Chinese Science Bulletin

, Volume 53, Issue 2, pp 215–226 | Cite as

Systematic insertion mutagenesis of GntR family transcriptional regulator genes in Sinorhizobium meliloti

  • Yu AiYuan 
  • Chen AiMin 
  • Wang Yi 
  • Luo Li 
  • Zhu JiaBi 
  • Yu GuanQiao 
  • Wang YanZhang Email author
Articles Molecular Genetics


GntR-type transcriptional regulators regulate the most diverse biological processes in bacteria. Although GntR-type transcriptional regulators consist of the second largest family of transcriptional regulators in Sinorhizobium meliloti, little is known about their functions. In this study, we investigated 54 putative genes encoding GntR family of transcriptional regulators in S. meliloti Rm1021. Secondary structure analysis of the C-terminal domain of these putative transcriptional regulators indicated that thirty-seven were members of the FadR subfamily, ten of the HutC subfamily and five of the MocR subfamily. The remaining two did not fall into any specific subfamily category, and may form two new subfamilies. The 54 gntR genes were mutagenized by plasmid insertion mutagenesis to investigate their roles. We found that, of the 54 mutants, only the gtrA1 and gtrB1 mutants had slower growth rates and cell maximal yields on both rich medium and minimal medium, and lower cell motility on swarming plate than wild type Rm1021. All mutants, with the exception of gtrA1 and gtrB1, can establish effective symbioses with alfalfa. Plants inoculated with gtrA1 and gtrB1 mutants grew shorter than those inoculated with wild type, and formed relatively smaller, round and light pink nodules, which were mainly located on lateral roots. And there was an abnormal increase in the number of nodules induced by both mutants. These results suggested that the gtrA1 and gtrB1 mutants were symbiotically deficient. Our work presents a global overview of GntR-like transcriptional regulators involved in symbiosis in S. meliloti, and provides new insight into the functions of GntR-like transcriptional regulators.


Sinorhizobium meliloti GntR-like transcriptional regulator nodulation plasmid insertion mutagenesis 


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. 1.
    Galibert F, Finan T M, Long S R, et al. The composite genome of the legume symbiont Sinorhizobium meliloti. Science, 2001, 293: 668–672PubMedCrossRefGoogle Scholar
  2. 2.
    Honma M A, Ausubel F M. Rhizobium meliloti has three functional copies of the nodD symbiotic regulatory gene. Proc Natl Acad Sci USA, 1987, 84: 8558–8562PubMedCrossRefGoogle Scholar
  3. 3.
    Mulligan J T, Long S R. A family of activator genes regulates expression of Rhizobium meliloti nodulation genes. Genetics, 1989, 122: 7–18PubMedGoogle Scholar
  4. 4.
    Swanson J A, Mulligan J T, Long S R. Regulation of syrM and nodD3 in Rhizobium meliloti. Genetics, 1993, 134: 435–444PubMedGoogle Scholar
  5. 5.
    Kondorosi E, Pierre M, Cren M, et al. Identification of NolR, a negative transacting factor controlling the nod regulon in Rhizobium meliloti. J Mol Biol, 1991, 222: 885–896PubMedCrossRefGoogle Scholar
  6. 6.
    Luo L, Yao SY, Becker A, et al. Two new Sinorhizobium meliloti LysR-Type transcriptional regulators required for nodulation. J Bacteriol, 2005, 187: 4562–4572PubMedCrossRefGoogle Scholar
  7. 7.
    Rigali S, Derouaux A, Giannotta F, et al. Subdivision of the helix-turn-helix GntR family of bacterial regulators in the FadR, HutC, MocR, and YtrA subfamilies. J Biol Chem, 2001, 277: 12507–12515PubMedCrossRefGoogle Scholar
  8. 8.
    Haydon D J, Guest J R. A new family of bacterial regulatory proteins. FEMS Microbiol Lett, 1991, 79: 291–296CrossRefGoogle Scholar
  9. 9.
    Lee M H, Scherer M, Rigali S, et al. PlmA, a new member of the GntR family, has plasmid maintenance functions in Anabaena sp. strain PCC 7120. J Bacteriol, 2003, 85: 4315–4325CrossRefGoogle Scholar
  10. 10.
    Fujita Y, Fujita T. The gluconate operon gnt of Bacillus subtilis encodes its own transcriptional negative regulator. Proc Natl Acad Sci USA, 1987, 84: 4524–4528PubMedCrossRefGoogle Scholar
  11. 11.
    Yoshida K I, Fujita Y, Ehrlich S D. An operon for a putative ATP-binding cassette transport system involved in acetoin utilization of Bacillus subtilis. J Bacteriol, 2000, 182: 5454–5461PubMedCrossRefGoogle Scholar
  12. 12.
    Sa-Nogueira I, Mota L J. Negative regulation of L-arabinose metabolism in Bacillus subtilis: Characterization of the araR (araC) gene. J Bacteriol, 1997, 179: 1598–1608PubMedGoogle Scholar
  13. 13.
    Seo J W, Ohnishi Y, Hirata A, et al. ATP-binding cassette transport system involved in regulation of morphological differentiation in response to glucose in Streptomyces griseus. J Bacteriol, 2002, 184: 91–103PubMedCrossRefGoogle Scholar
  14. 14.
    Hillerich B, Westpheling J. A new GntR family transcriptional regulator in Streptomyces coelicolor is required for morphogenesis and antibiotic production and controls transcription of an ABC transporter in response to carbon source. J Bacteriol, 2006, 188: 7477–7487PubMedCrossRefGoogle Scholar
  15. 15.
    Hoskisson P A, Rigali S, Fowler K, et al. DevA, a GntR-like transcriptional regulator required for development in Streptomyces coelicolor. J Bacteriol, 2006, 188: 5014–5023PubMedCrossRefGoogle Scholar
  16. 16.
    Casali N, White A M, Riley L W. Regulation of the Mycobacterium tuberculosis mce1 operon. J Bacteriol, 2006, 188: 441–449PubMedCrossRefGoogle Scholar
  17. 17.
    Haine V, Sinon A, Van Steen F, et al. Systematic targeted mutagenesis of Brucella melitensis 16M reveals a major role for GntR regulators in the control of virulence. Infect Immun, 2005, 73: 5578–5586PubMedCrossRefGoogle Scholar
  18. 18.
    Finan T M, Hartweig E, LeMieux K, et al. General transduction in Rhizobium meliloti. J Bacteriol, 1984, 159: 120–124PubMedGoogle Scholar
  19. 19.
    Leigh J A, Signer E R, Walker G C. Exopolysaccharide deficient mutants of Rhizobium meliloti that form ineffective nodules. Pro Natl Acad Sci USA, 1985, 82: 6231–6235CrossRefGoogle Scholar
  20. 20.
    Sambrook J, Fritsch E F, Maniatis T. Molecular cloning: A laboratory manual. 2nd ed. New York: Cold Spring Harbor Laboratory Press, 1989Google Scholar
  21. 21.
    Vincent J M. A manual for the practical study of root-nodule bacteria. IBP Handbook No. 75. Oxford: Blackwells, 1970Google Scholar
  22. 22.
    Stanier R Y, Ingraham J L, Wheelis M L, et al. The Microbial World. 5th ed. Englewood Cliffs: Prentice-Hall, 1986Google Scholar
  23. 23.
    Ames O, Schluederberg S A, Bergman K. Behavioural mutants of Rhizobium meliloti. J Bacteriol, 1980, 141: 722–727PubMedGoogle Scholar
  24. 24.
    Fraysse N, Couderc F, Poinsot V. Surface polysaccharide involvement in establishing the rhizobium-legume symbiosis. Eur J Biochem, 2003, 270: 1365–1380PubMedCrossRefGoogle Scholar
  25. 25.
    Leigh J A, Reed J W, Hanks J F, et al. Rhizobium meliloti mutants that fail to succinylatetheir calcofluor-binding exopolysaccharide are defective in nodule invasion. Cell, 1987, 51: 579–587PubMedCrossRefGoogle Scholar
  26. 26.
    Vasse J, de Billy F, Camut S, et al. Correlation between ultrastructural differentiation of bacteroids and nitrogen fixation in alfalfa nodules. J Bacteriol, 1990, 172: 4295–4306PubMedGoogle Scholar
  27. 27.
    Chun Y L, Stacey G. A Bradyrhizobium japonicum gene essential for nodulation competitiveness is differentially regulated from two promoters. Mol Plant Microbe Interact, 1994, 7: 248–255PubMedGoogle Scholar
  28. 28.
    Sanjuan J, Olivares J. Implication of nifA in regulation of genes located on a Rhizobium meliloti cryptic plasmid that affect nodulation efficiency. J Bacteriol, 1987, 171: 4154–4161Google Scholar
  29. 29.
    Bittinger M A, Milner J L, Saville B J, et al. RosR, a determinant of nodulation competitiveness in Rhizobium etli. Mol Plant-Microbe Interact, 1997, 10: 180–186PubMedCrossRefGoogle Scholar
  30. 30.
    Barsomian G D, Urzainqui A, Lohman K, et al. Rhizobium meliloti mutants unable to synthesize anthranilate display a novel symbiotic phenotype. J Bacteriol, 1992, 174: 4416–4426PubMedGoogle Scholar
  31. 31.
    Fry J, Wood M, Poole P S. Investigation of myo-inositol catabolism in Rhizobium leguminosarum bv. viciae and its effect on nodulation competitiveness. Mol Plant-Microbe Interact, 2001, 14: 1016–1025PubMedCrossRefGoogle Scholar
  32. 32.
    Glenn A R, Arwas R, McKay I A, et al. Fructose metabolism in wild type, fructokinase-negative and revertant strains of Rhizobium leguminosarum. J Gen Microbiol, 1984, 130: 231–237Google Scholar
  33. 33.
    Lambert A, Østerås M, Mandon K, et al. Fructose uptake in Sinorhizobium meliloti is mediated by a high-affinity ATP-binding cassette transport system. J Bacteriol, 2001, 183: 4709–4717PubMedCrossRefGoogle Scholar
  34. 34.
    Davidson A L, Chen J. ATP-binding cassette transporters in bacteria. Annu Rev Biochem, 2004, 73: 241–268PubMedCrossRefGoogle Scholar
  35. 35.
    Kelly D J, Thomas G H. The tripartite ATP-independent periplasmic (TRAP) transporters of bacteria and archaea. FEMS Microbiol Rev, 2001, 25: 405–424PubMedCrossRefGoogle Scholar
  36. 36.
    Mauchline T H, Fowler J E, East A K, et al. Mapping the Sinorhizobium meliloti 1021 solute-binding protein-dependent transportome. Proc Natl Acad Sci USA, 2006, 103: 17933–17938PubMedCrossRefGoogle Scholar
  37. 37.
    Jensen J B, Peters N K, Bhuvaneswari T V. Redundancy in periplasmic binding protein-dependent transport systems for trehalose, sucrose, and maltose in Sinorhizobium meliloti. J Bacteriol, 2002, 184: 2978–2986PubMedCrossRefGoogle Scholar

Copyright information

© Science in China Press 2008

Authors and Affiliations

  • Yu AiYuan 
    • 1
  • Chen AiMin 
    • 1
  • Wang Yi 
    • 1
  • Luo Li 
    • 2
  • Zhu JiaBi 
    • 1
  • Yu GuanQiao 
    • 1
  • Wang YanZhang 
    • 1
    Email author
  1. 1.National Key Laboratory of Plant Molecular Genetics, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological SciencesChinese Academy of SciencesShanghaiChina
  2. 2.Biological Sciences Department, Lehman CollegeThe City University of New YorkNew YorkUSA

Personalised recommendations