The dynamics and structure of these communities are greatly influenced by interbacterial competition through the secretion of toxic effectors.
Bacteria have evolved several systems to outcompete their neighbors by poisoning them through a contact-dependent killing (including effectors of type V and VI secretion systems) or the release of soluble toxins (including colicins) in the environment.
Polymorphic toxins are bacterial exotoxins which share common features regarding their domain architecture.
The fact that toxic domains are shared between several families of PTs is a hallmark of this category of toxins.
[3] PTs are involved in killing or inhibiting the growth of bacterial competitors lacking the adequate immunity protein.