Journal of Biosciences

, Volume 20, Issue 1, pp 17–28 | Cite as

Pleiotropic effects of purine auxotrophy inRhizobium meliloti on cell surface molecules

  • S. K. Swamynathan
  • Aqbal Singh


Rhizobial purine auxotrophs have earlier been shown to be defective in symbiosis, though the exact reason for this failure is not clear. Using various dyes that specifically bind different cell surface molecules, we show that there are multiple changes in the cell surface molecules associated with different purine auxotrophs. Affected molecules in different purine auxotrophs that were tested include (i) acidic exopolysaccharides, (ii) cellulose fibrils, and (iii) beta (1–3) glucans. Our results show that the symbiotic deficiency of purine auxotrophs is likely to be a result of these associated changes on the cell surface


Rhizobium meliloti Medicago saliva purine biosynthesis exopolysaccharides symbiosis 


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  1. Batut J, Terzaghi B, Gherardi M, Haguet M, Terzaghi E, Garnerone A M, Boistard P and Haguet T 1985 Localization of a symbiotic fix region onRhizobium meliloti pSym megaplasmid more than 200 kilo bases fromnod-nif region;Mol. Gen. Genet. 199 232–239CrossRefGoogle Scholar
  2. Boyer H S and Roulland-Dussoix D 1969 A complementation analysis of the restriction and modification of DNA inEscherichia coli;J. Mol. Biol. 41 459–472CrossRefGoogle Scholar
  3. Brewin NJ 1991 Development of the legume root nodule;Anna. Rev. Cell Biol. 7 191–226CrossRefGoogle Scholar
  4. Doherty D, Leigh J A, Glazebrook J and Walker G C 1988Rhizobium meliloti mutants that over produce theR. meliloti acidic calcafluor binding exopolysaccharide;J. Bacteriol. 170 4249–4256CrossRefGoogle Scholar
  5. Dudman W F 1984 The polysaccharides and oligosaccharides ofRhizobium and their role in infection process; inAdvance in nitrogen fixation research (eds) C Veeger and W E Newton (The Hague: Martinus Nijhoff Publishers) pp 397–404CrossRefGoogle Scholar
  6. Finan T M. Hirsch A M, Leigh J A, Johnson E, Kuldan G A, Deegan S, Walker G C and Signer E R 1985 Symbiotic mutants ofRhizobium meliloti that uncouple plant from bacterial differentiation;Cell 40 869–877CrossRefGoogle Scholar
  7. Finan T N. Kunkel B, Devos G F and Signer E R 1956 Second symbiotic megaplasmid inRhizobium meliloti carrying exopolysaccharide and thiamine synthesis genes;J. Bacteriol. 167 66–72CrossRefGoogle Scholar
  8. Geremia R A, Cavaignae S. Zorreguieta A, Toro N, Olivares J and Ugalde R A 1987 A.Rhizobium meliloti mutant that forms ineffective pseudonodules in alfalfa produces exopolysaccharides but fails to form beta (1–2) glucan;J. Bacteriol 169 880–884CrossRefGoogle Scholar
  9. Glazebrook J and Walker G C 1989 A novel exopolysaccharide can function in place of the calcafluor binding exopolysaccharide in nodulation of alfalfa byRhizobium meliloti;Cell 56 661 -672CrossRefGoogle Scholar
  10. Gray J X and Rolfe B G 1990 Exopolysaccharide production inRhizobium and its role in invasion;Mol. Microbiol. 4 1425–1431CrossRefGoogle Scholar
  11. Khanuja S P S and Kumar S 1985 Isolation of phages forRhizobium meliloti AK631;Indian J. Exp. Biol. 26 665–667Google Scholar
  12. Khanuja S P S and Kumar S 1989 Symbiotic and galactose utilization properties of phage RMP64 resistant mutants affecting three complementation groups inRhizobium meliloti;J. Genet 68 93–108CrossRefGoogle Scholar
  13. Leigh J A, Signer E R and Walker G C 1985 Exopolysaccharide deficient mutants ofRhizobium meliloti that form ineffective nodules;Proc. Natl Acad. Sci. USA 82 6231–6235CrossRefGoogle Scholar
  14. Long S, Reed J W. Himawan J and Walker G C 1988 Genetic analysis of a cluster of genes required for synthesis of the calcafluor binding exopolysaccharide ofRhizobium melitotic;J Bacteriol. 170 4239–4248CrossRefGoogle Scholar
  15. Long S R 1989Rhizobium-legume nodulation; life together in the underground;Cell 56 203–214CrossRefGoogle Scholar
  16. Moffatt B and Somerville C 1988 Positive selection for male sterile mutants ofArabidapsis thaliana lacking adenine phosphoribosyl transferase activity;Plant Physiol. 86 1150–1154CrossRefGoogle Scholar
  17. Nakanishi I. Kimura K, Suzuki T. Ishikavwa M. Banno I, Sakane T and Harada T 1976 Demonstration of curdlan type polysaecharides und some other beta (1–3) glucan in microorganisms with aniline blue,J. Gen. Appl. Microbiol. 22 1–11CrossRefGoogle Scholar
  18. Noel K D, Diebold R J, Cava J R and Brink B A 1988 Rhizobial purine and pyrimidine auxotrophs; nutrient supplementation, genetic analysis and the symbiotic requirement forde novo purine biosynthesis;Arch, Microbiol. 149 499–566CrossRefGoogle Scholar
  19. Reuber T L, Urzainqui A, Glazebrook J. Reed J W and Walker G C 1991Rhizobium meliloti exopolysaccharides. Structures, genetic analysis and symbiotic roles;Ann. N.Y. Acad, Sci 646 61–68CrossRefGoogle Scholar
  20. Speiser D M, Oritz D F. Kreppel L, Scheel G. McDonald G and Ow D W 1992 Purine biosynthetic genes are required for cadmium tolerance inSchizosaccharomyces pombe;Mol. Cell. Biol. 12 5301–5310CrossRefGoogle Scholar
  21. Swamynathan S K 1990Isolation and characterization of mutants of the purine biosynthetic pathway in Rhizobium meliloti, M.Sc. thesis, Indian Agricultural Research Institute, New DelhiGoogle Scholar
  22. Swamynathan S K and Singh A 1992Rhizobium melioti purine auxotrophs arenod + but defective in nitrogen fixation;J. Genet. 75 11–21CrossRefGoogle Scholar

Copyright information

© Indian Academy of Sciences 1995

Authors and Affiliations

  • S. K. Swamynathan
    • 1
  • Aqbal Singh
    • 1
  1. 1.Biotechnology CentreIndian Agricultural Research InstituteNew DelhiIndia

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