Аннотация:Basal glume rot caused by Pseudomonas syringae pv. atrofaeiens (PSA), has emerged as a major bacterial disease of wheat, barley, and rye in Russia. Forty-nine suspect strains of PSA isolated from diseased cereal plants from different regions of Russia were tentatively identified by production of a fluorescent pigment and confirmed by pathogenicity tests on the host of origin. F.ach strain was then grouped according to LOPAT (/cvan, oxidase, potato rot, argininc dihydrolasc, and fobacco hypersensitivity) assays. Ten strains were assigned to LOPAT group la, 13 to group lb, 5 to group 2, 4 to group 3, and 16 to group 5. Strains of each group were then characterized by I6S-23S rRNA Intergcnic Transcribed Region (ITR) sequencing and fingerprinted by restriction fragment length polymorphism of ITR. and repetitive PCR using REP. ERIC, and BOX primers. A phylogenetictree constructed from ITR sequence data revealed two discrete dusters, designated "syringae" and "fluorescens". ERIC-PCR did not work well. However, BOX PCR produced very useful differential genomic fingerprints. There was a high correlation between LOPAT group la and BOX PCR patterns. The remaining groups showed a low correlation to BOX PCR patterns and a high level of genetic diversity.