ARS | Publication request: INTERACTIONS BETWEEN MYXOBACTERIA AND PLANT ASSOCIATED MICROORGANISMS

Submitted to: International Congress of Plant Pathology Abstracts and Proceedings
Publication Type: Proceedings
Publication Acceptance Date: November 20, 2002
Publication Date: February 20, 2003
Citation: Bull, C.T. 2003. Interactions between myxobacteria and plant associated microorganisms. International Congress of Plant Pathology Abstracts and Proceedings. p. 43.

Technical Abstract: Myxobacteria are soil dwelling gram-negative gliding bacteria, which form fruiting bodies containing resistant myxospores. Although they produce a wide range of antibiotics and lytic enzymes, their role in controlling plant pathogens has received little attention. We have conducted studies to determine if myxobacteria have potential as biological control agents for diseases of strawberry and lettuce. Six myxobacterial species belonging to the genus Myxococcus were tested in vitro against nine soilborne plant pathogenic fungi (Cylindrocarpon spp., Fusarium oxysporum f. sp. apii, Phytopthora capsici, Pythium ultimum, Rhizoctonia spp., Sclerotinia minor, S. sclerotiorum, Verticillium albo-atrum, and V. dahliae) and against selected fungal (Gliocladium virens, Trichoderma viride, Talaromyces flavus, and Coniothyrium minitans) and bacterial (Bacillus subtilis, Pseudomonas aureofaciens, and Pl fluorescens) biological control agents. Myxobacteria exhibited a strong inhibitory effect on both pathogenic and beneficial fungal growth in vitro although the degree of inhibition varied with the species tested. The ability of myxobacteria to lyse plant associated bacteria varied. The ability of bacterial biological control agents to produce certain antibiotics had an effect on their interaction with myxobacteria. In general, antibiotic producing strains were not lysed or inhibited by the myxobacteria while isogenic antibiotic minus mutants were lysed. Antibiotic production by biological control agents may protect them from lysis by myxobacteria. We are currently studying the interaction between myxobacteria and plant associated bacteria in situ.