Biology and Fertility of Soils

, Volume 25, Issue 3, pp 240–244

Biocontrol strain Pseudomonas fluorescens CHA0 and its genetically modified derivative with enhanced biocontrol capability exert comparable effects on the structure of a Sinorhizobium meliloti population in gnotobiotic systems

  • S. Niemann
  • C. Keel
  • A. Pühler
  • W. Selbitschka
ORIGINAL PAPER

DOI: 10.1007/s003740050309

Cite this article as:
Niemann, S., Keel, C., Pühler, A. et al. Biol Fertil Soils (1997) 25: 240. doi:10.1007/s003740050309

Abstract

The impact of biocontrol strain Pseudomonas fluorescens CHA0 and of its genetically modified, antibiotic-overproducing derivative CHA0/pME3424 on a reconstructed population of the plant-beneficial Sinorhizobiummeliloti bacteria was assessed in gnotobiotic systems. In sterile soil, the final density of the reconstructed S. meliloti population decreased by more than one order of magnitude in the presence of either of the Pseudomonas strains when compared to a control without addition of P. fluorescens. Moreover, there was a change in the proportion of each individual S. meliloti strain within the population. Plant tests also revealed changes in the nodulating S. meliloti population in the presence of strains CHA0 or CHA0/pME3424. In both treatments one S. meliloti strain, f43, was significantly reduced in its root nodule occupancy. Analysis of alfalfa yields showed a slight but statistically significant increase in shoot dry weight when strain CHA0 was added to the reconstructed S. meliloti population whereas no such effect was observed with CHA0/pME3424.

Key words Ecological impactGenetically modifiedorganismsMicrocosm studiesSymbiotic nitrogenfixationPlant-beneficial bacteriaSinorhizobium meliloti

Copyright information

© Springer-Verlag Berlin Heidelberg 1997

Authors and Affiliations

  • S. Niemann
    • 1
  • C. Keel
    • 2
  • A. Pühler
    • 1
  • W. Selbitschka
    • 1
  1. 1.Lehrstuhl für Genetik, Fakultät für Biologie, Universität Bielefeld, Postfach 100131, D-33501 Bielefeld, Germany Tel: (521) 106-2990; Fax: (521) 106-5626; e-mail: werner@genetik.uni-bielefeld.deDE
  2. 2.Laboratoire de Biologie Microbienne, Université de Lausanne, CH-1015 Lausanne-Dorigny, SwitzerlandCH