Characterization of Novel Factors Involved in Swimming and Swarming Motility in Salmonella enterica Serovar Typhimurium

PLoS One. 2015 Aug 12;10(8):e0135351. doi: 10.1371/journal.pone.0135351. eCollection 2015.

Abstract

Salmonella enterica utilizes flagellar motility to swim through liquid environments and on surfaces. The biosynthesis of the flagellum is regulated on various levels, including transcriptional and posttranscriptional mechanisms. Here, we investigated the motility phenotype of 24 selected single gene deletions that were previously described to display swimming and swarming motility effects. Mutations in flgE, fliH, ydiV, rfaG, yjcC, STM1267 and STM3363 showed an altered motility phenotype. Deletions of flgE and fliH displayed a non-motile phenotype in both swimming and swarming motility assays as expected. The deletions of STM1267, STM3363, ydiV, rfaG and yjcC were further analyzed in detail for flagellar and fimbrial gene expression and filament formation. A ΔydiV mutant showed increased swimming motility, but a decrease in swarming motility, which coincided with derepression of curli fimbriae. A deletion of yjcC, encoding for an EAL domain-containing protein, increased swimming motility independent on flagellar gene expression. A ΔSTM1267 mutant displayed a hypermotile phenotype on swarm agar plates and was found to have increased numbers of flagella. In contrast, a knockout of STM3363 did also display an increase in swarming motility, but did not alter flagella numbers. Finally, a deletion of the LPS biosynthesis-related protein RfaG reduced swimming and swarming motility, associated with a decrease in transcription from flagellar class II and class III promoters and a lack of flagellar filaments.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bacterial Proteins / genetics
  • Bacterial Proteins / metabolism
  • Flagella / genetics*
  • Flagella / metabolism
  • Gene Deletion
  • Movement*
  • Salmonella typhimurium / genetics*
  • Salmonella typhimurium / metabolism
  • Salmonella typhimurium / physiology

Substances

  • Bacterial Proteins
  • FlgE protein, Bacteria
  • fliH protein, Bacteria

Grants and funding

This work was supported by Helmholtz Association Young Investigator grant number VH-NG-932 and the People Programme (Marie Curie Actions) of the European Unions’s Seventh Framework Programme grant number 334030 (to ME). JAD, IS and CK acknowledge support by the President’s Initiative and Networking Funds of the Helmholtz Association of German Research Centers (HGF) under contract number VH-GS-202. SF was funded in the Zoonosis PhD program via a Lichtenberg Fellowship from the Niedersächsiche Ministerium für Wissenschaft und Kultur (MWK). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.