Vibrio parahaemolyticus T6SS2 effector repertoires

ABSTRACT

All strains of the marine bacterium Vibrio parahaemolyticus harbor a type VI secretion system (T6SS) named T6SS2, suggesting that this system plays an important role in the life cycle of this emerging pathogen. Although T6SS2 was recently shown to play a role in interbacterial competition, its effector repertoire remains unknown. Here, we employed proteomics to investigate the T6SS2 secretome of two V. parahaemolyticus strains, and we identified several antibacterial effectors encoded outside of the main T6SS2 gene cluster. We revealed two T6SS2-secreted proteins that are conserved in this species, indicating that they belong to the core secretome of T6SS2; other identified effectors are found only in subsets of strains, suggesting that they comprise an accessory effector arsenal of T6SS2. Remarkably, a conserved Rhs repeat-containing effector serves as a quality control checkpoint and is required for T6SS2 activity. Our results reveal effector repertoires of a conserved T6SS, including effectors that have no known activity and that have not been previously associated with T6SSs.

KEYWORDS:

• Vibrio
• effector
• competition
• antibacterial
• secretion
• type VI secretion system

Acknowledgments

We thank members of the Salomon and Bosis labs for helpful discussions and suggestions. We also thank the Smoler Proteomics Center at the Technion for performing and analyzing the mass spectrometry data. This work was performed in partial fulfillment of the requirements for a PhD degree for D. Tchelet at the Sackler Faculty of Medicine, Tel Aviv University.

Data availability statement

The authors confirm that the data supporting the findings of this study are available within the article and its supplementary material. The mass spectrometry raw data files were deposited in ProteomeXchange under the accession numbers indicated in the Materials and Methods section. The data can be accessed via the following links: For strain BB22OP http://www.ebi.ac.uk/pride/archive/projects/PXD037864; for strain RIMD 2210633 http://www.ebi.ac.uk/pride/archive/projects/PXD037980.

Disclosure statement

The authors declare that they have no conflict of interest.

Supplementary material

Supplemental data for this article can be accessed online at https://doi.org/10.1080/19490976.2023.2178795

Additional information

Funding

This work was supported by the Israel Science Foundation [grant number 1362/21 to E. Bosis and D. Salomon, and grant number 920/17 to D. Salomon].