The Xanthomonas campestris gumD gene required for synthesis of xanthan gum is involved in normal pigmentation and virulence in causing black rot

Biochem Biophys Res Commun. 1997 Apr 7;233(1):265-9. doi: 10.1006/bbrc.1997.6365.


A cloned 4.1-kb EcoRI fragment from Xanthomonas campestris pv. campestris was previously shown to complement the non-mucoid mutant P22 and increase xanthan gum production after being transformed into the wild-type strain Xc17. The gene responsible for these effects was identified, sequenced, and shown to be the gumD gene which has previously been proposed to encode glucose transferase activity, an enzyme required for adding the first glucose residue to the isoprenoid glycosyl carrier lipid during xanthan synthesis. A gumD mutant, isolated from Xc17 by gene replacement, was shown to possess altered pigment xanthomonadin profiles and exhibit reduced virulence in causing black rot in broccoli. This study appears to be the first to demonstrate that interruption of a gene required for xanthan synthesis can lead to reduced virulence of X. campestris.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bacterial Proteins / genetics*
  • Genetic Complementation Test
  • Mutation
  • Pigmentation / genetics*
  • Plant Diseases / genetics*
  • Polysaccharides, Bacterial / biosynthesis*
  • Virulence / genetics
  • Xanthomonas campestris / genetics*
  • Xanthomonas campestris / pathogenicity


  • Bacterial Proteins
  • GumD protein, Xanthomonas campestris
  • Polysaccharides, Bacterial
  • xanthan gum

Associated data

  • GENBANK/X69956