[Isolation and genetic study of Erwinia mutants devoid of common components of the phosphoenolpyruvate-dependent...

Mutants of bacteria belonging the genus Erwinia (Erwinia chrysanthemi and Erwinia carotovora) with pleiotropic disturbances in the utilization of many substrates were obtained through chemical and transposon mutagenesis. Genetic studies revealed that these mutants had defective ptsI or ptsH genes responsible for the synthesis of common components of the phosphoenolpyruvate-dependent phosphotransferase system, enzyme I and the HPr protein, respectively. The ptsI+ allele in both Erwinia species was cloned in vivo. Mapping of obtained mutations indicated that the ptsI and ptsH genes of E. chrysanthemi do not constitute a linkage group. The ptsI gene is located at 100 min of the chromosomal map, whereas the ptsH gene is located at 175 min. Sequencing of a portion of the E. chrysanthemi ptsI gene showed that a product of the cloned DNA region had up to 68% homology with the N terminus of Escherichia coli enzyme I.