|DE La Fuente, Leonardo - WASHINGTON STATE UNIV|
|Landa, Blanca - UNIVERSIDAD DE CORDOBA|
Submitted to: APS Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: May 20, 2004
Publication Date: July 20, 2004
Citation: De La Fuente, L., Landa, B.B., Thomashow, L.S., Weller, D.M. 2004. Dynamics of rhizosphere competition among genotypes of 2,4-diacetylphlorogucinol(dapg)-producing pseudomonas fluorescens depends on host crop. APS Annual Meeting. Phytopathology 94:S24. Technical Abstract: DAPG-producing P. fluorescens strains are responsible for the natural suppressiveness of certain soils to root pathogens. Seventeen distinct BOX-PCR genotypes (A-Q) of DAPG producers have been identified, some of which differ in ability to colonize the rhizosphere. Alfalfa, bean, barley, flax, lentil, lupine, oat, pea and wheat were grown in a pea wilt suppressive soil containing indigenous A, D, L, O, P and Q isolates. After six consecutive 3-week cycles, populations of these genotypes differed quantitatively and qualitatively in the rhizosphere of the nine crops. A hierarchy was observed when a virgin soil was inoculated with strains from three genotypes that aggressively colonize wheat or pea. When introduced together, the P-genotype displaced D- and K-genotype strains in the pea rhizosphere. K- and D-genotype strains were equally competitive in the pea rhizosphere when co-inoculated, but the K genotype displaced genotypes D and P on wheat roots.