Differential responses of the antioxidant system of ametryn and clomazone tolerant bacteria

• Published in: PloS one 2014-11, Vol.9 (11), p.e112271
• Main Authors: Peters, Leila Priscila, Carvalho, Giselle, Martins, Paula Fabiane, Dourado, Manuella Nóbrega, Vilhena, Milca Bartz, Pileggi, Marcos, Azevedo, Ricardo Antunes
• Format: Article
• Language: English
• Subjects: Agrochemicals; Analysis; Antioxidants; Antioxidants (Nutrients); Antioxidants - metabolism; Bacteria; Biochemistry; Biodegradation; Biology and Life Sciences; Catalase; Catalase - metabolism; Contaminants; Cultivation; Environmental degradation; Enzymes; Gene sequencing; Glutathione; Glutathione - metabolism; Glutathione Peroxidase - metabolism; Glutathione reductase; Glutathione Reductase - metabolism; Glutathione transferase; Glutathione Transferase - metabolism; Herbicides; Herbicides - metabolism; Hydrogen peroxide; Isoxazoles - metabolism; Lipid peroxidation; Lipid Peroxidation - drug effects; Metabolism; Microbial degradation; Microorganisms; Oxazolidinones - metabolism; Oxidative stress; Oxidative Stress - drug effects; Oxygen; Peroxidation; Pesticides; Phylogeny; Pseudomonas - drug effects; Pseudomonas - enzymology; Pseudomonas - genetics; Pseudomonas - metabolism; Pseudomonas aeruginosa; Pseudomonas fulva; Reactive oxygen species; Reactive Oxygen Species - metabolism; RNA; RNA, Ribosomal, 16S - genetics; rRNA 16S; Sediment pollution; Soil bacteria; Soil contamination; Soil degradation; Soil Microbiology; Soil Pollutants - metabolism; Soil pollution; Soil water; Strains (organisms); Sugarcane; Superoxide dismutase; Superoxide Dismutase - metabolism; Superoxides; Triazines - metabolism; Water pollution; Weeds
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0112271

The herbicides ametryn and clomazone are widely used in sugarcane cultivation, and following microbial degradation are considered as soil and water contaminants. The exposure of microorganisms to pesticides can result in oxidative damage due to an increase in the production of reactive oxygen species (ROS). This study investigated the response of the antioxidant systems of two bacterial strains tolerant to the herbicides ametryn and clomazone. Bacteria were isolated from soil with a long history of ametryn and clomazone application. Comparative analyses based on 16S rRNA gene sequences revealed that strain CC07 is phylogenetically related to Pseudomonas aeruginosa and strain 4C07 to P. fulva. The two bacterial strains were grown for 14 h in the presence of separate and combined herbicides. Lipid peroxidation, reduced glutathione content (GSH) and antioxidant enzymes activities were evaluated. The overall results indicated that strain 4C07 formed an efficient mechanism to maintain the cellular redox balance by producing reactive oxygen species (ROS) and subsequently scavenging ROS in the presence of the herbicides. The growth of bacterium strain 4C07 was inhibited in the presence of clomazone alone, or in combination with ametryn, but increased glutathione reductase (GR) and glutathione S-transferase (GST) activities, and a higher GSH concentration were detected. Meanwhile, reduced superoxide dismutase (SOD), catalase (CAT) and GST activities and a lower concentration of GSH were detected in the bacterium strain CC07, which was able to achieve better growth in the presence of the herbicides. The results suggest that the two bacterial strains tolerate the ametryn and clomazone herbicides with distinctly different responses of the antioxidant systems.