The causal organism of brown rot disease Ralstonia solanacearumis a common and dangerous pathogen
affecting several economically important crop species. R. solanacearum has a wide range of occurrence and
severity in potatoes and other nightshades such as eggplant, tomatoes and green peppers. The main goal of this
study is to detect the genetic variation between 14 isolates of R. solanacearum from diverse geographic
ecoregions of Egypt using the Start Codon Targeted Technique (SCoT). Ten SCoT primers were used to amplify
SCoT markers, taking into account genetic diversity and phylogenetic distance between target isolates. The results
showed 143 bands in a range of 130 to 2100 bp, of which 112 bands (76.40%) were polymorphic and 31 bands
(23.60%) were monomorphic. Nei's genetic distance and UPGMA method divided the dendrogram of the
fourteen isolates into two major groups. Isolates 1, 11, 12, 13 and 14 were grouped together in Group I, while
Group II was divided into two main subgroups, in which isolates 5 and 6 were grouped in Subgroup I and isolates
2 and 3 in Subgroup II became. The third group was divided into three subgroups, with the first subgroup
including Isolate 4 and Isolate 7. The second subgroup contained isolate 8 and isolate 9. Interestingly, isolate 10
was only grouped in the third subgroup and showed a diversity profile of unique and less related. to other isolates.
Regarding disease diversity, this isolate may have different characteristics that will be considered in the future.