Plant and Soil

, Volume 83, Issue 3, pp 399–409 | Cite as

Effects on winter wheat seedling growth by toxin-producing rhizobacteria

  • J. K. Fredrickson
  • L. F. Elliott


Root-colonizing pseudomonads capable of inhibiting seedling winter wheat (Triticum aestivum L.) root growth in an agar seedling bioassay also significantly inhibited wheat root growth in vermiculite; however, the inhibitory trait is quite labile in laboratory culturing. The extent of inhibition in both the agar and vermiculite medium depended on inoculum level. These pseudomonads were found to produce a toxin capable of inhibiting growth ofEscherichia coli C-la andBacillus subtilis. Field isolates that strongly inhibit growth of indicator bacteria also inhibited root growth. Toxin production by the bacteria appeared necessary for inhibition of root growth and indicator bacteria as toxin-negative (TOX) mutants no longer inhibited either. Antibiosis towardsE. coli as well as wheat seedling root inhibition in agar was reversed by L-methionine, providing further evidence that a toxin, produced by these organisms, is involved in growth retardation.

Key words

Inhibitory bacteria Pseudomonads Root growth Triticum aestivum 


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Copyright information

© Martinus Nijhoff/Dr W. Junk Publishers 1985

Authors and Affiliations

  • J. K. Fredrickson
    • 1
  • L. F. Elliott
    • 1
  1. 1.Department of Agronomy and Soils, and USDA-ARSWashington State UniversityPullmanUSA

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