title: Distribution of Secretion Systems in the GenusLegionellaand Its Correlation with Pathogenicity.
abstract: The genusLegionellacomprises over 60 species, which are important human pathogens. Secretion systems inLegionella pneumophilahave been studied extensively because of the essential role of protein secretion in bacterial infection. However, there are few reports describing the secretion systems in non-L. pneumophilaspecies. In this study, we analyzed the distribution of secretion systems inL. pneumophilaand 18 species of non-L. pneumophilabased on whole genome sequences. A total of 74 whole genome sequences from 19 species ofLegionellawere analyzed. Type II and IVB secretion systems were detected in allLegionellastrains, but the type I secretion systems was restricted toL. pneumophila.The type IVA secretion system was randomly distributed among different species. Furthermore, we found the type VI secretion system in three non-L. pneumophilastrains (Legionella cherriiDSM 19213,Legionella dumoffiiTex-KL, andLegionella gormaniiATCC 33297). In population structure analysis,L. pneumophilaformed a conservative cluster and was located at the terminal of the evolutionary tree. At the same time,L. pneumophila, especially eight clone groups (named MCGG1-MCGG8), showed higher intracellular growth ability than non-L. pneumophilaspecies. These results suggest thatL. pneumophilahas acquired additional secretion systems during evolution, resulting in increased pathogenicity.
authors.affiliation: State Key Laboratory for Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and PreventionBeijing, China; Collaborative Innovation Center for Diagnosis and Treatment of Infectious DiseasesHangzhou, China.
authors.forename: Tian
authors.initials: T
authors.lastname: Qin
authors.affiliation: State Key Laboratory for Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and PreventionBeijing, China; Collaborative Innovation Center for Diagnosis and Treatment of Infectious DiseasesHangzhou, China.
authors.forename: Haijian
authors.initials: H
authors.lastname: Zhou
authors.affiliation: State Key Laboratory for Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention Beijing, China.
authors.forename: Hongyu
authors.initials: H
authors.lastname: Ren
authors.affiliation: Novogene Bioinformatics Technology Co. Ltd Beijing, China.
authors.forename: Wenbin
authors.initials: W
authors.lastname: Liu
keywords: L. pneumophila; Legionella; pathogenicity evolution; population structure; secretion systems; whole genome sequence