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United States Department of Agriculture

Agricultural Research Service

Title: Impact of Myxobacteria on the Ecology of Bacterial Plant Pathogens

Author
item Bull, Carolee

Submitted to: International Myxobacteria Meeting
Publication Type: Proceedings
Publication Acceptance Date: July 10, 2003
Publication Date: July 12, 2003
Citation: Bull, C.T. 2003. Impact of myxobacteria on the ecology of bacterial plant pathogens. International Myxobacteria Meeting. Proceeding of the 30th International Conference on the Biology of the Myxobacteria. p. 10.

Technical Abstract: Relative lysis of bacterial plant pathogens by myxobacteria was evaluated. Bacterial plant pathogens were lysed by Myxococcus xanthus DK1622. For example, Pseudomonas syringae pv. alisalensis (Psa), an important pathogen of crucifers, was lysed to the same extent as Escherichia coli by strain DK1622. To-date, lysis by strains isolated from strawberry production fields was less than that of DK1622. To test the ability of plant pathogens to induce myxospores germination, myxospores were generated on starvation agar. A 30-µl suspension of Psa was deposited on the plate over M. xanthus fruiting bodies. Lysis of the Psa surrounding fruiting bodies was the first indication that myxospores germinated in response to Psa. In a parallel series of experiments we evaluated the relative lysis of bacteria that are used to control diseases caused by soilborne fungal pathogens. Most biological control agents tested were not significantly lysed. In some cases myxobacteria were inhibited in the presence of biological control agents from the soil, perhaps due to antimicrobial compounds produced by these organisms. In contrast, a foliar biological control strain was lysed to the same extent as the control. In general, the extent to which DK1622 lysed foliar bacteria was greater than its lysis of soilborne organisms. To test the hypothesis that foliar organisms are more susceptible to lysis than are soilborne organisms, we evaluated the relative ability of DK1622 to lyse organisms isolated from various habitats associated with strawberry plants. Preliminary data indicate that organisms from some habitats may be more susceptible to lysis than those from other habitats.

Last Modified: 7/24/2014