Sequence analysis of EZ-Tn5 insertion in the galU mutants. (A) Genomic location of galU on the X. citri subsp. citri chromosome and transposon insertion sites in the galU mutants. kefB encodes a transport protein, galU encodes a UTP-glucose-1-phosphate uridylyltransferase, and XCC2293 encodes a dehydratase protein. Bg, BglII restriction site. (B) PCR analysis confirming insertion of EZ-Tn5 into the galU gene: agarose gel electrophoresis of DNA amplified using primers galU-F1 and galU-R1 targeting the interior region of the galU gene from the X. citri subsp. citri wild-type 306, D12, and F6 strains. Lane 1, Invitrogen 1 Kb Plus DNA size marker; lane 2, D12, lane 3, F6, lane 4, X. citri subsp. citri 306. (C) Southern blot of DNA of X. citri subsp. citri wild-type strain 306 and galU mutants F6 and D12 digested with BglII. The membrane was probed with a 675-bp kan-2 gene fragment that was amplified using PCR with primers Kan-F1 and Kan-R1. Wt, wild type.