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Title: Characterization of the Pseudomonas genus of bacteria for plant-parasitic nematode control

item Walter, Nathalie
item Okubara, Patricia

Submitted to: ASM Conference
Publication Type: Abstract Only
Publication Acceptance Date: 8/26/2007
Publication Date: 8/26/2007
Citation: Aly, H., Kamalay, J., Walter, N., Okubara, P.A., Taylor, C.G. 2007. Characterization of the Pseudomonas genus of bacteria for plant-parasitic nematode control. ASM Conference.

Interpretive Summary:

Technical Abstract: Plant-parasitic nematodes are among the most destructive plant pests, causing substantial economic losses to agronomic crops worldwide. Current methods of using bacteria as biocontrol agents for plant-parasitic nematodes have met with limited success in part due to limited knowledge about mechanisms of biocontrol and biotic factors that are important to rhizosphere persistence. Using a C. elegans bioassay we have screened over 12,000 bacterial isolates from a variety of natural sources (water, soil, plants) and identified over 60 different isolates of Pseudomonas that interfere with nematode growth and development. A third of these strains exhibit activity in plate and soil assays against root-knot and soybean cyst nematodes. We have characterized the nematode-active Pseudomonas isolates for motility, exoprotease activity and production of siderophores, HCN, polysaccharides and fluorescence to determine if commonalities exist among plant-parasitic nematode lethal strains. Using a transposon knockout strategy, we identified several C. elegans non-lethal isolates for Pseudomonas strain 15G2. Testing of the transposon tagged isolates (non-lethal) for HCN production showed significant reduction in HCN production. Additionally, in vitro root-knot nematode tests showed limited or no activity against RKN while the wild-type Pseudomonas 15G2 strain showed lethality to both RKN and C. elegans nematodes. These data indicate that HCN is potentially an important compound with activity against RKN as well as C. elegans and demonstrates that C. elegans is a useful model system for studying plant-parasitic nematode control using Pseudomonas.