govantes et al, 2009;Solomon et al, 2013;Abigail et al, 2013), while deethylation of ethanamine substituents seems to be characteristic for fungal strains and mammals (Chirnside et al, 2011;Pereira et al, 2013, Sciali et al, 2014. Figure 6.…”

A novel marine bacterium Isoptericola sp. JS-C42 with the ability to saccharifying the plant biomasses for the aid in cellulosic ethanol production

“…The 16S rRNA gene was amplified by PCR as described by Solomon et al [13] using 16S rRNA gene specific 27F and 1492 universal primers. The amplified product was purified by QIAquick PCR purification kit (Qiagen, USA) according to the manufacturer's instruction, cloned into pGEM-T easy vector (Promega, USA) and confirmed positive clone was sequenced by Applied Biosystems 3730XL DNA analyzer with the sequencing reaction components derived from BigDye Terminator v3.1 cycle sequencing kit (Applied Biosystems, USA).…”