A DNA fragment containing a Klebsiella oxytoca gene for polygalacturonate trans-eliminase was cloned into the kanamycin resistance transposon Tn5. This new transposon, designated Tn5-Pga+, had a transposition frequency of 1 X 10(-6). The broad host range plasmid pR751::Tn5-Pga+ was conjugally transferred to a variety of genetic backgrounds. The ability to degrade polygalacturonate was expressed in Aeromonas hydrophila, Alcaligenes eutrophus, Azotomonas insolita, Escherichia coli, Pseudomonas putida and Rhodopseudomonas sphaeroides, but not in Zymomonas mobilis.