The Evolutionary Diversity and Biological Function of Phenazine Metabolite Biosynthesis in Burkholderia SPP

<p><em>Burkholderia </em>encompass a group of ubiquitous Gram-negative bacteria that include numerous saprophytes, as well as several species that cause infections in animals, immunocompromised patients, and plants. Some species of <em>Burkholderia </em>produce colored redox-active secondary metabolites called phenazines (Phz). In the model opportunistic pathogen <em>Pseudomonas aeruginosa</em>, phenazines strongly contribute to the competitiveness, formation of biofilms, and virulence in multiple models of infection. Similar depth of knowledge on the diversity, biosynthesis, and biological functions of phenazines in <em>Burkholderia</em>is missing<em>. </em>This project aimed to bridge this gap in knowledge by focusing on phenazine pathways of <em>B. lata </em>and closely related species. My results revealed that <em>phz</em>genes are present in genomes of many <em>Burkholderia</em>that have a worldwide origin and belong to different species of the genus. Most Phz+ strains were in the Bcc group, but the capacity to synthesize phenazines was also found in some isolates of the <em>B. pseudomallei</em>clade and the plant pathogen <em>B. glumae</em>. My findings also suggest that the phenazine biosynthetic pathway of <em>Burkholderia</em>has a complex evolutionary history, which likely involved horizontal gene transfers among several distantly related groups of producing organisms. I also analyzed isogenic mutants and plasmid deletion derivatives of <em>Burkholderia lata</em>, which helped to identify phenazines produced by species of the ubiquitous <em>B. cepacia</em>(Bcc) group and characterize the role of phenazine-modifying genes in the synthesis of 4,9-dihydroxyphenazine-1,6-dicarboxylic acid dimethylester.My functional studies failed to link the production of phenazines with the capacity of <em>Burkholderia</em>to kill fruit flies and rot onions, but other experiments revealed a link between the presence and amount of phenazines and the dynamics of biofilm growth flow in the flow cell and static experimental systems.</p>

Name thesis:degree_name

Master of Science (MS)

Level thesis:degree_level

Masters Thesis

Year dc:date.available

2019

Author dc:creator

• Hendry, Samuel

Contributors dc:contributor

• Dmitri Mavrodi
• Janet Donaldson
• Mohamed Elasri

• phenazines
• burkholderia
• biology
• diversity
• Bacteriology

Repository record dc:identifier

https://aquila.usm.edu/masters_theses/653

OAI identifier oai:identifier

oai:aquila.usm.edu:masters_theses-1684