Plant and Soil

, Volume 268, Issue 1, pp 285–292

Study of mechanisms for plant growth promotion elicited by rhizobacteria in Arabidopsis thaliana

  • Choong-Min Ryu
  • Chia-Hui Hu
  • Robert D. Locy
  • Joseph W. Kloepper


Plant growth-promoting rhizobacteria (PGPR) colonize plant roots and exert beneficial effects on plant health and development. We are investigating the mechanisms by which PGPR elicit plant growth promotion from the viewpoint of signal transduction pathways within plants. We report here our first study to determine if well-characterized PGPR strains, which previously demonstrated growth promotion of various other plants, also enhance plant growth in Arabidopsis thaliana. Eight different PGPR strains, including Bacillus subtilis GB03, B. amyloliquefaciens IN937a, B. pumilus SE-34, B. pumilus T4, B. pasteurii C9, Paenibacillus polymyxa E681, Pseudomonas fluorescens 89B-61, and Serratia marcescens 90-166, were evaluated for elicitation of growth promotion of wild-type and mutant Arabidopsis in vitro and in vivo. In vitro testing on MS medium indicated that all eight PGPR strains increased foliar fresh weight of Arabidopsis at distances of 2, 4, and 6 cm from the site of bacterial inoculation. Among the eight strains, IN937a and GB03 inhibited growth of Arabidopsis plants when the bacteria were inoculated 2 cm from the plants, while they significantly increased plant growth when inoculated 6 cm from the plants, suggesting that a bacterial metabolite that diffused into the agar accounted for growth promotion with this strain. In vivo, eight PGPR strains promoted foliar fresh weight under greenhouse conditions 4 weeks after sowing. To define signal transduction pathways associated with growth promotion elicited by PGPR, various plant-hormone mutants of Arabidopsis were evaluated in vitro and in vivo. Elicitation of growth promotion by PGPR strains in vitro involved signaling of brassinosteroid, IAA, salicylic acid, and gibberellins. In vivo testing indicated that ethylene signaling was involved in growth promotion. Results suggest that elicitation of growth promotion by PGPR in Arabidopsis is associated with several different signal transduction pathways and that such signaling may be different for plants grown in vitro vs. in vivo.


Arabidopsis thaliana plant growth promotion plant growth-promoting rhizobacteria 


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  1. Alonso, J M, Hirayama, T, Roman, G, Nourizadeh, S, Ecker, J R 1999EIN2, a bifunctional transducer of ethylene and stress responses in ArabidopsisScience28421482152PubMedGoogle Scholar
  2. Antoun H and Kloepper J (2001). Plant Growth Promoting Rhizobacteria in Encyclopedia of Genetics. Eds. S Brenner and J Miller. pp.~1477–1480 Academic Press.Google Scholar
  3. Berner, D K, Schaad, N W, Völksch, B 1999Use of ethylene-producing bacteria for stimulation of Striga spp. seed germinationBiological Control15274282Google Scholar
  4. Bowling, S A, Guo, A, Cao, H, Gordon, A S, Klessig, D F, Dong, X 1994A mutation in Arabidopsis that leads to constitutive expression of systemic acquired resistancePlant Cell6184557PubMedGoogle Scholar
  5. Bloemberg, G V, Lugtenberg, B J J 2001Molecular basis of plant growth promotion and biocontrol by rhizobacteriaCurr. Opinion Plant Biol4343350Google Scholar
  6. Cao, H, Glazebrook, J, Clarke, J D, Volko, S, Dong, X N 1997The Arabidopsis NPR1 gene that controls systemic acquired resistance encodes a novel protein containing ankyrin repeatsCell885763PubMedGoogle Scholar
  7. Dobbelaere, S, Vanderleyden, J, Okon, Y 2003Plant growth-promoting effects of diazotrophs in the rhizosphereCrit. Rev. Plant Sci22107149Google Scholar
  8. Glick, B R 1995The enhancement of plant growth by free-living bacteriaCan. J. Microbiol41109117Google Scholar
  9. Glick, B R, Penrose, D M, Li, J. 1998A model for the lowering of plant ethylene concentrations by plant growth-promoting bacteriaJ. Theor. Biol1906368PubMedGoogle Scholar
  10. Gutierrez-Maner, F J, Ramos-Solano, B, Probanza, A, Mehouachi, J, Tadeo, F R, Talon, M 2001The plant-growth-promoting rhizobacteria Bacillus pumilus and Bacillus licheniformis produce high amounts of physiologically active gibberellinsPhysiol. Plant111206211Google Scholar
  11. Idriss, E E, Makarewicz, O, Farouk, A, Rosner, K, Greiner, R, Bochow, H, Richter, T, Borriss, R 2002Extracellular phytase activity of Bacillus amyloliquefaciens FZB45 contributes to its plant-growth-promoting effectMicrobiology14820972109PubMedGoogle Scholar
  12. Kauschmann, A, Jessop, A, Koncz, C, Szekeres, M, Willmitzer, L, Altmann, T 1996Genetic evidence for an essential role of brassinosteroids in plant developmentPlant J9701713Google Scholar
  13. Kloepper, J W 1992

    Plant growth-promoting rhizobacteria as biological control agents

    Metting, F. B.,Jr eds. Soil Microbial Ecology: Applications in Agricultural and Environmental Management.Marcel Dekker IncNew York USA255274
    Google Scholar
  14. Kloepper J W, Ryu C-M and Zhang S 2004a Induced systemic resistance and promotion of plant growth by Bacillusspp. Phytopathology (in press).Google Scholar
  15. Kloepper J W and Ryu C-M 2004b Bacterial endophytes as elicitors of induced systemic resistance In: Microbial Root Endophytes Eds. B Schulz, C Boyle and T Sieber. Kluwer Inc. (in press).Google Scholar
  16. Luschnig, C, Gaxiola, R A, Grisafi, P, Fink, G R. 1998EIR1, a root-specific protein involved in auxin transport, is required for gravitropism in Arabidopsis thalianaGenes Dev1221752187PubMedGoogle Scholar
  17. McCourt, P 1999Genetics of hormone signal transductionAnnu. Rev. Plant Physiol. Mol. Biol50219243Google Scholar
  18. Mantelin, S, Touraine, B 2004Plant growth-promoting bacteria and nitrate availability: Impacts on root development and nitrate uptakeJ. Exp. Bot552734PubMedGoogle Scholar
  19. Murashige, T, Skoog, F 1962A revised medium for rapid growth and bioassays with tobacco tissue culturesPhysiol Plant15473497Google Scholar
  20. Nemhauser, J L, Chory, J 2004Bring it on: New insights into the mechanism of brassinosteroid action JExp. Bot55265270Google Scholar
  21. O’Callaghan, K J, Dixon, R A, Cocking, E C 2001Arabidopsis thaliana: A model for study of colonization by non-pathogenic and plant-growth-promoting rhizobacteriaAust. J. Plant Physiol28975982Google Scholar
  22. Peng, J, Harberd, N P 1993Derivative alleles of the arabidopsis gibberellin-insensitive (gai) mutation confer a wild-type phenotypePlant Cell5351360Google Scholar
  23. Persello-Cartieaux, F, David, P, Sarrobert, C, Thibaud, M-C, Achouak, W, Robaglia, C, Nussaume, L 2001Utilization of mutants to analyze the interaction between Arabidopsis thaliana and its naturally root-associated PseudomonasPlanta212190198PubMedGoogle Scholar
  24. Persello-Cartieaux, F, Nussaume, L, Robaglia, C 2003Tales from the underground: Molecular plant-rhizobacteria interactionsPlant Cell Environ26186199Google Scholar
  25. Press, C M, Wilson, M, Tuzun, S, Kloepper, J W 1997Salicylic acid produced by Serratia marcescens 90–166 is not the primary determinant of induced systemic resistance in cucumber or tobaccoMol. Plant Microbe Interact10761768Google Scholar
  26. Ryu, C-M, Hu, C-H, Reddy, M S, Kloepper, J W 2003aDifferent signaling pathways of induced resistance by rhizobacteria in Arabidopsis thaliana against two pathovars of Pseudomonas syringaeNew Phytologist160413420Google Scholar
  27. Ryu, C-M, Farag, M A, Hu, C-H, Reddy, M S, Wei, H X, Pare, P W, Kloepper, J W 2003Bacterial volatiles promote growth in ArabidopsisProc. Natl. Acad. Sci. U.S.A10049274932PubMedGoogle Scholar
  28. Ryu, C-M, Farag, M A, Hu, C-H, Reddy, M S, Kloepper, J W, Pare, P W 2004Bacterial volatiles induce systemic resistance in ArabidopsisPlant Physiol13410171026PubMedGoogle Scholar
  29. Schipper, B, Bakker, A W, Bakker, P A H M 1987Interactions of deleterious and beneficial rhizosphere microorganisms and the effect of cropping practicesAnnu. Rev. Phytopathol25339358Google Scholar
  30. Van Loon, LC, Bakker, PAHM, Pierterse, CMJ 1998Systemic resistance induced by rhizosphere bacteriaAnnu. Rev. Phytopathol36453483PubMedGoogle Scholar
  31. Whipps, J M 2001Microbial interactions and biocontrol in the rhizosphereJ. Exp. Bot52487511PubMedGoogle Scholar
  32. Xie, D X, Feys, B F, James, S, Nieto-Rostro, M, Turner, J G 1998COI1: An Arabidopsis gene required for jasmonate-regulated defense and fertilityScience28010911094PubMedGoogle Scholar

Copyright information

© Springer 2005

Authors and Affiliations

  • Choong-Min Ryu
    • 1
    • 3
  • Chia-Hui Hu
    • 1
  • Robert D. Locy
    • 2
  • Joseph W. Kloepper
    • 1
  1. 1.Department of Entomology and Plant PathologyAuburn UniversityUSA
  2. 2.Department of Biological ScienceAuburn UniversityAuburnUSA
  3. 3.Plant Biology DivisionSamuel Roberts Noble FoundationArdmoreUSA

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