Root Colonization and Quorum Sensing of the Antagonistic Bacterium Pseudomonas fluorescens 2112 involved in the Red-pepper Rhizosphere

생물방제균 Pseudomonas fluorescens 2112의 고추 근권정착능과 Quorum-sensing 기능

  • Jung, Byung-Kwon (Department of Applied Microbiology and Biotechnology, School of Biotechnology, Yeungnam University) ;
  • Kim, Yo-Hwan (Department of Applied Microbiology and Biotechnology, School of Biotechnology, Yeungnam University) ;
  • Kim, Sang-Dal (Department of Applied Microbiology and Biotechnology, School of Biotechnology, Yeungnam University)
  • 정병권 (영남대학교 미생물생명공학과) ;
  • 김요환 (영남대학교 미생물생명공학과) ;
  • 김상달 (영남대학교 미생물생명공학과)
  • Received : 2012.10.17
  • Accepted : 2012.11.15
  • Published : 2013.03.28


Biofilm formation of multifunctional plant growth promoting rhizobacterium (PGPR), Pseudomonas fluorescens 2112 is necessary for P. fluorescens 2112 to have a positive impact on the rhizosphere of red-pepper. This study investigated whether signal molecules of the quorum sensing AHLs are produced in order to confirm biofilm formative ability. Through the use of Petri dish bioassays a blue circle formed evidence of AHLs. It was confirmed that P. fluorescens 2112 produced six-carbon-chain-long AHLs by TLC bioassay. The bacterial density of P. fluorescens 2112 on the top and bottom of pepper plant roots was estimated as $3{\times}10^5$ and $8{\times}10^3$ CFU/g root, respectively. P. fluorescens 2112 exist more with high-density of $3.5{\times}10^6$ CFU/g soil at a depth of 1 cm but at a low-density of $1.1{\times}10$ CFU/g soil at a depth of 5 cm, from the surface of rhizosphere soil. In addition, biofilm formation of P. fluorescens 2112 on the epidermises and the tips of the red-pepper roots were confirmed visually by SEM. Thus, the production of AHLs by P. fluorescens 2112 brings about quorum sensing signaling and the formation of biofilm on the roots which has a positive effect on economically important crops such as red-pepper by additionally producing a variety of antifungal substances and auxin.


Quorum sensing;biofilm;PGPR;biological control;P. fluorescens 2112


  1. Ahmand, J. S. and R. Baker. 1987. Rhizosphere competence of Trichoderma harizianum. Phytopathol. 77: 182-189.
  2. Brelles-Marino, G. and E. J. Bedmar. 2001. Detection, purification and characterization of quorum-sensing signal molecules in plant-associated bacteria. J. Biotechnol. 91: 197-209.
  3. Costerton, J. W., P. S. Stewart, and E. P. Greenberg. 1999. Bacterial biofilms: a common cause of persistent infections. Science 284: 318-322.
  4. Egamberdiyeva D. 2007. The effect of plant growth promoting bacteria on growth and nutrient uptake of maize in two different soils. Appl. Soil Ecol. 36: 184-189.
  5. Fuqua, C., M. R. Parsek, and E. P. Greenberg. 2001. Regulation of gene expression by cell-to-cell communication: acyl-homoserine lactone quorum sensing. Annu. Rev. Genet. 35: 439-468.
  6. Khan, A. G. 2005. Role of soil microbes in the rhizospheres of plants growing on trace metal contaminated soils in phytoremediation. J. Trace Elem. Med. Biol. 18: 355-364.
  7. Kim, J. W., O. H. Choi, J. H. Kang, C. M. Ryu, M. J. Jeong, J. W. Kim, and C. S. Park. 1998. Tracing of some root colonizing Pseudomonas in the rhizosphere using lux gene introduced bacteria. Kor. J. Plant Pathol. 14: 13-18.
  8. Kim, S. D., L. D. L. Fuente, D. M. Weller, and L. S. Thomashow. 2012. Colonizing ability of Pseudomonas fluorescens 2112, among collections of 2,4-Diacetylphloroglucinol-producing Pseudomonas fluorescens spp. in pea rhizosphere. J. Microbiol. Biotechnol. 22: 763-770.
  9. Lee, E. T. and S. D. Kim. 2000. Selection and actifungal activity of antagonistic bacterium Pseudomonas sp. 2112 against red-pepper rotting Phytophthora capsici. Kor. J. Appl. Microbiol. Biotechnol. 28: 334-340.
  10. Lee, E. T. and S. D. Kim. 2001. An antifungal substance, 2,4- Diacetylphloroglucinol, produced from antagonistic bacterium Pseudomonas fluorescens 2112 against phytophthora capsici. Kor. J. Appl. Microbiol. Biotechnol. 29: 37-42.
  11. Lee, E. T., S. K. Lim, D. H. Nam, Y. H. Khang, and S. D. Kim. 2003. Pyoverdin2112 of Pseudomonas fluorescens 2112 inhibits Phytophthora capsici, a red-pepper blight-causing fungus. J. Microbiol. Biotechnol. 13: 415-421.
  12. Lim, J. H., H. Y. Jung, and S. D. Kim. 2009. Development of the microbial corsortium for the environmental friendly agriculture by the antagonistic rhizobacteria. J. Appl. Biol. Chem. 52: 116-120.
  13. Newton, J. A. and R. G. Fray. 2004. Integration of environmental and host-derived signals with quorum sensing during plant-microbe interactions. Cell Microbiol. 6: 213-224.
  14. Park, J. H., I. G. Hwang, J. W. Kim, S. O. Lee, B. Conway, E. P. Greenberg, and K. Lee. 2001. Characterization of quorumsensing signaling molecules produced by Burkholderia cepacia G4. J. Microbiol. Biotechnol. 11: 804-811.
  15. Rad, U. V., I. Klein, P. I. Dobrev, J. Kottova, E. Zazimalova, A. Fekete, A. Hartmann, P. Schmitt-Kopplin, and J. Durner. 2008. Response of Arabidopsis thaliana to N-hexaonyl-DL-homoserine lactone, a bacterial quorum sensing molecule produced in the rhizosphere. Planta 229: 73-85.
  16. Ramey, B. E., M. Koutsoudis, S. B. von Bodman, and C. Fuqua. 2004. Biofilm formation in plant-microbe associations. Curr. Opin. Mircobiol. 7: 602-609.
  17. Rosser, B. T., P. A. Taylor, P. A. Cix, and R. Cluland. 1987. Methods for evaluating antibiotics on bacterial biofilms. Antimicrob. Agents Chemother. 31: 1502-1506.
  18. Sahu, S. K., K. K. Patnaik, M. Sharmila, and N. Sethunathan. 1990. Degradation of alpha-, beta-, and gamma-hexachlorocyclohexane by soil bacterium under aerobic conditions. Appl. Environ. Microbiol. 56: 3620-3622.
  19. Sharma, A., M. Sahgal, and B. N. Johri. 2003. Microbial communication in the rhizosphere: Operation of quorum sensing. Curr. Sci. 85: 1164-1172.
  20. Smith, R. S. and B. H. Iglewski. 2003. P. aeruginosa quorumsensing systems and virulence. Curr. Opin. Microbiol. 6: 56-60.
  21. Tsavkelova, E. A., T. A. Cherdyntseva, S. G. Botina, and A. I. Netrusov. 2007. Bacteria associated with orchid roots and microbial production of auxin. Microbiol. Res. 162: 69-76.
  22. Whipps, J. M. 2001. Microbial interactions and biocontrol in the rhizosphere. J. Exp. Bot. 52: 487-511.
  23. Yoon, S. S. 2006. Quorum sensing mechanism in bacterial communities and their potential applications. Kor. J. Food Sci. Ani. Resour. 26: 402-409.