IncP1

IncP-1 is a plasmid incompatibility group comprising broad-host-range, conjugative plasmids predominantly found in Gram-negative bacteria. Members of this group are capable of transferring by conjugation across diverse hosts, enabling horizontal gene transfer in natural and engineered communities. IncP-1 plasmids are typically medium-sized, around 50–80 kilobases, and encode a complete set of tra genes for conjugative transfer, in addition to replication and maintenance modules that ensure stable inheritance in daughter cells.

Key genetic features include a replication region with repA, a mobilization region with the transfer genes (including oriT) and a partitioning system (par) and post-segregational killing mechanisms, helping stable maintenance.

Subgroups and host range: The IncP-1 group is subdivided into several subgroups (for example α, β, γ, δ, ε), with variations in host range and cargo capacity. They have been isolated from soil, wastewater, clinical and environmental isolates, and commonly carry antibiotic resistance genes and catabolic gene clusters enabling degradation of various xenobiotics.

Applications and significance: Due to their broad host range and well-characterized transfer systems, IncP-1 plasmids and derivatives (vectors) are widely used in molecular biology as shuttle vectors for gene cloning and expression in diverse Gram-negative bacteria. They also play a central role in studies of horizontal gene transfer and environmental dissemination of resistance determinants.