title: Genomic analysis of 38 Legionella species identifies large and diverse effector repertoires.
abstract: Infection by the human pathogen Legionella pneumophila relies on the translocation of ∼ 300 virulence proteins, termed effectors, which manipulate host cell processes. However, almost no information exists regarding effectors in other Legionella pathogens. Here we sequenced, assembled and characterized the genomes of 38 Legionella species and predicted their effector repertoires using a previously validated machine learning approach. This analysis identified 5,885 predicted effectors. The effector repertoires of different Legionella species were found to be largely non-overlapping, and only seven core effectors were shared by all species studied. Species-specific effectors had atypically low GC content, suggesting exogenous acquisition, possibly from the natural protozoan hosts of these species. Furthermore, we detected numerous new conserved effector domains and discovered new domain combinations, which allowed the inference of as yet undescribed effector functions. The effector collection and network of domain architectures described here can serve as a roadmap for future studies of effector function and evolution.
authors.affiliation: Department of Cell Research and Immunology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel.
authors.forename: David
authors.initials: D
authors.lastname: Burstein
authors.affiliation: Department of Microbiology, University of Chicago, Chicago, Illinois, USA.
authors.forename: Francisco
authors.initials: F
authors.lastname: Amaro
authors.affiliation: Department of Molecular Microbiology and Biotechnology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel.
authors.forename: Tal
authors.initials: T
authors.lastname: Zusman
authors.affiliation: Department of Molecular Microbiology and Biotechnology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel.
authors.forename: Ziv
authors.initials: Z
authors.lastname: Lifshitz
authors.affiliation: Department of Cell Research and Immunology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel.
authors.forename: Ofir
authors.initials: O
authors.lastname: Cohen
authors.affiliation: Biology Division, Argonne National Laboratory and Department of Ecology and Evolution, University of Chicago, Chicago, Illinois, USA.
authors.forename: Jack A
authors.initials: JA
authors.lastname: Gilbert
authors.affiliation: Department of Cell Research and Immunology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel.
authors.forename: Tal
authors.initials: T
authors.lastname: Pupko
authors.affiliation: Department of Microbiology, University of Chicago, Chicago, Illinois, USA.
authors.forename: Howard A
authors.identifier: http://orcid.org/0000-0001-7955-8709
authors.initials: HA
authors.lastname: Shuman
authors.affiliation: Department of Molecular Microbiology and Biotechnology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel.
authors.forename: Gil
authors.initials: G
authors.lastname: Segal
mesh_terms: D019143:Evolution, Molecular; D016680:Genome, Bacterial; D007875:Legionella / Q000145:classification / Q000235:genetics*; D010802:Phylogeny; D013045:Species Specificity