Potential role of flavobacterial gliding-motility and type IX secretion system complex in root colonization and plant defense

Max Kolton, Omer Frenkel, Yigal Elad, Eddie Cytryn

Research output: Contribution to journalArticlepeer-review

39 Scopus citations


Members of the Flavobacterium genus are often highly abundant in the rhizosphere. Nevertheless, the physiological characteristics associated with their enhanced rhizosphere competence are currently an enigma. Flavobacteria possess a unique gliding-motility complex that is tightly associated with a recently characterized Bacteroidetes-specific type IX protein secretion system, which distinguishes them from the rest of the rhizosphere microbiome. We hypothesize that proper functionality of this complex may confer a competitive advantage in the rhizosphere. To test this hypothesis, we constructed mutant and complement root-Associated flavobacterial variants with dysfunctional secretion and gliding motility, and tested them in a series of in planta experiments. These mutants demonstrated significantly lower rhizosphere persistence (approximately 10-fold), plant root colonization (approximately fivefold), and seed adhesion capacity (approximately sevenfold) than the wild-type strains. Furthermore, the biocontrol capacity of the mutant strain toward foliar-Applied Clavibacter michiganensis was significantly impaired relative to the wild-type strain, suggesting a role of the gliding and secretion complex in plant protection. Collectively, these results provide an initial link between the high abundance of flavobacteria in the rhizosphere and their unique physiology, indicating that the flavobacterial gliding-motility and secretion complex may play a central role in root colonization and plant defense.

Original languageEnglish
Pages (from-to)1005-1013
Number of pages9
JournalMolecular Plant-Microbe Interactions
Issue number9
StatePublished - 1 Jan 2014
Externally publishedYes

ASJC Scopus subject areas

  • Physiology
  • Agronomy and Crop Science


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