PromA plasmids of Hydrogenophaga genomes

PromA group plasmids are broad host range plasmids, which are often cryptic and have an uncertain ecological role.In this study, we present three new PromA gamma plasmids which carry genes related to linuron degradation, two of which originate from unrelated Hydrogenophaga hosts and one which was isolated by exogenous plasmid capture from an on-farm biopurification system. The plasmids which were isolated from Hydrogenophaga carry all necessary genes for the complete degradation of linuron, while the exogenously captured plasmid only has the gene to perform the initial degradation step. In each case, IS1071 elements are associated with the catabolic genes, which had common insertion sports in most of the plasmids. We have shown that within the host, the PromA plasmids are very heterogenous in the cargo that they carry and offer genetic plasticity to the host organism. Additionally, the host organisms have potentially mobilizable megaplasmids which carry functions related to heavy metal resistance, efflux and intracellular trafficking. These results indicate that PromA plasmids can play an important role in the dissemination of catabolic genes in various host organisms and environments.