Pectobacterium carotovorum subsp. actinidiae subsp. nov., a new bacterial pathogen causing canker‐like symptoms in yellow kiwifruit, Actinidia chinensis

In this study, symptoms closely resembling those caused by Pseudomonas syringae pv. actinidiae were found in kiwifruit plants ( Actinidia chinensis cv. Hort16A) growing in Jeju province, Korea. Bacterial strains including strain KKH3 T were isolated from representative lesions on kiwifruit plants. Comparative 16S rRNA gene sequence‐based phylogenetic analysis placed these bacteria in a separate cluster within the genus Pectobacterium . Strain KKH3 T showed the highest similarity (98.7%) to the recognised bacteria Pectobacterium carotovorum subsp. carotovorum and Pectobacterium wasabiae . To justify subspecies level differentiation, the partial nucleotide sequences of atpD , carA and recA from strain KKH3 T were compared with those from other members of the family Enterobacteriaceae . Distant relationships between strain KKH3 T and six reference strains of Pectobacterium spp. were evident in the phylogenetic tree. The results of the DNA–DNA hybridisation and polyphasic analysis revealed that strain KKH3 T belongs to another subspecies of P . carotovorum , for which the name Pectobacterium carotovorum subsp. actinidiae subsp. nov. is hereby proposed.