Ralstonia solanacearum is the bacterium that causes brown rot in potatoes. It poses a serious threat to the global output of potatoes, especially in warm-growing regions like the Mediterranean. Infections with brown rot can be extremely harmful and result in significant yield losses. Several extracellular enzymes that degrade plant cells wall are produced by Ralstonia solanacearum and are considered virulence factors. These comprise two exopolygalacturonase -PGs, pehB and pehC, and one endopolygalacturonase (PG), pehA. Five isolates of R. solanacearum were isolated and identified, namely BR1, BR2, BR3, BR4, and BR5. After the isolates' pathogenicity was assessed, it was found that isolates BR3 and BR4 were extremely virulent, isolate BR2 was moderately virulent, and the virulence of isolates BR1 and BR5 was weak mildly. To investigate the existence of the Polygalacturonase (PehA) gene, a specific primer was employed in R. solancearum isolates to identify molecular weight 500 bp present in all isolates. Every isolate has a band with a molecular weight of roughly 52 kilodaltons (kDa) visible on the SDS/PAGE gel. The highest  of the  gene expression level of pehA gene was recorded in NB+PGA than NB+potato tubers compared with the gene expression level in NB medium (control). Moreover, the gene expression level was high in BR3 isolate expression and BR4 isolates, while the low gene expression was observed at BR1 and BR5 isolates. The BR2 isolate was moderate gene expression.