Production of 2,4-diacetylphloroglucinol by the biocontrol agent Pseudomonas fluorescens Pf-5

2,4-Diacetylphloroglucinol was detected in and isolated from culture extracts of the biological control bacterium Pseudomonas fluorescens Pf-5. Its structure was identified using a combination of chromatographic techniques and NMR spectroscopic methods. Carbon source influenced 2,4-diacetylphloroglucinol production by Pf-5 in culture media. 2,4-Diacetylphloroglucinol inhibited growth of the plant pathogenic fungi Pythium ultimum and Rhizoctonia solani, and the plant pathogenic bacterium Erwinia carotovora subsp. atroceptica, which cause diseases that are suppressed by strain Pf-5. The results of this study provide further evidence for the prevalence of 2,4-diacetylphloroglucinol production among strains of Pseudomonas fluorescens that suppress plant diseases.