Аннотация
The article discusses the morphological changes of birch trees due to bacterial dropsy growing in the "Green Belt" artificial forest in the surrounding of the Nur-Sultan city.Samples of kernel were taken from diseased tree trunks, and, afterward, isolated bacterial cultures were grown in a nutrient medium.For molecular genetic studies, one strain (designated as DDdd-1), the most typical of morphological characteristics, was selected, the colonies of which showed the greatest growth on nutrient media.The nucleotide sequences 8F and 806R of 16SrRNA were determined on the basis of sequencing.The resulting sequences were compared in GenBank from the NCBI database showing related species and their similarities.Extraction of cores from infected birch trunks, isolation of pure strains of the pathogen, molecular identification of ribosomal RNA 16S nucleotide chains were performed using modern methods in the field of bacteriology.Then, the results obtained were compared with relevant data from the International Genbank database.Molecular characteristics of isolated bacterial DDdd-1 strain have been found to correspond to typical Dickeya dadantii by 96.72%.According to the International Genbank, the DDdd-1 strain is defined as pathovar D. dadantii pv.betulae.The data obtained demonstrate close relation of DDdd-1 strain Dickeya dadantii pv.betulae to some strains of Dickeya chrysanthemi.The species identified in International Genbank as Erwinia chrysanthemi with index numbers KJ541470.1 and AF373175.1 are assumed to be identical to D. dadantii pv.betulae.Dickeya is a complex taxon that still requires a lot of research efforts on species composition, close family bonds, the size and structure of host plants.