Data for: Constitutive expression of the Type VI secretion system carries no measurable fitness cost in Vibrio cholerae

The Type VI Secretion System (T6SS) is a widespread and highly effective mechanism of microbial warfare; it confers the ability to efficiently kill susceptible cells within close proximity. Due to its large physical size, complexity, and ballistic basis for intoxication, it has widely been assumed to incur significant growth costs in the absence of improved competitive outcomes. In this study, we precisely examine the fitness costs of constitutive T6SS firing in the bacterium Vibrio cholerae. We find that, contrary to expectations, constitutive expression of the T6SS has a negligible impact on growth, reducing growth fitness by 0.025 ± 0.5% (95% CI) relative to a T6SS- control. Mathematical modeling of microbial populations demonstrates that, due to clonal interference, constitutive expression of the T6SS will often be neutral, with little impact on evolutionary outcomes. Our findings underscore the importance of precisely measuring the fitness costs of microbial social behaviors, and h..., Bacterial strains and media: Bacterial strains were grown aerobically at 37°C overnight in lysogeny broth (LB) (1% w/v tryptone (Teknova, Hollister CA, USA), 0.5% w/v yeast extract (Hardy Diagnostics, Santa Maria CA, USA), 1% w/v NaCl (VWR Life Sciences, Radnor PA, USA)) with constant shaking or on LB agar (1.5% w/v agar; Genesee Scientific, San Diego CA, USA) standing at 37°C. LB-X-gal was made by mixing in 40 μg/mL of X-gal (GoldBio, St. Louis MO, USA) to LB agar while it is liquid.
Mutant Construction: All V. cholerae mutant strains were made using the pKAS allelic exchange system described by Skorupski et al using pKAS32 (Skorupski & Taylor, 1996). JT101 and SN598 [Supplemental Data File 1] were described in previous studies (Ng et al., 2022; Thomas et al., 2017). CZ005 and CZ006 were generated through an insertion of a spectinomycin resistance cassette into the lacZ gene of JT101 and SN598 respectively. All insertions and changes to phenotype were confirmed with PCR, antibiotic..., , # Data for: Constitutive expression of the Type VI secretion system carries no measurable fitness cost in Vibrio cholerae

[https://doi.org/10.5061/dryad.9cnp5hqqc](https://doi.org/10.5061/dryad.9cnp5hqqc)

Public repository for model and data collected by Christopher Zhang as a part of a manuscript describing the cost of the Type 6 Secretion System.

Manuscript Preprint may be found here: [https://www.biorxiv.org/content/10.1101/2023.03.24.534098v1](https://www.biorxiv.org/content/10.1101/2023.03.24.534098v1)

## Description of the data and file structure

**Supplementary Data Table 1:** .ods file containing list of strains used, measured results, values, and calculations. May be accessed with some spreadsheet editors like LibreOffice Calc.

* **Strain List Tab**: A list of strains used in the publication
* **Metabolic Cost Competition Experiment Tab:** For the metabolic cost experiment run on plates; raw CFU counts per day, calculated hypothetical bacterial quantities, calculated ...