Ramsay, J. P. & Firth, N. Diverse mobilization strategies facilitate transfer of non-conjugative mobile genetic elements. Curr. Opin. Microbiol. 38, 1–9 (2017)
Read this - to figure out, how often do plasmids with OriT but no relaxase occur?
Context :
Further, numerous small plasmids do not encode for relaxases and undergo transfer by exploiting the relaxosome of other conjugative elements in trans85,6