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An integrated biochemical system for nitrate assimilation and nitric oxide detoxification in Bradyrhizobium japonicum.
Cabrera, Juan J; Salas, Ana; Torres, María J; Bedmar, Eulogio J; Richardson, David J; Gates, Andrew J; Delgado, María J.
Afiliación
  • Cabrera JJ; Estación Experimental del Zaidín, CSIC, PO Box 419, Granada 18080, Spain.
  • Salas A; Estación Experimental del Zaidín, CSIC, PO Box 419, Granada 18080, Spain.
  • Torres MJ; Estación Experimental del Zaidín, CSIC, PO Box 419, Granada 18080, Spain.
  • Bedmar EJ; Estación Experimental del Zaidín, CSIC, PO Box 419, Granada 18080, Spain.
  • Richardson DJ; Centre for Molecular and Structural Biochemistry, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, U.K. School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, U.K.
  • Gates AJ; Centre for Molecular and Structural Biochemistry, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, U.K. School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, U.K. a.gates@uea.ac.uk mariajesus.delgado@eez.csic.es.
  • Delgado MJ; Estación Experimental del Zaidín, CSIC, PO Box 419, Granada 18080, Spain a.gates@uea.ac.uk mariajesus.delgado@eez.csic.es.
Biochem J ; 473(3): 297-309, 2016 Feb 01.
Article en En | MEDLINE | ID: mdl-26564204
Rhizobia are recognized to establish N2-fixing symbiotic interactions with legume plants. Bradyrhizobium japonicum, the symbiont of soybeans, can denitrify and grow under free-living conditions with nitrate (NO3 (-)) or nitrite (NO2 (-)) as sole nitrogen source. Unlike related bacteria that assimilate NO3 (-), genes encoding the assimilatory NO3 (-) reductase (nasC) and NO2 (-) reductase (nirA) in B. japonicum are located at distinct chromosomal loci. The nasC gene is located with genes encoding an ABC-type NO3 (-) transporter, a major facilitator family NO3 (-)/NO2 (-) transporter (NarK), flavoprotein (Flp) and single-domain haemoglobin (termed Bjgb). However, nirA clusters with genes for a NO3 (-)/NO2 (-)-responsive regulator (NasS-NasT). In the present study, we demonstrate NasC and NirA are both key for NO3 (-) assimilation and that growth with NO3 (-), but not NO2 (-) requires flp, implying Flp may function as electron donor to NasC. In addition, bjgb and flp encode a nitric oxide (NO) detoxification system that functions to mitigate cytotoxic NO formed as a by-product of NO3 (-) assimilation. Additional experiments reveal NasT is required for NO3 (-)-responsive expression of the narK-bjgb-flp-nasC transcriptional unit and the nirA gene and that NasS is also involved in the regulatory control of this novel bipartite assimilatory NO3 (-)/NO2 (-) reductase pathway.
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Texto completo: 1 Banco de datos: MEDLINE Asunto principal: Bradyrhizobium / Nitratos / Óxido Nítrico Idioma: En Revista: Biochem J Año: 2016 Tipo del documento: Article País de afiliación: España

Texto completo: 1 Banco de datos: MEDLINE Asunto principal: Bradyrhizobium / Nitratos / Óxido Nítrico Idioma: En Revista: Biochem J Año: 2016 Tipo del documento: Article País de afiliación: España