Phloroglucinol functions as an intracellular and intercellular chemical messenger influencing gene expression in Pseudomonas protegens.
Bacteria can be both highly communicative and highly competitive in natural habitats and antibiotics are thought to play a role in both of these processes. The soil bacterium Pseudomonas protegens Pf-5 produces a spectrum of antibiotics, two of which, pyoluteorin and 2,4-diacetylphloroglucinol (DAPG), function in intracellular and intercellular communication, both as autoinducers of their own production. Here, we demonstrate that phloroglucinol, an intermediate in DAPG biosynthesis, can serve as an intercellular signal influencing the expression of pyoluteorin biosynthesis genes, the production of pyoluteorin, and inhibition of Pythium ultimum, a phytopathogenic oomycete sensitive to pyoluteorin. Through analysis of RNAseq data sets, we show that phloroglucinol had broad effects on the transcriptome of Pf-5, significantly altering the transcription of more than two hundred genes. The effects of nanomolar versus micromolar concentrations of phloroglucinol differed both quantitatively and qualitatively, influencing the expression of distinct sets of genes or having opposite effects on transcript abundance of certain genes. Therefore, our results support the concept of hormesis, a phenomenon associated with signalling molecules that elicit distinct responses at different concentrations. Phloroglucinol is the first example of an intermediate of antibiotic biosynthesis that functions as a chemical messenger influencing gene expression in P. protegens.
US Department of Agriculture, Agricultural Research Service, Horticultural Crops Research Laboratory, Corvallis, OR, USA.
Jennifer C
JC
Clifford
Department of Botany and Plant Pathology and Center for Genome Research and Biocomputing, Oregon State University, Corvallis, OR, USA.
Alex
A
Buchanan
College of Pharmacy, Oregon State University, Corvallis, OR, USA.
Oliver
O
Vining
US Department of Agriculture, Agricultural Research Service, Horticultural Crops Research Laboratory, Corvallis, OR, USA.
Teresa A
TA
Kidarsa
Department of Botany and Plant Pathology and Center for Genome Research and Biocomputing, Oregon State University, Corvallis, OR, USA.
Jeff H
JH
Chang
College of Pharmacy, Oregon State University, Corvallis, OR, USA.
Kerry L
KL
McPhail
US Department of Agriculture, Agricultural Research Service, Horticultural Crops Research Laboratory, Corvallis, OR, USA. joyce.loper@ars.usda.gov.|Department of Botany and Plant Pathology and Center for Genome Research and Biocomputing, Oregon State University, Corvallis, OR, USA. joyce.loper@ars.usda.gov.
Joyce E
JE
Loper
D000900:Anti-Bacterial Agents / Q000096:biosynthesis / Q000494:pharmacology; D015870:Gene Expression; D015964:Gene Expression Regulation, Bacterial / Q000502:physiology*; D010636:Phenols / Q000378:metabolism*; D010696:Phloroglucinol / Q000031:analogs & derivatives* / Q000378:metabolism; D011549:Pseudomonas / Q000235:genetics* / Q000378:metabolism*; D011758:Pyrroles / Q000378:metabolism*; D015398:Signal Transduction / Q000502:physiology
D000900:Anti-Bacterial Agents; D010636:Phenols; D011758:Pyrroles; C095503:pyoluteorin; C059817:2,4-diacetylphloroglucinol; D010696:Phloroglucinol