[Genetic regulation of pathogenicity and virulence factors in bacteria Erwinia carotovora subsp. atroseptica: identification of kduD gene].

A mutant that cannot utilize pectin substances of plant cell walls was obtained via insertion of mini-mini-Tn5xylE transposon into the chromosome of phytopathogenic bacteria Erwinia carotovora subsp. atroseptica. The inability of mutant cells to utilize these substrates was caused by a failure to accomplish the catabolism of unsaturated digalacturonic acid (UDA). Study of enzymatic activities has established that mutant bacteria lost the ability to produce 2,5-diketo-3-deoxygluconate dehydrogenase, an enzyme of intracellular UDA utilization. Molecular cloning of the mutant gene was conducted, and its nucleotide sequence was determined. It was shown that the nucleotide sequence of this gene had an 82% homology with the sequence of Erwinia chrysanthemi EC3937 kduD gene encoding 2,5-diketo-3-deoxygluconate dehydrogenase. The intergene kdul-kduD region in bacteria Erwinia carotovora subsp. atroseptica is shorter in length by 98 nucleotides than the corresponding region of Erwinia chrysanthemi and does not contain promoter sequences. The kduD gene was located at 126.8 min of the Erwinia carotovora subsp. atroseptica genetic map.