title: A type VI secretion-related pathway in Bacteroidetes mediates interbacterial antagonism.
abstract: Bacteroidetes are a phylum of Gram-negative bacteria abundant in mammalian-associated polymicrobial communities, where they impact digestion, immunity, and resistance to infection. Despite the extensive competition at high cell density that occurs in these settings, cell contact-dependent mechanisms of interbacterial antagonism, such as the type VI secretion system (T6SS), have not been defined in this group of organisms. Herein we report the bioinformatic and functional characterization of a T6SS-like pathway in diverse Bacteroidetes. Using prominent human gut commensal and soil-associated species, we demonstrate that these systems localize dynamically within the cell, export antibacterial proteins, and target competitor bacteria. The Bacteroidetes system is a distinct pathway with marked differences in gene content and high evolutionary divergence from the canonical T6S pathway. Our findings offer a potential molecular explanation for the abundance of Bacteroidetes in polymicrobial environments, the observed stability of Bacteroidetes in healthy humans, and the barrier presented by the microbiota against pathogens.
authors: Department of Microbiology, University of Washington, Seattle, WA 98195, USA.
authors: Alistair B
authors: AB
authors: Russell
authors: Department of Microbial Pathogenesis and Microbial Diversity Institute, Yale University School of Medicine, New Haven, CT 06536, USA.
authors: Aaron G
authors: AG
authors: Wexler
authors: Department of Microbiology, University of Washington, Seattle, WA 98195, USA.
authors: Brittany N
authors: BN
authors: Harding
authors: Department of Microbiology, University of Washington, Seattle, WA 98195, USA.
authors: John C
authors: JC
authors: Whitney
authors: Department of Microbiology, University of Washington, Seattle, WA 98195, USA.
authors: Alan J
authors: AJ
authors: Bohn
authors: Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland, Baltimore, MD 21201, USA.
authors: Young Ah
authors: YA
authors: Goo
authors: Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland, Baltimore, MD 21201, USA.
authors: Bao Q
authors: BQ
authors: Tran
authors: Department of Microbial Pathogenesis and Microbial Diversity Institute, Yale University School of Medicine, New Haven, CT 06536, USA.
authors: Natasha A
authors: NA
authors: Barry
authors: Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147, USA.
authors: Hongjin
authors: H
authors: Zheng
authors: Department of Microbiology, University of Washington, Seattle, WA 98195, USA.
authors: S Brook
authors: SB
authors: Peterson
authors: Department of Microbiology, University of Washington, Seattle, WA 98195, USA.
authors: Seemay
authors: S
authors: Chou
authors: Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147, USA.
authors: Tamir
authors: T
authors: Gonen
authors: Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland, Baltimore, MD 21201, USA.
authors: David R
authors: DR
authors: Goodlett
authors: Department of Microbial Pathogenesis and Microbial Diversity Institute, Yale University School of Medicine, New Haven, CT 06536, USA. Electronic address: andrew.goodman@yale.edu.
authors: Andrew L
authors: AL
authors: Goodman
authors: Department of Microbiology, University of Washington, Seattle, WA 98195, USA. Electronic address: mougous@u.washington.edu.
authors: Joseph D
authors: JD
authors: Mougous
mesh_terms: D000898:Antibiosis; D001426:Bacterial Proteins / Q000737:chemistry / Q000378:metabolism; D058947:Bacterial Secretion Systems; D005417:Flavobacterium / Q000502:physiology*; D005798:Genes, Bacterial; D005810:Multigene Family; D010802:Phylogeny
chemical_list: D001426:Bacterial Proteins; D058947:Bacterial Secretion Systems