Submitted to: Applied Microbiology and Biotechnology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/1/2009
Publication Date: 2/20/2010
Citation: Mavrodi, D.V., Peever, T.L., Mavrodi, O.V., Parejko, J.A., Raaijmakers, J.M., Lemanceau, P., Mazurier, S., Heide, L., Blankenfeldt, W., Weller, D.M., Thomashow, L.S. 2010. Diversity and Evolution of the Phenazine Biosynthesis Pathway. Applied Microbiology and Biotechnology. Feb, 2010, p. 866-879. Interpretive Summary: Certain bacterial species produce small molecules called phenazines that have antibiotic activity against plant pathogens. In this study, phenazine biosynthesis genes from 94 bacterial strains of worldwide origin were compared. The results showed that most phenazine-producing bacteria live in the soil or in association with plants. The phenazine genes are inherited by bacterial species within the genus Pseudomonas, but can be acquired by horizontal gene transfer in strains of Burkholderia and Pectobacterium. Genes for the production of phenazine compounds were found in soil associated with the roots of wheat grown in commercial farm fields located in central Washington State, indicating that phenazine-producing bacterial strains are naturally present in these field soils.
Technical Abstract: Phenazines are versatile secondary metabolites of bacterial origin that function in biological control of plant pathogens and contribute to the ecological fitness and pathogenicity of the producing strains. In this study, we employed a collection of 94 strains having various geographic, environmental, and clinical origins to study the distribution and evolution of phenazine genes in members of the genera Pseudomonas, Burkholderia, Pectobacterium, Brevibacterium, and Streptomyces. Our results confirmed the diversity of phenazine producers and revealed that most of them appear to be soil-dwelling and/or plant-associated species. Genome analyses and comparisons of phylogenies inferred from sequences of the key phenazine biosynthesis (phzF) and housekeeping (rrs, recA, rpoB, atpD, and gyrB) genes revealed that the evolution and dispersal of phenazine genes are driven by mechanisms ranging from conservation in Pseudomonas spp. to horizontal gene transfer in Burkholderia spp. and Pectobacterium spp. DNA extracted from cereal crop rhizospheres and screened for the presence of phzF contained sequences consistent with the presence of a diverse population of phenazine producers in commercial farm fields located in central Washington state, which provided the first evidence of United States soils enriched in indigenous phenazine-producing bacteria.