ARS | Publication request: A Saccharomyces cerevisiae genome-wide mutant screen for sensitivity to 2,4-diacetylphloroglucinol, a biocontrol antibiotic produced by Pseudomonas fluorescens

Submitted to: International Plant Growth Promoting Rhizobacteria Workshop
Publication Type: Abstract Only
Publication Acceptance Date: February 16, 2009
Publication Date: N/A

Technical Abstract: Strains of Pseudomonas fluorescens that produce the antibiotic 2,4-diacetylphloroglucinol (DAPG) are biocontrol agents of a variety of soilborne pathogens. DAPG is active against a broad spectrum of organisms ranging from bacteria to higher plants. This suggests that the antibiotic may target basic cellular processes or that there are multiple sites of action. The genetics and regulation of DAPG biosynthesis by P. fluorescens have been well studied. However, the effect of DAPG on target pathogens and the host plant has not been well described. We screened a Saccharomyces cerevisiae genome-wide deletion mutant pool (approximately 5,000 mutnats) as a first step to understanding the mechanism of action of DAPG. The screen identified 231 mutants with increased sensitivity to DAPG, including 22 multi-drug resistant related mutants. These targets included major cellular pathways such as membrane function, reactive oxygen regulation and cell homeostasis. Physiological studies with wild-type yeast validated the results of sodium azide and hydrogen peroxide in a high throughput screening profile. Collectively, these findings suggest that DAPG acts through multiple mechanisms which would make development of resistance in target pathogens unlikely.