Phenotypic and genotypic diversity of Pectobacterium carotovorum subsp carotovorum causing soft rot disease of potatoes in Morocco

The species Pectobacterium carotovorum include a diverse subspecies of bacteria that cause disease on a wide variety of plants. In Morocco, approximately 95 % of the P. carotovorum isolates from potato plants with tuber soft rot are P. carotovorum subsp carotovorum. The aim was to monitor this Moroccan population in time and to continue the work carried out to understand the genetic diversity of these subspecies. The diversity of 30 strains of P. carotovorum subsp carotovorum collected between 2012 and 2013 from potato soft rot from different Moroccan regions was evaluated. On the basis of phenotypic characteristics, the isolates were classified into four different biovars and in three groups based on the aggressiveness traits. Moreover, the genetic variability was also investigated by fingerprint analysis. The typing by ERIC and REP sequences of the new collection compared to ERIC-PCR and phylogenetic analysis of pmrA sequences, demonstrated that there is a considerable genetic diversity in P. carotovorum subsp. carotovorum strains, which can be divided into two distinct groups, independently to their source of isolation, by their pathogenicity.