Location: Horticultural Crops ResearchTitle: Genomics-guided discovery of secondary metabolites and their regulation in Pseudomonas protegens Pf-5
|Yan, Qing - Oregon State University|
|Paulsen, Ian - Macquarie University|
|Gross, Harold - University Of Tubingen|
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 3/2/2015
Publication Date: 3/21/2015
Citation: Yan, Q., Paulsen, I., Gross, H., Clifford, J.M., Loper, J.E. 2015. Genomics-guided discovery of secondary metabolites and their regulation in Pseudomonas protegens Pf-5 [abstract]. 11th Annual Genomics of Energy & Environmental Meeting.
Technical Abstract: Pseudomonas protegens strain Pf-5 is a well-characterized rhizosphere bacterium known for its production of a diverse spectrum of secondary metabolites and its capacity to suppress plant diseases caused by soilborne fungal, bacterial and oomycete pathogens. Metabolites produced by Pf-5 include 2,4-diacetylphloroglucinol (2,4-DAPG), pyoluteorin, pyrrolnitrin, hydrogen cyanide, rhizoxin analogs, the cyclic lipopeptide orfamide A, toxoflavin, and the siderophores enantio-pyochelin and pyoverdine. The genomic sequence of Pf-5 was published in 2005, providing the opportunity for genomics-guided discovery of several metabolites (orfamide A, enantio-pyochelin, rhizoxin analogs, and toxoflavin) and other traits (bacteriocins and the insect toxin FitD) that contribute to multitrophic interactions in the rhizosphere. Additional orphan gene clusters have been identified through transcriptomic analysis of Pf-5 and derivatives with mutations in regulatory genes, through an approach termed global-regulator-based genome mining. Our current studies focus on the intricate coordination of secondary metabolite production in P. protegens Pf-5. Among the large spectrum of antibiotics produced by this bacterium, two—pyoluteorin and 2,4-DAPG— are known to function in intracellular and intercellular communication, both as autoinducers of their own production. The production of pyoluteorin and 2,4-DAPG is balanced in Pf-5, suggesting coordinate regulation of the two pathways. Here, we report that phloroglucinol, an intermediate in the biosynthesis of 2,4-DAPG, regulates the transcription of genes in the pyoluteorin biosynthesis cluster in a concentration-dependent manner. Furthermore, phloroglucinol had broad effects on the transcriptome of Pf-5, significantly altering the transcription of 289 genes by at least two fold. The genes most highly regulated by phloroglucinol fall into 14 role categories, reflecting the influence of phloroglucinol on diverse aspects of bacterial physiology and highlighting interactions between primary and secondary metabolic pathways.