About this Research Topic
Dissemination of virulence, antibiotic resistance, and metabolic pathways between bacteria is often due to plasmids. A more widely studied example is the broad host range Ti-plasmid of Agrobacterium tumefaciens that can transfer between diverse bacteria and is able to even direct horizontal gene transfer to plant, fungal, or mammalian cells. Multiple plasmids can coexist in the same bacterial cell, and the interactions between plasmids of related or different families are under complex regulatory mechanisms controlling plasmid gene transcription, copy number, and conjugal transfer inhibition. Host bacteria, likewise, also employ strategies to control the entry, replication, or maintenance of the plasmids. Plasmid transfer in response to physiological and environmental conditions, such as that mediated by quorum sensing, secondary metabolites, or inducers/inhibitors, is still poorly understood and can be closely tied to the pathogenicity of the bacteria.
Bacteria residing in the same environmental niche often freely exchange genetic material via conjugation or natural transformation. In addition to the fully autonomous conjugative plasmids, other plasmids can be mobilized during conjugation of co-resident plasmids. Complex microbiota in soils, animal guts, and extreme environments have been explored with rigor and new bacterial species, as well as new plasmids, are being identified at an unprecedented rate. Further understanding of how plasmids are transferred in the natural environment will have a broad impact.
The rise of antibiotic resistance in human, animal and plant pathogens is a major concern for human health and agriculture and has therefore been under intense scrutiny and a major research focus in recent decades. The spread of antibiotic resistance genes to pathogens often involves the transmission of plasmids. However, many details about molecular mechanisms, ecology and evolution of plasmid transfer systems in various bacterial groups are still lacking, thus limiting the development of strategies to prevent the spread of antibiotic resistance.
The study of plasmid transfer pre-dates the discipline of molecular biology itself; early research on the IncF, IncP, and other antibiotic resistance plasmids laid a solid foundation for modern molecular microbiology and biotechnology. The present time is ideal to re-contextualize fundamental mechanisms and further broaden knowledge of plasmid biology. The new era of high-throughput sequencing methodologies and bioinformatics has encouraged scientists to take a broad, holistic approach to many research questions generating a wealth of DNA sequence data including plasmid genomes. These sequences can be used to further the understanding of transfer genes and mechanisms, and shed light on the evolution and family relationships of plasmids.
This Research Topic is intended to cover the whole spectrum of plasmid transfer from fundamental to applied research, and welcomes all types of articles including original research, (mini-)reviews, and opinions/perspectives. Reviews offering historical perspectives are encouraged. The subject areas of interest include, but are not limited to:
1. Structure and function of the conjugative plasmid transfer machinery/ Type IV secretion systems
2. Regulation of plasmid transfer
3. Interplay between co-resident conjugative and non-conjugative plasmids or other mobile genetic elements
4. Bacterial host range and the impact of cellular context for conjugative transfer of plasmids
5. Comparative genomics, phylogenetic analysis and evolution of conjugal transfer (e.g. tra) genes
6. Applications of and tools derived from transmissible plasmids in biotechnology, bioremediation, and biocontrol
7. Plasmid transfer in natural environments, including diverse microbiota associated with plants, animals and humans
Keywords: plasmid, conjugation, mobilization, horizontal gene transfer, Type IV secretion
Important Note: All contributions to this Research Topic must be within the scope of the section and journal to which they are submitted, as defined in their mission statements. Frontiers reserves the right to guide an out-of-scope manuscript to a more suitable section or journal at any stage of peer review.