1887

Abstract

In , nitrogen fixation is regulated in response to oxygen concentration through the FixL-FixJ two-component system (TCS). Besides this conserved TCS, the field isolate SM11 also encodes the hFixL-FxkR TCS, which is responsible for the microoxic response in . Through genetic and physiological assays, we evaluated the role of the hFixL-FxkR TCS in SM11. Our results revealed that this regulatory system activates the expression of a f orthologue (a), in response to low oxygen concentration. Null mutations in either hFixL or FxkR promote upregulation of 1, a direct target of FixJ. Furthermore, the absence of this TCS translates into higher nitrogen fixation values as well as higher expression of 1 in nodules. Individual mutations in each of the -like regulators encoded in the SM11 genome do not completely restrict 1 or 2 expression, pointing towards redundancy among these regulators. Both copies of are necessary to achieve optimal levels of nitrogen fixation. This work provides evidence that the hFixL-FxkR TCS is activated in response to low oxygen concentration in SM11 and that it negatively regulates the expression of 1, 1 and nitrogen fixation.

Loading

Article metrics loading...

/content/journal/micro/10.1099/mic.0.000284
2016-06-01
2024-03-29
Loading full text...

Full text loading...

/deliver/fulltext/micro/162/6/979.html?itemId=/content/journal/micro/10.1099/mic.0.000284&mimeType=html&fmt=ahah

References

  1. Batut J., Daveran-Mingot M. L., David M., Jacobs J., Garnerone A. M., Kahn D. 1989; fixK, a gene homologous with fnr and crp from E scherichia coli, regulates nitrogen fixation genes both positively and negatively in R hizobium meliloti . EMBO J 8:1279–1286[PubMed]
    [Google Scholar]
  2. Bravo A., Mora J. 1988; Ammonium assimilation in Rhizobium phaseoli by the glutamine synthetase-glutamate synthase pathway. J Bacteriol 170:980–984[PubMed]
    [Google Scholar]
  3. David M., Daveran M. L., Batut J., Dedieu A., Domergue O., Ghai J., Hertig C., Boistard P., Kahn D. 1988; Cascade regulation of nif gene expression in Rhizobium meliloti . Cell 54:671–683 [View Article][PubMed]
    [Google Scholar]
  4. Dixon R., Kahn D. 2004; Genetic regulation of biological nitrogen fixation. Nat Rev Microbiol 2:621–631 [View Article][PubMed]
    [Google Scholar]
  5. Downie J. A. 2005; Legume haemoglobins: symbiotic nitrogen fixation needs bloody nodules. Curr Biol 15:R196–R198 [View Article][PubMed]
    [Google Scholar]
  6. Fahraeus G. 1957; The infection of clover root hairs by nodule bacteria studied by a simple glass slide technique. J Gen Microbiol 16:374–381 [View Article][PubMed]
    [Google Scholar]
  7. Figurski D. H., Helinski D. R. 1979; Replication of an origin -containing derivative of plasmid RK2 dependent on a plasmid function provided in trans. Proc Natl Acad Sci U S A 76:1648–1652 [View Article][PubMed]
    [Google Scholar]
  8. Fischer H. M. 1994; Genetic regulation of nitrogen fixation in rhizobia. Microbiol Rev 58:352–386[PubMed]
    [Google Scholar]
  9. Foussard M., Garnerone A. M., Ni F., Soupène E., Boistard P., Batut J. 1997; Negative autoregulation of the Rhizobium meliloti fixk gene is indirect and requires a newly identified regulator, FixT. Mol Microbiol 25:27–37 [View Article][PubMed]
    [Google Scholar]
  10. Galibert F., Finan T. M., Long S. R., Pühler A., Abola P., Ampe F., Barloy-Hubler F., Barnett M. J., Becker A., other authors. 2001; The composite genome of the legume symbiont Sinorhizobium meliloti . Science 27:668–672 [View Article]
    [Google Scholar]
  11. García-de Los Santos A., Brom S., Romero D. 1996; Rhizobium plasmids in bacteria-legume interactions. World J Microbiol Biotechnol 12:119–125 [View Article][PubMed]
    [Google Scholar]
  12. Garnerone A. M., Cabanes D., Foussard M., Boistard P., Batut J. 1999; Inhibition of the FixL sensor kinase by the FixT protein in Sinorhizobium meliloti . J Biol Chem 5:32500–32506 [CrossRef]
    [Google Scholar]
  13. Girard L., Brom S., Dávalos A., López O., Soberón M., Romero D. 2000; Transcriptional activity of the symbiotic plasmid of Rhizobium etli is affected by different environmental conditions. Microbiology 142:2647–2856 [View Article]
    [Google Scholar]
  14. Girard L., Romero D., Valderrama B., Palacios R., Dávila G. 1996; Differential regulation of fixN-reiterated genes in Rhizobium etli by a novel fixL-fixK cascade. Mol Plant Microbe Interact 13:1283–1292 [View Article]
    [Google Scholar]
  15. Gong W., Hao B., Mansy S. S., Gonzalez G., Gilles-Gonzalez M. A., Chan M. K. 1998; Structure of a biological oxygen sensor: a new mechanism for heme-driven signal transduction. Proc Natl Acad Sci U S A 95:15177–15182 [View Article][PubMed]
    [Google Scholar]
  16. Granados-Baeza M. J., Gómez-Hernández N., Mora Y., Delgado M. J., Romero D., Girard L. 2007; Novel reiterated Fnr-type proteins control the production of the symbiotic terminal oxidase cbb 3 in Rhizobium etli CFN42. Mol Plant Microbe Interact 20:1241–1249 [View Article][PubMed]
    [Google Scholar]
  17. Hardy R. W., Holsten R. D., Jackson E. K., Burns R. C. 1968; The acetylene-ethylene assay for N2 fixation: laboratory and field evaluation. Plant Physiol 43:1185–1207 [View Article][PubMed]
    [Google Scholar]
  18. Hynes M. F., McGregor N. F. 1990; Two plasmids other than the nodulation plasmid are necessary for formation of nitrogen-fixing nodules by Rhizobium leguminosarum . Mol Microbiol 4:567–574 [View Article][PubMed]
    [Google Scholar]
  19. Keen N. T., Tamaki S., Kobayashi D., Trollinger D. 1988; Improved broad-host-range plasmids for DNA cloning in gram -negative bacteria. Gene 70:191–197 [View Article][PubMed]
    [Google Scholar]
  20. Kuhn S., Stiens M., Pühler A., Schlüter A. 2007; Prevalence of pSmeSM11a-like plasmids in indigenous Sinorhizobium meliloti strains isolated in the course of a field release experiment with genetically modified S. meliloti strains. FEMS Microbiol Ecol 63:118–131 [View Article][PubMed]
    [Google Scholar]
  21. Landeta C., Dávalos A., Cevallos M.Á., Geiger O., Brom S., Romero D. 2011; Plasmids with a chromosome-like role in rhizobia. J Bacteriol 193:1317–1326 [View Article][PubMed]
    [Google Scholar]
  22. LaRue T. A., Child J. J. 1979; Sensitive fluorometric assay for leg hemoglobin. Anal Biochem 92:11–15 [View Article][PubMed]
    [Google Scholar]
  23. Lois A. F., Weinstein M., Ditta G. S., Helinski D. R. 1993; Autophosphorylation and phosphatase activities of the oxygen-sensing protein fixl of Rhizobium meliloti are coordinately regulated by oxygen. J Biol Chem 268:4370–4375[PubMed]
    [Google Scholar]
  24. Mandon K., Kaminski P. A., Elmerich C. 1994; Functional analysis of the fixNOQP region of Azorhizobium caulinodans . J Bacteriol 176:2560–2568[PubMed]
    [Google Scholar]
  25. Martinez-Salazar J. M., Romero D. 2000; Role of the ruvB gene in homologous and homeologous recombination in Rhizobium etli . Gene 243:125–131 [View Article][PubMed]
    [Google Scholar]
  26. Mercado-Blanco J., Toro N. 1996; Plasmids in rhizobia: the role of nonsymbiotic plasmids. Mol Plant Microbe Interact 9:535–545 [View Article]
    [Google Scholar]
  27. Mitrophanov A. Y., Groisman E. A. 2008; Signal integration in bacterial two-component regulatory systems. Genes Dev 22:2601–2611 [View Article][PubMed]
    [Google Scholar]
  28. Noel K. D., Sanchez A., Fernandez L., Leemans J., Cevallos M. A. 1984; Rhizobium phaseoli symbiotic mutants with transposon Tn5 insertions. J Bacteriol 158:148–155[PubMed]
    [Google Scholar]
  29. Patschkowski T., Schlüter A., Priefer U. B. 1996; Rhizobium leguminosarum bv. viciae contains a second fnr/fixK-like gene and an unusual fixL homologue. Mol Microbiol 21:267–280[PubMed] [CrossRef]
    [Google Scholar]
  30. Preisig O., Anthamatten D., Hennecke H. 1993; Genes for a microaerobically induced oxidase complex in Bradyrhizobium japonicum are essential for a nitrogen-fixing endosymbiosis. Proc Natl Acad Sci U S A 90:3309–3313[PubMed] [CrossRef]
    [Google Scholar]
  31. Quandt J., Hynes M. F. 1993; Versatile suicide vectors which allow direct selection for gene replacement in gram-negative bacteria. Gene 127:15–21 [View Article][PubMed]
    [Google Scholar]
  32. Reutimann L., Mesa S., Hennecke H. 2010; Autoregulation of fixK(2) gene expression in Bradyrhizobium japonicum . Mol Genet Genomics 284:25–32 [View Article][PubMed]
    [Google Scholar]
  33. Sambrook J., Fritsch E. F., Maniatis T. 1989 Molecular Cloning: A Laboratory Manual, 2nd edn. Cold Spring Harbor, NY: Cold Spring Harbor Laboratory;
    [Google Scholar]
  34. Schlüter, Patschkowski, Quandt J., Selinger L. B., Weidner S., Krämer M., Zhou L., Hynes M. F., Priefer U. B. 1997; Functional and regulatory analysis of the two copies of the fixNOQP operon of Rhizobium leguminosarum strain VF39. Mol Plant Microbe Interact 10:605–616 [View Article][PubMed]
    [Google Scholar]
  35. Schneiker-Bekel S., Wibberg D., Bekel T., Blom J., Linke B., Neuweger H., Stiens M., Vorhölter F. J., Weidner S. et al. 2011; The complete genome sequence of the dominant Sinorhizobium meliloti field isolate SM11 extends the S. meliloti pan-genome. J Biotechnol 155:20–33 [View Article][PubMed]
    [Google Scholar]
  36. Schäfer A., Tauch A., Jäger W., Kalinowski J., Thierbach G., Pühler A. 1994; Small mobilizable multi-purpose cloning vectors derived from the Escherichia coli plasmids pK18 and pK19: selection of defined deletions in the chromosome of Corynebacterium glutamicum . Gene 145:69–73 [View Article][PubMed]
    [Google Scholar]
  37. Selbitschka W., Keller M., Miethling-Graff R., Dresing U., Schwieger F., Krahn I., Homann I., Dammann-Kalinowski T., Pühler A. et al. 2006; Long-term field release of bioluminescent Sinorhizobium meliloti strains to assess the influence of a recA mutation on the strains survival. Microb Ecol 52:583–595 [View Article][PubMed]
    [Google Scholar]
  38. Sousa E. H., Tuckerman J. R., Gondim A. C., Gonzalez G., Gilles-Gonzalez M. A. 2013; Signal transduction and phosphoryl transfer by a FixL hybrid kinase with low oxygen affinity: importance of the vicinal PAS domain and receiver aspartate. Biochemistry 52:456–465 [View Article][PubMed]
    [Google Scholar]
  39. Stiens M., Schneiker S., Keller M., Kuhn S., Pühler A., Schlüter A. 2006; Sequence analysis of the 144-kilobase accessory plasmid pSmeSM11a, isolated from a dominant Sinorhizobium meliloti strain identified during a long-term field release experiment. Appl Environ Microbiol 72:3662–3672 [View Article][PubMed]
    [Google Scholar]
  40. Stiens M., Schneiker S., Pühler A., Schlüter A. 2007; Sequence analysis of the 181-kb accessory plasmid pSmeSM11b, isolated from a dominant Sinorhizobium meliloti strain identified during a long-term field release experiment. FEMS Microbiol Lett 271:297–309 [View Article][PubMed]
    [Google Scholar]
  41. Udvardi M., Poole P. S. 2013; Transport and metabolism in legume-rhizobia symbioses. Annu Rev Plant Biol 64:781–805 [View Article][PubMed]
    [Google Scholar]
  42. Zamorano-Sánchez D., Reyes-González A., Gómez-Hernández N., Rivera P., Georgellis D., Girard L. 2012; FxkR provides the missing link in the fixL-fixK signal transduction cascade in Rhizobium etli CFN42. Mol Plant Microbe Interact 25:1506–1517 [View Article][PubMed]
    [Google Scholar]
http://instance.metastore.ingenta.com/content/journal/micro/10.1099/mic.0.000284
Loading
/content/journal/micro/10.1099/mic.0.000284
Loading

Data & Media loading...

Supplements

Supplementary File 1

PDF
This is a required field
Please enter a valid email address
Approval was a Success
Invalid data
An Error Occurred
Approval was partially successful, following selected items could not be processed due to error