Molecular, morphological and pathogenic characterization of Clavibacter michiganensis subsp. sepedonicus strains of different geographic origins in Georgia

Potato ring rot and its causative pathogen Clavibacter michiganensis subsp. sepedonicus (Cms) have been studied in Georgia for the first time. The samples were collected in the fields and potato storage facilities in various potato producing regions of Georgia. Potato tubers were also collected at agrarian markets and the border checkpoints, from which potatoes are imported from neighboring countries. In 124 potato samples the detection of Cms was performed using specific PCR analysis and bioassay test. A total of 20 Cms isolates were purified and identified by subspecies-specific PSA-1 and PSA-R primers set. The isolates were characterized according to cell morphology, cultural-biochemical properties and virulence. The study of genetic diversity using molecular typing methods of PCR melting profile with different restriction enzymes and variable number tandem repeats PCR revealed significant differences between Cms isolates, which is not related to their geographical origin.