Wet rot disease of banana (Musa sp.) caused by Pectobacterium carotovorum subsp. carotovorum in Turkey

In the late winter of 2016, an unusual bacterial disease was suspected of causing severe wet rot (tip over) of banana plants grown in various greenhouses in the Mersin province of Turkey. The symptoms of the disease included small round or irregular areas of wet rot, collar rotting, yellowing of the leaves, sucker tip over, and plant death. Infected pseudo-stem samples were collected for isolation of the putative pathogen. The pathogen was identified as Pectobacterium carotovorum subsp. carotovorum (Pcc) after subjecting all isolates to conventional nested PCR with EXPCCF/EXPCCR and INPCCR/INPCCF primer sets, which produced amplification fragments of 550 and 400 bp in the first and the second PCR reactions, respectively. BLAST analysis of amplified PCR products of pel gene and 16S rRNA and the phylogenetic relationships among the various Pcc strains showed high similarities, which ranged from 99-100% with those retrieved from the NCBI GenBank nucleotide database. Real-time PCR was conducted using a locked nucleic acid (LNA) probe specific to Pcc. The pathogenicity tests of all the Pcc isolates were confirmed on banana cultivar Grand Naine' and potato slices by inoculation with bacterial suspension and subsequent re-isolation of the pathogen from the infected plants. To our knowledge, this is the first time Pcc has been detected, identified and implicated as the causal agent of wet rot disease of banana plants in Turkey.