TssB is essential for virulence and required for type VI secretion system in Ralstonia solanacearum

Microb Pathog. 2014 Sep;74:1-7. doi: 10.1016/j.micpath.2014.06.006. Epub 2014 Jun 24.


The type VI secretion system (T6SS) is recently discovered machinery in Gram-negative bacteria for translocation of proteins and also is required for full virulence. TssB is a highly conserved protein among the T6SSs, and indispensable for composition and function of T6S. The plant pathogenic bacterium Ralstonia solanacearum also harbours T6SS gene clusters, and a homologue of TssB, hereafter designated as TssBRS, but up to date its characterization and function remain unclear. In this study, we showed that TssBRS of R. solanacearum was required for secretion of Hcp, the haemolysin coregulated protein and a hallmark of T6S pathway. Deletion of tssBRS in R. solanacearum GMI1000 strain resulted in defect of biofilm formation, and the expression of the flagella operon is decreased, leading to decreased motility. More importantly, tssBRS mutant strain had significantly attenuated its virulence on tomato plants. TssB is essential for virulence and required for type VI secretion system in R. solanacearum.

Keywords: Ralstonia solanacearum; TssB; Type VI secretion; Virulence.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bacterial Proteins / genetics*
  • Bacterial Proteins / metabolism*
  • Bacterial Secretion Systems*
  • Biofilms / growth & development
  • Gene Deletion
  • Locomotion
  • Lycopersicon esculentum / microbiology
  • Plant Diseases / microbiology*
  • Ralstonia solanacearum / genetics*
  • Ralstonia solanacearum / metabolism*
  • Ralstonia solanacearum / physiology
  • Virulence Factors / genetics
  • Virulence Factors / metabolism


  • Bacterial Proteins
  • Bacterial Secretion Systems
  • Virulence Factors