Vibrio parahaemolyticus Type VI Secretion System 1 Is Activated in Marine Conditions to Target Bacteria, and Is Differentially Regulated from System 2

Dor Salomon, Herman Gonzalez, Barrett L. Updegraff, Kim Orth

Research output: Contribution to journalArticle

74 Citations (Scopus)

Abstract

Vibrio parahaemolyticus is a marine bacterium that thrives in warm climates. It is a leading cause of gastroenteritis resulting from consumption of contaminated uncooked shellfish. This bacterium harbors two putative type VI secretion systems (T6SS). T6SSs are widespread protein secretion systems found in many Gram-negative bacteria, and are often tightly regulated. For many T6SSs studied to date, the conditions and cues, as well as the regulatory mechanisms that control T6SS activity are unknown. In this study, we characterized the environmental conditions and cues that activate both V. parahaemolyticus T6SSs, and identified regulatory mechanisms that control T6SS gene expression and activity. We monitored the expression and secretion of the signature T6SS secreted proteins Hcp1 and Hcp2, and found that both T6SSs are differentially regulated by quorum sensing and surface sensing. We also showed that T6SS1 and T6SS2 require different temperature and salinity conditions to be active. Interestingly, T6SS1, which is found predominantly in clinical isolates, was most active under warm marine-like conditions. Moreover, we found that T6SS1 has anti-bacterial activity under these conditions. In addition, we identified two transcription regulators in the T6SS1 gene cluster that regulate Hcp1 expression, but are not required for immunity against self-intoxication. Further examination of environmental isolates revealed a correlation between the presence of T6SS1 and virulence of V. parahaemolyticus against other bacteria, and we also showed that different V. parahaemolyticus isolates can outcompete each other. We propose that T6SS1 and T6SS2 play different roles in the V. parahaemolyticus lifestyles, and suggest a role for T6SS1 in enhancing environmental fitness of V. parahaemolyticus in marine environments when competing for a niche in the presence of other bacterial populations.

Original languageEnglish (US)
Article numbere61086
JournalPLoS One
Volume8
Issue number4
DOIs
StatePublished - Apr 16 2013

Fingerprint

Vibrio parahaemolyticus
Bacteria
bacteria
Shellfish
Cues
Transcription
Ports and harbors
Gene expression
Quorum Sensing
protein secretion
quorum sensing
Genes
Salinity
gastroenteritis
Gastroenteritis
Multigene Family
shellfish
regulator genes
Gram-Negative Bacteria
Climate

ASJC Scopus subject areas

  • Agricultural and Biological Sciences(all)
  • Biochemistry, Genetics and Molecular Biology(all)
  • Medicine(all)

Cite this

Vibrio parahaemolyticus Type VI Secretion System 1 Is Activated in Marine Conditions to Target Bacteria, and Is Differentially Regulated from System 2. / Salomon, Dor; Gonzalez, Herman; Updegraff, Barrett L.; Orth, Kim.

In: PLoS One, Vol. 8, No. 4, e61086, 16.04.2013.

Research output: Contribution to journalArticle

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