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United States Department of Agriculture

Agricultural Research Service

Research Project: BIOLOGY AND MANAGEMENT OF SOILBORNE DISEASES OF HORTICULTURAL CROPS Title: Three Strains of Pseudomonas fluorescens Exhibit Differential Toxicity Against Drosophila melanogaster

item Olcott, Marika -
item Rosen, Kise -
item Walker, Francesca -
item Sneh, Baruch -
item Loper, Joyce
item Taylor, Barbara -

Submitted to: International Plant Growth Promoting Rhizobacteria Workshop
Publication Type: Abstract Only
Publication Acceptance Date: April 15, 2009
Publication Date: May 17, 2009
Citation: Olcott, M., Rosen, K., Walker, F., Sneh, B., Loper, J.E., Taylor, B. 2009. Three strains of Pseudomonas fluorescens exhibit differential toxicity against Drosophila melanogaster. International Plant Growth Promoting Rhizobacteria Workshop. p. 71.

Technical Abstract: Three strains of Pseudomonas fluorescens were tested for toxicity to Drosophila melanogaster in an insect feeding assay. Insect eggs were placed on the surface of a non-nutritive agar plate supplemented with a food source that was non-inoculated or inoculated with P. fluorescens Pf0-1, SBW25, or Pf-5, and insect development and survival were evaluated over time. Strain Pf0-1 had no significant effect on insect survival and development, whereas strain Pf-5 caused dose-dependent lethality and morphological defects in eyes and wings in the surviving adult flies. In addition, Pf-5 caused a dose dependent delay in the onset of metamorphosis relative to non-inoculated controls. A gacA mutant of Pf-5 caused no significant mortality, morphological defects, or developmental delay, indicating that factors responsible for these effects are controlled by the GacS/GacA global regulatory system. Strain SBW25 also caused insect mortality, but to a lower level than caused by Pf-5, and surviving larvae did not exhibit developmental delays. Strain SBW25 ingestion caused some insects to exhibit a profound, fatal systemic melanization reaction at larval, pupal or adult stages. These experiments demonstrate that P. fluorescens Pf-5 and SBW25, when introduced through natural routes of infection, can cause mortality of D. melanogaster. Furthermore, strain Pf-5 causes delays in the onset of metamorphosis and produces morphological defects in surviving adult flies that are independent of host survival.

Last Modified: 8/28/2016
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