Submitted to: APS Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 5/20/2004
Publication Date: 7/20/2004
Citation: Bankhead, B.S., Brown, A., Son, M.Y., Thomashow, L.S., Weller, D.M. 2004. Population dynamics and non-target effects of transgenic pseudomonas fluorescens in the rhizosphere of wheat and pea. APS Annual Meeting. Phytopathology 94: S8.
Technical Abstract: Pseudomonas fluorescens strain Q8r1-96 produces 2,4-diacetylphloroglucinol (DAPG). Transgenic strains Z30-97, Z32-97, Z33-97, and Z34-97, constructed by inserting the phenazine-1-carboxylic acid (PCA) biosynthetic locus into Q8r1-96, produce both antibiotics. Both PCA and DAPG have been shown to suppress root diseases such as take-all of wheat The population dynamics of these strains were monitored in the rhizosphere of field grown wheat during two seasons after application as a seed treatment and in the rhizosphere of greenhouse-grown pea during multiple growth cycles after introduction into soil. The non-target effects of the introduced strains on the indigenous rhizosphere bacteria were determined by using terminal restriction fragment length polymorphism (T-RFLP) analysis. In general, the transgenic strains did not differ from Q8r1-96 in their ability to colonize the rhizosphere of wheat and pea. However, when Q8r1-96 and a transgenic strain were present on the same root, the wild type often out-competed the transgenic strain.