Phosphate solubilization activity of rhizobia native to Iranian soils

  • H. A. Alikhani
  • N. Saleh-Rastin
  • H. Antoun
Conference paper
Part of the Developments in Plant and Soil Sciences book series (DPSS, volume 102)


Agricultural soils in Iran are predominantly calcareous with very low plant available phosphorus (P) content. In addition to their beneficial N2-fixing activity with legumes, rhizobia can improve plant P nutrition by mobilizing inorganic and organic P. Isolates from different cross-inoculation groups of rhizobia, obtained from Iranian soils were tested for their ability to dissolve inorganic and organic phosphate. From a total of 446 rhizobial isolates tested for P solubilization by the formation of visible dissolution halos on agar plates, 198 (44%) and 341(76%) of the isolates, solubilized Ca3(PO4)2 (TCP) and inositol hexaphosphate (IHP), respectively. In the liquid Sperber TCP medium, phosphate-solubilizing bacteria (Bacillus sp. and Pseudomonas fluorescens) used as positive controls released an average of 268.6 mg L−1 of P after 360 h incubation. This amount was significantly (P < 0.05) higher than those observed with all rhizobia tested. The group of Rhizobium leguminosarum bv. viciae mobilized in liquid TCP Sperber medium significantly (P < 0.05) more P (197.1 mg L−1 in 360 h) than other rhizobia tested,. This group also showed the highest dissolution halo on the TCP solid Sperber medium. The release of soluble P was significantly correlated with a drop in the pH of the culture filtrates indicating the importance of acid production in the mobilization process. None of the 70 bradyrhizobial isolates tested was able to solubilize TCP. These results indicate that many rhizobia isolated from soils in Iran are able to mobilize P from organic and inorganic sources and this beneficial effect should be tested with crops grown in Iran.

Key words

calcium phosphate legumes inositol hexaphosphate PGPR pH Rhizobium 


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. Abd-Alla M H 1994 Use of organic phosphorus by Rhizobium leguminosarum bv. viciae phosphatases. Biol. Fertil. Soils 8, 216–218.CrossRefGoogle Scholar
  2. Antoun H A, Beauchamp C J, Goussard N, Chabot R and Lalande R 1998 Potential of Rhizobium and Bradyrhizobium species as plant growth promoting rhizobacteria on non-legumes: effect on radishes (Raphanus sativus L.). Plant Soil 204, 57–67.CrossRefGoogle Scholar
  3. Barea J M, Azcón R and Azcón-Aguilar C 2002 Mycorhizo-sphere interactions to improve plant fitness and soil quality. Antonie van Leeuwenhoek 81, 343–351.PubMedCrossRefGoogle Scholar
  4. Chabot R, Antoun H, Kloepper J W and Beauchamp C J 1996 Root colonization of maize and lettuce by bioluminescent Rhizobium leguminosarum biovar phaseoli. Appl. Environ. Microbiol. 62, 2767–2772.PubMedGoogle Scholar
  5. Goldstein A H 1986 Bacterial solubilization of mineral phosphates: historical perspectives and future prospects. Am. J. Altern. Agric. 1, 51–57.Google Scholar
  6. Gupta R, Singal R, Shankar A, Kuhad R C and Saxena R K 1994 A modified plate assay for screening phosphate solubilizing microorganisms. J. Gen. Appl. Microbiol. 40, 255–260.Google Scholar
  7. Halder A K and Chakrabartty P K 1993 Solubilization of inorganic phosphate by Rhizobium. Folia Microbiol. 38, 325–330.Google Scholar
  8. Mehata S and Nautiyal C S 2001 An efficient method for qualitative screening of phosphate-solubilizing bacteria. Curr. Microbiol. 43, 51–56.CrossRefGoogle Scholar
  9. Nahas E 1996 Factors determining rock phosphate solubilization by microorganisms isolated from soil. World J. Microbiol. Biotechnol. 12, 567–572.CrossRefGoogle Scholar
  10. Nautiyal C S 1999 An efficient microbiological growth medium for screening phosphate solubilizing microorganisms. FEMS Microbiol. Lett. 170, 265–270.PubMedCrossRefGoogle Scholar
  11. Olsen S R and Sommers L E 1982 Phosphorus. In Methods of Soil Analysis, Part 2-chemical and Microbiological Properties, 2nd edn., Ed. Page AL. Am Soc. Agron. and Soil Sci. Soc. A. Madison, Wisconsin, USA.Google Scholar
  12. Peix A, Rivas-Boyero A A, Mateos P F, Rodriguez-Barrueco C, Martinez-Molina E and Velazquez E 2001 Growth promotion of chickpea and barley by a phosphate solubilizing strain of Mesorhizobium mediterraneum under growth chamber conditions. Soil Biol. Biochem. 33, 103–110.CrossRefGoogle Scholar
  13. Richardson A E 2001 Prospects for using soil microorganisms to improve the acquisition of phosphorus by plants. Aust. J. Plant Physiol. 28, 897–906.Google Scholar
  14. Robson A D, O’Hara G W and Abbott L K 1981 Involvement of phosphorus in nitrogen fixation by subterranean clover (Trifolium subterraneum L.). Aust. J. Plant Physiol. 8, 427–436.CrossRefGoogle Scholar
  15. Rodriguez H and Fraga R 1999 Phosphate solubilizing bacteria and their role in plant growth promotion. Biotech. Adv. 17, 319–339.CrossRefGoogle Scholar
  16. SAS, Institute Inc 1990 SAS procedure guide version 6 edn. SAS Institute Inc Cary, NC, 705 p.Google Scholar
  17. Schloter M, Wiehe W, Assmus B, Steindl H, Beke H, Höflich G and Hartmann A 1997 Root colonization of different plants by plant-growth-promoting Rhizobium leguminosarum bv. trifolii R39 studied with monosporic polyclonal antisera. Appl. Environ. Microbiol. 63, 2038–2046.PubMedGoogle Scholar
  18. Silva Filho G N and Vidor C 2000 Phosphate solubilization by microorganisms in the presence of different carbon sources. R. Bras. Ci. Solo. 24, 311–319.Google Scholar
  19. Sperber J I 1958 The incidence of apatite solubilizing organisms in the rhizosphere and soil. Aust. J. Agric. Res. 9, 778–781.CrossRefGoogle Scholar
  20. Somasegaran P and Hoben H J 1994 Handbook for Rhizobia — Methods in Legume-Rhizobium Technology. Springer-Verlag, New York.Google Scholar
  21. Vincent J M 1970 A Manual for the Practical Study of Root Nodule Bacteria. IBP handbook 15 Blackwell Scientific Publications, Oxford.Google Scholar
  22. Whitelaw M A 2000 Growth promotion of plants inoculated with phosphate-solubilizing fungi. Adv. Agron. 69, 99–151.CrossRefGoogle Scholar
  23. Yanni Y G, Rizk R Y, Abd El-Fattah F K, Squartini A, Corich V, Giacomini A, de Bruin F, Rademaker J, Mayra-Flores J, Ostrom P, Vega-Hernandez M, Hollingsworth R I, Martinez-Molina E, Mateos P, Velazquez E, Wopereis J, Triplett E, Umali-Garcia M, Anarna J A, Rolfe B G, Ladha J K, Hill J, Mujoo R, Ng P K and Dazzo F B 2001 The beneficial plant growth-promoting association of Rhizobium leguminosarum bv. trifolii with rice roots. Aust. J. Plant Physiol. 28, 845–870.Google Scholar

Copyright information

© Springer 2007

Authors and Affiliations

  • H. A. Alikhani
    • 1
  • N. Saleh-Rastin
    • 1
  • H. Antoun
    • 2
  1. 1.Department of Soil Science, College of AgricultureTehran UniversityTehranIran
  2. 2.Département des Sols et de Génie AgroalimentaireUniversité LavalQuébecCanada

Personalised recommendations