title: Flavodoxin overexpression confers tolerance to oxidative stress in beneficial soil bacteria and improves survival in the presence of the herbicides paraquat and atrazine.
abstract: OBJECTIVE
  To determine whether expression of a cyanobacterial flavodoxin in soil bacteria of agronomic interest confers protection against the widely used herbicides paraquat and atrazine.
  
  
  RESULTS
  The model bacterium Escherichia coli, the symbiotic nitrogen-fixing bacterium Ensifer meliloti and the plant growth-promoting rhizobacterium Pseudomonas fluorescens Aur6 were transformed with expression vectors containing the flavodoxin gene of Anabaena variabilis. Expression of the cyanobacterial protein was confirmed by Western blot. Bacterial tolerance to oxidative stress was tested in solid medium supplemented with hydrogen peroxide, paraquat or atrazine. In all three bacterial strains, flavodoxin expression enhanced tolerance to the oxidative stress provoked by hydrogen peroxide and by the reactive oxygen species-inducing herbicides, witnessed by the enhanced survival of the transformed bacteria in the presence of these oxidizing agents.
  
  
  CONCLUSIONS
  Flavodoxin overexpression in beneficial soil bacteria confers tolerance to oxidative stress and improves their survival in the presence of the herbicides paraquat and atrazine. Flavodoxin could be considered as a general antioxidant resource to face oxidative challenges in different micro-organisms.
  
  
  CONCLUSIONS
  The use of plant growth-promoting rhizobacteria or nitrogen-fixing bacteria with enhanced tolerance to oxidative stress in contaminated soils is of significant agronomic interest. The enhanced tolerance of flavodoxin-expressing bacteria to atrazine and paraquat points to potential applications in herbicide-treated soils.
authors.affiliation: Instituto de Ciencias Agrarias, Consejo Superior de Investigaciones Científicas, Madrid, Spain.
authors.forename: T
authors.initials: T
authors.lastname: Coba de la Peña
authors.forename: F J
authors.initials: FJ
authors.lastname: Redondo
authors.forename: M F
authors.initials: MF
authors.lastname: Fillat
authors.forename: M M
authors.initials: MM
authors.lastname: Lucas
authors.forename: J J
authors.initials: JJ
authors.lastname: Pueyo
mesh_terms: D000975:Antioxidants / Q000378:metabolism*; D001280:Atrazine / Q000633:toxicity; D001419:Bacteria / Q000254:growth & development*; D004926:Escherichia coli / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D005418:Flavodoxin / Q000235:genetics / Q000378:metabolism*; D006540:Herbicides / Q000633:toxicity*; D006861:Hydrogen Peroxide / Q000633:toxicity; D050296:Microbial Viability; D018384:Oxidative Stress; D010269:Paraquat / Q000633:toxicity; D012988:Soil Microbiology; D014169:Transformation, Bacterial
chemical_list: D000975:Antioxidants; D005418:Flavodoxin; D006540:Herbicides; D006861:Hydrogen Peroxide; D010269:Paraquat; D001280:Atrazine