Phylogenetic evolution and origin of natural plasmids of Lactobacillus plantarum

Abstract:

[Objective] In order to explore the evolutionary relationship and origin of natural plasmid of Lactobacillus plantarum.[Methods] We analyzed phylogenetic relationships and origins of 75 natural plasmids of L. plantarum by replication initiation protein (Rep) phylogenetic tree, genomic collinearity, genomic GC content and host range.[Results] Rep phylogenetic tree and genomic collinearity analysis simultaneously showed that all natural plasmids of L. plantarum could be divided into 6 families with close evolutionary relationships, 2 complex plasmids with special evolution form and 1 independent evolution plasmid pLP2140. The complex plasmids pMRI5.2 and pLP12-1 were fused by 2 different plasmids of the family 1-2 and family 5-6. Therefore, the natural plasmids of L. plantarum could be originated from 7 ancestors. The genomic collinearity analysis showed that the 6 family plasmids could be further divided into 17 subfamily groups with closer evolutionary relationships, and the phylogenetic relationships among plasmids could be clearly and effectively revealed at the subfamily level. Finally, the analysis of genomic GC content and host range provided further evidence for the phylogenetic relationship and origin of the natural plasmid of L. plantarum.[Conclusion] Therefore, the above research can accurately and effectively reveal the phylogenetic relationship and origin of the natural plasmids of Lactobacillus plantarum, which is of great reference value for the acquaintance and study of the evolution and origin of the natural plasmids of Lactobacillus plantarum. We proposed a more effective research strategy and analytical method of the evolution and origin of natural plasmids by comparing and combining the characteristics of the analytical methods of Rep phylogenetic tree and genome collinearity, and this method may be applicable to all bacterial natural plasmids, so it may have universal methodological significance for the study of the evolution and origin of natural plasmids.