Enhanced detoxification and degradation of herbicide atrazine by a group of O-methyltransferases in rice

Chemosphere. 2016 Dec:165:487-496. doi: 10.1016/j.chemosphere.2016.09.025. Epub 2016 Sep 30.


Atrazine (ATR) as a toxic herbicide has become one of the seriously environmental contaminants worldwide due to its long-term intensive use in crop production. This study identified novel methyltransferases (MTs) involved in detoxification and degradation of ATR residues in rice plants. From a subset of MTs differentially expressed in ATR-exposed rice, forty-four O-methyltransferase genes were investigated. Total activities were significantly enhanced by ATR in rice tissues. To prove detoxifying capacity of the MTs in rice plants, two rice O-MTs (LOC_Os04g09604 and LOC_Os11g15040) were selected and transformed into yeast cells (Pichia pastoris X-33). The positive transformants accumulated less ATR and showed less toxicity. Using UPLC-TOF-MS/MS, ATR-degraded products in rice and yeast cells were characterized. A novel O-methylated-modified metabolite (atraton) and six other ATR-derivatives were detected. The topological interaction between LOC_Os04g09604 enzyme and its substrate was specially analyzed by homology modeling programs, which was well confirmed by the molecular docking analysis. The significance of the study is to provide a better understanding of mechanisms for the specific detoxification and degradation of ATR residues in rice growing in environmentally relevant ATR-contaminated soils and may hold a potential engineering perspective for generating ATR-resistant rice that helps to minimize ATR residues in crops.

Keywords: Atrazine; Methyltransferase; Rice (Oryza sativa); UPLC-LTQ-MS(2).

MeSH terms

  • Atrazine / metabolism*
  • Herbicides / metabolism*
  • Inactivation, Metabolic
  • Methyltransferases / genetics
  • Methyltransferases / metabolism*
  • Molecular Docking Simulation
  • Oryza / enzymology*
  • Oryza / genetics
  • Pichia / genetics
  • Plant Proteins / genetics
  • Plant Proteins / metabolism
  • Soil Pollutants / metabolism*
  • Tandem Mass Spectrometry


  • Herbicides
  • Plant Proteins
  • Soil Pollutants
  • Methyltransferases
  • Atrazine