Establishment and improvement of genetic manipulation tools for Fusobacterium nucleatum

An imbalance in oral microbial homeostasis is significantly associated with the onset and progression of several systemic diseases. Fusobacterium nucleatum, a ubiquitous periodontitis-causing bacterium in the oral cavity, is frequently detected in focal sites and contributes to the pathogenesis of many extraoral diseases, including cancers, cardiovascular diseases, and adverse pregnancy outcomes (APOs). F. nucleatum is one of the few oral anaerobes that can be cultured purely in vitro and is a 'model species' for studying the impact of oral health on systemic health. The establishment and development of genetic manipulation tools for F. nucleatum and the construction of pathogenic gene-disrupted strains are important strategies for studying the pathogenicity of F. nucleatum. Here, we review the establishment and development of the genetic manipulation systems for F. nucleatum and summarize the characteristics of various genetic manipulation tools, such as suicide plasmid-based systems for gene inactivation, replicable plasmid-based systems controlling gene expression, and transposon-based random mutagenesis systems. Notably, we summarize and analyze their applications in the study of the pathogenic mechanisms of F. nucleatum. We hope to provide reference information and ideas for future research on genetic manipulation tools and the pathogenic mechanisms of F. nucleatum and other Fusobacterium species.