Sequence and expression analysis of the hrpB pathogenicity operon of Xanthomonas campestris pv. vesicatoria which encodes eight proteins with similarity to components of the Hrp, Ysc, Spa, and Fli secretion systems

Mol Plant Microbe Interact. Nov-Dec 1995;8(6):845-54. doi: 10.1094/mpmi-8-0845.


In this paper we describe the molecular characterization of hrpB, the largest operon in the Xanthomonas campestris pv. vesicatoria hrp cluster. The hrpB region encompasses 6 kb and encodes eight putative proteins, seven of which were expressed in Escherichia coli. The HrpB3 protein is the only one carrying a signal peptide sequence at the N-terminus and is a putative lipoprotein localized in the outer membrane of X. campestris pv. vesicatoria. The HrpB4 and HrpB8 proteins contain one and five putative transmembrane domains, respectively, and are most likely associated with the inner membrane. The HrpB3, HrpB5, HrpB6, and HrpB8 proteins show sequence similarity to putative components of different type III protein secretion pathways in bacteria. Examples include Hrp proteins from other plant pathogens, YscJ, YscN, YscL, and YscT of Yersinia spp., and MxiJ, Spa47, adn Spa29 of Shigella flexneri. The transcription start site and the hrpB promoter was identified. The minimal hrpB promoter region of 90 bp contains a novel sequence motif, the PIP-box, which might play a role in transcription activation of the hrpB operon and possibly other plant-induced genes of X. campestris pv. vesicatoria.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Bacterial Outer Membrane Proteins / genetics
  • Bacterial Proteins / biosynthesis
  • Bacterial Proteins / genetics*
  • Bacterial Proteins / metabolism
  • Base Sequence
  • DNA-Binding Proteins*
  • Escherichia coli / genetics
  • Genes, Bacterial*
  • Lipoproteins / genetics
  • Membrane Proteins / genetics
  • Molecular Sequence Data
  • Multigene Family
  • Operon*
  • Plant Diseases / microbiology
  • Promoter Regions, Genetic
  • Recombinant Proteins / biosynthesis
  • Repressor Proteins / genetics*
  • Sequence Analysis, DNA
  • Sequence Homology, Amino Acid
  • Transcription Factors*
  • Transcription, Genetic
  • Vegetables / microbiology
  • Xanthomonas campestris / genetics*
  • Xanthomonas campestris / pathogenicity


  • Bacterial Outer Membrane Proteins
  • Bacterial Proteins
  • DNA-Binding Proteins
  • Lipoproteins
  • Membrane Proteins
  • Recombinant Proteins
  • Repressor Proteins
  • Transcription Factors
  • hrpB protein, Ralstonia solanacearum

Associated data

  • GENBANK/U33548