Mini-Tn7 vectors as genetic tools for gene cloning at a single copy number in an industrially important and phytopathogenic bacteria, Xanthomonas spp.

Transposon mini-Tn 7 vectors insert into the chromosome of several Gram-negative bacteria in a site-specific manner. Here, we showed the application of mini-Tn 7 as single copy site-specific integration vector system for Xanthomonas campestris pv. campestris . The transposition of the mini-Tn 7 into the bacterial genome was detected at a Tn 7 attachment ( att Tn 7 ) site located downstream of glmS1 . Furthermore, using a newly constructed vector pBBR1FLP2 containing the flipase (FLP) recombinase for site-specific excision of the sequence between the FLP recombinase target (FRT) sites, and a sacB counter selection marker, an unmarked mini-Tn 7 insertion mutant was created. Mini-Tn 7 insertion did not affect bacterial virulence on the tested plant. The mini-Tn 7 and FLP–FRT systems also work well in Xanthomonas oryzae pv. oryzae .