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Title: Constitutive expression of the Type VI Secretion System carries no measurable fitness cost in Vibrio cholerae
Abstract 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 bacteriumVibrio 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 help explain the prevalence of the T6SS across Gram‐negative bacteria.  more » « less
Award ID(s):
1845363 2003721
PAR ID:
10520857
Author(s) / Creator(s):
; ; ;
Publisher / Repository:
Ecology and Evolution
Date Published:
Journal Name:
Ecology and Evolution
Volume:
14
Issue:
3
ISSN:
2045-7758
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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