Putative origin of Myxococcus fulvus 124B02 plasmid, pMF1, from a chromosomal segment in another Myxococcus species

Myxobacteria or order Myxococcales (old nomenclature) or phylum Myxococcota (new terminology) are fascinating organisms well known for their diverse peculiar physiological, taxonomic, and genomic properties. Researchers have long sought to identify plasmids within these organisms, yet thus far, only two organisms from different families have been found to harbor a plasmid. This study delves into the origin and evolution of one of these plasmids, i.e., pMF1 present in M. fulvus 124B02 in the suborder Cystobacterineae and family Myxococcaceae. Here we first reannotated the pMF1 plasmid genome sequence and identified two additional genes which were not annotated till now. We further reported that all pMF1 plasmid genes depict homology with M. stipitatus CYD1 draft genome (contig 28) and a chromosomal segment of M. stipitatus DSM14675 in a syntenic manner, suggesting the presence of plasmid-like structure in M. stipitatus CYD1 but integrated as part of its chromosome. To comprehend the relationship among these three species, we conducted phylogenetic analyses using 16S and concatenated housekeeping genes and GGDC analysis, which confirmed that M. stipitatus CYD1 is a distinct and novel species within the genus Myxococcus. Overall, this study sheds light on the putative origin of the pMF1 plasmid, which likely originated from a closely related yet distinct species, possibly through the partition from its chromosome as a segment. ImportanceMyxobacteria are not well-known to have plasmids. Till now, only two organisms have been shown to have plasmids, raising a pertinent question about how these plasmids evolved randomly within the phylum Myxococcota. The study presented in this manuscript delves into the origin and evolution of the pMF1 plasmid found in Myxococcus fulvus 124B02, a member of the suborder Cystobacterineae and family Myxococcaceae. Our research addresses the intriguing topic of plasmid identification and evolution within Myxobacteria, which are a group of fascinating organisms that have garnered significant interest due to their diverse physiological, taxonomic, and genomic properties.