Characterization of IS1389, a new member of the IS3 family of insertion sequences isolated from Xanthomonas campestris pv. amaranthicola

IS1389, a new insertion sequence belonging to the IS3 family, has been iden tified in Xanthomonas campestris pv. amaranthicola. The genome of this bact erium contains at least 11 copies of the element, whereas no hybridizing se quences were detected in other Xanthomonas species [X. axonopodis, X. fraga ridae, X. phaseoli, and X. (Stenotrophomonas) maltophila]. Two nearly ident ical copies of the element (IS1389-A and IS1389-B) were characterized. Acco rding to analysis of sequence alignments and similar structural features, I S1389 belongs to the IS407 subgroup of the IS3 family, which duplicates 4bp of target DNA upon insertion. IS1389-A was found in the proximity of the m odification gene of the XamI restriction-modification system.