Figure 1: DGGE analysis using a linear denaturing-agent gradient of 35-65%. DNA from samples were amplified using DGGE-specific primers designed against the 16 rRNA gene. Lanes 1 and 2: positive controls using purified Ralstonia and Klebsiella DNA, respectively. Lane 3: additional positive control consisting of mixed purified Ralstonia and Klebsiella DNA. Lane 4: mixed sample consisting of mixed purified Ralstonia and Klebsiella DNA, as well as DNA from Enterobacter aerogenes, E. cloacae and Escherichia coli, which are closely related to Klebsiella and found associated with ironwood. Lane 5: Ralstonia-inoculated plant sample. Lane 6: Klebsiella-inoculated plant sample. Lane 7: plant sample inoculated with Ralstoniaand Klebsiella. Red boxes indicate the characteristic Ralstoniaband. Green boxes indicate the characteristic Klebsiella band. Characteristic bands were excised and sequenced from all lanes.