2,4-Diacetylphloroglucinol alters plant root development

Jessica N. Brazelton, Emily E. Pfeufer, Teresa A. Sweat, Brian B. McSpadden Gardener, Catharina Coenen

Research output: Contribution to journalArticlepeer-review

123 Scopus citations


Pseudomonas fluorescens isolates containing the phlD gene can protect crops from root pathogens, at least in part through production of the antibiotic 2,4-diacetylphloroglucinol (DAPG). However, the action mechanisms of DAPG are not fully understood, and effects of this antibiotic on host root systems have not been characterized in detail. DAPG inhibited primary root growth and stimulated lateral root production in tomato seedlings. Roots of the auxin-resistant diageotropica mutant of tomato demonstrated reduced DAPG sensitivity with regards to inhibition of primary root growth and induction of root branching. Additionally, applications of exogenous DAPG, at concentrations previously found in the rhizosphere of plants inoculated with DAPG-producing pseudomonads, inhibited the activation of an auxin-inducible GH3 promoter::luciferase reporter gene construct in transgenic tobacco hypocotyls. In this model system, supernatants of 17 phlD+ P. fluorescens isolates had inhibitory effects on luciferase activity similar to synthetic DAPG. In addition, a phlD- mutant strain, unable to produce DAPG, demonstrated delayed inhibitory effects compared with the parent wild-type strain. These results indicate that DAPG can alter crop root architecture by interacting with an auxin-dependent signaling pathway.

Original languageEnglish
Pages (from-to)1349-1358
Number of pages10
JournalMolecular Plant-Microbe Interactions
Issue number10
StatePublished - Oct 2008

ASJC Scopus subject areas

  • Physiology
  • Agronomy and Crop Science


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